Proliferation and mitogenic response to PDGF-BB of fibroblasts isolated from chronic venous leg ulcers is ulcer-age dependent.

Several pathophysiologic mechanisms have been proposed to explain slow-healing leg ulcers, but little is known about the growth behavior of cells in these wounds. Platelet-derived growth factor-BB applied topically to chronic wounds has shown beneficial effects, although the effects have been less pronounced than would have been expected based on studies on acute wounds. The objective of this study was to compare fibroblasts in culture obtained from chronic wounds (non-healing chronic venous leg ulcers), acute wounds and normal dermis regarding growth, mitogenic response to platelet-derived growth factor-BB and levels ofplatelet-derived growth factor alpha-receptor and beta-receptor. Fibroblasts were obtained by an explant technique and expanded in vitro using fibroblast growth medium supplemented with 10% fetal bovine serum and used for the assays at their third passage. Growth of chronic wound fibroblasts (n = 8) was significantly (p < 0.05) decreased compared with those from acute wounds (n = 10) and normal dermis (n = 5). Fibroblasts from ulcers older than 3 y grew significantly (p < 0.01) slower than those from ulcers that had been present for less than 3 y. Morphology and size of fibroblasts from the oldest chronic wounds deviated substantially from those of acute wounds and normal dermis, and resembled in vitro aged or senescent fibroblasts. Mitogenic response of chronic wound fibroblasts to human recombinant platelet-derived growth factor-BB was also reduced with ulcer age. No significant differences were found in the amount of either platelet-derived growth factor alpha-receptor or beta-receptor among the three groups. The features decreased growth related to ulcer age, altered morphology, and reduced response to platelet-derived growth factor, indicating that fibroblasts in some chronic wounds have approached or even reached the end of their lifespan (phase III). This might provide one explanation for the non-healing state and therapy resistance to topical platelet-derived growth factor-BB of some venous leg ulcers.

A fibre-free alginate dressing in the treatment of split thickness skin graft donor sites.

BACKGROUND: Alginate dressings are gaining acceptance in would management although comparative published data with conventional treatment is inconclusive. AIMS: The aim of this randomised controlled study was to compare a fibre-free alginate dressing (Comfeel SeaSorb) with conventional treatment of standardised split-thickness skin graft donor sites in 17 patients regarding initial absorption of blood and healing. RESULTS: The alginate dressing absorbed 40% (P < 0.05) more blood, measured as total iron content of used dressings, during the first 10 post-wounding minutes than fine mesh gauze, resulting in less subsequent bleeding. Light microscopic examination of punch biopsies obtained from 10 wounds on post-operative day 6 demonstrated that nine wounds treated with the alginate dressing compared with seven wounds treated conventionally with paraffin-impregnated gauze (Jelonet) were completely epithelialized, a statistically non-significant difference (P = 0.46). CONCLUSIONS: In conclusion, the fibre-free alginate dressing showed increased initial blood absorption resulting in quicker haemostasis but showed no greater beneficial effect on epithelialisation of split-thickness skin graft donor sites compared with conventional topical treatment.

Growth factors and wound healing.

This paper is based on the thesis Growth Factors and Formation of Granulation Tissue, University of Göteborg, 1992. For the last decade, it has been acknowledged that growth factors are essential for regulating the cellular events involved in the formation of granulation tissue and in wound healing. Recently, clinical trials were initiated to study the wound healing effect of applying growth factors and growth hormone to human wounds. However, in order to apply growth factors in these trials in an intelligent and effective manner, it is important to understand their physiology and their role in wound healing. This review paper is about the growth factors: IGF-I, IGF-II, PDGF, bFGF, TGF-beta, EGF, TGF-alpha, TNF-alpha, SF-HGF and Growth Hormone and their role and effect in soft tissue wound healing in animals and humans.

Gene expression of insulin-like growth factor-I and IGF-I receptor during wound healing in rats.

OBJECTIVE: To measure the time course of changes in the concentrations of insulin-like growth factor-I (IGF-I), IGF-I messenger RNA (mRNA), and IGF-I receptor mRNA during wound healing. DESIGN: Open experimental study. MATERIAL: 40 male Sprague-Dawley rats, each weighing 300 g. INTERVENTION: Stainless steel wire mesh cylinders implanted in the subcutaneous tissue of the back. Five rats killed at each time point (1.5, 2, 3, 4, 5, 7, 11, and 18 weeks). MAIN OUTCOME MEASURES: Wet weight and concentrations of IGF-I mRNA, and IGF-I receptor mRNA of granulation tissue, and concentration of IGF-I in wound fluid. RESULTS: The wet weight of granulation tissue increased significantly between week 1.5 and weeks 4-5, and then decreased. IGF-I mRNA concentration (amol/microgram DNA) increased significantly (threefold) between week 1.5 and weeks 3-5, and decreased between weeks 5 and 7. The concentration of IGF-I receptor RNA remained constant throughout the study, and the concentration of IGF-I in wound fluid remained constant until week 8 and then increased to a higher level at weeks 11-18. CONCLUSION: There is a transient rise in the gene expression of IGF-I but not of IGF-I receptor mRNA during wound healing.

[Growth hormone and surgery]. / Vaeksthormon og kirurgi.

Development of biosynthetic human growth hormone (b-hGH) may be a beneficial supplement in the treatment of surgical patients with major traumas in future. As a result of its anabolic actions, b-hGH has proved to be protein conserving in patients who have undergone major gastrointestinal operations with a net decrease in urinary protein excretion, increased fat oxidation and preservation of grip strength and lean body mass. In addition, animal experiments have shown a pronounced stimulatory effect on the healing of tibial fractures in both young and old rats and in the healing of colon anastomoses, as evaluated from the biomechanical properties of the tissues. Experimental skin wounds have also been shown to benefit from b-hGH treatment but only in the early phases of the healing process. Studies on woundhealing in humans have revealed beneficial effects of b-hGH on donor-site healing in skin grafting of patients with severe burns on systemic administration and on healing of chronic leg ulcers on topical application. Further studies in humans with characterization of patients who may benefit from the treatment and the dose-response relations are required to evaluate possible employment of growth hormone in surgical practice.

Growth hormone stimulates granulation tissue formation and insulin-like growth factor-I gene expression in wound chambers in the rat.

It has been reported that GH stimulates fibroblast growth and wound healing. In the present study we measured the effect of locally applied GH on insulin-like growth factor (IGF-I) mRNA concentrations and granulation tissue formation in wound cylinders, implanted s.c. Four stainless-steel wiremesh cylinders were implanted s.c. in the back of male rats (280 g). Each cylinder was then injected every day with either 0.014 or 0.14 U human GH, or vehicle only. Ingrown granulation tissue and wound fluid was obtained on day 17 after implantation. The wet weight of granulation tissue was determined and concentrations of IGF-I mRNA in the tissue were measured by solution hybridization/RNAase protection assay. Similar assays were used to measure the levels of IGF-I receptor mRNA and GH receptor mRNA, while the IGF-I concentration in wound fluid and serum was determined by radioimmunoassay (RIA) after acid-ethanol extraction. The concentrations of IGF-I mRNA in ingrown granulation tissue as well as the wet weight of this tissue were significantly higher in the GH-treated cylinders. There was no significant effect of GH on IGF-I receptor mRNA and GH receptor mRNA levels. Consistent with the results of previous studies, wound fluid IGF-I levels were lower than serum IGF-I levels, but no significant difference was found between the GH-treated cylinders and the control cylinders. The results of the present study show that GH stimulates granulation tissue formation and increases the concentration of IGF-I mRNA in the ingrown granulation tissue.

Effects of heavy hyperventilation on transcutaneous and arterial oxygen tensions in healthy adults.

Transcutaneous pO2 on thorax and the volar part of the forearm was measured in six healthy volunteers during heavy hyperventilation, and the values compared with simultaneously measured arterial blood pO2. We found a significant rise in arterial pO2 during hyperventilation with a lesser increase in thoracic transcutaneous pO2. When measured on arm the transcutaneous pO2 did not even rise significantly. After hyperventilation pO2 fell to values below the resting level. The transcutaneous/arterial pO2 index, fell significantly during hyperventilation with the greatest reduction in the arm index. After hyperventilation the arm index returned to the control values, whereas the thoracic index remained low. We suggest, that the significant fall in transcutaneous/arterial blood pO2 index during hyperventilation is caused primarily by skin vasoconstriction, whereas the fall in pO2 after hyperventilation is caused by hypoxia. When measured on areas with increased muscular activity transcutaneous pO2 might depend on the local blood flow and skin oxygen consumption also, causing problems in interpretation with certain patient groups.

Selective effects of tumor necrosis factor-alpha on wound healing in rats.

Many growth factors are believed to act simultaneously in wounds. Tumor necrosis factor-alpha (TNF-alpha) is a cytokine released by activated macrophages. In various concentrations it has inflammatory, cytolytic, mitogenic, antitumor, and possibly angiogenic or antiangiogenic effects; therefore it is likely to affect wound healing. With stainless steel wire mesh wound cylinders implanted in rats, we tested topical TNF-alpha in wounds, alone and in combination with platelet-derived growth factor (PDGF) and transforming growth factor-beta (TGF-beta). The cylinders were injected daily for a total of 12 days, after which we measured the accumulation of protein, DNA, and hydroxyproline in each cylinder. TNF-alpha had little effect by itself; it inhibited the growth-promoting effects of TGF-beta, but it did not influence the effects of PDGF. These results agree with the in vitro studies showing synergism of TNF-alpha and PDGF and antagonism between TGF-beta and TNF-alpha. They also suggest that TGF-beta may have a negligible role in normal healing and emphasize that interaction of growth factors must be understood before appropriate clinical use can be planned.

The importance of internal urethrotomy a.m. Otis for the incidence of urethral stricture following transurethral prostatectomy.

The most frequent late postoperative complication of transurethral prostatectomy (TURP) is the formation of urethral stricture. Several studies indicate that the number of strictures can be reduced by performing internal urethrotomy a.m. Otis just before TURP. We compared the incidence of urethral stricture in 218 patients, who in 1982 had TURP without preceding internal urethrotomy a.m. Otis as against 183 patients, who in 1983 had TURP with preceding internal urethrotomy a.m. Otis. In 1982 (-Otis group) the incidence of urethral stricture was 7.3%, and in 1983 (+Otis group) it was 4.4%. This difference is not significant, but the tendency and results from other studies make us recommend the method until a larger controlled trial has been performed.

Transcutaneous PO2 and laser Doppler blood flow measurements in 40 patients with venous leg ulcers.

The study included 40 patients with clinically venous leg ulcer(s) in one leg only and with a systolic toe blood pressure above 50 mmHg in both legs. Transcutaneous oxygen tension was measured on both lower legs at equivalent sites, on the affected leg immediately proximal to the ulcer(s). Similarly, skin blood flow was measured in both legs at a skin temperature of 32 degrees C and 44 degrees C by means of laser Doppler velocimetry, and for each leg the index of blood flow 44 degrees C/flow 32 degrees C was calculated to express the degree of blood flow increment following local hyperthermia. Transcutaneous oxygen tension measurements were significantly lower on affected legs (p less than 0.01) as was flow increment (p less than 0.01), mainly due to a high flow measurement at 32 degrees C on affected legs rather than to a low measurement at 44 degrees C. The results of our flow measurements suggest a state of (relative) hyperemia in the vicinity of venous leg ulcers, also confirmed by the clinical findings. This could be interpreted as an arteriolar response to lowered oxygen tension or (it could) be part of reactive reparative processes leading to increased O2 consumption in the tissues.