Effect of empagliflozin on ectopic fat stores and myocardial energetics in type 2 diabetes: the EMPACEF study.

BACKGROUND: Empagliflozin is a sodium-glucose cotransporter 2 (SGLT2) inhibitor that has demonstrated cardiovascular and renal protection in patients with type 2 diabetes (T2D). We hypothesized that empaglifozin (EMPA) could modulate ectopic fat stores and myocardial energetics in high-fat-high-sucrose (HFHS) diet mice and in type 2 diabetics (T2D). METHODS: C57BL/6 HFHS mice (n = 24) and T2D subjects (n = 56) were randomly assigned to 12 weeks of treatment with EMPA (30 mg/kg in mice, 10 mg/day in humans) or with placebo. A 4.7 T or 3 T MRI with 1H-MRS evaluation-myocardial fat (primary endpoint) and liver fat content (LFC)-were performed at baseline and at 12 weeks. In humans, standard cardiac MRI was coupled with myocardial energetics (PCr/ATP) measured with 31P-MRS. Subcutaneous (SAT) abdominal, visceral (VAT), epicardial and pancreatic fat were also evaluated. The primary efficacy endpoint was the change in epicardial fat volume between EMPA and placebo from baseline to 12 weeks. Secondary endpoints were the differences in PCr/ATP ratio, myocardial, liver and pancreatic fat content, SAT and VAT between groups at 12 weeks. RESULTS: In mice fed HFHS, EMPA significantly improved glucose tolerance and increased blood ketone bodies (KB) and ß-hydroxybutyrate levels (p < 0.05) compared to placebo. Mice fed HFHS had increased myocardial and liver fat content compared to standard diet mice. EMPA significantly attenuated liver fat content by 55%, (p < 0.001) but had no effect on myocardial fat. In the human study, all the 56 patients had normal LV function with mean LVEF = 63.4 ± 7.9%. Compared to placebo, T2D patients treated with EMPA significantly lost weight (- 2.6 kg [- 1.2; - 3.7]) and improved their HbA1c by 0.88 ± 0.74%. Hematocrit and EPO levels were significantly increased in the EMPA group compared to placebo (p < 0.0001, p = 0.041). EMPA significantly increased glycosuria and plasma KB levels compared to placebo (p < 0.0001, p = 0.012, respectively), and significantly reduced liver fat content (- 27 ± 23 vs. - 2 ± 24%, p = 0.0005) and visceral fat (- 7.8% [- 15.3; - 5.6] vs. - 0.1% [- 1.1;6.5], p = 0.043), but had no effect on myocardial or epicardial fat. At 12 weeks, no significant change was observed in the myocardial PCr/ATP (p = 0.57 between groups). CONCLUSIONS: EMPA effectively reduced liver fat in mice and humans without changing epicardial, myocardial fat or myocardial energetics, rebutting the thrifty substrate hypothesis for cardiovascular protection of SGLT2 inhibitors. Trial registration NCT, NCT03118336. Registered 18 April 2017, https://clinicaltrials.gov/ct2/show/NCT03118336.

Active site rearrangement and structural divergence in prokaryotic respiratory oxidases.

Cytochrome bd-type quinol oxidases catalyze the reduction of molecular oxygen to water in the respiratory chain of many human-pathogenic bacteria. They are structurally unrelated to mitochondrial cytochrome c oxidases and are therefore a prime target for the development of antimicrobial drugs. We determined the structure of the Escherichia coli cytochrome bd-I oxidase by single-particle cryo-electron microscopy to a resolution of 2.7 angstroms. Our structure contains a previously unknown accessory subunit CydH, the L-subfamily-specific Q-loop domain, a structural ubiquinone-8 cofactor, an active-site density interpreted as dioxygen, distinct water-filled proton channels, and an oxygen-conducting pathway. Comparison with another cytochrome bd oxidase reveals structural divergence in the family, including rearrangement of high-spin hemes and conformational adaption of a transmembrane helix to generate a distinct oxygen-binding site.

Pheromone dispensers, including organic polymer fibers, described in the crop protection literature: comparison of their innovation potential.

Pheromone dispensers, although known in a variety of different designs, are one of the few remaining technical bottlenecks along the way to a sustainable pheromone based strategy in integrated pest management (IPM). Mating disruption with synthetic pheromones is a viable pest management approach. Suitable pheromone dispensers for these mating disruption schemes, however, are lagging behind the general availability of pheromones. Specifically, there is a need for matching the properties of the synthetic pheromones, the release rates suitable for certain insect species, and the environmental requirements of specific crop management. The "ideal" dispenser should release pheromones at a constant but pre-adjustable rate, should be mechanically applicable, completely biodegradable and thus save the costs for recovering spent dispensers. These should be made from renewable, cheap organic material, be economically inexpensive, and be toxicologically and eco-toxicologically inert to provide satisfactory solutions for the needs of practicing growers. In favourable cases, they will be economically competitive with conventional pesticide treatments and by far superior in terms of environmental and eco-toxicological suitability. In the course of the last 40 years, mating disruption, a non-toxicological approach, provided proof for its potential in dozens of pest insects of various orders and families. Applications for IPM in many countries of the industrialized and developing world have been reported. While some dispensers have reached wide circulation, only few of the key performing parameters fit the above requirements ideally and must be approximated with some sacrifice in performance. A fair comparison of the innovation potential of currently available pheromone dispensers is attempted. The authors advance here the use of innovative electrospun organic fibers with dimensions in the "meso" (high nano- to low micrometer) region. Due to their unique multitude of adjustable parameters, they hold considerable promise for future pest control against a variety of pest insects. In combination with well known synthetic sex pheromones, they can be used for communication disruption studies. One example, the pheromone of the European grape vine moth Lobesia botrana (Lepidoptera: Tortricidae), in combination with Ecoflex fibers, has been thoroughly tested in vineyards of Freiburg, Southwest Germany, with promising results. Seven weeks of communication disruption have been achieved, long enough to cover any one of several flights of this multivoltine grape pest. Disruption effects of around 95% have been achieved which are statistically indistinguishable from positive controls tested simultaneously with Isonet LE fibers, while an untreated negative control is significantly different. Ecoflex is a cheap organic co-polyester and completely biodegradable within half a year. Thus, an extra recovery step as with some other dispensers is unnecessary. This co-polyester is also of proven non-toxicity. The extension of the seven week disruption period towards half a year (the entire duration of all 3 Lobesia flights combined) is desirable and is under additional investigation in the near future. The discovery of suitable mesofibers is protected by European and US patents. The pheromone literature appearing between 1959 and today contains more than 25,000 references. This wealth of information is immediately applicable to pest management. It has major impacts on chemical ecology and IPM. In this paper, an attempt is made to compare the systems described in the literature and to derive some predictions about their prospective innovation potential. Special emphasis is given to the new development of organic biodegradable microfibers. To this end, a new electronic searching algorithm is introduced for reviewing the entries to be found in 4 specific databases. Its prominent features will be described. Surprisingly we found no previous entries in the literature linking pheromones with biodegradable organic polymer fibers whose diameters are in the dimension range of low micrometers and in the upper nanometer scale. In conclusion, the microfiber-pheromone combination must be considered as a novel approach whose virtues should be further explored for IPM in the near future.

New dispenser types for integrated pest management of agriculturally significant insect pests: an algorithm with specialized searching capacity in electronic data bases.

Pheromone effects discovered some 130 years, but scientifically defined just half a century ago, are a great bonus for basic and applied biology. Specifically, pest management efforts have been advanced in many insect orders, either for purposes or monitoring, mass trapping, or for mating disruption. Finding and applying a new search algorithm, nearly 20,000 entries in the pheromone literature have been counted, a number much higher than originally anticipated. This compilation contains identified and thus synthesizable structures for all major orders of insects. Among them are hundreds of agriculturally significant insect pests whose aggregated damages and costly control measures range in the multibillions of dollars annually. Unfortunately, and despite a lot of effort within the international entomological scene, the number of efficient and cheap engineering solutions for dispensing pheromones under variable field conditions is uncomfortably lagging behind. Some innovative approaches are cited from the relevant literature in an attempt to rectify this situation. Recently, specifically designed electrospun organic nanofibers offer a lot of promise. With their use, the mating communication of vineyard insects like Lobesia botrana (Lep.: Tortricidae) can be disrupted for periods of seven weeks.

Holocaust survivors: the pain behind the agony. Increased prevalence of fibromyalgia among Holocaust survivors.

OBJECTIVES: To assess the frequency of fibromyalgia among a population of Holocaust survivors in Israel as well as the occurrence of post-traumatic stress disorder (PTSD) and concurrent psychiatric symptoms, including depression and anxiety among survivors. METHODS: Eighty-three survivors of the Nazi Holocaust and 65 age-matched individuals not exposed to Nazi occupation were recruited. Physical examination and manual tender point assessment was performed for the establishment of the diagnosis of fibromyalgia and information was collected regarding quality of life (SF-36), physical function and health (FIQ), psychiatric symptoms (SCL-90) and PTSD symptoms (CAPS). RESULTS: Significantly increased rates of fibromyalgia were identified among Holocaust survivors compared with controls (23.81% vs. 10.94, p<0.05). Significantly increased rates of posttraumatic symptoms and measures of mental distress were also identified among survivors. CONCLUSIONS: The results indicate a significantly increased prevalence of fibromyalgia among Holocaust survivors six decades after the end of the Second World War. This finding furthers our knowledge regarding the long-term effect of stress on the development of fibromyalgia.

Early endothelial dysfunction in young type 1 diabetics.

OBJECTIVES: Endothelial dysfunction is a known precursor of atherosclerosis and can be assessed by measuring the brachial artery flow-mediated dilatation (FMD) via ultrasonography. This study investigated endothelial function in young type 1 diabetics without cardiovascular morbidity or diabetes-related pathology. METHODS: Young diabetics and healthy controls were recruited, both meeting strict inclusion and exclusion criteria. To prove absence of subclinical atherosclerosis, intima-media thickness (IMT) measurements at the carotid bifurcation were done in all of them. FMD was measured at the brachial artery. The results were compared using the t-test and the influences of different variables on FMD were assessed using multiple linear regression. RESULTS: Twenty-six diabetics (23.4+/-5.8 years) and 36 healthy volunteers (23.1+/-2.8 years) were recruited. The duration of diabetes was 9.2+/-5.3 years; metabolic control was moderate (HbA1c 7.6+/-1.0%) and IMT was normal in both groups. FMD was significantly impaired in type 1 diabetics (7.13+/-0.43 vs. 8.77+/-0.43%; p=0.002). The FMD grade was associated with diabetes and age. Patients with a good metabolic control (HbA1c

Reconsideration of discharge data to measure competition in the hospital industry.

Economists have long used state-collected discharge data to construct Hirschman-Herfindahl (HH) indices measuring hospital competition. Since data are collected to determine the facility providing the service rather than ownership, the difference between the number of reporting facilities and the number of competitors has grown over time due to mergers and networking activities. Consequently, the validity of the discharge HH methodology, as currently employed, is in doubt. Comparing the annual census of New York state acute-care hospitals by the State and the American Hospital Association (AHA), we find that it is increasingly important to account for changes in ownership when constructing such indices.

An alternative approach to depigmentation by soybean extracts via inhibition of the PAR-2 pathway.

The protease-activated receptor 2, expressed on keratinocytes but not on melanocytes, has been ascribed functional importance in the regulation of pigmentation by phagocytosis of melanosomes. Inhibition of protease-activated receptor 2 activation by synthetic serine protease inhibitors requires keratinocyte-melanocyte contact and results in depigmentation of the dark skinned Yucatan swine, suggesting a new class of depigmenting mechanism and agents. We therefore examined natural agents that could exert their effect via the protease-activated receptor 2 pathway. Here we show that soymilk and the soybean-derived serine protease inhibitors soybean trypsin inhibitor and Bowman-Birk inhibitor inhibit protease-activated receptor 2 cleavage, affect cytoskeletal and cell surface organization, and reduce keratinocyte phagocytosis. The depigmenting activity of these agents and their capability to prevent ultraviolet-induced pigmentation are demonstrated both in vitro and in vivo. These results imply that inhibition of the protease-activated receptor 2 pathway by soymilk may be used as a natural alternative to skin lightening.

Clinical significance of low titer anti-nuclear antibodies in early rheumatoid arthritis: implications on the presentation and long-term course of the disease.

The objective of this study was to evaluate the clinical significance of anti-nuclear antibodies (ANA) detected in the early stages of rheumatoid arthritis (RA), by a retrospective comparison of the clinical, laboratory, and therapeutic characteristics of patients with or without ANA. The files of 99 longstanding seropositive RA patients were reviewed. Data relating to demographics, medical history, family history, physical findings, extra-articular complications, laboratory tests, drugs [dosage, duration. efficacy, combinations, adverse effects (AEs)], intra-articular injections, and surgery were recorded. Patients with or without ANA at presentation of their disease were compared using chi-square and t-tests. Fifty-two ANA positive (group 1) and 47 ANA negative (group 2) patients were enrolled in the study. All were comparable in terms of their mean age, age at diagnosis, follow-up duration (approximately 10.5 years), and male:female (M:F) ratio. On admission, pain complaints were more pronounced in group 1 (P = 0.004 in the feet), but the physical findings did not differ. Deformities and nodules developed in similar numbers. Extra-articular complications were evenly distributed; vasculitis, however, was significantly more prevalent in ANA positive (10/52) than in ANA negative (2/47) patients. Thyroid disease was more common in group 2 (10/47 vs 3/52). Laboratory tests (presentation and maximal values) were similar, with the exception of higher anti-DNA (but within normal ranges) and gamma-globulin% in group 1. Group 1 used more drugs prior to diagnosis. Corticosteroids and disease-modifying anti-rheumatic drugs (DMARDs) were evenly used. Combination therapy, joint injections, and surgery were more prevalent in group 2. AEs to various DMARDs were more common in group 1. Although similar in many aspects, RA patients with ANA tend to present with more pain complaints, a higher risk of vasculitis and AEs relating to use of DMARDs, while those without ANA needed more aggressive therapeutic modalities.

Inhibition of melanosome transfer results in skin lightening.

The chemical basis of melanogenesis is well documented, but the mechanism of melanosome transfer and the regulation of pigmentation by keratinocyte-melanocyte interactions are not well understood. Therefore we examined the effects of serine protease inhibitors on skin pigmentation and found that the protease-activated receptor 2, expressed on keratinocytes, may regulate pigmentation via keratinocyte-melanocyte interactions. Here we show that modulation of protease-activated receptor 2 activation affects melanosome transfer into keratinocytes, resulting in changes in pigment production and deposition. SLIGRL, the protease-activated receptor 2 activating peptide, enhanced melanosome ingestion by keratinocytes, thus increasing pigment deposition. RWJ-50353, a serine protease inhibitor, led to reduced pigment deposition in melanocytes and depigmentation. Electron microscopy studies illustrated an accumulation of immature melanosomes inside melanocytes and abnormal dendrite dynamics in RWJ-50353-treated epidermal equivalents. RWJ-50353 induced a visible and dose-dependent skin lightening effect in the dark-skinned Yucatan swine. Examinations by electron microscopy indicated that the in vivo transfer of melanosomes from melanocytes to keratinocytes was affected. Our data suggest that modulation of keratinocyte-melanocyte interactions via the protease-activated receptor 2 pathway affects melanosome transfer. The use of RWJ-50353 to modulate protease-activated receptor 2 activation could lead to a new class of depigmenting agents.

The protease-activated receptor-2 upregulates keratinocyte phagocytosis.

The protease-activated receptor-2 (PAR-2) belongs to the family of seven transmembrane domain receptors, which are activated by the specific enzymatic cleavage of their extracellular amino termini. Synthetic peptides corresponding to the tethered ligand domain (SLIGRL in mouse, SLIGKV in human) can activate PAR-2 without the need for receptor cleavage. PAR-2 activation is involved in cell growth, differentiation and inflammatory processes, and was shown to affect melanin and melanosome ingestion by human keratinocytes. Data presented here suggest that PAR-2 activation may regulate human keratinocyte phagocytosis. PAR-2 activation by trypsin, SLIGRL or SLIGKV increased the ability of keratinocytes to ingest fluorescently labeled microspheres or E. coli K-12 bioparticles. This PAR-2 mediated increase in keratinocyte phagocytic capability correlated with an increase in actin polymerization and *-actinin reorganization, cell surface morphological changes and increased soluble protease activity. Moreover, addition of serine protease inhibitors downmodulated both the constitutive and the PAR-2 mediated increases in phagocytosis, suggesting that serine proteases mediate this functional activity in keratinocytes. PAR-2 involvement in keratinocyte phagocytosis is a novel function for this receptor.

Induction of heat-shock (stress) protein gene expression by selected natural and anthropogenic disturbances in the octocoral Dendronephthya klunzingeri.

Previously it was found that the expression of selected heat-shock proteins is upregulated in corals after exposure to elevated temperature. We published that HSPs are suitable markers in sponges to monitor the degree of environmental stress on these animals. In the present study the heat-shock proteins (HSPs) with a molecular weight of 90 kDa have been selected to prove their potential usefulness as biomarkers under controlled laboratory conditions and in the field. The studies have been performed with the octocoral Dendronephthya klunzingeri4.5-fold higher steady-state level of the respective mRNA. Also animals taken from stressed locations in the field showed an increased expression. The amount of HSP90 protein in D. klunzingeri was found to be strongly increased under thermal stress, or exposure to polychlorinated biphenyl (congener 118), but not after treatment with cadmium. Field studies revealed that samples taken from a nonstressed area have a low level of HSP90, but those collected from locations at which the corals are under physical stress (sedimentation through landfilling) show a high expression of HSP90. It is concluded that the chaperone HSP90 might become a suitable biomarker to monitor environmental stress on corals.

The protease-activated receptor 2 regulates pigmentation via keratinocyte-melanocyte interactions.

Close association exists between melanocytes, the pigment melanin-producing cells in the body, and their neighboring keratinocytes. Keratinocytes are the pigment recipients and skin pigmentation is the result of this interaction. While the chemical basis of melanin production (melanogenesis) is well documented, the molecular mechanism of melanosome transfer needs to be elucidated. We are now providing first evidence that the protease-activated receptor 2 (PAR-2) expressed on keratinocytes, but not on melanocytes, is involved in melanosome transfer and therefore may regulate pigmentation. Activation of PAR-2 with trypsin or with the peptide agonist SLIGRL induced pigmentation in both two- and three-dimensional cocultures of keratinocytes and melanocytes, but not in cocultures that were spatially separated, indicating the need for intimate cell-cell contact. Topical application of SLIGRL on human skin transplanted on SCID mice resulted in a visible skin darkening. Histological examination revealed increased deposits of melanin in the keratinocytes. Inhibition of PAR-2 activation by RWJ-50353, a serine protease inhibitor, resulted in depigmentation and changes in expression of melanogenic-specific genes. Keratinocyte-melanocyte contact was essential for this depigmenting effect. Topical application of this inhibitor induced lightening of the dark skin Yucatan swine, which was confirmed by histochemical analysis. The results presented here suggest a novel mechanism for the regulation of pigmentation, mediated by the activation or inhibition of the keratinocyte receptor PAR-2.

Perlecan, basal lamina proteoglycan, promotes basic fibroblast growth factor-receptor binding, mitogenesis, and angiogenesis.

A survey of defined species of cell surface and extracellular matrix heparan sulfate proteoglycans (HSPG) was performed in a search for cellular proteoglycans that can promote bFGF receptor binding and biological activity. Of the various affinity-purified HSPGs tested, perlecan, the large basement membrane HSPG, is found to induce high affinity binding of bFGF both to cells deficient in HS and to soluble FGF receptors. Heparin-dependent mitogenic activity of bFGF is strongly augmented by perlecan. Monoclonal antibodies to perlecan extract the receptor binding promoting activity from active HSPG preparations. In a rabbit ear model for in vivo angiogenesis, perlecan is a potent inducer of bFGF-mediated neovascularization. These results identify perlecan as a major candidate for a bFGF low affinity, accessory receptor and an angiogenic modulator.

Nutrient intake of endurance runners with ovo-lacto-vegetarian diet and regular western diet.

During an endurance run (1,000 km in 20 days) it was investigated whether an ovo-lacto-vegetarian diet (OLVD) could cover the nutritional requirements of endurance athletes. A regular western diet (RWD) was used as reference. Both diets were offered with an energy content of 4,500 kcal per day and an energy percentage of carbohydrate:fat:protein of 60:30:10. The runners were divided into two dietary groups according to their usual dietary habits. The results of the 55 participants who completed the race show that runners from both groups had the same intake of energy, carbohydrate, fat and protein. Runners of the OLVD group consumed more dietary fiber and polyunsaturated fatty acids as well as less cholesterol. With the exception of sodium chloride and cobalamin, the intake of the calculated minerals and vitamins was higher in the OLVD and exceeded the official recommendations. This study shows that an OLVD with a high nutrient density is adequate to cover the nutritional requirements of endurance-athletes. The intake and absorption of iron should be monitored closely in all diet groups.

VEGF receptor subtypes KDR and FLT1 show different sensitivities to heparin and placenta growth factor.

Vascular endothelial growth factor (VEGF) is an angiogenic growth factor which binds to two structurally related tyrosine kinase receptors denoted KDR and FLT1. To compare the interaction of VEGF with each receptor, cell lines which express individual receptor subtypes were identified using Northern blot hybridization. Bovine aortic endothelial (ABAE) cells and WM35 melanoma cells were found to express KDR, while FLT1 was primarily expressed on SK-MEL-37. Both receptor subtypes were detected on another melanoma cell line (WM9). Heparin augmented VEGF binding to KDR-expressing cells (ABAE and WM35), but inhibited VEGF binding to FLT1-expressing cells (SK-MEL-37 and WM9). The concentration of heparin required for half maximal stimulation of VEGF binding to KDR-expressing cells (500 ng/ml) was 25 times greater than that required for half maximal inhibition of binding to FLT1-expressing cells (20 ng/ml). In WM9 cells, the effect of heparin was bimodal; low concentration inhibited, while higher concentrations stimulated binding of 125I-VEGF. Placenta growth factor (PIGF-1) is a recently described growth factor structurally similar to VEGF. PIGF-1 had a negligible or no effect on 125I-VEGF binding to KDR-expressing cells (ABAE, WM35), but did complete for binding to FLT1-expressing cells (SK-MEL-37 and WM9). Addition of heparin had no effect on its ability to compete for binding with 125I-VEGF. The data indicate differential regulation of the two VEGF receptors by heparin and extended specificity of FLT1 receptor, but not KDR, for binding PIGF-1 growth factor.

Tumor necrosis factor enhances GD3 ganglioside expression in cultured human melanocytes.

Human skin melanocytes and melanocytes cultured in vitro express GM3 ganglioside almost exclusively, whereas malignant melanomas express high levels of both GM3 and GD3. We now show that treatment of cultured melanocytes with tumor necrosis factor-alpha, particularly in the presence of tetradecanoylphorbol-13-acetate, results in a change in morphology from spindle-shaped to epithelioid and greatly enhanced expression of GD3 ganglioside. This effect is specific and no other ganglioside is affected, except that GM3 expression (which is already high) is also increased. In contrast, these agents did not enhance the already high expression of GD3 on melanoma cells. This result provides an example of the plasticity of glycolipid expression in mammalian cells and their susceptibility to the influence of biological agents.

In vitro fibroblast seeding of prosthetic anterior cruciate ligaments. A preliminary study.

To evaluate the effect of in vitro seeding of fibroblasts on the connective tissue encapsulation of implanted ligament prostheses, canine skin fibroblasts were grown in tissue culture and seeded onto knitted Dacron prostheses. When the cells on the prostheses reached contact growth inhibition, as determined by growth curves, the prostheses were implanted into the dogs' knees as ACL replacements. Gross and histologic evaluation at 4 and 8 weeks revealed that the seeded prostheses consistently showed more uniform and abundant encapsulation with connective tissue than did the control (unseeded) prostheses. The giant cell response observed in the tissue surrounding the unseeded prostheses was not noted in the seeded prostheses. This may be because seeding a prosthesis with fibroblasts prior to implantation "walls off" the prosthesis from the environment of the joint, and therefore the prosthesis may not elicit as great a foreign body response as does an unseeded prosthesis. The results of this preliminary study suggest that the in vitro seeding of a ligament prosthesis with fibroblasts accelerates the connective tissue encapsulation of the implanted prosthesis.

Growth regulation of skin cells by epidermal cell-derived factors: implications for wound healing.

Epidermal cell-derived factors (EDF), present in extracts and supernatant fluids of cultured epidermal cells, were found to stimulate the proliferation of keratinocytes but to inhibit fibroblasts. In vitro, the effect of EDF on epidermal cells resulted in an increased number of rapidly proliferating colonies composed mainly of basal keratinocytes. Control cultures grown in the absence of EDF had a high proportion of terminally differentiated cells. In fibroblast cultures EDF inhibited the ability of fibroblasts to cause contraction of collagen sponges by 90%. Epidermal growth factor, basic fibroblast growth factor, platelet-derived growth factor, transforming growth factor beta, nerve growth factor, and extracts of WI-38 cells (human embryonic lung fibroblasts) did not have this inhibitory activity. Application of EDF to surgical wounds stimulated extensive migration and proliferation of keratinocytes from remnants of glands, hair follicles, and wound edges. The restoration of complete epidermal coverage of wounds treated with EDF occurred twice as rapidly as that of control wounds. In addition, regenerating dermis in the EDF-treated wounds contained 1/5th to 1/15th as many cells as wounds treated with epidermal growth factor, urogastrone, transforming growth factor, or phosphate-buffered saline. The use of EDF to enhance re-epithelization and to prevent scar formation is proposed.