The unexpected anabolic phenotype and extended longevity of skin fibroblasts after chronic glucocorticoid excess.

Intense stress can challenge tissue homeostasis and accelerate the ageing process. However, several lines of evidence indicate that repeated mild stresses can have beneficial and even life-prolonging effects. Hypersecretion of glucocorticoids (GC) represents the major hormonal response to stress. Besides its life-sustaining role, GC excess, usually due to several side-effects that promote a "catabolic" phenotype, can be detrimental for several tissues. Cushing's syndrome patients are characterized by chronic endogenous GC excess and consequently at the time of diagnosis they have an atrophic elderly-like skin. Interestingly, when Cushing's syndrome fibroblasts were removed from the high-GC milieu in vivo and cultured in vitro under standard conditions they express an "anabolic" phenotype, i.e. they restore their ability for collagen synthesis, they secrete reduced levels of metalloproteases (MMP-1 and MMP-2) and have an increased proliferative capacity and contractility. Furthermore, these cells exhibit a significant extension of their proliferative lifespan, while they respond better to exogenous stress by producing significantly higher levels of heat-shock protein-70 (HSP70). These results imply that long-term hypercortisolism in vivo can have beneficial consequences on fibroblast physiology in vitro.

The impact of chronic in vivo glucocorticoid excess on the functional characteristics of human skin fibroblasts obtained from patients with endogenous Cushing's syndrome.

OBJECTIVE: Chronic exposure to elevated glucocorticoid (GC) concentrations induces detrimental effects in several tissues. In the skin, GCs provoke intense alterations on various parameters of the physiology of fibroblasts, cumulatively leading to skin atrophy and impaired wound healing. As there are concerns that GCs may generate permanent adverse functional changes, we have investigated whether chronic in vivo exposure to GC excess results in persisting defects in skin fibroblasts. DESIGN AND METHODS: We have studied in vitro primary skin fibroblast cultures obtained from patients suffering from endogenous Cushing's syndrome (CF), as well as from sex- and age-matched normal donors (NF). The following functional parameters were investigated: cell proliferation, secretion of collagen, matrix metalloproteinases (MMPs) and their inhibitors (tissue inhibitors of metalloproteinases; TIMPs) and contractile capacity. RESULTS: CFs, grown under standard culture conditions in the absence of a hypercortisolemic milieu, exhibited an increased proliferative capacity and a higher final cell culture density compared with NFs. Collagen synthesis, in the absence or presence of transforming growth factor-beta, was equal to that of NFs. However, CFs secreted comparatively lower levels of MMP-1, MMP-2 and TIMP-1, and nearly equal levels of TIMP-2. CFs also exhibited an increased ability to contract gels of polymerized collagen. CONCLUSIONS: Collectively, these functional characteristics of CFs are in contrast to the known catabolic effects of GCs, and suggest that prior exposure to GC excess is not associated with a persisting adverse outcome in the functional phenotype of the fibroblasts.

mRNA assessment for procollagen production in women with genuine stress urinary incontinence.

The aim of the study was to examine changes in the levels of mRNA for procollagen type I and III in women with or without genuine stress incontinence (GSI). The study was performed in the 2nd Department of Obstetrics and Gynecology of University of Athens. Sixty-eight women participated in the study and they were divided in two groups. We did not find statistically significant difference between the two groups of patients in relation to the amount of mRNA of procollagen type I and III (p>0.05), but the quantity of collagen type I and III was significantly reduced in patients with stress incontinence (p<0.05). The possible cause for the reduction in the amount of collagen in women with GSI could be attributed to either a disturbance in the translation of mRNA to protein (collagen) or increased catabolism of collagen by its collagenase.

Differential proliferative response of fetal and adult human skin fibroblasts to transforming growth factor-beta.

Since pronounced differences exist between the fetal and adult repair processes, we studied the proliferative response of skin fibroblasts from these two stages to transforming growth factor-beta (TGF-beta), a cytokine with a broad range of activities in tissue repair. Here, we present evidence that TGF-beta inhibits fetal human skin fibroblasts, while it is stimulatory for adult ones. This proliferative effect of TGF-beta was found to be concentration- dependent, but isoform-independent. Furthermore, even a transient exposure of the cells to this growth factor was sufficient to exert its stimulatory or inhibitory action. Accordingly, we have studied the immediate responses provoked by TGF-beta in major signaling pathways, and we have found that it induces a rapid activation of the SMAD pathway, i.e., phosphorylation and nuclear translocation of SMAD2, followed by dephosphorylation, most probably due to degradation by the proteasome. However, similar intensity and kinetics of this activation have been observed in both fetal and adult fibroblasts. On the other hand, curcumin, a natural product with wound healing properties that inhibits several intracellular signaling pathways, was found to completely abrogate the inhibitory effect of TGF-beta1 on human fetal skin fibroblasts, without affecting the stimulatory action on fibroblasts from adult donors. In conclusion, there is a major radical in the proliferative response of fetal and adult human skin fibroblasts to TGF-beta, possibly reflecting the different repair strategies followed in these two stages of development.

Chronic in vivo exposure to glucocorticoids prolongs cellular lifespan: the case of Cushing's syndrome-patients' fibroblasts.

Glucocorticoid (GC) hypersecretion constitutes the major hormonal response to stress. In an effort to investigate the impact of a long-lasting exposure to high GC levels in vivo on cellular longevity, we have studied the lifespan of skin fibroblasts from patients suffering from Cushing's syndrome, who are characterised by chronic endogenous GC excess. Interestingly, we have observed that these cells exhibit a significant increase in their proliferative lifespan when cultured in vitro, under standard conditions, compared to fibroblasts from normal donors. In parallel, these cells secrete lower levels of transforming growth factor-beta, known to be implicated in stress-induced premature senescence. Furthermore, they also exhibit an intense stress reaction (near 2-fold, compared to normal cells) in terms of heat-shock protein-70 induction. These results support the hypothesis that stress response may have beneficial consequences in cellular longevity, as well as in tissue homeostasis.