Genetic Polymorphisms in Nitric Oxide Synthase 3 Gene and Implications for Kidney Disease: A Meta-Analysis

Background/Aims: The NOS3 gene is a biological and positional candidate for diabetic nephropathy. However, the relationship between NOS3 polymorphisms and renal disease is inconclusive. This study aimed to clarify the association of NOS3 variants with nephropathy in individuals with type 1 diabetes. Methods: We conducted a case-control study examining all common SNPs in the NOS3 gene by a tag SNP approach. Individuals with type 1 diabetes and persistent proteinuria (cases, n = 718) were compared with individuals with type 1 diabetes but no evidence of renal disease (controls, n = 749). Our replication collection comprised 1,105 individuals with type 1 diabetes recruited to a nephropathy case group and 862 control individuals with normal urinary albumin excretion rates. Meta-analysis was conducted for SNPs where more than three genotype datasets were available. Results: A novel association was identified in the discovery collection (rs1800783, p(genotype) = 0.006, p(allele) = 0.002, OR = 1.26, 95% CI: 1.08-1.47) and supported by independent replication using a tag SNP (rs4496877, pairwise r(2) = 0.96 with rs1800783) in the replication collection (p(genotype) = 0.002, p(allele) = 0.0006, OR = 1.27, 95% CI: 1.10-1.45). Conclusion: The A allele of rs1800783 is a significant risk factor for nephropathy in individuals with type 1 diabetes, and further comprehensive studies are warranted to confirm the definitive functional variant in the NOS3 gene. Copyright (C) 2010 S. Karger AG, Basel

Short-term phytoestrogen supplementation alters insulin-like growth factor profile but not lipid or antioxidant status

Phytoestrogens are plant compounds that have been proposed to have a variety of health benefits. The aim of this study was to assess the effects of these compounds on a number of physiological endpoints. Subjects were given a single intake of a phytoestrogen-rich (80 mg total phytoestrogens) supplement containing soy, rye and linseed (Phase 1), followed by a week-long intervention using the same supplement (Phase 2) (80 mg total phytoestrogens daily). A number of biochemical endpoints were assessed including urinary phytoestrogen metabolites, lipids, antioxidant status, DNA damage and insulin-like growth factor-1 (IGF-1) and IGF binding protein-1 (IGFBP-1) and -3 (IGFBP-3). Ten healthy female subjects took part in the study. Excretion of the isoflavones genistein, daidzein and equol in urine increased in both phases of the study. No other endpoint was altered in Phase 1. However, in Phase 2, concentrations of IGF-1 and IGFBP-3 were increased by phytoestrogen supplementation [IGF-1, median (IQ range), baseline 155 (123, 258), postweek 265 (228, 360) ng/ml, P

Preconditioning protects the guinea-pig urinary bladder against ischaemic conditions in vitro

Aims: To investigate the ability of ischaemic preconditioning (IPC) to protect guinea-pig detrusor from damage caused by a subsequent more prolonged exposure to ischaemic conditions.

Materials and Methods: Smooth muscle strips were mounted for tension recording in small organ baths continuously superfused with Krebs' solution at 37 degrees C. Ischaemia was mimicked by removing oxygen and glucose from the superfusing solution. Contractile responses to electrical field stimulation (EFS) and carbachol were monitored. Three regimes of preconditioning were examined: 15, 10, and 5 min of ischaemic conditions followed by 15, 10, and 5 min of normal conditions, respectively.

Results: Without preconditioning, nerve-mediated responses were significantly and proportionally reduced by periods of ischaemic conditions lasting for 45, 60, and 90 min, but recovered fully after exposure to ischaemic conditions for 30 min. The recovery of the responses to EFS was significantly improved in preconditioned strips when the period of ischaemic conditions was 45 or 60 min. However, no significant differences were seen with preconditioning when the period of ischaemic conditions was 90 min. The recovery of responses to carbachol was much greater than for the responses to EFS, and no significant differences were found between control and preconditioned strips.

Conclusions: It is suggested that in vivo short periods of transient ischaemia may be able to protect the guinea-pig bladder from the impairment associated with longer periods of ischaemia and reperfusion, which might happen in obstructed micturition. Our results also indicate that the phenomenon affects mainly the intrinsic nerves, which are more susceptible to ischaemic damage than the smooth muscle.

Altered distribution of interstitial cells and innervation in the rat urinary bladder following spinal cord injury

Introduction Changes in the distribution of interstitial cells (IC) are reportedly associated with dysfunctional bladder. The present study investigated whether spinal cord injury (SCI) resulted in changes to IC subpopulations (vimentin-positive with the ultrastructural profile of IC), smooth muscle and nerves within the bladder wall and correlated cellular remodelling with functional properties. Methods Bladders from SCI (T8/9 transection) and sham-operated rats five-weeks post-injury were used for ex vivo pressure-volume experiments or processed for morphological analysis with transmission electron microscopy (TEM) and light/confocal microscopy. Results Pressure-volume relationships revealed low-pressure, hypercompliance in SCI bladders indicative of decompensation. Extensive networks of vimentin-positive IC were typical in sham lamina propria and detrusor but were markedly reduced post-SCI; semi-quantitative analysis showed significant reduction. Nerves labelled with anti-neurofilament and anti-vAChT were notably decreased post-SCI. TEM revealed lamina propria IC and detrusor IC which formed close synaptic-like contacts with vesicle-containing nerve varicosities in shams. Lamina propria and detrusor IC were ultrastructurally damaged post-SCI with retracted/lost cell processes and were adjacent to areas of cellular debris and neuronal degradation. Smooth muscle hypertrophy was common to SCI tissues. Conclusions IC populations in bladder wall were decreased five weeks post-SCI, accompanied with reduced innervation, smooth muscle hypertrophy and increased compliance. These novel findings indicate that bladder wall remodelling post-SCI affects the integrity of interactions between smooth muscle, nerves and IC, with compromised IC populations. Correlation between IC reduction and a hypercompliant phenotype suggests that disruption to bladder IC contribute to pathophysiological processes underpinning the dysfunctional SCI bladder.

Novel, antibacterial silicone biomaterials for the prevention of microbial adherence and infection in urinary catheters

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Infection-Responsive Drug Delivery from Urinary Biomaterials Controlled by a Novel Kinetic and Thermodynamic Approach

Purpose. The pH-dependent physicochemical properties of the antimicrobial quinolone, nalidixic acid, were exploited to achieve ‘intelligent’ drug release from a potential urinary catheter coating, poly(2-hydroxyethylmethacrylate) (p(HEMA)), in direct response to the elevated pH which occurs at the onset of catheter infection.
Methods. p(HEMA) hydrogels, and reduced-hydrophilicity copolymers incorporating methyl methacrylate, were loaded with nalidixic acid by a novel, surface particulate localization method, and characterized in terms of pH-dependent drug release and microbiological activity against the common urease-producing urinary pathogen Proteus mirabilis.
Results. The pH-dependent release kinetics of surface-localized nalidixic acid were 50- and 10-fold faster at pH 9, representing the alkaline conditions induced by urease-producing urinary pathogens, compared to release at pH 5 and pH 7 respectively. Furthermore, microbiological activity against P. mirabilis was significantly enhanced after loading surface particulate nalidixic acid in comparison to p(HEMA) hydrogels conventionally loaded with dispersed drug. The more hydrophobic methyl methacrylate-containing copolymers also demonstrated this pH responsive behavior, but additionally exhibited a sustained period of zero-order release.
Conclusions. The paradigm presented here provides a system with latent, immediate infection-responsive drug release followed by prolonged zero-order antimicrobial delivery, and represents an ‘intelligent’, infection-responsive, self-sterilizing biomaterial.

A comparison of the effects of ibuprofen and indomethacin upon renal haemodynamics and electrolyte excretion in the presence and absence of frusemide

1. This study has compared the effects of ibuprofen and indomethacin upon renal haemodynamics, electrolyte excretion and renin release in the presence and absence of frusemide under sodium replete conditions in eight healthy volunteers. 2. Neither ibuprofen (400 mg and 800 mg) nor indomethacin (50 mg) affected renal blood flow, glomerular filtration rate or electrolyte excretion in the basal state. 3. Frusemide had no effect on renal blood flow, but significantly increased glomerular filtration rate. This latter change was suppressed significantly only by ibuprofen 400 mg. Frusemide-induced diuresis was inhibited by all treatments, while natriuresis following frusemide was inhibited by indomethacin only. 4. Significant increments in plasma renin activity, which were suppressed by all treatments, were observed after frusemide. The degree of inhibition of the renin responses was significantly greater in the presence of indomethacin than with either dose of ibuprofen. 5. In a sodium replete setting in healthy volunteers, indomethacin and ibuprofen had no detrimental effects on basal renal function. In the presence of frusemide, indomethacin had more anti-natriuretic and renin-suppressing effect than ibuprofen. There was no evidence for a dose-related effect of ibuprofen.

Comparison of the acute renal and peripheral vascular responses to frusemide and bumetanide at low and high dose

1. The effects of equipotent doses of frusemide (10 mg and 100 mg) and bumetanide (250 micrograms and 2.5 mg) upon renal and peripheral vascular responses, urinary prostaglandin excretion, plasma renin activity, angiotensin II and noradrenaline were compared in nine healthy volunteers. 2. Frusemide (10 mg and 100 mg) and bumetanide (2.5 mg) increased renal blood flow acutely compared with placebo but bumetanide (250 micrograms) had no effect. The changes in peripheral vascular responses were not significantly different from placebo. 3. Urinary prostaglandin metabolite excretion was acutely increased by all treatments, with no inter-treatment difference. Plasma renin activity was increased acutely by both doses of frusemide and by bumetanide (2.5 mg) compared with placebo and to bumetanide (250 micrograms). There were no differences between the latter two treatments. Angiotensin II was increased significantly 30 min after frusemide 100 mg and bumetanide 2.5 mg, and by all four treatments at 50 min when compared with placebo. There were no significant differences between either of the low doses or the higher doses. Plasma noradrenaline was unchanged by all treatments. 4. Frusemide 100 mg and bumetanide 2.5 mg have the same effects on the renal vasculature and the renin-angiotensin-prostaglandin system. Under the conditions of this study, frusemide 10 mg had different effects on plasma renin activity than bumetanide 250 micrograms.

The effects of cilazapril alone and in combination with frusemide in healthy subjects

1. In a fourway double-blind placebo controlled study, the effects of cilazapril, a new angiotensin converting enzyme inhibitor, on renal function and the responses to intravenous frusemide were studied in a group of twelve salt depleted male volunteers. 2. Cilazapril produced an increase in effective renal plasma flow and urinary output of prostaglandin E2 metabolite (PGE2-M) but no effect on sodium, potassium or water excretion. 3. Pretreatment with cilazapril antagonised the effects of frusemide on glomerular filtration, PGE2-M and sodium excretion.