Metformin Induces Cell Cycle Arrest, Reduced Proliferation, Wound Healing Impairment In Vivo and Is Associated to Clinical Outcomes in Diabetic Foot Ulcer Patients

Abstract

BackgroundSeveral epidemiological studies in diabetic patients have demonstrated a protective effect of metformin to the development of several types of cancer. The underlying mechanisms of such phenomenon is related to the effect of metformin on cell proliferation among which, mTOR, AMPK and other targets have been identified. However, little is known about the role that metformin treatment have on other cell types such as keratinocytes and whether exposure to metformin of these cells might have serious repercussions in wound healing delay and in the development of complications in diabetic patients with foot ulcers or in their exacerbation.Material and MethodsHaCaT Cells were exposed to various concentrations of metformin and cell viability was evaluated by a Resazurin assay; Proliferation was also evaluated with a colony formation assay and with CFSE dilution assay by flow cytometry. Cell cycle was also evaluated by flow cytometry by PI staining. An animal model of wound healing was used to evaluate the effect of metformin in wound closure. Also, an analysis of patients receiving metformin treatment was performed to determine the effect of metformin treatment on the outcome and wound area. Statistical analysis was performed on SPSS v. 18 and GraphPad software v.5.ResultsMetformin treatment significantly reduces cell proliferation; colony formation and alterations of the cell cycle are observed also in the metformin treated cells, particularly in the S phase. There is a significant increase in the area of the wound of the metformin treated animals at different time points (P<0.05). There is also a significant increase in the size and wound area of the patients with diabetic foot ulcers at the time of hospitalization. A protective effect of metformin was observed for amputation, probably associated with the anti inflammatory effects reported of metformin.ConclusionsMetformin treatment reduces cell proliferation and reduces wound healing in an animal model and affects clinical outcomes in diabetic foot ulcer patients. Chronic use of this drug should be further investigated to provide evidence of their security in association with DFU.

Anti‐aging pharmacology in cutaneous wound healing: effects of metformin, resveratrol, and rapamycin by local application

“…Several intriguing issues arise with our present findings that are interesting to be addressed in future studies. As stated, it should be cautious that systemic administration of these agents may result in more unpredictable side effects and failed therapeutics in the skin, potentially underlying differential effects of MET by local and systemic applications (Baraka & Deif, ; Ochoa‐Gonzalez et al ., ). Therefore, topically targeting AMPK by MET may become a feasible approach to the chronic nonhealing wounds in both young and aged population, or function as a useful supplement to current treatments such as glucocorticoids (Hofman et al ., ) and epidermal growth factor (EGF) (Brown et al ., ).…”

“…MET, a biguanide agent and AMPK activator, has long been used to treat diabetic hyperglycemia, which substantially impairs wound healing (Madiraju et al ., ). However, controversial results exist regarding whether AMPK activation by MET improves healing of diabetic wounds, in that negative effects on foot ulcers (Ochoa‐Gonzalez et al ., ) and positive effects on gastric ulcers (Baraka & Deif, ) upon oral administration of MET have both been reported, suggesting differential effects of MET by systemic and local applications. RSV, a natural polyphenol in red wine and grapes, stimulates both Sirt1 and AMPK pathways, leading to activation of the metabolic regulator peroxisome proliferator‐activated receptor gamma coactivator‐1 alpha (PGC‐1α) (Park et al ., ).…”

Hypoxia Regulates mTORC1-Mediated Keratinocyte Motility and Migration via the AMPK Pathway

“…In addition to its role in metabolism, AMPK has been strongly linked to cell migration, playing variable roles in different cells and contexts [14, 15]. Recently, Met, an AMPK activator, has been shown to reduce cell proliferation and delay wound healing [16], indicating that AMPK may be involved in cellular biology in keratinocyte during the process of wound repair. Additionally, a growing number of studies have identified an interactional relationship between AMPK and mTORC1 [17, 18].…”

Atypical Diabetic Foot Ulcer Keratinocyte Protein Signaling Correlates with Impaired Wound Healing

“…For example, the diabetes drug Metformin, an activator of AMPK-directed inhibition of Akt/mTOR-mediated proliferation and Cyclin D1 synthesis, reduces the incidence and progression of some cancers [25]. In diabetics, Metformin may be associated with larger ulcerations and inhibition of keratinocyte proliferation, but these DFUs do not progress to amputation [49]. These results suggest that activation of survival inhibition and senescence signaling pathways, like p53 and β -catenin, may contribute to nonhealing DFUs.…”