Characterization of angiotensin-converting enzyme expression during epidermis morphogenesis in humans: a potential marker for epidermal stem cells.

BACKGROUND: Recent evidence has revealed that angiotensin-converting enzyme (ACE) participates in cutaneous wound healing and contributes to the pathophysiological process of some skin diseases. However, little is known about the role of ACE in epidermis morphogenesis during development. OBJECTIVE: To clarify the expression pattern of ACE during embryonic development of human skin. METHODS: Skin samples were obtained from aborted fetuses at different gestational ages and from healthy individuals. Localization of ACE, together with beta(1)-integrin, keratin 19 (K19) and p63 was examined by immunofluorescence and immunohistochemical staining. RESULTS: In human fetal skin, at 11-13 weeks of gestation, ACE-positive cells were observed in the primitive epidermis. As the fetuses developed, ACE-positive cells appeared in all the epidermal layers. From 21 weeks of gestation, ACE expression was largely restricted to the basal layer of the fetal epidermis. In contrast, ACE-positive cells were found only in the adult skin basal layer which harbours epidermal stem cells. To explore the possible link between ACE and epidermal stem cells, we further examined the expression of beta(1)-integrin, K19 and p63, the putative markers for epidermal stem cells. Consistent with the results of ACE expression, from 21 weeks of gestation, the expression of beta(1)-integrin, K19 and p63 was mainly confined to the basal layer. Immunofluorescent double labelling revealed that ACE-positive cells substantially overlapped with beta(1)-integrin-, K19- and p63-positive cells. CONCLUSIONS: Our results suggest that ACE may play a role in human epidermis morphogenesis during fetal life and serve as an unrecognized marker for keratinocyte progenitor cells.

The involvement of multiple protease-antiprotease systems and gut origin sepsis in zymosan-associated endothelial barrier injury and multiple organ dysfunction in rats.

Multiple organ dysfunction syndrome is a dominant cause of mortality in the intensive care unit. Experimentally, a condition similar to the multiple organ dysfunction syndrome can be induced by the intraperitoneal injection of sterile zymosan. In the present study we investigate potential alterations in multiple organ functions, endothelial permeability, and antiproteinases after intraperitoneal injection of zymosan at various doses. Zymosan-induced generalized inflammation lead to endothelial barrier injury in multiple organs/tissues, a decrease in systemic arterial pressure, impaired organ function and gut defence function, and consumption of protease inhibitors, particularly the consumption of alpha2 antiplasmin. Endothelial barrier injury appears to present a dose- and organ-dependent pattern in multiple organs/tissues, and the increase in endothelial barrier permeability occurred prior to organ dysfunction. Zymosan induced the development of multiple organ dysfunction syndrome, probably initiating multiple protease-antiprotease systems, particularly the fibrinolytic system, leading to endothelial barrier injury, tissue edema, parenchymal cell damage, and eventual organ dysfunction, potentially augmented by a secondary bacterial infection.

[The stimulating effects of bFGF on fibroblast function and its C-fos gene expression].

OBJECTIVE: To study the stimulating effects of basic fibroblast growth factor(bFGF) on fibroblast function and its ability to expression of c-fos gene. Furthermore, to explore the possible network action between bFGF and oncogene in modulating wound healing. METHODS: Cultured rat fibroblasts were divided into bFGF stimulating group and control group. Fibroblasts in bFGF stimulating group were treated with bFGF in a dosage of 40 ng/culture hole, while the control fibroblasts were treated with the same vehicle without bFGF. The morphology, cell vitality and their ability to express c-fos gene in the fibroblasts in both groups were studied with MTT and immunohistochemical methods. RESULTS: All fibroblasts in bFGF treated groups were enlarged and showed increased vitality with MTT method. C-fos gene expression in bFGF stimulating group was increased, especially in nucleus when compared with those in control group. CONCLUSION: The results show that the function and the ability to express c-fos gene in bFGF treated fibroblasts are enhanced. Combined with our previous studies, it may make a conclusion that there is a network regulation mechanism between growth factors and some oncogenes.

[The expression characteristics and their biological significance of epidermal growth factor and basic fibroblast growth factor in rat skins at different development stages].

OBJECTIVE: To explore the localization and expression characteristics of epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) in rat skins at different development stages (embryonic, newborn, adult). METHODS: Skins from embryonic, newborn and adult rats were taken, and detected by immunohistochemical technique. RESULTS: Positive immunohistochemical signal of EGF could be found in skins from embryonic, newborn and adult rats, mainly in the cytoplasm of the epidermal cells, fibroblasts, hair follicle epithelial cells, and endothelial cells. With the increase in age, the expression amount of EGF was increased. The positive signal of bFGF could be found in skins of newborn and adult rats, while the signal of bFGF in skin of embryonic rats was negative. CONCLUSION: The results indicate that endogenous EGF plays important role in epidermal development in embryonic stage and wound healing in adult after injury. The negative expression of bFGF in skin of embryonic rat indicate that the absence of bFGF may be one of the reasons for the non-scar healing in embryonic stage.

[Characteristics of bFGF and TGF-beta expression in dermal chronic ulcers and hypertrophic scars and their effects on tissue repair].

OBJECTIVE: To localize the distribution of basic fibroblast growth factor (bFGF) and transforming growth factor-beta(TGF-beta) in tissues from dermal chronic ulcer and hypertrophic scar and to explore their effects on tissue repair. METHODS: Twenty-one cases were detected to localize the distribution of bFGF and TGF-beta, among them, there were 8 cases with dermal chronic ulcers, 8 cases with hypertrophic scars, and 5 cases of normal skin. RESULTS: Positive signal of bFGF and TGF-beta could be found in normal skin, mainly in the keratinocytes. In dermal chronic ulcers, positive signal of bFGF and TGF-beta could be found in granulation tissues. bFGF was localized mainly in fibroblasts cells and endothelial cells and TGF-beta mainly in inflammatory cells. In hypertrophic scar, the localization and signal density of bFGF was similar with those in granulation tissues, but the staining of TGF-beta was negative. CONCLUSION: The different distribution of bFGF and TGF-beta in dermal chronic ulcer and hypertrophic scar may be the reason of different results of tissue repair. The pathogenesis of wound healing delay in a condition of high concentration of growth factors may come from the binding disorder of growth factors and their receptors. bFGF may be involved in all process of formation of hypertrophic scar, but TGF-beta may only play roles in the early stage.

[Transforming growth factor beta 1 and interleukin 6 mRNA expression in wound tissues of patients with diabetic ulcers].

OBJECTIVE: To study the relationship between the changes of mRNA expression in wound tissues of diabetic ulcers and tissue repair. METHODS: The mRNA expression of TGF-beta 1 and IL-6 in eight bioptic samples of diabetic ulcers were detected by RT-PCR and pathologic methods, and the surrounding normal skins from the same patients were measured as control group. RESULTS: The mRNA expression levels of TGF-beta 1 were markedly decreased in the diabetic ulcers compared with control group, while the mRNA expression levels of IL-6 were increased at the same reaction conditions. CONCLUSION: The different changes of mRNA expression level of TGF-beta 1 and IL-6 in wound tissue result in low production and decreased activity of TGF-beta 1 and IL-6, which lower the reparative ability of wound tissue.

[Comparative study of epidermal growth factor and basic fibroblast growth factor on wound healing].

OBJECTIVE: The biological effects of recombinant human epidermal growth factor (rhEGF) and recombinant human fibroblast growth factor (rhFGF) were evaluated on the model of incised wounds in mini pigs. METHODS: Total of 160 incised wounds in 16 mini pigs were divided into two groups (rhEGF group and rhFGF group), each containing 80 wounds. In rhEGF group, 60 incised wounds were treated with different dosages of rhEGF (50, 10 and 0.5 micrograms/wound), and another 20 wounds were treated with solvent as control group. In rhFGF group, all wounds were treated in the same way as described in rhEGF group, the dosages of rhFGF were 150, 90 and 30 U/cm2 respectively. The measurements of cavity volume and area in wound, histological examination were used to evaluate the results of wound healing. RESULTS: The results showed that wound healing was accelerated in all wounds treated with rhEGF and rhFGF. In rhEGF group, the velocity of re-epithelialization was faster than that of rhFGF group, however, new granulation tissue in rhFGF was more than that of rhEGF group. CONCLUSION: The results indicate that rhEGF and rhFGF can stimulate wound healing, however, the mechanisms and the biological effects involved in these processes are quite different. It suggests that it is better to use rhFGF in those wounds which need more granulation tissue formation and use rhEGF in the wounds which mainly need re-epithelialization.

[Electrophoretic analysis of the protein patterns of the nuclear transplant rabbit embryos].

The qualitative patterns of protein synthesis in nuclear transplant rabbit embryos were examined by SDS-polyacrylamide gel electrophoresis followed by silver staining. The results indicated that the qualitative pattern of several protein synthesis in NT embryos was very different from the protein pattern of donor morulae or recipient oocytes, and also not as the same as the protein pattern obtained from fertilized ova at pronuclear formation stage. After fertilization or nuclear transfer, several maternal proteins were no longer synthesized or decreased in the embryo, and some new bands were observed and several protein synthesis were increased obviously. The most intriguing aspect of this study was the observation that all major changes in the protein pattern took place after fertilization or nuclear transfer and were rather similar. It is suggested that the gene activities of the donor nucleus from rabbit morulae are reprogrammed by the oocyte cytoplasm in current nuclear transfer technology, but the reprogramming is incomplete. This paper stresses on the paternal effect during fertilization on gene expression in nuclear transplant rabbit embryos.