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Thorough biological safety testing of topical therapeutic compounds and antimicrobials is a critical prerequisite for appropriate cutaneous wound care. Increasing pathogen resistance rates to traditional antibiotics and antifungals are driving the development and registration of novel chemical entities. Although they are notably useful for animal testing reduction, the gold standard in vitro cytotoxicity assays in continuous cell lines (HaCaT keratinocytes, 3T3 fibroblasts) may be discussed from a translational relevance standpoint. The aim of this study was thus to establish and validate a sustainable primary cell banking model with a view to performing optimized in vitro cytotoxicity assay development. Primary dermal fibroblasts and adipose-derived stem cell (ASC) types were established from four infant polydactyly sources. A multi-tiered primary cell banking model was then applied to prepare highly sustainable and standardized dermal fibroblast and ASC working cell banks (WCBs), potentially allowing for millions of biological assays to be performed. The obtained cellular materials were then validated for use in cytotoxicity assays through in vitro biosafety testing of topical antiseptics (chlorhexidine, hypochlorous acid) and an antifungal compound (AR-12) of interest for optimized burn wound care. The experimental results confirmed that IC50 values were comparable between cytotoxicity assays, which were performed with cell lines and with primary cells. The results also showed that hypochlorous acid (HOCl) displayed an enhanced toxicological profile as compared to the gold standard chlorhexidine (CLX). Generally, this study demonstrated that highly sustainable primary cell sources may be established and applied for consistent topical compound biological safety assessments with enhanced translational relevance. Overall, the study underscored the safety-oriented interest of functionally benchmarking the products that are applied on burn patient wounds for the global enhancement of burn care quality.

The human skin is a remarkable organ capable of extensive regeneration, especially after severe injuries such as burns and related wounds. The de-epidermized dermis (DED) model has become a valuable in vitro tool for skin regeneration studies, particularly for testing the mechanism of action and the efficacy of clinical cutaneous cell therapies. To further improve the quality and robustness of these applications, our study focused on optimizing and standardizing DED tissue preparation and storage, enhancing its effectiveness for clinical testing. Therefore, we optimized the air-liquid interfacial culture medium composition by simplifying the historical formulation without compromising keratinocyte (therapeutic cell model) viability or proliferation. Furthermore, we investigated the impacts of adding burn wound exudates in the model by focusing on cell behavior for enhanced translational significance. The results revealed notable differences in keratinocyte adhesion and proliferation between burn wound exudates collected at the early stages and late stages of acute patient treatment, providing new information on a possible therapeutic window to apply cell therapies on burn patients. Generally, this study reported a robust method for the preclinical in vitro assessment of keratinocyte-based cutaneous cell therapies using DED models. Overall, the study underscored the importance of using in vitro models with enhanced translational relevance to better predict the clinical effects of cutaneous cell therapies in burn patient populations.

Background/Objectives: Biological products are emerging as therapeutic management options for intervertebral disc (IVD) degenerative affections and lower back pain. Autologous and allogeneic cell therapy protocols have been clinically implemented for IVD repair. Therein, several manufacturing process design considerations were shown to significantly influence clinical outcomes. The primary objective of this study was to preclinically qualify (chondrogenic potential, safety, resistance to hypoxic and inflammatory stimuli) cryopreserved primary progenitor cells (clinical grade FE002-Disc cells) as a potential cell source in IVD repair/regeneration. The secondary objective of this study was to assess the cell source’s delivery potential as cell spheroids (optimization of culture conditions, potential storage solutions). Methods/Results: Safety (soft agar transformation, β-galactosidase, telomerase activity) and functionality-related assays (hypoxic and inflammatory challenge) confirmed that the investigated cellular active substance was highly sustainable in defined cell banking workflows, despite possessing a finite in vitro lifespan. Functionality-related assays confirmed that the retained manufacturing process yielded strong collagen II and glycosaminoglycan (GAG) synthesis in the spheroids in 3-week chondrogenic induction. Then, the impacts of various process parameters (induction medium composition, hypoxic incubation, terminal spheroid lyophilization) were studied to gain insights on their criticality. Finally, an optimal set of technical specifications (use of 10 nM dexamethasone for chondrogenic induction, 2% O2 incubation of spheroids) was set forth, based on specific fine tuning of finished product critical functional attributes. Conclusions: Generally, this study qualified the considered FE002-Disc progenitor cell source for further preclinical investigation based on safety, quality, and functionality datasets. The novelty and significance of this study resided in the establishment of defined processes for preparing fresh, off-the-freezer, or off-the-shelf IVD spheroids using a preclinically qualified allogeneic human cell source. Overall, this study underscored the importance of using robust product components and optimal manufacturing process variants for maximization of finished cell-based formulation quality attributes.

Primary chondroprogenitors obtained from standardized cell sources (e.g., FE002 clinical grade cell sources) may be cultured in vitro and may be cytotherapeutically applied in allogeneic musculoskeletal regenerative medicine. Multicentric translational research on FE002 human primary chondroprogenitors under the Swiss progenitor cell transplantation program has notably validated their robustness and high versatility for therapeutic formulation in clinically compatible prototypes, as well as a good safety profile in diverse in vivo preclinical models. Therein, stringently controlled primary cell source establishment and extensive cell manufacturing optimization have technically confirmed the adequation of FE002 primary chondroprogenitors with standard industrial biotechnology workflows for consistent diploid cell biobanking under GMP. Laboratory characterization studies and extensive qualification work on FE002 progenitor cell sources have elucidated the key and critical attributes of the cellular materials of interest for potential and diversified human cytotherapeutic uses. Multiple formulation studies (i.e., hydrogel-based standardized transplants, polymeric-scaffold-based tissue engineering products) have shown the high versatility of FE002 primary chondroprogenitors, for the obtention of functional allogeneic cytotherapeutics. Multiple in vivo preclinical studies (e.g., rodent models, GLP goat model) have robustly documented the safety of FE002 primary chondroprogenitors following implantation. Clinically, FE002 primary chondroprogenitors may potentially be used in various forms for volumetric tissue replacement (e.g., treatment of large chondral/osteochondral defects of the knee) or for the local management of chondral affections and pathologies (i.e., injection use in mild to moderate osteoarthritis cases). Overall, standardized FE002 primary chondroprogenitors as investigated under the Swiss progenitor cell transplantation program were shown to constitute tangible contenders in novel human musculoskeletal regenerative medicine approaches, for versatile and safe allogeneic clinical cytotherapeutic management.

Hyaluronic acid (HA) hydrogels are commonly used for facial dermal filling and for alternative medical aesthetic purposes. High diversity exists in commercial formulations, notably for the optimization of finished product stability, functionality, and performance. Polyvalent ingredients such as calcium hydroxylapatite (CaHA) or vitamin B3 (niacinamide) are notably used as bio-stimulants to improve skin quality attributes at the administration site. The aim of the present study was to perform multi-parametric characterization of two novel cross-linked dermal filler formulas (HAR-1 “Instant Refine” and HAR-3 “Maxi Lift”) for elucidation of the various functional impacts of vitamin B3 incorporation. Therefore, the HAR products were firstly comparatively characterized in terms of in vitro rheology, cohesivity, injectability, and resistance to chemical or enzymatic degradation (exposition to H2O2, AAPH, hyaluronidases, or xanthine oxidase). Then, the HAR products were assessed for cytocompatibility and in vitro bio-stimulation attributes in a primary dermal fibroblast model. The results showed enhanced resilience of the cohesive HAR hydrogels as compared to JUVÉDERM® VOLBELLA® and VOLUMA® reference products in a controlled degradation assay panel. Furthermore, significant induction of total collagen synthesis in primary dermal fibroblast cultures was recorded for HAR-1 and HAR-3, denoting intrinsic bio-stimulatory effects comparable or superior to those of the Radiesse® and Sculptra™ reference products. Original results of high translational relevance were generated herein using robust and orthogonal experimental methodologies (hydrogel degradation, functional benchmarking) and study designs. Overall, the reported results confirmed the dual functionalization role of vitamin B3 in cross-linked HA dermal fillers, with a significant enhancement of hydrogel system stability attributes and the deployment of potent bio-stimulatory capacities.

Primary progenitor tenocytes are diploid cells that may be cultured in vitro and therapeutically used for allogeneic musculoskeletal regenerative medicine. Firstly, technical aspects of cell banking, biotechnological manufacturing, and extensive preclinical characterization data have confirmed that FE002-Ten primary progenitor tenocytes may be safely considered for human cytotherapeutic use (e.g., in tissue engineering products, standardized transplants). Parallelly, lyophilized progenitor tenocyte extracts (e.g., stabilized cells or cell-free derivatives) were shown to optimally act as potent hyaluronan-based hydrogel functionalizing agents, useful for stability enhancement against oxidative product degradation. Therefore, primary progenitor tenocytes (e.g., FE002-Ten cell source) may potentially be used in diverse clinical presentations of tendon-related pathologies, ranging from volumetric tissue replacement (i.e., for the promotion of enhanced graft bio-integration) to local management of tissular inflammation and pain (i.e., ancillary action of the cellular extracts for the functional enhancement of injectable hyaluronan-based preparations). Overall, the primary progenitor tenocytes investigated under the Swiss progenitor cell transplantation program were shown to represent highly standardized biotechnological materials with a versatility of potential therapeutic uses after formulation into an array of cytotherapeutic preparations or cell-free devices.

Niacinamide (or nicotinamide) is a small-molecule hydrosoluble vitamin with essential metabolic functions in mammalian cells. Niacinamide has become a key functional ingredient in diverse skincare products and cosmetics. This vitamin plays a pivotal role in NAD+ synthesis, notably contributing to redox reactions and energy production in cutaneous cells. Via diversified biochemical mechanisms, niacinamide is also known to influence human DNA repair and cellular stress responses. Based on decades of safe use in cosmetics, niacinamide recently gained widespread popularity as an active ingredient which aligns with the “Kligman standards” in skincare. From a therapeutic standpoint, the intrinsic properties of niacinamide may be applied to managing acne vulgaris, melasma, and psoriasis. From a cosmeceutical standpoint, niacinamide has been widely leveraged as a multipurpose antiaging ingredient. Therein, it was shown to significantly reduce cutaneous oxidative stress, inflammation, and pigmentation. Overall, through multimodal mechanisms, niacinamide may be considered to partially prevent and/or reverse several biophysical changes associated with skin aging. The present narrative review provides multifactorial insights into the mechanisms of niacinamide’s therapeutic and cosmeceutical functions. The ingredient’s evolving role in skincare was critically appraised, with a strong focus on the biochemical mechanisms at play. Finally, novel indications and potential applications of niacinamide in dermal fillers and alternative injectable formulations were prospectively explored.

Historically, primary human progenitor cells (e.g., WI-38 and MRC-5 diploid-cell sources) have been industrially applied in research and in manufacturing processes for vaccines and for biologicals. Furthermore, tissue-specific primary progenitor-cell banks have recently been developed and exploited for the provision of safe, consistent, and effective cellular active pharmaceutical ingredients (API) in homologous allogeneic regenerative medicine applications. Notably, the modern legal and regulatory frameworks for novel therapeutic products and for progenitor-cell therapy development have been iteratively optimized to guarantee utmost product safety, quality, and efficacy. Over 50 years of global technical hindsight around progenitor-cell biotechnological substrates and over 30 years of in-house clinical experience around the therapeutic uses of standardized progenitor-cell sources in Switzerland have demonstrated the importance of such biological materials for public health. The aim of this entry work was to summarize the evolution of the industrial applications of selected primary progenitor-cell sources, ranging from the use as robust biotechnological substrates to standardized cellular API manufacture and their clinical uses in highly specialized regenerative medicine.

While many injectable viscosupplementation products are available for osteoarthritis (OA) management, multiple hydrogel functional attributes may be further optimized for efficacy enhancement. The objective of this study was to functionally benchmark four commercially available hyaluronan-based viscosupplements (Ostenil, Ostenil Plus, Synvisc, and Innoryos), focusing on critical (rheological, lubricative, adhesive, and stability) attributes. Therefore, in vitro and ex vivo quantitative characterization panels (oscillatory rheology, rotational tribology, and texture analysis with bovine cartilage) were used for hydrogel product functional benchmarking, using equine synovial fluid as a biological control. Specifically, the retained experimental methodology enabled the authors to robustly assess and discuss various functional enhancement options for hyaluronan-based hydrogels (chemical cross-linking and addition of antioxidant stabilizing agents). The results showed that the Innoryos product, a niacinamide-augmented linear hyaluronan-based hydrogel, presented the best overall functional behavior in the retained experimental settings (high adhesivity and lubricity and substantial resistance to oxidative degradation). The Ostenil product was conversely shown to present less desirable functional properties for viscosupplementation compared to the other investigated products. Generally, this study confirmed the high importance of formulation development and control methodology optimization, aiming for the enhancement of novel OA-targeting product critical functional attributes and the probability of their clinical success. Overall, this work confirmed the tangible need for a comprehensive approach to hyaluronan-based viscosupplementation product functional benchmarking (product development and product selection by orthopedists) to maximize the chances of effective clinical OA management.

Autologous cell therapy manufacturing timeframes constitute bottlenecks in clinical management pathways of severe burn patients. While effective temporary wound coverings exist for high-TBSA burns, any means to shorten the time-to-treatment with cytotherapeutic skin grafts could provide substantial therapeutic benefits. This study aimed to establish proofs-of-concept for a novel combinational cytotherapeutic construct (autologous/allogeneic DE-FE002-SK2 full dermo-epidermal graft) designed for significant cutaneous cell therapy manufacturing timeframe rationalization. Process development was based on several decades (four for autologous protocols, three for allogeneic protocols) of in-house clinical experience in cutaneous cytotherapies. Clinical grade dermal progenitor fibroblasts (standardized FE002-SK2 cell source) were used as off-the-freezer substrates in novel autologous/allogeneic dermo-epidermal bilayer sheets. Under vitamin C stimulation, FE002-SK2 primary progenitor fibroblasts rapidly produced robust allogeneic dermal templates, allowing patient keratinocyte attachment in co-culture. Notably, FE002-SK2 primary progenitor fibroblasts significantly outperformed patient fibroblasts for collagen deposition. An ex vivo de-epidermalized dermis model was used to demonstrate the efficient DE-FE002-SK2 construct bio-adhesion properties. Importantly, the presented DE-FE002-SK2 manufacturing process decreased clinical lot production timeframes from 6–8 weeks (standard autologous combined cytotherapies) to 2–3 weeks. Overall, these findings bear the potential to significantly optimize burn patient clinical pathways (for rapid wound closure and enhanced tissue healing quality) by combining extensively clinically proven cutaneous cell-based technologies.

Cytotherapies are often necessary for the management of symptomatic large knee (osteo)-chondral defects. While autologous chondrocyte implantation (ACI) has been clinically used for 30 years, allogeneic cells (clinical-grade FE002 primary chondroprogenitors) have been investigated in translational settings (Swiss progenitor cell transplantation program). The aim of this study was to comparatively assess autologous and allogeneic approaches (quality, safety, functional attributes) to cell-based knee chondrotherapies developed for clinical use. Protocol benchmarking from a manufacturing process and control viewpoint enabled us to highlight the respective advantages and risks. Safety data (telomerase and soft agarose colony formation assays, high passage cell senescence) and risk analyses were reported for the allogeneic FE002 cellular active substance in preparation for an autologous to allogeneic clinical protocol transposition. Validation results on autologous bioengineered grafts (autologous chondrocyte-bearing Chondro-Gide scaffolds) confirmed significant chondrogenic induction (COL2 and ACAN upregulation, extracellular matrix synthesis) after 2 weeks of co-culture. Allogeneic grafts (bearing FE002 primary chondroprogenitors) displayed comparable endpoint quality and functionality attributes. Parameters of translational relevance (transport medium, finished product suturability) were validated for the allogeneic protocol. Notably, the process-based benchmarking of both approaches highlighted the key advantages of allogeneic FE002 cell-bearing grafts (reduced cellular variability, enhanced process standardization, rationalized logistical and clinical pathways). Overall, this study built on our robust knowledge and local experience with ACI (long-term safety and efficacy), setting an appropriate standard for further clinical investigations into allogeneic progenitor cell-based orthopedic protocols.

Hand tendon/ligament structural ruptures (tears, lacerations) often require surgical reconstruction and grafting, for the restauration of finger mechanical functions. Clinical-grade human primary progenitor tenocytes (FE002 cryopreserved progenitor cell source) have been previously proposed for diversified therapeutic uses within allogeneic tissue engineering and regenerative medicine applications. The aim of this study was to establish bioengineering and surgical proofs-of-concept for an artificial graft (Neoligaments Infinity-Lock 3 device) bearing cultured and viable FE002 primary progenitor tenocytes. Technical optimization and in vitro validation work showed that the combined preparations could be rapidly obtained (dynamic cell seeding of 105 cells/cm of scaffold, 7 days of co-culture). The studied standardized transplants presented homogeneous cellular colonization in vitro (cellular alignment/coating along the scaffold fibers) and other critical functional attributes (tendon extracellular matrix component such as collagen I and aggrecan synthesis/deposition along the scaffold fibers). Notably, major safety- and functionality-related parameters/attributes of the FE002 cells/finished combination products were compiled and set forth (telomerase activity, adhesion and biological coating potentials). A two-part human cadaveric study enabled to establish clinical protocols for hand ligament cell-assisted surgery (ligamento-suspension plasty after trapeziectomy, thumb metacarpo-phalangeal ulnar collateral ligamentoplasty). Importantly, the aggregated experimental results clearly confirmed that functional and clinically usable allogeneic cell-scaffold combination products could be rapidly and robustly prepared for bio-enhanced hand ligament reconstruction. Major advantages of the considered bioengineered graft were discussed in light of existing clinical protocols based on autologous tenocyte transplantation. Overall, this study established proofs-of-concept for the translational development of a functional tissue engineering protocol in allogeneic musculoskeletal regenerative medicine, in view of a pilot clinical trial.

Thermo-responsive hyaluronan-based hydrogels and FE002 human primary chondroprogenitor cell sources have both been previously proposed as modern therapeutic options for the management of osteoarthritis (OA). For the translational development of a potential orthopedic combination product based on both technologies, respective technical aspects required further optimization phases (e.g., hydrogel synthesis upscaling and sterilization, FE002 cytotherapeutic material stabilization). The first aim of the present study was to perform multi-step in vitro characterization of several combination product formulas throughout the established and the optimized manufacturing workflows, with a strong focus set on critical functional parameters. The second aim of the present study was to assess the applicability and the efficacy of the considered combination product prototypes in a rodent model of knee OA. Specific characterization results (i.e., spectral analysis, rheology, tribology, injectability, degradation assays, in vitro biocompatibility) of hyaluronan-based hydrogels modified with sulfo-dibenzocyclooctyne-PEG4-amine linkers and poly(N-isopropylacrylamide) (HA-L-PNIPAM) containing lyophilized FE002 human chondroprogenitors confirmed the suitability of the considered combination product components. Specifically, significantly enhanced resistance toward oxidative and enzymatic degradation was shown in vitro for the studied injectable combination product prototypes. Furthermore, extensive multi-parametric (i.e., tomography, histology, scoring) in vivo investigation of the effects of FE002 cell-laden HA-L-PNIPAM hydrogels in a rodent model revealed no general or local iatrogenic adverse effects, whereas it did reveal some beneficial trends against the development of knee OA. Overall, the present study addressed key aspects of the preclinical development process for novel biologically-based orthopedic combination products and shall serve as a robust methodological basis for further translational investigation and clinical work.

Background: Systemic fungal infections are an important mortality factor when considering severely burned patients. Preventive topical pharmacotherapeutic management of deep fungal infections remains of secondary concern when initially treating a burn victim, despite high inherent lethal risks. Indeed, the possible subsequent invasions of newly accessible deep tissues and bone by opportunistic fungi often prove fatal. Amphotericin B is a broad-spectrum antifungal agent of choice for infections in burn victims. Intravenous administration is limited by drug-related nephrotoxicity. Novel topical Amphotericin B preparations to be applied in burn centers would therefore limit the systemic adverse effects of the active principle while preventing dissemination of sensitive pathogens and thus help reducing infectious and drug-related mortality. Objective: To establish the need for new topical pharmacotherapeutic management options to treat burn wound fungal infections and conceptually determine the applicability of liposomal Amphotericin B for such cases. Methods: Experimental liposomal Amphotericin B was prepared with commercial components and tested in vitro in our mycology laboratory to determine efficacy, stability and potential for topical application on our burn patients. Results: Data showed equivalent or superior in vitro activity of liposomal Amphotericin B versus unbound drug against Aspergillus fumigatus and superior physical and pharmacologic effect stability over time. Conclusion: Topical and relatively inexpensive liposomal Amphotericin B as described in this work is an interesting, potentially mortality-reducing candidate regarding fungal infections in early and severe burn wound management.

Platelet-rich plasma (PRP) preparations have recently become widely available in sports medicine, facilitating their use in regenerative therapy for ligament and tendon affections. Quality-oriented regulatory constraints for PRP manufacturing and available clinical experiences have underlined the critical importance of process-based standardization, a pre-requisite for sound and homogeneous clinical efficacy evaluation. This retrospective study (2013–2020) considered the standardized GMP manufacturing and sports medicine-related clinical use of autologous PRP for tendinopathies at the Lausanne University Hospital (Lausanne, Switzerland). This study included 48 patients (18–86 years of age, with a mean age of 43.4 years, and various physical activity levels), and the related PRP manufacturing records indicated a platelet concentration factor most frequently in the range of 2.0–2.5. The clinical follow-up showed that 61% of the patients reported favorable efficacy outcomes (full return to activity, with pain disappearance) following a single ultrasound-guided autologous PRP injection, whereas 36% of the patients required two PRP injections. No significant relationship was found between platelet concentration factor values in PRP preparations and clinical efficacy endpoints of the intervention. The results were in line with published reports on tendinopathy management in sports medicine, wherein the efficacy of low-concentration orthobiologic interventions appears to be unrelated to sport activity levels or to patient age and gender. Overall, this study confirmed the effectiveness of standardized autologous PRP preparations for tendinopathies in sports medicine. The results were discussed in light of the critical importance of protocol standardization for both PRP manufacturing and clinical administration to reduce biological material variability (platelet concentrations) and to enhance the robustness of clinical interventions (comparability of efficacy/patient improvement).

Providing accurate and up-to-date practical tools enabling oversight of platelet-rich plasma (PRP) legislation and of the appropriate standards to be implemented for its manufacture and use in Europe is a demanding task. This is due to rapid medico-technological advancements, slowness and disparity in legislation updates and enforcement between member states, and many reported gray-zone practices, notably for autologous PRP use. The levels of risk associated with blood manipulation processes generally dictate the manufacturing requirements for PRP preparations, which have gradually shifted toward good manufacturing practices (GMP) for standardization and overall quality enhancement. This work firstly outlines Western European and Swiss legislation for PRP products/preparations, providing key simplified information and recommendations for medical doctors seeking to implement this biological-based therapy for safe use in hospital settings, clinics, or private offices. This work secondly shows the importance of PRP-based product manufacturing standardization, which subsequently enables sound clinical evaluation of therapeutic interventions. Although the applicable legal bases provide guidelines for GMP manufacturing infrastructure and basic process design, paramount importance is set on the definition of workflows, technical specifications, and key parameters for PRP preparation and delivery. Overall, the development of simple and robust technologies and processes for PRP preparation is critical for guaranteeing the high therapeutic quality of the intervention, in collaboration with qualified GMP manufacturing platforms. Importantly, this work aims to serve as a practical tool for clinicians based in Western Europe who are willing to appropriately (i.e., administratively and technically) implement autologous PRP treatments in musculoskeletal regenerative medicine workflows, to ensure they make informed and optimal regulatory or process-based decisions.

Cryopreservation and lyophilization processes are widely used for conservation purposes in the pharmaceutical, biotechnological, and food industries or in medical transplantation. Such processes deal with extremely low temperatures (e.g., −196 °C) and multiple physical states of water, a universal and essential molecule for many biological lifeforms. This study firstly considers the controlled laboratory/industrial artificial conditions used to favor specific water phase transitions during cellular material cryopreservation and lyophilization under the Swiss progenitor cell transplantation program. Both biotechnological tools are successfully used for the long-term storage of biological samples and products, with reversible quasi-arrest of metabolic activities (e.g., cryogenic storage in liquid nitrogen). Secondly, similarities are outlined between such artificial localized environment modifications and some natural ecological niches known to favor metabolic rate modifications (e.g., cryptobiosis) in biological organisms. Specifically, examples of survival to extreme physical parameters by small multi-cellular animals (e.g., tardigrades) are discussed, opening further considerations about the possibility to reversibly slow or temporarily arrest the metabolic activity rates of defined complex organisms in controlled conditions. Key examples of biological organism adaptation capabilities to extreme environmental parameters finally enabled a discussion about the emergence of early primordial biological lifeforms, from natural biotechnology and evolutionary points of view. Overall, the provided examples/similarities confirm the interest in further transposing natural processes and phenomena to controlled laboratory settings with the ultimate goal of gaining better control and modulation capacities over the metabolic activities of complex biological organisms.

Cultured primary progenitor tenocytes in lyophilized form were previously shown to possess intrinsic antioxidant properties and hyaluronan-based hydrogel viscosity-modulating effects in vitro. The aim of this study was to prepare and functionally characterize several stabilized (lyophilized) cell-free progenitor tenocyte extracts for inclusion in cytotherapy-inspired complex injectable preparations. Fractionation and sterilization methods were included in specific biotechnological manufacturing workflows of such extracts. Comparative and functional-oriented characterizations of the various extracts were performed using several orthogonal descriptive, colorimetric, rheological, mechanical, and proteomic readouts. Specifically, an optimal sugar-based (saccharose/dextran) excipient formula was retained to produce sterilizable cytotherapeutic derivatives with appropriate functions. It was shown that extracts containing soluble cell-derived fractions possessed conserved and significant antioxidant properties (TEAC) compared to the freshly harvested cellular starting materials. Progenitor tenocyte extracts submitted to sub-micron filtration (0.22 µm) and 60Co gamma irradiation terminal sterilization (5–50 kGy) were shown to retain significant antioxidant properties and hyaluronan-based hydrogel viscosity modulating effects. Hydrogel combination products displayed important efficacy-related characteristics (friction modulation, tendon bioadhesivity) with significant (p < 0.05) protective effects of the cellular extracts in oxidative environments. Overall, the present study sets forth robust control methodologies (antioxidant assays, H2O2-challenged rheological setups) for stabilized cell-free progenitor tenocyte extracts. Importantly, it was shown that highly sensitive phases of cytotherapeutic derivative manufacturing process development (purification, terminal sterilization) allowed for the conservation of critical biological extract attributes.

Allogeneic dermal progenitor fibroblasts constitute cytotherapeutic contenders for modern cutaneous regenerative medicine. Based on advancements in the relevant scientific, technical, and regulatory fields, translational developments have slowly yet steadily led to the clinical application of such biologicals and derivatives. To set the appropriate general context, the first aim of this study was to provide a current global overview of approved cell and gene therapy products, with an emphasis on cytotherapies for cutaneous application. Notable advances were shown for North America, Europe, Iran, Japan, and Korea. Then, the second and main aim of this study was to perform a retrospective analysis on the various applications of dermal progenitor fibroblasts and derivatives, as clinically used under the Swiss progenitor cell transplantation program for the past three decades. Therein, the focus was set on the extent and versatility of use of the therapies under consideration, their safety parameters, as well as formulation options for topical application. Quantitative and illustrative data were summarized and reported for over 300 patients treated with various cell-based or cell-derived preparations (e.g., progenitor biological bandages or semi-solid emulsions) in Lausanne since 1992. Overall, this study shows the strong current interest in biological-based approaches to cutaneous regenerative medicine from a global developmental perspective, as well as the consolidated local clinical experience gathered with a specific and safe allogeneic cytotherapeutic approach. Taken together, these current and historical elements may serve as tangible working bases for the further optimization of local and modern translational pathways for the provision of topical cytotherapeutic care.

We report the cases of 2 patients admitted to our hospital at a 17-year interval, both with 90% total body surface area (TBSA) burns. These two young patients were in good health before their accident, but major differences in time of intensive care and hospitalization were observed: 162 versus 76 days in intensive care unit and 18 versus 9.5 months for hospitalization, respectively. We have analyzed the different parameters side-by-side during their medical care and we have identified that the overall improved outcomes are mainly due to a better adapted fluid reanimation in combination with the evolution of the surgical management to encompass allogenic cellular therapy (Biological Bandages). Indeed, autologous cell therapy using keratinocytes has been used for over 30 years in our hospital with the same technical specifications; however, we have integrated the Biological Bandages and routinely used them for burn patients to replace cadaver skin since the past 15 years. Thus, patient 1 versus patient 2 had, respectively, 83% versus 80% TBSA for autologous cells, and 0% versus 189% for allogenic cells. Notably, it was possible that patient 2 was able to recover ∼6% TBSA with the use of Biological Bandages, by stimulating intermediate burn zones toward a spontaneous healing without requiring further skin grafting (on abdomen and thighs). The body zones where Biological Bandages were not applied, such as the buttocks, progressed to deeper-stage burns. Despite inherent differences to patients at their admission and the complexity of severe burn care, the results of these two case reports suggest that integration of innovative allogenic cell therapies in the surgical care of burn patients could have major implications in the final outcome.

Safety, quality, and regulatory-driven iterative optimization of therapeutic cell source selection has constituted the core developmental bedrock for primary fetal progenitor cell (FPC) therapy in Switzerland throughout three decades. Customized Fetal Transplantation Programs were pragmatically devised as straightforward workflows for tissue procurement, traceability maximization, safety, consistency, and robustness of cultured progeny cellular materials. Whole-cell bioprocessing standardization has provided plethoric insights into the adequate conjugation of modern biotechnological advances with current restraining legislative, ethical, and regulatory frameworks. Pioneer translational advances in cutaneous and musculoskeletal regenerative medicine continuously demonstrate the therapeutic potential of FPCs. Extensive technical and clinical hindsight was gathered by managing pediatric burns and geriatric ulcers in Switzerland. Concomitant industrial transposition of dermal FPC banking, following good manufacturing practices, demonstrated the extensive potential of their therapeutic value. Furthermore, in extenso, exponential revalorization of Swiss FPC technology may be achieved via the renewal of integrative model frameworks. Consideration of both longitudinal and transversal aspects of simultaneous fetal tissue differential processing allows for a better understanding of the quasi-infinite expansion potential within multi-tiered primary FPC banking. Multiple fetal tissues (e.g., skin, cartilage, tendon, muscle, bone, lung) may be simultaneously harvested and processed for adherent cell cultures, establishing a unique model for sustainable therapeutic cellular material supply chains. Here, we integrated fundamental, preclinical, clinical, and industrial developments embodying the scientific advances supported by Swiss FPC banking and we focused on advances made to date for FPCs that may be derived from a single organ donation. A renewed model of single organ donation bioprocessing is proposed, achieving sustained standards and potential production of billions of affordable and efficient therapeutic doses. Thereby, the aim is to validate the core therapeutic value proposition, to increase awareness and use of standardized protocols for translational regenerative medicine, potentially impacting millions of patients suffering from cutaneous and musculoskeletal diseases. Alternative applications of FPC banking include biopharmaceutical therapeutic product manufacturing, thereby indirectly and synergistically enhancing the power of modern therapeutic armamentariums. It is hypothesized that a single qualifying fetal organ donation is sufficient to sustain decades of scientific, medical, and industrial developments, as technological optimization and standardization enable high efficiency.

Cultured primary progenitor cell types are worthy therapeutic candidates for regenerative medicine. Clinical translation, industrial transposition, and commercial implementation of products based on such cell sources are mainly hindered by economic or technical barriers and stringent regulatory requirements. Applied research in allogenic cellular therapies in the Lausanne University Hospital focuses on cell source selection technique optimization. Use of fetal progenitor cell sources in Switzerland is regulated through Federal Transplantation Programs and associated Fetal Biobanks. Clinical applications of cultured primary progenitor dermal fibroblasts have been optimized since the 1990s as “Progenitor Biological Bandages” for pediatric burn patients and adults presenting chronic wounds. A single organ donation procured in 2009 enabled the establishment of a standardized cell source for clinical and industrial developments to date. Non-enzymatically isolated primary dermal progenitor fibroblasts (FE002-SK2 cell type) served for the establishment of a clinical-grade Parental Cell Bank, based on a patented method. Optimized bioprocessing methodology for the FE002-SK2 cell type has demonstrated that extensive and consistent progenitor cell banks can be established. In vitro mechanistic characterization and in vivo preclinical studies have confirmed potency, preliminary safety and efficacy of therapeutic progenitor cells. Most importantly, highly successful industrial transposition and up-scaling of biobanking enabled the establishment of tiered Master and Working Cell Banks using Good Manufacturing Practices. Successive and successful transfers of technology, know-how and materials to different countries around the world have been performed. Extensive developments based on the FE002-SK2 cell source have led to clinical trials for burns and wound dressing. Said trials were approved in Japan, Taiwan, USA and are continuing in Switzerland. The Swiss Fetal Transplantation Program and pioneer clinical experience in the Lausanne Burn Center over three decades constitute concrete indicators that primary progenitor dermal fibroblasts should be considered as therapeutic flagships in the domain of wound healing and for regenerative medicine in general. Indeed, one single organ donation potentially enables millions of patients to benefit from high-quality, safe and effective regenerative therapies. This work presents a technical and translational overview of the described progenitor cell technology harnessed in Switzerland as cellular therapies for treatment of burns and wounds around the globe.

Cultured autologous human articular chondrocyte (HAC) implantation has been extensively investigated for safe and effective promotion of structural and functional restoration of knee cartilage lesions. HAC-based cytotherapeutic products for clinical use must be manufactured under an appropriate quality assurance system and follow good manufacturing practices (GMP). A prospective clinical trial is ongoing in the Lausanne University Hospital, where the HAC manufacturing processes have been implemented internally. Following laboratory development and in-house GMP transposition of HAC cell therapy manufacturing, a total of 47 patients have been treated to date. The main aim of the present study was to retrospectively analyze the available manufacturing records of the produced HAC-based cytotherapeutic products, outlining the inter-individual variability existing among the 47 patients regarding standardized transplant product preparation. These data were used to ameliorate and to ensure the continued high quality of cytotherapeutic care in view of further clinical investigations, based on the synthetic analyses of existing GMP records. Therefore, a renewed risk analysis-based process definition was performed, with specific focus set on process parameters, controls, targets, and acceptance criteria. Overall, high importance of the interdisciplinary collaboration and of the manufacturing process robustness was underlined, considering the high variability (i.e., quantitative, functional) existing between the treated patients and between the derived primary HAC cell types.

Empirically studied by Dr. Brown-Séquard in the late 1800s, cytotherapies were later democratized by Dr. Niehans during the twentieth century in Western Switzerland. Many local cultural landmarks around the Léman Riviera are reminiscent of the inception of such cell-based treatments. Despite the discreet extravagance of the remaining heirs of “living cell therapy” and specific enforcements by Swiss health authorities, current interest in modern and scientifically sound cell-based regenerative medicine has never been stronger. Respective progress made in bioengineering and in biotechnology have enabled the clinical implementation of modern cell-based therapeutic treatments within updated medical and regulatory frameworks. Notably, the Swiss progenitor cell transplantation program has enabled the gathering of two decades of clinical experience in Lausanne for the therapeutic management of cutaneous and musculoskeletal affections, using homologous allogeneic cell-based approaches. While striking conceptual similarities exist between the respective works of the fathers of cytotherapy and of modern highly specialized clinicians, major and important iterative updates have been implemented, centered on product quality and risk-analysis-based patient safety insurance. This perspective article highlights some historical similarities and major evolutive differences, particularly regarding product safety and quality issues, characterizing the use of cell-based therapies in Switzerland over the past century. We outline the vast therapeutic potential to be harnessed for the benefit of overall patient health and the importance of specific scientific methodological aspects.

Cultured progenitor cells and derivatives have been used in various homologous applications of cutaneous and musculoskeletal regenerative medicine. Active pharmaceutical ingredients (API) in the form of progenitor cell derivatives such as lysates and lyophilizates were shown to retain function in controlled cellular models of wound repair. On the other hand, hyaluronan-based hydrogels are widely used as functional vehicles in therapeutic products for tendon tissue disorders. The aim of this study was the experimental characterization of formulations containing progenitor tenocyte-derived APIs and hyaluronan, for the assessment of ingredient compatibility and stability in view of eventual therapeutic applications in tendinopathies. Lyophilized APIs were determined to contain relatively low quantities of proteins and growth factors, while being physicochemically stable and possessing significant intrinsic antioxidant properties. Physical and rheological quantifications of the combination formulas were performed after hydrogen peroxide challenge, outlining significantly improved evolutive viscoelasticity values in accelerated degradation settings. Thus, potent effects of physicochemical protection or stability enhancement of hyaluronan by the incorporated APIs were observed. Finally, combination formulas were found to be easily injectable into ex vivo tendon tissues, confirming their compatibility with further translational clinical approaches. Overall, this study provides the technical bases for the development of progenitor tenocyte derivative-based injectable therapeutic products or devices, to potentially be applied in tendinous tissue disorders.

Human fetal progenitor tenocytes (hFPT) produced in defined cell bank systems have recently been characterized and qualified as potential therapeutic cell sources in tendon regenerative medicine. In view of further developing the manufacture processes of such cell-based active pharmaceutical ingredients (API), the effects of hypoxic in vitro culture expansion on key cellular characteristics or process parameters were evaluated. To this end, multiple aspects were comparatively assessed in normoxic incubation (i.e., 5% CO2 and 21% O2, standard conditions) or in hypoxic incubation (i.e., 5% CO2 and 2% O2, optimized conditions). Experimentally investigated parameters and endpoints included cellular proliferation, cellular morphology and size distribution, cell surface marker panels, cell susceptibility toward adipogenic and osteogenic induction, while relative protein expression levels were analyzed by quantitative mass spectrometry. The results outlined conserved critical cellular characteristics (i.e., cell surface marker panels, cellular phenotype under chemical induction) and modified key cellular parameters (i.e., cell size distribution, endpoint cell yields, matrix protein contents) potentially procuring tangible benefits for next-generation cell manufacturing workflows. Specific proteomic analyses further shed some light on the cellular effects of hypoxia, potentially orienting further hFPT processing for cell-based, cell-free API manufacture. Overall, this study indicated that hypoxic incubation impacts specific hFPT key properties while preserving critical quality attributes (i.e., as compared to normoxic incubation), enabling efficient manufacture of tenocyte-based APIs for homologous standardized transplant products.

The objective of this review is to describe the evolution of lung tissue-derived diploid progenitor cell applications, ranging from historical biotechnological substrate functions for vaccine production and testing to current investigations around potential therapeutic use in respiratory tract regenerative medicine. Such cell types (e.g., MRC-5 or WI-38 sources) were extensively studied since the 1960s and have been continuously used over five decades as safe and sustainable industrial vaccine substrates. Recent research and development efforts around diploid progenitor lung cells (e.g., FE002-Lu or Walvax-2 sources) consist in qualification for potential use as optimal and renewed vaccine production substrates and, alternatively, for potential therapeutic applications in respiratory tract regenerative medicine. Potentially effective, safe, and sustainable cell therapy approaches for the management of inflammatory lung diseases or affections and related symptoms (e.g., COVID-19 patients and burn patient severe inhalation syndrome) using local homologous allogeneic cell-based or cell-derived product administrations are considered. Overall, lung tissue-derived progenitor cells isolated and produced under good manufacturing practices (GMP) may be used with high versatility. They can either act as key industrial platforms optimally conforming to specific pharmacopoeial requirements or as active pharmaceutical ingredients (API) for potentially effective promotion of lung tissue repair or regeneration.

Cultured fibroblast progenitor cells (FPC) have been studied in Swiss translational regenerative medicine for over two decades, wherein clinical experience was gathered for safely managing burns and refractory cutaneous ulcers. Inherent FPC advantages include high robustness, optimal adaptability to industrial manufacture, and potential for effective repair stimulation of wounded tissues. Major technical bottlenecks in cell therapy development comprise sustainability, stability, and logistics of biological material sources. Herein, we report stringently optimized and up-scaled processing (i.e., cell biobanking and stabilization by lyophilization) of dermal FPCs, with the objective of addressing potential cell source sustainability and stability issues with regard to active substance manufacturing in cutaneous regenerative medicine. Firstly, multi-tiered FPC banking was optimized in terms of overall quality and efficiency by benchmarking key reagents (e.g., medium supplement source, dissociation reagent), consumables (e.g., culture vessels), and technical specifications. Therein, fetal bovine serum batch identity and culture vessel surface were confirmed, among other parameters, to largely impact harvest cell yields. Secondly, FPC stabilization by lyophilization was undertaken and shown to maintain critical functions for devitalized cells in vitro, potentially enabling high logistical gains. Overall, this study provides the technical basis for the elaboration of next-generation off-the-shelf topical regenerative medicine therapeutic products for wound healing and post-burn care.

The earliest attempts at cell therapy can be attributed to Charles-Edward Brown-Séquard (1817–1894), who sought to treat senescence and aging by injecting animal gonad shreds into his contemporaries, a practice that was widespread in late 19th century. Since then, advances in science have enabled the development of biological substitutes to restore the function of various tissues. Skin was one of the first tissues to be regenerated. For severe burns, patient survival depends on the restoration of skin function as a barrier against pathogens and control of body temperature and fluid loss. We aim here to overview the different cell therapy techniques implemented at the University Hospital of Lausanne (CHUV), one of the two Swiss national centres of highly specialised medicine for burn care. In particular, we will describe the specific indications for each of the different therapies as well as future perspectives.

Tendon defects require multimodal therapeutic management over extensive periods and incur high collateral burden with frequent functional losses. Specific cell therapies have recently been developed in parallel to surgical techniques for managing acute and degenerative tendon tissue affections, to optimally stimulate resurgence of structure and function. Cultured primary human fetal progenitor tenocytes (hFPT) have been preliminarily considered for allogeneic homologous cell therapies, and have been characterized as stable, consistent, and sustainable cell sources in vitro. Herein, optimized therapeutic cell sourcing from a single organ donation, industrial transposition of multi-tiered progenitor cell banking, and preliminary preclinical safety of an established hFPT cell source (i.e., FE002-Ten cell type) were investigated. Results underlined high robustness of FE002-Ten hFPTs and suitability for sustainable manufacturing upscaling within optimized biobanking workflows. Absence of toxicity or tumorigenicity of hFPTs was demonstrated in ovo and in vitro, respectively. Furthermore, a 6-week pilot good laboratory practice (GLP) safety study using a rabbit patellar tendon partial-thickness defect model preliminarily confirmed preclinical safety of hFPT-based standardized transplants, wherein no immune reactions, product rejection, or tumour formation were observed. Such results strengthen the rationale of the multimodal Swiss fetal progenitor cell transplantation program and prompt further investigation around such cell sources in preclinical and clinical settings for musculoskeletal regenerative medicine.

Progenitor Biological Bandages (PBB) have been continuously applied clinically in the Lausanne Burn Center for over two decades. Vast translational experience and hindsight have been gathered, specifically for cutaneous healing promotion of donor-site grafts and second-degree pediatric burns. PBBs constitute combined Advanced Therapy Medicinal Products, containing viable cultured allogeneic fetal dermal progenitor fibroblasts. Such constructs may partly favor repair and regeneration of functional cutaneous tissues by releasing cytokines and growth factors, potentially negating the need for subsequent skin grafting, while reducing the formation of hypertrophic scar tissues. This retrospective case-control study (2010–2018) of pediatric second-degree burn patients comprehensively compared two initial wound treatment options (i.e., PBBs versus Aquacel® Ag, applied during ten to twelve days post-trauma). Results confirmed clinical safety of PBBs with regard to morbidity, mortality, and overall complications. No difference was detected between groups for length of hospitalization or initial relative burn surface decreasing rates. Nevertheless, a trend was observed in younger patients treated with PBBs, requiring fewer corrective interventions or subsequent skin grafting. Importantly, significant improvements were observed in the PBB group regarding hypertrophic scarring (i.e., reduced number of scar complications and related corrective interventions). Such results establish evidence of clinical benefits yielded by the Swiss fetal progenitor cell transplantation program and favor further implementation of specific cell therapies in highly specialized regenerative medicine.

Diverse cell therapy approaches constitute prime developmental prospects for managing acute or degenerative cartilaginous tissue affections, synergistically complementing specific surgical solutions. Bone marrow stimulation (i.e., microfracture) remains a standard technique for cartilage repair promotion, despite incurring the adverse generation of fibrocartilagenous scar tissue, while matrix-induced autologous chondrocyte implantation (MACI) and alternative autologous cell-based approaches may partly circumvent this effect. Autologous chondrocytes remain standard cell sources, yet arrays of alternative therapeutic biologicals present great potential for regenerative medicine. Cultured human epiphyseal chondro-progenitors (hECP) were proposed as sustainable, safe, and stable candidates for chaperoning cartilage repair or regeneration. This study describes the development and industrial transposition of hECP multi-tiered cell banking following a single organ donation, as well as preliminary preclinical hECP safety. Optimized cell banking workflows were proposed, potentially generating millions of safe and sustainable therapeutic products. Furthermore, clinical hECP doses were characterized as non-toxic in a standardized chorioallantoic membrane model. Lastly, a MACI-like protocol, including hECPs, was applied in a three-month GLP pilot safety evaluation in a caprine model of full-thickness articular cartilage defect. The safety of hECP transplantation was highlighted in xenogeneic settings, along with confirmed needs for optimal cell delivery vehicles and implantation techniques favoring effective cartilage repair or regeneration.

Although tissue engineering and cell therapies are becoming realistic approaches for medical therapeutics, it is likely that musculoskeletal applications will be among the first to benefit on a large scale. Cell sources for tissue engineering and cell therapies for tendon pathologies are reviewed with an emphasis on small defect tendon injuries as seen in the hand which could adapt well to injectable cell administration. Specifically, cell sources including tenocytes, tendon sheath fibroblasts, bone marrow or adipose-derived stem cells, amniotic cells, placenta cells and platelet-derivatives have been proposed to enhance tendon regeneration. The associated advantages and disadvantages for these different strategies will be discussed and evolving regulatory requirements for cellular therapies will also be addressed. Human progenitor tenocytes, along with their clinical cell banking potential, will be presented as an alternative cell source solution. Similar cell banking techniques have already been described with other progenitor cell types in the 1950’s for vaccine production, and these “old” cell types incite potentially interesting therapeutic options that could be improved with modern innovation for tendon regeneration and repair.

Current restrictions for human cell-based therapies have been related to technological limitations with regards to cellular proliferation capacity, maintenance of differentiated phenotype for primary human cell culture, and transmission of communicable diseases. We have seen that cultured primary fetal cells from one organ donation could possibly meet the exigent and stringent technical aspects for development of therapeutic products. We could develop a master cell bank (MCB) of 50 homogenous ampoules of 4–5 million cells each from one fetal organ donation (skin) in short periods of time compared to other primary cell types. Safety tests were performed at all stages of the cell banking. MCB ampoules could create a working cell bank to be used for clinical or research use. Monolayer culture of fetal skin cells had a life span of 12–17 passages, and independent cultures obtained from the same organ donation were consistent for protein concentration (with 1.4-fold maximal difference between cultures) as well as gene expression of MMP-14, MMP-3, TIMP-3, and VEGF (1.4-, 1.9-, 2.1-, and 1.4-fold maximal difference between cultures, respectively). Cell cultures derived from four independent fetal skin donations were consistent for cell growth, protein concentration, and gene expression of MDK, PTN, TGF-β1, and OPG. As it is the intention that banked primary fetal cells can profit from the potential treatment of hundreds of thousands of patients with only one organ donation, it is imperative to show consistency, tracability, and safety of the process, including donor tissue selection, cell banking, cell testing, and growth of cells in upscaling for the preparation of cell transplantation.

Wound healing in fetal skin is characterized by the absence of scar tissue formation, which is not dependent on the intrauterine environment and amniotic fluid. Fetal cells have the capacity of extraordinary expansion and we describe herein the development of a fetal skin cell bank where from one organ donation (2–4 cm2) it is possible to produce several hundred million fetal skin constructs of 9 × 12 cm2. Fetal cells grow three to four times more rapidly than older skin cells cultured in the same manner and these banked fetal cells are very resistant against physical and oxidative stress when compared to adult skin cells under the same culture conditions. They are up to three times more resistant to UVA radiation and two times more resistant towards hydrogen peroxide treatment. This mechanism may be of major importance for fetal cells when they are delivered to hostile wound environments. For fetal cell delivery to patients, cells were associated with a collagen matrix to form a three-dimensional construct in order to analyze the capacity of these cells for treating various wounds. We have seen that fetal cells can modify the repair response of skin wounds by accelerating the repair process and reducing scarring in severe burns and wounds of various nature in children. Hundreds of thousands of patients could potentially be treated for acute and chronic wounds from one standardized and controlled cell bank.