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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% CO 2 and 21% O 2 , standard conditions) or in hypoxic incubation (i.e., 5% CO 2 and 2% O 2 , 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.

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.

Clinical experience gathered over two decades around therapeutic use of primary human dermal progenitor fibroblasts in burn patient populations has been at the forefront of regenerative medicine in Switzerland. Relative technical simplicity, ease of extensive serial multitiered banking, and high stability are major advantages of such cell types, assorted to ease of safety and traceability demonstration. Stringent optimization of cell source selection and standardization of biobanking protocols enables the safe and efficient harnessing of the considerable allogenic therapeutic potential yielded by primary progenitor cells. Swiss legal and regulatory requirements have led to the procurement of fetal tissues within a devised Fetal Progenitor Cell Transplantation Program in the Lausanne University Hospital. Proprietary nonenzymatic isolation of primary musculoskeletal cell types and subsequent establishment of progeny tiered cell banks under cGMP standards have enabled safe and effective management of acute and chronic cutaneous affections in various patient populations. Direct off-the-freezer seeding of viable dermal progenitor fibroblasts on a CE marked equine collagen scaffold is the current standard for delivery of the therapeutic biological materials to patients suffering from extensive and deep burns. Diversification in the clinical indications and delivery methods for these progenitor cells has produced excellent results for treatment of persistent ulcers, autograft donor site wounds, or chronic cutaneous affections such as eczema. Herein we describe the standard operating procedures for preparation and therapeutic deployment of the progenitor biological bandages within our translational musculoskeletal regenerative medicine program, as they are routinely used as adjuvants in our Burn Center to treat critically ailing patients.

Non-enzymatically isolated primary dermal progenitor fibroblasts derived from fetal organ donations are ideal cell types for allogenic musculoskeletal regenerative therapeutic applications. These cell types are differentiated, highly proliferative in standard in vitro culture conditions and extremely stable throughout their defined lifespans. Technical simplicity, robustness of bioprocessing and relatively small therapeutic dose requirements enable pragmatic and efficient production of clinical progenitor fibroblast lots under cGMP standards. Herein we describe optimized and standardized monolayer culture expansion protocols using dermal progenitor fibroblasts isolated under a Fetal Transplantation Program for the establishment of GMP tiered Master, Working and End of Production cryopreserved Cell Banks. Safety, stability and quality parameters are assessed through stringent testing of progeny biological materials, in view of clinical application to human patients suffering from diverse cutaneous chronic and acute affections. These methods and approaches, coupled to adequate cell source optimization, enable the obtention of a virtually limitless source of highly consistent and safe biological therapeutic material to be used for innovative regenerative medicine applications.

Primary progenitor cell types adequately isolated from fetal tissue samples present considerable therapeutic potential for a wide range of applications within allogeneic musculoskeletal regenerative medicine. Progenitor cells are inherently differentiated and extremely stable in standard bioprocessing conditions and can be culture-expanded to establish extensive and robust cryopreserved cell banks. Stringent processing conditions and exhaustive traceability are prerequisites for establishing a cell source admissible for further cGMP biobanking and clinical-grade production lot manufacture. Transplantation programs are ideal platforms for the establishment of primary progenitor cell sources to be used for manufacture of cell therapies or cell-based products. Well-defined and regulated procurement and processing of fetal biopsies after voluntary pregnancy interruptions ensure traceability and safety of progeny materials and therapeutic products derived therefrom. We describe herein the workflows and specifications devised under the Swiss Fetal Progenitor Cell Transplantation Program in order to traceably isolate primary progenitor cell types in vitro and to constitute Parental Cell Banks fit for subsequent industrial-scale cGMP processing. When properly devised, derived, and maintained, such cell sources established after a single organ donation can furnish sufficient progeny materials for years of development in translational musculoskeletal regenerative medicine.

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. [ABSTRACT FROM AUTHOR]

Definition: 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. [ABSTRACT FROM AUTHOR]

Definition: 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Definition: 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Summary Introduction Sciatic experimental surgery in rat often leads to hindlimb autophagy, with considerable ethical and research issues. In this work, the distal part of the sciatic nerve was split following the natural bifurcation between tibial and peroneal branches, before applying regenerative stem cells in a fibrin conduit on the peroneal segment. The new microsurgical model was tested in terms of animal morbidity and consistency of research outcomes, particularly comparing to the standard total sciatic axotomy procedure. Materials and Methods After dissection of sciatic the nerve, the tibial and peroneal fibres were split upwards and a total axotomy was performed in the peroneal side. The 1 cm nerve gap between the proximal sciatic nerve and peroneal nerve was crossed using fibrin conduits. The tibial nerve was not included. Experimental groups involved either empty or fibrin conduit seeded with Schwann cell-like differentiated adipose derived stem cells (dASC) (Fib + dASC). Autografts and sham rats were used as controls (total n = 20). At 12 weeks post-implantation, an extensive histomorphometric analysis was performed. Functional aspects of regeneration were analysed by walking track analysis. Results No major autophagy occurred using the split-sciatic technique. A detailed histomorphometric analysis showed consistent results with previous literature using fibrin conduits in a full sciatic axotomy experimental setting. Walking track analysis reflected the histological regeneration pattern, displaying superior regeneration in both autograft and dASC groups. Conclusion Split-Sciatic nerve surgery reduced animal morbidity, while being representative of the whole nerve as regeneration outcomes were consistent with previous data obtained on the whole sciatic nerve. The decreased autophagy rate allowed for a more efficient functional evaluation. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]