Venous ulcer fibroblasts respond to basic fibroblast growth factor at the cell cycle protein level

A highly infectious chimeric adenovirus expressing basic fibroblast growth factor exerts potent targeted therapy for rabbit ear chronic ischemic wounds

BACKGROUND

Poor angiogenesis and impaired proliferation of cells responsible for the repair of chronic ischemic wounds result in impaired wound healing. The continuous and efficient expression of therapeutic factors by means of gene transfection is an ideal adjuvant treatment method to promote cell proliferation and angiogenesis.

METHODS

A chimeric recombinant adenoviral vector, Ad5F35ET1-bFGF, was constructed that carried the basic fibroblast growth factor (bFGF) gene and used the endothelin-1 promoter to control the targeted expression of bFGF in endothelial cells and fibroblasts. Thus, the authors established a targeted gene therapy for chronic ischemic wounds.

RESULTS

The chimeric adenovirus Ad5F35ET1-bFGF efficiently infected the endothelin-1-positive endothelial cells and fibroblasts, specifically expressed bFGF, and promoted cell proliferation. In the rabbit wound healing model, the chimeric recombinant adenovirus expressed a high level of bFGF in wound tissues, which continuously promoted angiogenesis and cell proliferation and thus accelerated wound healing.

CONCLUSION

Targeted gene therapy that uses bFGF as a therapeutic gene provides an effective candidate strategy for the treatment of chronic ischemic wounds.

Expression of cell proliferation cycle negative regulators in fibroblasts of an ischemic diabetic foot ulcer. A clinical case report

Wound chronification and opportunistic infections stand as major factors leading to lower extremities amputations in diabetes. The molecular mechanisms underlying diabetic's torpid healing have not been elucidated. We present the case of a female diabetic patient that after a plantar abscess surgical drainage, tight glycaemia control and infection clearance; the wound bed evolved to chronification with poor matrix accumulation, scant angiogenesis and no evidence of dermo-epidermal contours contraction. Ulcer fibroblasts yet cultured under 'physiological' conditions exhibited a slow and declining proliferative response. Diabetic fibroblasts cycle arrest occurred earlier than non-diabetic counterparts. This in vitro premature arrest-senescence phenotype appeared related to the transcriptional upregulation of p53 and the proto-oncogene c-myc; with a concomitant expression reduction of the survival and cellular growth promoters Akt and mTOR. Importantly, immunocytochemistry of the diabetic ulcer-derived fibroblasts proved nuclear over expression of potent proliferation inhibitors and pro-senescence proteins as p53 phosphorylated on serine-15 and p21(Cip) (1). In line with this, cyclin D1 appeared substantially underexpressed in these cells. We postulate that the downregulation of the Akt/mTOR/cyclin D1 axis by the proximal activation of p53 and p21 due to stressor factors, impose an arrest/pro-senescence programme that translated in a torpid and slow healing process.

Spray-applied cell therapy with human allogeneic fibroblasts and keratinocytes for the treatment of chronic venous leg ulcers: a phase 2, multicentre, double-blind, randomised, placebo-controlled trial

BACKGROUND

Many patients with venous leg ulcers do not heal with standard care. HP802-247 is a novel spray-applied cell therapy containing growth-arrested allogeneic neonatal keratinocytes and fibroblasts. We compared different cell concentrations and dosing frequencies of HP802-247 for benefit and harm when applied to chronic venous leg ulcers.

METHODS

We enrolled adult outpatients from 28 centres in the USA and Canada with up to three ulcers, venous reflux confirmed by doppler ultrasonography, and adequate arterial flow in this phase 2, double-blind, randomised, placebo-controlled trial if at least one ulcer measured 2-12 cm(2) in area and had persisted for 6-104 weeks. Patients were randomly assigned by computer-generated block randomisation in a 1:1:1:1:1 ratio to 5·0×10(6) cells per mL every 7 days or every 14 days, or 0·5×10(6) cells per mL every 7 days or every 14 days, or to vehicle alone every 7 days. All five groups received four-layer compression bandages. The trial sponsor, trial monitors, statisticians, investigators, centre personnel, and patients were masked to treatment allocation. The primary endpoint was mean percentage change in wound area at the end of 12 weeks. Analyses were by intention to treat, excluding one patient who died of unrelated causes before first treatment. This trial is registered with ClinicalTrials.gov NCT00852995.

FINDINGS

45 patients were assigned to 5·0×10(6) cells per mL every 7 days, 44 to 5·0×10(6) cells per mL every 14 days, 43 to 0·5 ×10(6) cells per mL every 7 days, 46 to 0·5 ×10(6) cells per mL every 14 days, and 50 to vehicle alone. All required visits were completed by 205 patients. The primary outcome analysis showed significantly greater mean reduction in wound area associated with active treatment compared with vehicle (p=0·0446), with the dose of 0·5 ×10(6) cells/mL every 14 days showing the largest improvement compared with vehicle (15·98%, 95% CI 5·56-26·41, p=0·0028). Adverse events were much the same across all groups, with only new skin ulcers and cellulitis occurring in more than 5% of patients.

INTERPRETATION

Venous leg ulcers can be healed with a spray formulation of allogeneic neonatal keratinocytes and fibroblasts without the need for tissue engineering, at an optimum dose of 0·5×10(6) cells per mL every 14 days.

FUNDING

Healthpoint Biotherapeutics.

Wound Healing Society (WHS) venous ulcer treatment guidelines: what's new in five years?

Since the establishment of the guidelines for the treatment of venous ulcers by the Wound Healing Society in 2006, there has been an abundance of new literature, both in accord and discord with the guidelines. The goal of this update is to highlight new findings since the publication of these guidelines to assist practitioner and patient in appropriate health care decisions, as well as to drive future research endeavors.

Treatment of skin injury due to vinorelbine extravasation using bFGF and rhGM-CSF: an experimental study in a murine model

BACKGROUND AND OBJECTIVE

A murine model of skin injury from vinorelbine extravasation was established to evaluate the treatment efficacy of basic fibroblast growth factor (bFGF) and recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF).

MATERIALS AND METHOD

Experimental models were divided into bFGF, rhGM-CSF, and control (saline) groups, with 40 mice in each group. Edema and ulceration were measured on Days 1, 3, 5, 7, 10, 14, and 18 after the onset of extravasation; injuries were examined pathomorphologically in three mice/group/time point.

RESULTS

Edema reached maximum size on Day 3 in the bFGF and rhGM-CSF groups and Day 5 in the control group. The difference between the two experimental groups was not significant; differences between the control group and the experimental groups were statistically significant at all time points. Edema and ulceration began to improve on Day 10 in the bFGF and rhGM-CSF groups and Day 18 in the control group. Healing duration was 14-18 days in the experimental groups, with a (not significantly) shorter duration in the bFGF group. Healing was completed by Day 27.5 in the control group. Pathomorphological evaluation showed regular re-epithelization and newly formed granulation tissue in the bFGF and rhGM-CSF groups on Day 13. In the control group, wounds were partially healed, edema and shallow ulcers existed, and epithelization was fragile and disorganized on Day 18.

CONCLUSIONS

bFGF and rhGM-CSF are useful for the treatment of skin injury due to vinorelbine extravasation, but bFGF may be slightly more effective in decreasing time and improving quality of healing.

Primary cultured fibroblasts derived from patients with chronic wounds: a methodology to produce human cell lines and test putative growth factor therapy such as GMCSF

BACKGROUND

Multiple physiologic impairments are responsible for chronic wounds. A cell line grown which retains its phenotype from patient wounds would provide means of testing new therapies. Clinical information on patients from whom cells were grown can provide insights into mechanisms of specific disease such as diabetes or biological processes such as aging. The objective of this study was 1) To culture human cells derived from patients with chronic wounds and to test the effects of putative therapies, Granulocyte-Macrophage Colony Stimulating Factor (GM-CSF) on these cells. 2) To describe a methodology to create fibroblast cell lines from patients with chronic wounds.

METHODS

Patient biopsies were obtained from 3 distinct locations on venous ulcers. Fibroblasts derived from different wound locations were tested for their migration capacities without stimulators and in response to GM-CSF. Another portion of the patient biopsy was used to develop primary fibroblast cultures after rigorous passage and antimicrobial testing.

RESULTS

Fibroblasts from the non-healing edge had almost no migration capacity, wound base fibroblasts were intermediate, and fibroblasts derived from the healing edge had a capacity to migrate similar to healthy, normal, primary dermal fibroblasts. Non-healing edge fibroblasts did not respond to GM-CSF. Six fibroblast cell lines are currently available at the National Institute on Aging (NIA) Cell Repository.

CONCLUSION

We conclude that primary cells from chronic ulcers can be established in culture and that they maintain their in vivo phenotype. These cells can be utilized for evaluating the effects of wound healing stimulators in vitro.

Mitogen-Activated Protein Kinase p38 Pathway in Venous Ulcer Fibroblasts

Objective: Venous ulcer fibroblasts (w-fb) have attenuated growth compared to normal fibroblasts (n-fb). The MAPKp38 pathway mediates stress-responses in various diseases. We hypothesize that p38 pathway is altered in w-fb. Methods: W-fb were isolated from venous ulcers and n-fb from the ipsilateral thigh. Fibroblasts were analyzed for phosphorylated p38 using immunoblot. The relation between p38 and w-fb proliferation was assessed with SB203580 (p38 inhibitor). Fibroblasts were treated with bFGF, TNF-a, and IL-1 and p38 expression analyzed. Results: Phosphorylated p38 expression was increased in w-fb (AU%=233.5±59.7, P=0.039) compared to n-fb (AU%=99.9±14.6). W-fb treated with SB203580 demonstrated increased growth compared to untreated w-fb. W-fb treated with bFGF demonstrated decreased p38. TNF-α and IL-1β significantly increase p38 expression. Conclusions: MAPK p38 is up-regulated in w-fb. Regulation of w-fb proliferation is influenced by p38. Altering the p38 pathway in vivo with growth factors or cytokine inhibition may improve fibroblast proliferation and venous ulcer healing.