Farnesoid X receptor activation improves erectile dysfunction in models of metabolic syndrome and diabetes

The metabolic syndrome (MetS) is an insulin-resistant state characterized by a cluster of cardiovascular risk factors, including abdominal obesity, hyperglycemia, elevated blood pressure and combined dyslipidemia. In this review, we discuss the potential of farnesoid X receptor (FXR) agonists in the treatment of erectile dysfunction (ED), a multifactorial disorder often comorbid with MetS. FXR not only regulates lipid and glucose homeostasis but also influences endothelial function and atherosclerosis, suggesting a regulatory role for this hormone nuclear receptor in the cardiovascular complications associated with the MetS, including ED. MetS induces ED via several mechanisms, and in particular through endothelial dysfunction in penile vessels. In a high-fat diet rabbit model of MetS, a 3-month treatment with the potent and selective FXR agonist INT-747 restores endothelium-dependent relaxation in isolated cavernous tissue, normalizing responsiveness to acetylcholine and to electrical field stimulation. Accordingly, eNOS expression in the penis is greatly up-regulated by INT-747 treatment. Experiments in a rat model of chemically-induced type 1 diabetes further demonstrate that INT-747 treatment preserves erectile function induced by electrical stimulation of the cavernous nerve. These results add a new facet to the pleiotropic activities mediated by FXR, and reveal novel beneficial effects of FXR activation with potential clinical relevance. This article is part of a Special Issue entitled: Translating nuclear receptors from health to disease.     

Effects of heavy metal cations on the mitochondrial ornithine/citrulline transporter reconstituted in liposomes

The effect of heavy metal cations on the mitochondrial ornithine/citrulline transporter was tested in proteoliposomes reconstituted with the protein purified from rat liver. The transport activity was measured as [³H]ornithine uptake in proteoliposomes containing internal ornithine (ornithine/ornithine antiport mode) or as [³H]ornithine efflux in the absence of external substrate (ornithine/H⁺ transport mode). 0.1 mM Cu²⁺, Pb²⁺, Hg²⁺, Cd²⁺ and Zn²⁺ strongly inhibited (more than 85%) the antiport; whereas Mn²⁺, Co²⁺ and Ni²⁺ inhibited less efficiently (25, 47 and 69%, respectively). The IC₅₀ values of the transporter for the different metal ions ranged from 0.71 to 350 μM. Co²⁺ and Ni²⁺ also inhibited the [³H]ornithine efflux whereas Cu²⁺, Pb²⁺, Hg²⁺, Cd²⁺ and Zn²⁺ stimulated the [³H]ornithine efflux. The stimulation of the [³H]ornithine efflux by Cu²⁺ and Cd²⁺ (as well as by Pb²⁺, Hg²⁺ and Zn²⁺) was not prevented by NEM and was reversed by DTE. These features indicated that the inhibition of the antiport was due to the interaction of the Cu²⁺, Pb²⁺, Hg²⁺, Cd²⁺ and Zn²⁺ with a population of SH groups, of the transporter, responsible for the inhibition of the physiological function; whereas the stimulation of [³H]ornithine efflux was due to the induction of a pore-like function of the transporter caused by interaction of cations with a different population of SH groups. Differently, the inhibition of the ornithine transporter by Ni²⁺, Co²⁺ or Mn²⁺ was caused by interaction with the substrate binding site, as indicated by the competitive or mixed inhibition.     

Inflammation may modulate IL-6 and C-reactive protein gene expression in the adipose tissue: the role of IL-6 cell membrane receptor

Only few studies have been addressed to the presence and regulation of C-reactive protein (CRP) gene expression in different districts of adipose tissue, and no study has investigated the role of adipose tissue in presence of inflammation. Therefore, the aim of this study was to investigate the inflammatory involvement of either adipose tissue or adipose cells (adipocytes and stromal cells, respectively) in patients with chronic inflammatory disease, focusing on regional adipose tissue CRP gene expression. Eighteen patients with inflammatory disease and 14 healthy controls were enrolled. All subjects underwent specific surgical procedures. Inflamed and noninflamed patients provided samples of subcutaneous and/or omental adipose tissue. All samples were analyzed by RT-PCR and real-time PCR for specific gene expression. In addition, both adipocytes and stromal cells were studied by real-time PCR and immunoprecipitation to evaluate either gene or protein expression of CRP. Our results (real-time PCR) demonstrated a higher gene expression of CRP, IL-6, and both IL-6 membrane receptors in subcutaneous samples of inflamed patients than in healthy controls. Furthermore, in omental fragments of inflamed patients, an enhanced mRNA abundance of the same genes, compared with subcutaneous, was observed. The results obtained at cellular level did not provide evidence of any difference between adipocytes and stromal cell CRP gene expression, whereas immunoprecipitation demonstrated the presence of CRP in inflamed subjects. These results provide first-time evidence of the involvement of adipose tissue in the course of chronic inflammatory diseases, with a different degree of participation of the different adipose tissue districts.     

3,5-bis(3'-indolyl)pyrazoles, analogues of marine alkaloid nortopsentin: synthesis and antitumor properties

A series of 10 bis-indolylpyrazoles of type 9, 10 were obtained by cyclization of diketones 8 using hydrazine monohydrate or methylhydrazine in refluxing acetic acid/THF. Derivatives 9a,c,d were selected, by the National Cancer Institute (NCI, Bethesda, USA), to be evaluated against the full panel of about 60 human tumor cell lines derived from nine human cancer cell types and showed antiproliferative activity in the micromolar range. In particular, 9d, the most active compound was effective against all the tested cell lines with a GI(50) mean value of 3.23 microM; TGI and LC(50) values were 14.5 and 58.9 microM having positive response on 91% and 41% of the tested cell lines, respectively.     

Inhibition of prostate growth and inflammation by the vitamin D receptor agonist BXL-628 (elocalcitol)

The prostate is a target organ of vitamin D receptor (VDR) agonists and represents an extra-renal site of 1,25-dihydroxyvitamin D₃ synthesis, but its capacity to respond to VDR agonists has, so far, been almost exclusively probed for the treatment of prostate cancer. We have analyzed the capacity of VDR agonists to treat benign prostatic hyperplasia (BPH), a complex syndrome characterized by a static component related to prostate overgrowth, a dynamic one responsible for urinary irritative symptoms, and an inflammatory component. Preclinical data demonstrate that VDR agonists, and notably BXL-628 (elocalcitol), reduce the static component of BPH by inhibiting the activity of intra-prostatic growth factors downstream of the androgen receptor, and the dynamic component by targeting bladder cells. In addition, BXL-628 inhibits production of proinflammatory cytokines and chemokines by human BPH cells. These data have led to a proof-of-concept clinical study that has successfully shown arrest of prostate growth in BPH patients treated with BXL-628, with excellent safety. We have documented the anti-inflammatory effects of BXL-628 also in animal models of autoimmune prostatitis, observing a significant reduction of intra-prostatic cell infiltrate following administration of this VDR agonist, at normocalcemic doses, in mice with already established disease. These data extend the potential use of VDR agonists to novel indications that represent important unmet medical needs, and provide a sound rationale for further clinical testing.     

Bone-marrow derived hematopoietic stem/progenitor cells express multiple isoforms of NADPH oxidase and produce constitutively reactive oxygen species

Consolidated evidence highlights the importance of redox signalling in poising the balance between self-renewal and differentiation in adult stem cells. The present study shows that human hematopoietic stem/progenitor cells (HSCs) constitutively generate low levels of hydrogen peroxide whose production is inhibited by DPI, apocynin, catalase, and LY294002 and scarcely stimulated by PMA. Moreover, it is shown that HSCs express at the mRNA and protein levels the catalytic subunits of NOX1, NOX2, and NOX4 isoforms of the NADPH oxidase family along with the complete battery of the regulatory subunits p22, p40, p47, p67, rac1, rac2, NOXO1, and NOXA1 as well as the splicing variant NOX2s and that the three NOX isoforms are largely co-expressed in the same HSC. These findings are interpreted in terms of a positive feed-back mechanism of NOXs activation enabling a fine tuning of the ROS level to be possibly used in redox-mediated signalling for growth and differentiation of HSCs.     

Genotyping of the lactase-phlorizin hydrolase c/t-13910 polymorphism by means of a new rapid denaturing high-performance liquid chromatography-based assay in healthy subjects and colorectal cancer patients

Adult-type hypolactasia results from the progressive decline of lactase-phlorizin hydrolase activity in enterocytes after weaning. Lactase nonpersistence may determine a primary lactose intolerance with reduced diary product consumption, which is possibly related to an increased risk of colon cancer. Recently, a genetic variant C/T(-13910) upstream of the lactase-phlorizin hydrolase (LCT) gene has been strongly correlated with the lactase persistence/nonpersistence trait in both family and case-control studies. The authors validate a denaturing high-performance liquid chromatography (dHPLC)-based assay versus conventional genotype sequencing in detecting the C/T(-13910) polymorphism of LCT and evaluate its prevalence in 2 different Italian geographical areas and in colorectal cancer patients. DNA samples of 157 healthy subjects and 124 colon cancer patients from Apulia and of 97 healthy subjects from Sardinia were evaluated for the C/T(-13910) polymorphism by dHPLC, sequencing, and restriction fragment length polymorphism (RFLP). Under optimized conditions, dHPLC was as sensitive as DNA sequencing and detected a new genetic variant (T/C(-13913)) in 2 individuals that was not identified by RFLP assay. Frequency of lactase nonpersistence genotype (C/C(-13910)) was similar in healthy subjects from 2 different Italian geographical areas and not increased in patients with colorectal cancer. The results indicate that the dHPLC method may be used as a rapid, noninvasive, and labor-saving screening tool for genotyping C/T(-13910) polymorphism, with high success, low cost, and reproducibility.     

Candidemia in Internal Medicine: Facing the New Challenge

Mycopathologia - Candidemia is an alarming problem in critically ill patients including those admitted in Internal Medicine Wards (IMWs). Here, we analyzed all cases of candidemia in adult patients...