Search

Lower-extremity diabetic ulcers are responsible for 80% of annual worldwide nontraumatic amputations. Epidermal growth factor (EGF) reduction is one of the molecular pillars of diabetic ulcer chronicity, thus EGF administration may be considered a type of replacement therapy. Topical EGF administration to improve and speed wound healing began in 1989 on burn patients as part of an acute-healing therapy. Further clinical studies based on topically administering EGF to different chronic wounds resulted in disappointing outcomes. An analysis of the literature on unsuccessful clinical trials identified a lack of knowledge concerning: (I) molecular and cellular foundations of wound chronicity and (II) the pharmacodynamic requisites governing EGF interaction with its receptor to promote cell response. Yet, EGF intra- and perilesional infiltration were shown to circumvent the pharmacodynamic limitations of topical application. Since the first studies, the following decades of basic and clinical research on EGF therapy for problem wounds have shed light on potential uses of growth factors in regenerative medicine. EGF's molecular and biochemical effects at both local and systemic levels are diverse: (1) downregulation of genes encoding inflammation mediators and increased expression of genes involved in cell proliferation, angiogenesis and matrix secretion; (2) EGF intervention positively impacts both mesenchymal and epithelial cells, reducing inflammation and stimulating the recruitment of precursor circulating cells that promote the formation of new blood vessels; (3) at the subcellular level, upregulation of the EGF receptor with subsequent intracellular trafficking, including mitochondrial allocation along with restored morphology of multiple organelles; and (4) local EGF infiltration resulting in a systemic, organismal repercussion, thus contributing to attenuation of circulating inflammatory and catabolic reactants, restored reduction-oxidation balance, and decreased toxic glycation products and soluble apoptogenic effectors. It is likely that EGF treatment may rearrange critical epigenetic drivers of diabetic metabolic memory. [ABSTRACT FROM AUTHOR]

Diabetic healing failure is the clinical expression of countless molecular and cellular disorders having hyperglycemia as the proximal trigger. The fibroblast is a critical building-block cell type for the healing process. Under high glucose concentrations fibroblasts physiology is perturbed. The epidermal growth factor receptor (EGFR) signaling system is crucial for different healing events. We examined the effect of high glucose burden on healthy-donor' cutaneous fibroblasts proliferation, so as the EGFR autophosphorylation on a critical tyrosine residue, along with the activation of downstream signaling pathways proximal to cyclin D1 expression. Fibroblasts were cultured in 15% FBS at either 5 (normal glucose) or 35 (high glucose) mM under standard culture conditions. Concurrent osmotic control was included. After 6 days of incubation under high glucose, doubling time was calculated. Cells suspensions were plated, fixed and immunolabelled with antibodies directed to phosphorylated forms of EGFR (Y1197), AKT1 (S473) and mTOR (S2448), and native forms of PI3K p85 alpha subunit and cyclin D1. The ratio of cells positive to the diaminobenzidine/ peroxidase reaction was calculated and its intensity estimated according to published methodologies. High glucose concentration significantly increased doubling time 5-fold, as compared to cells grown in physiological conditions. Hyperglycemia reduced the constitutive EGFR autophosphorylation. Accordingly, PI3K was also significantly attenuated. Downstream switches AKT1 and mTOR were also affected and very significantly on the signal intensity. Cyclin D1 expression was completely abrogated due to high glucose burden. Collectively, these data suggest that high glucose exposure hinders fibroblasts proliferation by disrupting the EGFR/PI3K/AKT1/mTOR/Cyclin D1 axis. [ABSTRACT FROM AUTHOR]

Impaired healing in diabetes affects the resolution of both acute and chronic wounds. The vicious circle between wound chronicity and a deficient control of local infection is the cause that diabetic patients constitute 85% of all non-traumatic lower extremity amputations. From an etiological viewpoint, hyperglycemia is what triggers the onset and progression of biochemical disturbances that lead to systemic complications. In contrast to normal wound healing, physiological apoptotic clearance of inflammatory cells is prevented and the inflammatory phase is abnormally prolonged in diabetic wounds. Pro-inflammatory cytokines as tumor necrosis factor-alpha (TNF-α) and interleukin-1β (IL-1β) are increased in diabetic wounds with negative local and remote consequences. The etiopathogenic network consisting of inflammatory cytokines, local proteases, reactive oxygen and nitrogen species produces a cytotoxic and pro-degradation environment within the wound bed that impairs granulation and re-epithelialization. The non-enzymatic glycation of proteins, generating advanced glycation end-products (AGE), acts as an active pathogenic stream affecting healing. The accumulation of AGE interferes with DNA replication, cell anchoring, migration and proliferation. The binding of AGE to a receptor model (RAGE) may completely hamper the healing process. Diabetes impairs the recruitment and differentiation of bone marrow-derived stem cells, thereby limiting the availability of tissue repair cells. Re-epithelialization is also hindered by incomplete activation and/or differentiation of keratinocytes that impair migration. Novel and revolutionary pharmacological interventions are urgently needed to reduce diabetes complications, such as amputations of the lower extremities. [ABSTRACT FROM AUTHOR]

HeberNasvac, a therapeutic vaccine for chronic hepatitis B, is able to safely stimulate multiple Toll-like receptors, increasing antigen presentation in vitro and in a phase II clinical trial (Profira) in elderly volunteers who were household contacts of respiratory infection patients. Thus, a new indication as a postexposure prophylaxis or early therapy for respiratory infections has been proposed. In this study, we evaluated the expression of several interferon-stimulated genes (ISGs) after mucosal administration of HeberNasvac and compared this effect with the nasal delivery of interferon alpha 2b (Nasalferon). Molecular studies of blood samples of 50 subjects from the Profira clinical trial who were locally treated with HeberNasvac or Nasalferon and concurrent untreated individuals were compared based on their relative mRNA expression of OAS1, ISG15, ISG20, STAT1, STAT3, and DRB1-HLA II genes. In most cases, the gene expression induced by HeberNasvac was similar in profile and intensity to the expression induced by Nasalferon and significantly superior to that observed in untreated controls. The immune stimulatory effect of HeberNasvac on ISGs paved the way for its future use as an innate immunity stimulator in elderly persons and immunocompromised subjects or as part of Mambisa, a nasal vaccine to prevent severe acute respiratory syndrome coronavirus 2 infection.