Steroid withdrawal five days after renal transplantation allows for the prevention of wound-healing complications associated with sirolimus therapy.

BACKGROUND: Sirolimus (SRL) can increase the risk of wound complications. In this study, we investigated the impact of steroids when added to SRL, in this side effect. METHODS: One hundred and forty-eight patients entered prospective studies comparing early (fifth day) with late (sixth month) steroid withdrawal. All patients were on SRL, added either to Tacrolimus (n = 56) or to cyclosporine (n = 97). At 15th day after transplantation, 68 patients were on steroids (On-St group) and 80 were not (Off-St group). Wound complications considered were as follows: dehiscence, lymphocele, wound leakage, hematoma and seromas. Risk factors under analysis were as follows: body mass index, diabetes, rejection, creatininemia, length of dialysis before transplantation, recipient age, being on steroids at 15th day, SRL levels. RESULTS: The overall incidence of wound complications was significantly lower in Off-St group than in On-St group: 18.8% vs. 45.6%, respectively (p < 0.0004). In detail, lymphocele: 5.0% vs. 32.3% (p < 0.0001); dehiscence 0% vs. 10.3% (p < 0.009), leakage 6.2% vs. 8.8% (p = NS), seromas 1.4% vs. 7.5% (NS). At multivariate analysis, the addition of steroids to SRL increases 4.2-fold the risk for wound complications. CONCLUSIONS: Early steroid withdrawal is effective in preventing both the incidence and the severity of wound-healing complications because of SRL regime, even when started with a loading dose.

Receptor subtypes involved in the presynaptic and postsynaptic actions of dopamine on striatal interneurons.

By stimulating distinct receptor subtypes, dopamine (DA) exerts presynaptic and postsynaptic actions on both large aspiny (LA) cholinergic and fast-spiking (FS) parvalbumin-positive interneurons of the striatum. Lack of receptor- and isoform-specific pharmacological agents, however, has hampered the progress toward a detailed identification of the specific DA receptors involved in these actions. To overcome this issue, in the present study we used four different mutant mice in which the expression of specific DA receptors was ablated. In D1 receptor null mice, D1R-/-, DA dose-dependently depolarized both LA and FS interneurons. Interestingly, SCH 233390 (10 microm), a D1-like (D1 and D5) receptor antagonist, but not l-sulpiride (3-10 microm), a D2-like (D2, D3, D4) receptor blocker, prevented this effect, implying D5 receptors in this action. Accordingly, immunohistochemical analyses in both wild-type and D1R-/- mice confirmed the expression of D5 receptors in both cholinergic and parvalbumin-positive interneurons of the striatum. In mice lacking D2 receptors, D2R-/-, the DA-dependent inhibition of GABA transmission was lost in both interneuron populations. Both isoforms of D2 receptor, D2L and D2S, were very likely involved in this inhibitory action, as revealed by the electrophysiological analysis of the effect of the DA D2-like receptor agonist quinpirole in two distinct mutants lacking D2L receptors and expressing variable contents of D2S receptors. The identification of the receptor subtypes involved in the actions of DA on different populations of striatal cells is essential to understand the circuitry of the basal ganglia and to develop pharmacological strategies able to interfere selectively with specific neuronal functions.

Nerve growth factor induces the re-expression of functional androgen receptors and p75(NGFR) in the androgen-insensitive prostate cancer cell line DU145.

BACKGROUND: One of the paracrine/autocrine factors regulating prostate growth and differentiation is nerve growth factor (NGF). The role of NGF and its receptors in the prostate, however, remains controversial. We have shown that NGF treatment of human prostate cancer cell lines reduced their tumorigenicity, both in vitro and in vivo. OBJECTIVE: To investigate the involvement of NGF as a differentiation factor in prostate cancer cells. DESIGN: We exposed the androgen-independent/androgen receptor (AR)-negative prostate cancer cell line DU145 to NGF to study whether this neurotrophin could revert DU145 cells to a less malignant phenotype. METHODS: DU145 cells were treated with NGF, then ARs and NGF receptor p75(NGFR) expression and telomerase activity were studied. Finally, we investigated whether re-expression of ARs could restore the androgen sensitivity in this cell line. RESULTS AND CONCLUSIONS: NGF treatment induced a reversion of DU145 cells to a less malignant phenotype, characterized by the re-expression of ARs and p75(NGFR) NGF receptors. Re-expression of ARs restored the androgen sensitivity, as suggested by the fact that exposure to dihydrotestosterone stimulated the growth of NGF-treated DU145 cells. This effect was blocked by androgen antagonist drugs, such as hydroxyflutamide and cyproterone acetate, which also induced apoptotic death of NGF-treated cells. The hypothesis that a differentiation pathway is activated by exogenous NGF in DU145 cells is also supported by findings indicating that NGF-treated DU145 cells expressed a low telomerase activity, as a result of a decrease in human telomerase reverse transcriptase transcription.