Epidermal growth factor and keratinocyte growth factor differentially regulate epidermal migration, growth, and differentiation

Various growth factors such as epidermal growth factor and keratinocyte growth factor have been reported to promote wound closure and epidermal regeneration. In the present study epidermis reconstructed on de-epidermized dermis was used to investigate the effects of epidermal growth factor and keratinocyte growth factor on keratinocyte proliferation, migration and differentiation. Our results show that epidermal growth factor supplemented cultures share many of the features which are observed during regeneration of wounded epidermis: a thickening of the entire epidermis, an enhanced rate of proliferation and migration, and an increase in keratin 6, keratin 16, skin-derived antileukoproteinase, involucrin and transglutaminase 1 expression. The increase in transglutaminase 1 protein is accompanied by an increase in the amount of active transglutaminase 1 enzyme. Surprisingly no increase in keratin 17 is observed. Prolonging the culture period for more than two weeks results in rapid senescence and aging of the cultures. In contrast, keratinocyte growth factor supplemented cultures have a tissue architecture that is similar to healthy native epidermis and remains unchanged for at least 4 weeks of air-exposure. The rate of proliferation and the expression of keratins 6, 16 and 17, skin-derived antileukoproteinase, involucrin and transglutaminase 1 is similar to that found in healthy epidermis and furthermore keratinocyte migration does not occur. When the culture medium is supplemented with a combination of keratinocyte growth factor and a low concentration of epidermal growth factor, skin-derived antileukoproteinase, involucrin and keratins 6, 16 and 17 expression is similar to that found in cultures supplemented with keratinocyte growth factor alone and in healthy epidermis. Only high transglutaminase 1 expression remains similar to that observed in cultures supplemented with epidermal growth factor alone. Our results show that the regulation of keratinocyte growth, migration and differentiation depends on the availability of these growth factors. Epidermal growth factor may play a dominant early role in wound healing by stimulating keratinocyte proliferation and migration while keratinocyte growth factor may play a role later in the repair process by stabilizing epidermal turnover and barrier function.     

Isoflurane enhances spontaneous Ca2+ oscillations in developing rat hippocampal neurons in vitro

Background: During the nervous system development, spontaneous synchronized Ca²⁺ oscillations are thought to possess integrative properties because their amplitude and frequency can influence the patterning of neuronal connection, neuronal differentiation, axon outgrowth, and long-distance wiring. Accumulating studies have confirmed that some drugs such as volatile anesthetic isoflurane produced histopathologic changes in the central nervous system in juvenile animal models. Because the hippocampus plays an important role in learning and memory, the present work was designed to characterize the Ca²⁺ oscillations regulated by volatile anesthetic isoflurane in primary cultures of developing hippocampal neurons (5-day-cultured).
Methods: Primary cultures of rat hippocampal neurons (5-day-cultured) were loaded with the Ca²⁺ indicator Fluo-4AM (4 μM) and were studied with a confocal laser microscope.
Results: Approximately 22% of 5-day-cultured hippocampal neurons exhibited typical Ca²⁺ oscillations. These oscillations were dose-dependently enhanced by isoflurane (EC50 0.5 MAC, minimum alveolar concentration) and this effect could be reverted by bicuculline (50 μM), a specific γ-aminobutyric acid (GABA_A) receptor antagonist.
Conclusion: Unlike its depressant effect on the Ca²⁺ oscillations in adult neurons in previous researches, isoflurane dose-dependently enhanced calcium oscillations in developing hippocampal neurons by activating GABA_A receptors, a major excitatory receptor in synergy with N -methyl- d -aspartate receptors at the early stages of development. It may be involved in the mechanism of an isoflurane-induced neurotoxic effect in the developing rodent brain.     

Polymorphonuclear leucocyte rheology and cytosolic Ca2+ content after activation in chronic renal failure

SUMMARY: We evaluated polymorphonuclear leucocyte (PMN) flow properties in patients with clinically stable chronic renal failure (CRF) and in control subjects at baseline and after activation with 4-phorbol 12-myristate 13-acetate (PMA) and N -formyl-methionyl-leucyl-phenylalanine (fMLP). Initial relative flow rate (IRFR) and clogging particles (CPs) were obtained using the St. George's Filtrometer, and PMN membrane fluidity was assessed by marking PMNs with 1-(4-(trimethylamino)phenyl)-6-phenyl-1,3,5-hexatriene (TMA-DPH). PMN cytosolic Ca²⁺ concentration was determined by marking PMNs with Fura 2-AM. At baseline, CRF patients showed a significant increase only in PMN cytosolic Ca²⁺ content. After activation with PMA and fMLP, a decrease in IRFR and an increase in CP were observed in both control subjects and CRF patients, although the variation in IRFR present in the group of CRF patients was greater than in the control group. After activation with PMA and fMLP, we found a decrease in PMN membrane fluidity only in CRF patients, but no variation in PMN cytosolic Ca²⁺ concentration in either group was observed. These results provide evidence for PMN dysfunction in chronic renal failure.     

Activation of the Ca2+-Activated K+ Channel via Protein Kinase A-Dependent Phosphorylation in Human Prostatic Smooth Muscle Cells

Background: We investigated the functional importance of the Ca²⁺-activated K⁺ channel (K_Ca-channel) of human prostatic smooth muscle cells in cyclic adenosine 3', 5'-monophosphate (cAMP)-induced relaxation, to clarify signal transduction pathways and intracellular mechanisms of relaxation in prostatic smooth muscle.
Methods: Using the patch-clamp technique, we characterized the K_Ca-channel of cultured human prostatic smooth muscle cells. We also investigated the effects on the K_Ca-channels of forskolin, an activator of adenylate cyclase, amrinone, a phosphodiesterase inhibitor, and protein kinase A (A-kinase)-dependent phosphorylation.
Results: Single-channel current recordings from cultured human prostatic smooth muscle cells revealed the presence of K_Ca-channels (conductance 296.7±5.67 pS, n = 7). In cell-attached patch configurations, the K_Ca-channel was activated by forskolin (1CH mol/L) and amrinone (10⁻⁴ mol/L). In inside-out patch configurations, it was activated by catalytic subunits of A-kinase (10 U/mL).
Conclusions: We conclude that the K_Ca-channel of human prostatic smooth muscle cells is regulated by intracellular cAMP levels and that A-kinase mediates the cAMP-induced activation of the K_Ca-channel. This regulation of the K_Ca-channel by cAMP may at least partially explain cAMP-induced prostatic smooth muscle relaxation and the effectiveness of certain drugs for treatment of obstruction in benign prostatic hyperplasia.     

Immobilized gradients of epidermal growth factor promote accelerated and directed keratinocyte migration

Acceleration of wound closure results not only in decreased patient suffering and cost of wound treatment, but may also minimize scarring and lead to formation of a more stable closed wound. Cell migration is a critical element in wound healing, and it is believed that the ability to control the migration direction of cells will lead to accelerated closure of wounds. Thus, we have synthesized surfaces that are covalently modified with gradients of epidermal growth factor (EGF), a key molecule in the native wound-healing process, in order to create a platform that promotes directed cell migration. Standard photo-patterning techniques used herein enabled precise control over the spatial location of tethered EGF and the fabrication and quantitative characterization of gradient patterns of different types and slopes. Under serum-free conditions, human epidermal keratinocytes on immobilized EGF gradients preferentially migrated in the direction of higher EGF concentrations, and exhibited unidirectional migration speed and distance that was over five-fold greater than that observed on control surfaces. Treatment of migrating cells with an inhibitor of the EGF receptor resulted in immediate cessation of migration, thus verifying that the observed migration trends were directly attributable to keratinocyte interactions with immobilized EGF.     

Effect of calmodulin-like protein from buffalo (Bubalus bubalis) seminal plasma on Ca2+, Mg2+-ATPase of purified plasma membrane of buffalo spermatozoa

Summary. Buffalo sperm heads and tails were cleaved by sonication and isolated in relatively pure proportions i.e. 95% and 98% respectively, by discontinuous sucrose density-gradient centri-fugation. Purified plasma membranes from the isolated sperm heads and tails were obtained by hypotonic treatment and brief sonication followed by discontinuous sucrose density-gradient centrifugation. Ca²⁺, Mg²⁺-ATPase activity was evident in plasma membrane from sperm heads and tails, although activity was greater in the latter. A calmodulin-like protein isolated from buffalo seminal plasma increased the Ca²⁺, Mg²⁺-ATPase of plasma membrane from the sperm heads and tails by 128 and 136% respectively. Based upon the data obtained here and elsewhere (Sidhu & Guraya, 1989a) a model is proposed which explains regulation of Ca²⁺ in buffalo spermatozoa and implicates calmodulin-like protein and Ca²⁺, Mg²⁺-ATPase in sperm acrosome reaction.     

Ca2+ is Essential for the Motility of Plasma Membrane-Intact, but not of demembranated. Hamster Spermatozoa

Extracellular Ca2+ is essential for the flagellar motility of membrane-intact hamster spermatozoa. When suspended in a medium completely free of Ca2+, most spermatozoa quickly lost their motility, and remained motionless until they were transferred back to Ca2+-containing medium. The motility could not be restored after the spermatozoa had been in Ca2+-free medium for more than 2 hr. Unlike membrane-intact spermatozoa, demembranated spermatozoa (spermatozoa without plasma membranes) exhibited active movement in Ca2+-free medium, and their motility was inhibited by Ca2+. In view of these facts, we suggest that the "hyperactivated motility" which membrane-intact spermatozoa display upon capacitation may be due to the activation of a Ca2+-dependent adenylate cyclase (and the resultant increase in intracellular cAMP), rather than being a direct effect of a rise in the intracellular Ca2+ concentration.     

T cell receptor beta chain (TCR-Vβ) repertoire of circulating CD4+ CD25−, CD4+ CD25low and CD4+ CD25high T cells in patients with long-term renal allograft survival

The mechanisms underlying maintenance of renal allografts in humans under minimal or conventional immunosuppression are poorly understood. There is evidence that CD4⁺ CD25⁺ regulatory T cells and clonal deletion, among other mechanisms of tolerance, could play a key role in clinical allograft survival. Twenty‐four TCR‐Vβ families were assessed in CD4⁺ CD25^?, CD4⁺ CD25^low and CD4⁺ CD25^high T cells from patients with long‐term renal allograft survival (LTS), patients exhibiting chronic rejection (ChrRx), patients on dialysis (Dial) and healthy controls (HC) by flow cytometry. LTS patients presented a higher variability in their TCR‐Vβ repertoire, such decreased percentage of Vβ2⁺, Vβ8a⁺ and Vβ13⁺ in CD4⁺ CD25^low and ^high compared with CD4⁺ CD25^? subset and increased Vβ4 and Vβ7 families in CD4⁺ CD25^high T cells exclusively. Additionally, LTS patients, particularly those that were not receiving calcineurin inhibitors (CNI), had increased percentages of CD4⁺ CD25^high T cells when compared with Dial (P < 0.05) and ChrRx (P < 0.05) patients. Our results suggest that a differential expression of particular TCR‐Vβ families and high levels of circulating CD4⁺ CD25^high T cells in long‐term surviving renal transplant patients could contribute to an active and specific state of immunologic suppression. However, the increase in this T cell subset with regulatory phenotype can be affected by CNI.     

乳腺癌中HER2基质金属蛋白酶-2和9的表达及其相互关系

目的　研究乳腺癌中HER2基因、基质金属蛋白酶 (MMP) 2、基质金属蛋白酶(MMP) 9的表达情况、与临床病理指标之间的关系以及它们之间的相互关系。方法　采用免疫组织化学的方法对 114例乳腺癌组织标本中HER2、MMP 2、MMP 9的表达情况进行检测。结果　乳腺癌组织中HER2、MMP 2、MMP 9的表达阳性率分别是 46.49%、78.95 %、68.42 %。HER2表达与淋巴结转移相关。原发肿瘤 >2cm或有淋巴结转移的患者中 ,其MMP 2、MMP 9表达明显高于原发肿瘤≤ 2cm或无淋巴结转移的患者 (P <0 .0 5 ) ,且MMP 2表达与临床分期相关 (P <0 .0 5 )。HER2表达与MMP 2、MMP 9表达相关 (P <0 .0 5 )。结论　HER2、MMP 2、MMP 9的阳性表达提示乳腺癌有较强的浸润转移能力 ,这 3种蛋白的表达在乳腺癌浸润转移过程中可能起协同作用。     

The effects of a high salt diet on gene expression of Na+/H+ exchanger and growth factors in 5/6-nephrectomized rats

SUMMARY: The effects of a high salt diet on renal destruction and the therapeutic effects of amiloride (Na⁺/H⁺ exchanger inhibitor) and furosemide (Na⁺K⁺/2Cl⁻ exchanger inhibitor) were examined in 5/6-nephrectomized rats fed a high salt diet. A simultaneous analysis of the effects of a high salt intake on the renal expression of Na⁺/H⁺ exchanger-1 (NHE-1), transforming growth factor-β1 (TGF-β1) or platelet-derived growth factor-B (PDGF-B) mRNA was performed in this model. the 5/6-nephrectomized Sprague-Dawley rats were given a diet containing 8 or 1% sodium chloride for 5 weeks. This high salt diet accelerated the elevation of blood pressure and aggravated both glomerulosclerosis and interstitial fibrosis in 5/6-nephrectomized rats. the daily administration of amiloride was found to be protective against the elevation of blood pressure, glomerular hypertrophy and the aggravation of renal histology which were induced by a high salt diet. the expression of TGF-β1 and PDGF-B mRNA was up-regulated by a high salt diet, but the expression of NHE-1 mRNA was not. the overexpression of TGF-β1 and PDGF-B mRNA was reduced by the daily administration of amiloride but not by furosemide. In conclusion, the destructive effects of a high salt diet on the kidneys may be mediated through hypertension, glomerular hypertrophy and the overexpression of the growth factors. Amiloride may thus be more protective for high salt induced renal aggravation than furosemide, although the expression of NHE-1 mRNA did not show any substantial increase due to a high salt diet.     

Direct inhibition of testicular steroidogenesis and gonadotrophin receptor levels by [(imBzl)-D-His6, Pro9-NEt]GnRH and [D-Trp6, Pro9-NEt]GnRH, potent agonists of GnRH

The effects of [(imBzl)-D-His⁶, Pro⁹-NEt]GnRH and [D-Trp⁶. Pro⁹-NEt]GnRH on testicular function in rats was evaluated. In adult rats the administration of 0.01, 0.1 or 10 μg of either agonist induced rapid increases in serum LH, FSH and testosterone (T) levels which started to decline within several hours. Both agonists caused a decrease in testicular LH and FSH receptor concentrations. The testicular FSH receptor concentration started to decline earlier than the LH receptor concentration but, both reached their lowest levels by day 2 after the administration of the agonists. The recovery of FSH receptor content was slower than that of LH. The extrapituitary effects of the 2 agonists were investigated in immature hypophysectomized animals. Administration of hCG (5 IU daily) to hypophysectomized rats for 5 days caused an increase in serum T levels. Concomitant administration of either of the agonists (10 μg) inhibited the steroidogenic action of hCG. Administration of the agonists alone caused a reduction in testicular LH receptor concentration in hypophysectomized rats. Treatment of the hypophysectomized rats for 0–4 days suggested that the direct antitesticular action of the agonists requires 1 - 2 days to become evident.     

Histocytochemical study of Spot 35-calbindin-D28K and Ca2+-ATPase in rat kidney

Summary: We determined the distribution of Spot 35-calbindin-D28K, a vitamin-D dependent calciumbinding protein, in rat kidney using histochemical methods and compared it with the distribution of Ca²⁺-ATPase activity. Spot 35-calbindin-D28K immunoreactivity was localized in the cytosol of urinary epithelial cells in distal convoluted tubules (DCT), connecting tubules (CNT) and cortical collecting ducts (CCD), identifying the physiologically confirmed site of active transcellular calcium transport. In the cytosol, the immunoreactivity was clustered near the luminal plasma membrane and around the mitochondria. These findings indicated that Spot 35-calbindin-D28K seemed to have a cytosolic calcium buffering effect in the urinary tubular epithelial cells. Enzyme histochemical analysis showed that Ca²⁺-ATPase activity was localized at the basolateral plasma membrane of distal nephron segments and was strongest at the cortical thick ascending limb of Henle (CTAL), including the macula densa portion. Ca²⁺-ATPase activity was not evident in DCT, CNT or CCD. Strong Ca²⁺-ATPase activity and Spot 35-calbindin-D28K immunoreactivity did not coexist in a urinary tubular cell.     

Synergistic effect of keratinocyte transplantation and epidermal growth factor delivery on epidermal regeneration

Both keratinocyte transplantation and epidermal growth factor (EGF) delivery stimulate epidermal regeneration. In this study, we hypothesized that the combined therapy of keratinocyte transplantation and EGF delivery accelerates epidermal regeneration compared to the single therapy of either keratinocyte transplantation or EGF delivery. To test this hypothesis, we utilized fibrin matrix as a keratinocyte/EGF delivery vehicle for epidermal regeneration. Full-thickness wounds were created on the dorsum of athymic mice, and human keratinocytes and EGF in fibrin matrix were sprayed onto the wounds to regenerate epidermal layers (group 1). As controls, human keratinocytes in fibrin matrix (group 2), EGF in fibrin matrix (group 3), or fibrin matrix alone (group 4) was sprayed onto the wounds. Spraying keratinocytes suspended in fibrin matrix did not affect the keratinocyte viability, as the cell viabilities before and after spraying were not different. EGF was released from fibrin matrix for 3 days. The wounds were analyzed with histology and immunohistochemistry at 1 and 3 weeks after treatments. Compared with the control groups, initial wound closure rate was highest in group 1. Histological analyses indicated that group 1 exhibited faster and better epidermal regeneration than the other groups. Immunohistochemical analyses showed that regenerated epithelium in groups 1 and 2 stained positively for human involucrin at 3 weeks, whereas the tissue sections of the groups 3 and 4 stained negatively. Human laminin was detected at the dermal-epidermal junction of the regenerated tissues in groups 1 and 2 at 3 weeks and was not detected in groups 3 and 4. The epidermal thickness of the regenerated tissues in group 1 was significantly thicker than that of the other groups at all time points. These results suggest that the combined therapy of keratinocyte transplantation and EGF delivery is more efficacious for epidermal regeneration than each separate therapy alone.     

Different mechanisms of Campath-1H-mediated depletion for CD4+ and CD8+ T cells in peripheral blood

It is assumed that complement and noncomplement-mediated mechanisms are similarly responsible for Campath-1H-mediated killing of all T-cell subtypes in vivo. However, the differing surface expression of CD52 on T-cell subtypes suggests that may not be the case. The purpose of this study is to determine the extent and mechanism of Campath-1H-mediated elimination of different T-cell subtypes in peripheral blood. Whole blood or lymphocytes isolated from peripheral blood of healthy volunteers by Ficoll density centrifugation were incubated with Campath-1H, with or without complement and/or serum, and the resultant T-cell elimination mechanisms studied. For CD4(+) T lymphocytes, 60% and 40% cell death and for CD8(+) T lymphocytes 23% and 77% cell death, in peripheral blood, was mediated by complement and noncomplement mediated mechanisms, respectively. CD4(+) T cells demonstrated approximately twice the amount of surface CD52 compared with CD8(+) T cells, consistent with primarily complement-mediated killing for CD4(+) T cells. Thus, peripheral blood supports differential and partial elimination of T-cell subtypes, suggesting that the complete T-cell elimination seen in transplant recipients is most likely due to contribution from other lymphoid organs.     

Contrasting Alloreactive CD4+ and CD8+ T Cells: There''s More to It Than MHC Restriction

Surface expression of CD4 or CD8 is commonly used to identify T-cell subsets that recognize antigen presented by class II MHC or class I MHC, respectively. This holds true for T cells that respond to allogeneic MHC molecules that are directly recognized as foreign, as well as peptides from allogeneic MHC molecules that are indirectly presented by self MHC molecules. CD4 or CD8 expression was initially believed to define cytokine secreting helper T cells or cytotoxic cells, respectively. However, this association of phenotype and function is not absolute, in that CD4+ cells may possess lytic activity and CD8+ cells secrete cytokines, notably IFNgamma. Recently, additional fundamental differences in the immunobiology of these T-cell subsets have been identified. These include differences in costimulatory requirements, cytokine responsiveness, cytokine production, cell survival, and the maintenance of memory. This review will survey these differences, emphasizing alloreactive T-cell responses as well as relevant observations that have been made in other systems.     

Connective tissue growth factor increases matrix metalloproteinase-2 and suppresses tissue inhibitor of matrix metalloproteinase-2 production by cultured renal interstitial fibroblasts

The involvement of gelatinase (matrix metalloproteinase-2 [MMP-2] and MMP-9) in the matrix remodeling and development of tubulointerstitial fibrosis has been studied recently, but relatively little is known about the regulators and the mechanisms controlling the activation and expression of gelatinase in renal fibroblasts. In these studies, the production and underlying signaling pathway for gelatinase by exogenous connective tissue growth factor (CTGF) treatment were investigated. Here, we show that CTGF acts as a potent promoter of the activation and expression of MMP-2, but not MMP-9 in normal rat kidney fibroblasts cell line (NRK-49F). We found that CTGF significantly increased the activity of MMP-2, as well as MMP-2 protein in conditioned medium and MMP-2 mRNA levels in cells. In studies to address the mechanisms involved in the regulation of MMP-2 activity, we found that the tissue inhibitor of matrix metalloproteinase-2 (TIMP-2), the inhibitor of MMP-2, decreased significantly when cells were treated with CTGF. Further studies showed that extracellular signal-regulated kinase (ERK) signaling is responsible for most of the CTGF-induced MMP-2 expression and TIMP-2 suppression. When NRK-49F fibroblasts were incubated with CTGF, activation of ERK1/2 signaling was observed. Suppression of ERK1/2 activation with nontoxic concentrations of PD98059, a specific inhibitor of ERK activation, was associated with a reduction of CTGF-stimulated MMP-2 activity and protein expression. In addition, the CTGF-mediated reduction of TIMP-2 activity and protein expression was prevented when ERK1/2 activation was inhibited by PD98059. These results provide evidence that CTGF augments activation of MMP-2 through an effect on MMP-2 protein expression and TIMP-2 suppression, and that these effects are dependent on the activation of the ERK1/2 pathway.     

罗格列酮对肝星状细胞基质金属蛋白酶-2和-9基因表达的影响

目的 观察过氧化物酶体增殖物活化受体γ(PPARγ)特异配体罗格列酮对肝星状细胞(HSC)表达基质金属蛋白酶(MMP)-2和MMP-9的影响.方法 在培养的HSC株中加入不同浓度的罗格列酮(终质量浓度为5、10、15、20 μmol/L),于24 h后收取细胞,利用半定量逆转录-聚合酶链反应(RT-PCR)测定MMP-2、MMP-9 mRNA表达.结果 MMP-2表达水平在罗格列酮5、10、15、20 μmol/L组分别为0.5708±0.0609、0.8900±0.0823、1.1348±0.1205、1.4490±0.0832,而空白对照组为0.3237±0.0796.MMP-9表达水平在罗格列酮5、10、15、20 μmol/L组分别为0.5487±0.0770、0.7554±0.0510、0.9497±0.0451、1.1088±0.0777,空白对照组为0.3220±0.0592.结论 罗格列酮可增强HSC对MMP-2、MMP-9的表达,并在一定范围内,呈剂量依赖性.     

Mitogenic bovine whey extract modulates matrix metalloproteinase-2, -9, and tissue inhibitor of matrix metalloproteinase-2 levels in chronic leg ulcers

Matrix metalloproteinases (MMPs) and their tissue inhibitors play important roles in the wound-healing process. An imbalance in the expression of these molecules is thought to contribute to the failure of chronic ulcers to heal. We investigated whether a mitogenic bovine whey extract enriched with growth factors modulated the expression and activity of MMP-2 and -9, and the tissue inhibitor of MMP-2 (TIMP-2) in chronic leg ulcers. Wound fluids and biopsies were collected from chronic leg ulcer patients whose ulcers were treated topically for 4 weeks with placebo or mitogenic bovine whey extract at concentrations of 2.5, 10, and 20 mg/mL. The levels of MMP-2 and -9 in wound fluid samples was assessed by gelatin zymography and showed a decrease in active MMP-2 in the 2.5 and 10.0 mg/mL mitogenic bovine whey extract-treated ulcers compared with placebo (p<0.05). Immunohistochemical analysis of ulcer biopsies for MMP-2, -9, and TIMP-2 expression showed a reduction in the number of MMP-2-positive dermal fibroblasts in the mitogenic bovine whey extract-treated ulcers compared with pretreatment biopsies (p<0.05) that persisted over the course of the study. In contrast, a transient increase in the number of MMP-9- and TIMP-2-positive cells was observed in mitogenic bovine whey extract treated ulcer biopsies compared with pretreatment levels (p<0.05). These results show that topical application of mitogenic bovine whey extract was able to modulate the expression of MMP-2, -9, and TIMP-2 in chronic leg ulcers and that its constituent growth factors may have the potential to redress the proteolytic imbalance observed in nonhealing chronic ulcers.