Biomedical subjects

Monica G Ferrini

Publications and source records attributed to Monica G Ferrini.

10 recordsLinked to original sources

PubMed2006

Increased vaginal oxidative stress, apoptosis, and inducible nitric oxide synthase in a diabetic rat model: implications for vaginal fibrosis.

OBJECTIVE: To determine whether vaginal fibrosis occurs in diabetic animals and is associated with oxidative stress and cell death and with the expression of inducible nitric oxide synthase (iNOS), as a putative antifibrotic mechanism. DESIGN: Research experimental project. SETTING: University research laboratory. ANIMAL(S): Female Wistar rats. INTERVENTION(S): Female rats were injected with streptozotocin or saline and killed at 3 months. The vaginas were excised and processed for paraffin-embedded sections (n = 6 per group) or were frozen for biochemical and molecular biology procedures. MAIN OUTCOME MEASURE(S): Immunohistochemistry and quantitative image analysis were applied to tissue sections to measure alpha-smooth muscle actin, transforming growth factor beta1, plasminogen activator inhibitor, NOS isoforms, Cu/Zn superoxide dismutase, apoptotic index, and nitrotyrosine. Xanthine dehydrogenase, reactive oxygen species (ROS), and hydroxyproline were measured in fresh vaginal tissue (n = 5 per group). Reactive oxygen species also were determined in blood. RESULT(S): Diabetes was associated with vaginal fibrosis, as evidenced by increased collagen, transforming growth factor beta1, plasminogen activator inhibitor, and apoptosis, and by decreased alpha-smooth muscle actin. The increment of ROS and the reduction of superoxide dismutase indicated oxidative stress in diabetic tissue, accompanied by iNOS induction and increased nitric oxide-ROS reaction. CONCLUSION(S): Diabetes in the rat causes oxidative stress and fibrosis in the vagina, which may be compensated partially by iNOS induction to reduce ROS.

Actins↗

PubMed2006

Myostatin short interfering hairpin RNA gene transfer increases skeletal muscle mass.

BACKGROUND: Myostatin negatively regulates skeletal muscle growth. Myostatin knockout mice exhibit muscle hypertrophy and decreased interstitial fibrosis. We investigated whether a plasmid expressing a short hairpin interfering RNA (shRNA) against myostatin and transduced using electroporation would increase local skeletal muscle mass. METHODS: Short interfering RNAs (siRNAs) targeting myostatin were co-transfected with a myostatin-expressing plasmid into HEK293 cells and identified for myostatin silencing by Western blot. Corresponding shRNAs were cloned into plasmid shRNA expression vectors. Myostatin or a randomer negative control shRNA plasmid was injected and electroporated into the tibialis anterior or its contralateral muscle, respectively, of nine rats that were sacrificed after 2 weeks. Six other rats received a beta-galactosidase reporter plasmid and were sacrificed at 1, 2, and 4 weeks. Uptake of plasmid was examined by beta-galactosidase expression, whereas myostatin expression was determined by real-time polymerase chain reaction (PCR) and Western blotting. Muscle fiber size was determined by histochemistry. Satellite cell proliferation was determined by PAX7 immunohistochemistry. Myosin heavy chain type II (MHCII) expression was determined by Western blot. RESULTS: beta-Galactosidase reporter plasmid was expressed at 1 and 2 weeks but diminished by 4 weeks in tibialis anterior skeletal muscle. Myostatin shRNA reduced myostatin mRNA and protein expression by 27 and 48%, respectively. Tibialis anterior weight, fiber size, and MHCII increased by 10, 34, and 38%, respectively. Satellite cell number was increased by over 2-fold. CONCLUSIONS: This is the first demonstration that myostatin shRNA gene transfer is a potential strategy to increase muscle mass.

Animals↗

PubMed2006

Vardenafil prevents fibrosis and loss of corporal smooth muscle that occurs after bilateral cavernosal nerve resection in the rat.

OBJECTIVES: Impotence, specifically corporal veno-occlusive dysfunction (CVOD), occurs after radical prostatectomy. It results from the effects of cavernosal nerve damage, which causes smooth muscle (SM) loss and an increase in collagen within the corpora. Recent reports have suggested that long-term treatment with phosphodiesterase-5 inhibitors after radical prostatectomy may prevent such changes. We aimed to determine whether bilateral cavernosal nerve resection (BCNX) in the rat leads to CVOD and whether long-term phosphodiesterase-5 inhibition ameliorates these histologic and functional impairments. METHODS: Rats (n = 7 to 11/group) underwent either the sham operation, BCNX, or BCNX plus 30 mg/L vardenafil in the drinking water. Before the rats were killed 45 days later, CVOD was assessed by dynamic infusion cavernosometry. The corpora underwent histochemistry/immunohistochemistry with quantitative image analysis for SM/collagen ratio, collagen III/I ratio, alpha-SM actin, inducible nitric oxide synthase (iNOS), proliferating cell nuclear antigen, and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling as a marker of apoptosis. RESULTS: Compared with the sham group, the BCNX rats demonstrated CVOD as measured by the drop rate, a 60% reduction in the SM/collagen ratio, a twofold increase in iNOS expression, and a threefold increase in intracorporeal apoptosis. Compared with the BCNX group, vardenafil increased both iNOS and proliferating cell nuclear antigen expression (SM cell replication), with normalization of the dynamic infusion cavernosometry drop rate and SM/collagen ratio. CONCLUSIONS: Long-term treatment with vardenafil may prevent CVOD after radical prostatectomy by preserving SM content and inhibiting corporal fibrosis possibly by its effect on iNOS.

Animals↗

PubMed2006

Effects of long-term vardenafil treatment on the development of fibrotic plaques in a rat model of Peyronie's disease.

OBJECTIVES: To determine whether the phosphodiesterase-5 (PDE5) inhibitor, vardenafil, given orally and in different regimens, has a similar effect to that of the PDE5 inhibitor sildenafil, which prevented the development of a Peyronie's disease (PD)-like plaque formation induced by injecting transforming growth factor beta1 (TGF-beta1) into the tunica albuginea of the rat. MATERIALS AND METHODS: Vardenafil was given to male rats (eight per group) either in the drinking water or as an oral instillation once daily, at approximately 1 and approximately 3 mg/kg/day for 45 days after one injection with TGF-beta1 into the tunica albuginea, as an 'early preventive' treatment for TGF-beta1-induced formation of a PD-like plaque. Other groups received the two doses of vardenafil only in the drinking water, starting with a well-formed plaque, for 42 days ('late, therapeutic' administration). Sections of penile tissue were stained histochemically or immunohistochemically, followed by quantitative image analysis for collagen/smooth muscle and collagen III/I ratios, myofibroblast content (alpha-smooth muscle actin), TGF-beta1 expression, and apoptotic index. RESULTS: Preventative treatment with vardenafil at the higher dose (both continuous and once-daily treatments) reduced the collagen/smooth muscle and collagen III/I ratios, and the numbers of myofibroblasts and TGF-beta1-positive cells, and selectively increased the apoptotic index in the PD-like plaque. The lower dose was less effective, When vardenafil was given continuously in the drinking water for 41 days after the PD-like plaque was formed, there was only a partial reduction of the plaque. CONCLUSIONS: Long-term oral treatment with vardenafil slows and reverses the early stages of an experimental PD-like plaque in the rat, and might ameliorate a more advanced plaque.

Administration, Oral↗

PubMed2006

Pioglitazone prevents corporal veno-occlusive dysfunction in a rat model of type 2 diabetes mellitus.

OBJECTIVE: To determine whether corporal veno-occlusive dysfunction (CVOD), corporal smooth muscle (SM) loss, fibrosis and oxidative stress occur in a rat model of type 2 diabetes, and whether these are counteracted by pioglitazone, as pioglitazone is vasculoprotective, and corporal SM is an extension of arterial SM. MATERIALS AND METHODS: Male obese Zucker fa/fa rats were fed chow containing 0%, 0.001% or 0.02% pioglitazone for 2 or 5 months, using untreated lean Zucker and Fischer 344 rats as controls. Functional changes were determined by dynamic-infusion cavernosometry. Histological changes were assessed by histochemistry and immunohistochemistry followed by quantitative image analysis and/or quantitative Western blot. RESULTS: CVOD was detected at 4.5 months of diabetes, accompanied by a lower corporal SM/collagen ratio, and increases in collagen, collagen III/I ratio, apoptotic index, and systemic and tissue oxidative stress. In the short-term treatment, high-dose pioglitazone normalized glycaemia and ameliorated fibrosis and oxidative stress, but induced CVOD, whereas the effects with the low dose were not significant. However, low-dose pioglitazone for 5 months corrected all alterations. CONCLUSION: Type 2 diabetes in Zucker fa/fa rats was associated with penile corporal fibrosis, oxidative stress, and CVOD, which were ameliorated by long-term low-dose pioglitazone, suggesting that this drug might protect the SM, independently from its antidiabetic effect.

Animals↗

PubMed2006

Estrogens and neuroendocrine hypothalamic-pituitary-adrenal axis function.

The function of the HPA axis is subject to regulation by many factors, which achieve relevance under normal and pathological conditions. In the case of aging, this period of life is associated with disturbances of the HPA axis and signs of hippocampal vulnerability. We examined 20-month-old male rats, in which abnormalities of the HPA axis included altered response to stress, reduced effectiveness of the steroid negative feedback and low expression of hippocampal glucocorticoid receptors (GR). Estrogen treatment of aging rats normalized the response to stress, restored the dexamethasone inhibition of the stress response and increased GR density in defined hippocampal areas. Although estrogens could influence the hippocampus of aging animals directly, their effects could be also mediated by estrogen-sensitive forebrain cholinergic neurons projecting to the hippocampus. Additionally, estrogens normalized the deficient granule cell proliferation that aging mice present in the dentate gyrus, and attenuated several markers of hippocampal aging, such as astrocytosis, high lipofucsin content and neuronal loss in the hilus of the dentate gyrus. These effects may be important for the regulation of the HPA axis, in the context that hippocampal function as a whole was normalized by estrogen action. Therefore, estrogens are powerful neuroprotectants in cases of hippocampal dysfunction, and as part of this effect, they contribute to stabilize the function of the HPA axis.

Adrenal Glands↗

PubMed2004

Aging-related induction of inducible nitric oxide synthase is vasculo-protective to the arterial media.

OBJECTIVE: Aging associated erectile dysfunction (ED) is primarily caused by the reduction in smooth muscle cells (SMC) and an increase in collagen within the corpora cavernosa, assumed to result from an increase in reactive oxygen species (ROS). This is accompanied by the expression of inducible nitric oxide synthase (iNOS) to produce nitric oxide that scavenges ROS and inhibits collagen deposition. We investigated whether with aging similar processes occur within the arterial media SMC that share some common physiological functions with the cavernosal SMC. METHODS: Aged (22-24 months) male Brown Norway rats received water with or without an inhibitor of iNOS activity (L-N-(iminoethyl)-lysine acetate [L-NIL], 0.1 g/l), for 3 weeks. Young (3 months) untreated rats were used as control (n=5 per group). Tissue sections from the penis, abdominal aorta, femoral and brachial arteries were stained for collagen, SMC, iNOS, ROS plasminogen activator inhibitor (PAI) and apoptosis, and evaluated by quantitative image analysis. ROS were also determined in fresh tissue and whole blood by the GSH/GSSG ratio. RESULTS: It was observed that most aging-induced changes in the media of the arterial tree from the aorta to the resistance arteries in the penis are similar to what occurs in the corpora cavernosa, i.e. a decrease in the SMC/collagen ratio and an increase in ROS and iNOS, and specifically in the case of the resistance arteries, an increase in SMC apoptosis and PAI. iNOS inhibition by L-NIL further increased ROS and decreased the SMC/collagen ratio in the media. CONCLUSIONS: These observations suggest that ED and arteriosclerosis in the aging male may share a common etiology, and that the expression of iNOS by the SMC is an attempt to counteract this fibrosis.

Aging↗

PubMed2003

Penile neuronal nitric oxide synthase and its regulatory proteins are present in hypothalamic and spinal cord regions involved in the control of penile erection.

Control of penile erection requires the coordination of the hypothalamus and the L6-S1 region of the spinal cord. Erection requires the activation of neuronal nitric oxide synthase (nNOS), which is tightly regulated. Because variants of nNOS (penile nNOS: PnNOS) and the N-methyl-D-aspartate receptor (truncated NMDAR subunit 1: NMDAR1-T) as well as protein inhibitor of NOS (PIN) have all been located in the pelvic ganglia and penile nerves, this work aims to determine whether these proteins are also present in the hypothalamus. It was found that PnNOS, the brain-type nNOS, and PIN, were expressed in the hypothalamus. In contrast, NMDAR1-T was expressed only in the penis, whereas the brain-type NMDAR1 was present in the brain and sacral spinal cord and not in the penis. PnNOS was found in the media preoptic area, posterior magnocellular, and the parvocellular regions of the paraventricular nucleus, supraoptic nucleus, septohypothalamic nucleus, medial septum, cortex, and in some of the nNOS staining neurons throughout the brain. It was absent in the organum vasculosum of the lamina terminalis. PIN staining was present in neurons of the medial preoptic area, paraventricular nucleus, medial septum, and cortex, but not in the supraoptic nucleus, septohypothalamic nucleus, or organum vasculosum of the lamina terminalis. Colocalization between PnNOS and PIN was found in the medial preoptic area, medial septum, and cortex, and less in the paraventricular nucleus. PnNOS and oxytocin were colocalized in the paraventricular nucleus and supraoptic nucleus. In hypothalamic extracts, recombinant PIN-GST protein bound to PnNOS in the extracts and partially inhibited NOS activity. These results indicate that both nNOS variants, and their respective regulatory proteins are present and colocalize in the hypothalamic and spinal cord regions involved in penile erection.

Animals↗

PubMed2003

L-arginine and phosphodiesterase (PDE) inhibitors counteract fibrosis in the Peyronie's fibrotic plaque and related fibroblast cultures.

Inducible nitric oxide synthase (iNOS) is expressed in both the fibrotic plaque of Peyronie's disease (PD) in the human, and in the PD-like plaque elicited by injection of TGFbeta1 into the penile tunica albuginea (TA) of the rat. Long-term inhibition of iNOS activity, presumably by blocking nitric oxide (NO)- and cGMP-mediated effects triggered by iNOS expression, exacerbates tissue fibrosis through an increase in: (a) collagen synthesis, (b) levels of reactive oxygen species (ROS), and (c) the differentiation of fibroblasts into myofibroblasts. We have now investigated whether: (a) phosphodiesterase (PDE) isoforms, that regulate the interplay of cGMP and cAMP pathways, are expressed in both the human and rat TA; and (b) L-arginine, that stimulates NOS activity and hence NO synthesis, and PDE inhibitors, that increase the levels of cGMP and/or cAMP, can inhibit collagen synthesis and induce fibroblast/myofibroblast apoptosis, thus acting as antifibrotic agents. We have found by immunohistochemistry, RT/PCR, and Western blot that PDE5A-3 and PDE4A, B, and D variants are indeed expressed in human and rat normal TA and PD plaque tissue, as well as in their respective fibroblast cultures. As expected, in the PD fibroblast cultures, pentoxifylline (non-specific cAMP-PDE inhibitor) increased cAMP levels without affecting cGMP levels, whereas sildenafil (PDE5A inhibitor) raised cGMP levels. Both agents and L-arginine reduced the expression of collagen I (but not collagen III) and the myofibroblast marker, alpha-smooth muscle actin, as determined by immunocytochemistry and quantitative image analysis. These effects were mimicked by incubation with 8-Br-cGMP, which in addition increased apoptosis, as measured by TUNEL. When L-arginine (2.25 g/kg/day), pentoxifylline (10 mg/kg/day), or sildenafil (10 mg/kg/day) was given individually in the drinking water for 45 days to rats with a PD-like plaque induced by TGF beta1, each treatment resulted in a 80-95% reduction in both plaque size and in the collagen/fibroblast ratio, as determined by Masson trichrome staining. Both sildenafil and pentoxiphylline stimulated fibroblast apoptosis within the TA. Our results support the hypothesis that the increase in NO and/or cGMP/cAMP levels by long-term administration of nitrergic agents or inhibitors of PDE, may be effective in reversing the fibrosis of PD, and more speculatively, other fibrotic conditions.

Animals↗

PubMed2002

Effect of nitric oxide on the differentiation of fibroblasts into myofibroblasts in the Peyronie's fibrotic plaque and in its rat model.

The myofibroblast shares phenotypic features of both fibroblasts and smooth muscle cells. It plays a critical role in collagen deposition and wound healing and disappears by apoptosis when the wound is closed. Its abnormal persistence leads to hypertrophic scar formation and other fibrotic conditions. Myofibroblasts are present in the fibrotic plaque of the tunica albuginea (TA) of the penis in men with Peyronie's disease (PD), a localized fibrosis that is accompanied by a spontaneous induction of the inducible nitric oxide synthase (iNOS), also observed in the TGFbeta1-elicited, PD-like lesion in the rat model. iNOS expression counteracts fibrosis, by producing nitric oxide (NO) that reduces collagen deposition in part by neutralization of profibrotic reactive oxygen species. In this study we investigated whether fibroblast differentiation into myofibroblasts is enhanced in the human and rat PD-like plaque and in cultures of human tissue fibroblasts. We also examined whether NO reduces this cell differentiation and collagen synthesis. The myofibroblast content in the fibroblast population was measured by quantitative immunohistochemistry as the ratio between alpha-smooth muscle actin (ASMA; myofibroblast marker) and vimentin (general fibroblast marker) levels. We found that myofibroblast content was considerably increased in the human and TGFbeta1-induced rat plaques as compared to control TA. Inhibition of iNOS activity by chronic administration of L-iminoethyl-L-lysine to rats with TGFbeta1-induced TA lesion increased myofibroblast abundance and collagen I synthesis measured in plaque and TA homogenates from animals injected with a collagen I promoter construct driving the expression of beta-galactosidase. Fibroblast differentiation into myofibroblasts occurred with passage in the cell cultures from the human PD plaque, but was minimal in cultures from the TA. Induction of iNOS in PD and TA cultures with a cytokine cocktail and a NO donor, S-nitroso-N-acetyl penicillamine (SNAP), was detected by immunohistochemistry. Both treatments reduced the total number of cells and the number of ASMA positive cells, whereas only SNAP decreased collagen I immunostaining. These results support the hypotheses that myofibroblasts play a role in the development of the PD plaque and that the antifibrotic effects of NO may be mediated at least in part by the reduction of myofibroblast abundance and lead to a reduction in collagen I synthesis.

Actins↗