Changes in adiponectin multimer distribution in response to atorvastatin treatment in patients with type 2 diabetes

Effect of atorvastatin on testosterone levels

BACKGROUND

Statins are one of the most prescribed classes of drugs worldwide. Atorvastatin, the most prescribed statin, is currently used to treat conditions such as hypercholesterolaemia and dyslipidaemia. By reducing the level of cholesterol, which is the precursor of the steroidogenesis pathway, atorvastatin may cause a reduction in levels of testosterone and other androgens. Testosterone and other androgens play important roles in biological functions. A potential reduction in androgen levels, caused by atorvastatin might cause negative effects in most settings. In contrast, in the setting of polycystic ovary syndrome (PCOS), reducing excessive levels of androgens with atorvastatin could be beneficial.

OBJECTIVES

Primary objective To quantify the magnitude of the effect of atorvastatin on total testosterone in both males and females, compared to placebo or no treatment. Secondary objectives To quantify the magnitude of the effects of atorvastatin on free testosterone, sex hormone binding globin (SHBG), androstenedione, dehydroepiandrosterone sulphate (DHEAS) concentrations, free androgen index (FAI), and withdrawal due to adverse effects (WDAEs) in both males and females, compared to placebo or no treatment.

SEARCH METHODS

The Cochrane Hypertension Information Specialist searched the following databases for randomized controlled trials (RCTs) up to 9 November 2020: the Cochrane Hypertension Specialised Register; the Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE; Embase; ;two international trials registries, and the websites of the US Food and Drug Administration, the European Patent Office and the Pfizer pharmaceutical corporation. These searches had no language restrictions. We also contacted authors of relevant articles regarding further published and unpublished work.

SELECTION CRITERIA

RCTs of daily atorvastatin for at least three weeks, compared with placebo or no treatment, and assessing change in testosterone levels in males or females.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the citations, extracted the data and assessed the risk of bias of the included studies. We used the mean difference (MD) with associated 95% confidence intervals (CI) to report the effect size of continuous outcomes,and the risk ratio (RR) to report effect sizes of the sole dichotomous outcome (WDAEs). We used a fixed-effect meta-analytic model to combine effect estimates across studies, and risk ratio to report effect size of the dichotomous outcomes. We used GRADE to assess the certainty of the evidence.

MAIN RESULTS

We included six RCTs involving 265 participants who completed the study and their data was reported. Participants in two of the studies were male with normal lipid profile or mild dyslipidaemia (N = 140); the mean age of participants was 68 years. Participants in four of the studies were female with PCOS (N = 125); the mean age of participants was 32 years. We found no significant difference in testosterone levels in males between atorvastatin and placebo, MD -0.20 nmol/L (95% CI -0.77 to 0.37). In females, atorvastatin may reduce total testosterone by -0.27 nmol/L (95% CI -0.50 to -0.04), FAI by -2.59 nmol/L (95% CI -3.62 to -1.57), androstenedione by -1.37 nmol/L (95% CI -2.26 to -0.49), and DHEAS by -0.63 μmol/l (95% CI -1.12 to -0.15). Furthermore, compared to placebo, atorvastatin increased SHBG concentrations in females by 3.11 nmol/L (95% CI 0.23 to 5.99). We identified no studies in healthy females (i.e. females with normal testosterone levels) or children (under age 18). Importantly, no study reported on free testosterone levels.

AUTHORS' CONCLUSIONS

We found no significant difference between atorvastatin and placebo on the levels of total testosterone in males. In females with PCOS, atorvastatin lowered the total testosterone, FAI, androstenedione, and DHEAS. The certainty of evidence ranged from low to very low for both comparisons. More RCTs studying the effect of atorvastatin on testosterone are needed.

Effect of atorvastatin treatment on circulating adiponectin: a meta-analysis of randomized controlled trials

Background

Influences of atorvastatin on atherosclerosis and glycemic metabolism may be related to its potential impact on circulating adiponectin, an adipocyte that exerts anti-inflammatory, ant-atherosclerotic, and anti-oxidative effects. However, results of previous randomized controlled trials (RCTs) were not consistent. We performed a meta-analysis of RCTs to systematic evaluate the influence of atorvastatin on circulating adiponectin.

Methods

Relevant studies were identified via search of electronic databases of PubMed, Embase, and Cochrane’s Library. A random-effect model was applied to pool the results via incorporating the potential heterogeneity. Predefined meta-regression and subgroup analyses were used to evaluate the influences of study characteristics on the outcome.

Results

Fourteen datasets from ten RCTs including 931 patients were included. Pooled results showed that atorvastatin did not significantly affect circulating adiponectin as compared with controls (weighed mean difference = − 0.27 μg/mL, 95% confidence interval: − 0.89 to 0.35 μg/mL, p = 0.39). Results of univariate meta-regression analyses showed that study characteristics including number of patients, mean age, proportion of male patients, body mass index, dose of atorvastatin, or treatment duration did not significantly affect the outcome (p all > 0.05). Moreover, subgroup analyses showed that atorvastatin did not significantly affect circulating adiponectin in studies stratified according to these study characteristics (p all > 0.05).

Conclusions

Atorvastatin treatment does not significantly affect circulating adiponectin. Influences of atorvastatin on atherosclerosis and glycemic metabolism are not likely to be mediated by modulation of circulating adiponectin.

Systematic Review of Metabolic Syndrome Biomarkers: A Panel for Early Detection, Management, and Risk Stratification in the West Virginian Population

INTRODUCTION

Metabolic syndrome represents a cluster of related metabolic abnormalities, including central obesity, hypertension, dyslipidemia, hyperglycemia, and insulin resistance, with central obesity and insulin resistance in particular recognized as causative factors. These metabolic derangements present significant risk factors for cardiovascular disease, which is commonly recognized as the primary clinical outcome, although other outcomes are possible. Metabolic syndrome is a progressive condition that encompasses a wide array of disorders with specific metabolic abnormalities presenting at different times. These abnormalities can be detected and monitored via serum biomarkers. This review will compile a list of promising biomarkers that are associated with metabolic syndrome and this panel can aid in early detection and management of metabolic syndrome in high risk populations, such as in West Virginia.

METHODS

A literature review was conducted using PubMed, Science Direct, and Google Scholar to search for markers related to metabolic syndrome. Biomarkers searched included adipokines (leptin, adiponectin), neuropeptides (ghrelin), pro-inflammatory cytokines (IL-6, TNF-α), anti-inflammatory cytokines (IL-10), markers of antioxidant status (OxLDL, PON-1, uric acid), and prothrombic factors (PAI-1).

RESULTS

According to the literature, the concentrations of pro-inflammatory cytokines (IL-6, TNF-α), markers of pro-oxidant status (OxLDL, uric acid), and prothrombic factors (PAI-1) were elevated in metabolic syndrome. Additionally, leptin concentrations were found to be elevated in metabolic syndrome as well, likely due to leptin resistance. In contrast, concentrations of anti-inflammatory cytokines (IL-10), ghrelin, adiponectin, and antioxidant factors (PON-1) were decreased in metabolic syndrome, and these decreases also correlated with specific disorders within the cluster.

CONCLUSION

Based on the evidence presented within the literature, the aforementioned biomarkers correlate significantly with metabolic syndrome and could provide a minimally-invasive means for early detection and specific treatment of these disorders. Further research is encouraged to determine the efficacy of applying these biomarkers to diagnosis and treatment in a clinical setting.

Lipid-lowering efficacy of atorvastatin

BACKGROUND

This represents the first update of this review, which was published in 2012. Atorvastatin is one of the most widely prescribed drugs and the most widely prescribed statin in the world. It is therefore important to know the dose-related magnitude of effect of atorvastatin on blood lipids.

OBJECTIVES

Primary objective To quantify the effects of various doses of atorvastatin on serum total cholesterol, low-density lipoprotein (LDL)-cholesterol, high-density lipoprotein (HDL)-cholesterol and triglycerides in individuals with and without evidence of cardiovascular disease. The primary focus of this review was determination of the mean per cent change from baseline of LDL-cholesterol. Secondary objectives • To quantify the variability of effects of various doses of atorvastatin.• To quantify withdrawals due to adverse effects (WDAEs) in placebo-controlled randomised controlled trials (RCTs).

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 11, 2013), MEDLINE (1966 to December Week 2 2013), EMBASE (1980 to December Week 2 2013), Web of Science (1899 to December Week 2 2013) and BIOSIS Previews (1969 to December Week 2 2013). We applied no language restrictions.

SELECTION CRITERIA

Randomised controlled and uncontrolled before-and-after trials evaluating the dose response of different fixed doses of atorvastatin on blood lipids over a duration of three to 12 weeks.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed eligibility criteria for studies to be included and extracted data. We collected information on withdrawals due to adverse effects from placebo-controlled trials.

MAIN RESULTS

In this update, we found an additional 42 trials and added them to the original 254 studies. The update consists of 296 trials that evaluated dose-related efficacy of atorvastatin in 38,817 participants. Included are 242 before-and-after trials and 54 placebo-controlled RCTs. Log dose-response data from both trial designs revealed linear dose-related effects on blood total cholesterol, LDL-cholesterol, HDL-cholesterol and triglycerides. The Summary of findings table 1 documents the effect of atorvastatin on LDL-cholesterol over the dose range of 10 to 80 mg/d, which is the range for which this systematic review acquired the greatest quantity of data. Over this range, blood LDL-cholesterol is decreased by 37.1% to 51.7% (Summary of findings table 1). The slope of dose-related effects on cholesterol and LDL-cholesterol was similar for atorvastatin and rosuvastatin, but rosuvastatin is about three-fold more potent. Subgroup analyses suggested that the atorvastatin effect was greater in females than in males and was greater in non-familial than in familial hypercholesterolaemia. Risk of bias for the outcome of withdrawals due to adverse effects (WDAEs) was high, but the mostly unclear risk of bias was judged unlikely to affect lipid measurements. Withdrawals due to adverse effects were not statistically significantly different between atorvastatin and placebo groups in these short-term trials (risk ratio 0.98, 95% confidence interval 0.68 to 1.40).

AUTHORS' CONCLUSIONS

This update resulted in no change to the main conclusions of the review but significantly increases the strength of the evidence. Studies show that atorvastatin decreases blood total cholesterol and LDL-cholesterol in a linear dose-related manner over the commonly prescribed dose range. New findings include that atorvastatin is more than three-fold less potent than rosuvastatin, and that the cholesterol-lowering effects of atorvastatin are greater in females than in males and greater in non-familial than in familial hypercholesterolaemia. This review update does not provide a good estimate of the incidence of harms associated with atorvastatin because included trials were of short duration and adverse effects were not reported in 37% of placebo-controlled trials.

Effects of patient-tailored atorvastatin therapy on ameliorating the levels of atherogenic lipids and inflammation beyond lowering low-density lipoprotein cholesterol in patients with type 2 diabetes

Aims/Introduction

Recently, patient‐tailored statin therapy was proven effective for achieving target low‐density lipoprotein (LDL) cholesterol levels. It is unclear, however, whether this therapeutic modality would be effective for atherogenic lipid profiles and inflammation in patients with type 2 diabetes.

Materials and Methods

The present study was an 8‐week, multicenter, single‐step titration trial of patient‐tailored atorvastatin therapy (10, 20 and 40 mg) according to baseline LDL cholesterol levels in 440 patients with type 2 diabetes. We measured the LDL particle size by polyacrylamide gel electrophoresis, and used high‐sensitivity C‐reactive protein (hsCRP) and adiponectin as surrogate markers of inflammation.

Results

In the intention‐to‐treat analysis, 91% of the patients achieved their LDL cholesterol targets (<2.6 mmol/L) at week 8. There were significant reductions at week 8 in total cholesterol, triglycerides, non‐high‐density lipoprotein cholesterol (HDL) cholesterol, and the total cholesterol:HDL cholesterol ratio compared with the baseline values for all of the doses. The mean LDL particle size was significantly increased, and the small, dense LDL cholesterol levels were decreased in a dose‐dependent manner over the study period. In addition, the hsCRP levels were decreased in those high‐risk patients with baseline hsCRP levels over 3 mg/L (P < 0.001), and the adiponectin levels tended to increase with all of the doses (P = 0.004) at 8 weeks.

Conclusions

Patient‐tailored atorvastatin therapy based on LDL cholesterol at baseline was effective in ameliorating atherogenic LDL particle size and inflammation, in addition to achieving the target LDL cholesterol level without an undesirable effect on glycemic control in patients with type 2 diabetes. This trial was registered with ClinicalTrials.gov (no. NCT01239849).

Lipid lowering efficacy of atorvastatin

BACKGROUND

Atorvastatin is one of the most widely prescribed drugs and the most widely prescribed statin in the world. It is therefore important to know the dose-related magnitude of effect of atorvastatin on blood lipids.

OBJECTIVES

To quantify the dose-related effects of atorvastatin on blood lipids and withdrawals due to adverse effects (WDAE).

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) on The Cochrane Library Issue 4, 2011, MEDLINE (1966 to November 2011), EMBASE (1980 to November 2011), ISI Web of Science (1899 to November 2011) and BIOSIS Previews (1969 to November 2011). No language restrictions were applied.

SELECTION CRITERIA

Randomised controlled and uncontrolled before-and-after trials evaluating the dose response of different fixed doses of atorvastatin on blood lipids over a duration of 3 to 12 weeks.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. WDAE information was collected from the placebo-controlled trials.

MAIN RESULTS

Two hundred fifty-four trials evaluated the dose-related efficacy of atorvastatin in 33,505 participants. Log dose-response data revealed linear dose-related effects on blood total cholesterol, low-density lipoprotein (LDL)-cholesterol and triglycerides. Combining all the trials using the generic inverse variance fixed-effect model for doses of 10 to 80 mg/day resulted in decreases of 36% to 53% for LDL-cholesterol. There was no significant dose-related effects of atorvastatin on blood high-density lipoprotein (HDL)-cholesterol. WDAE were not statistically different between atorvastatin and placebo for these short-term trials (risk ratio 0.99; 95% confidence interval 0.68 to 1.45).

AUTHORS' CONCLUSIONS

Blood total cholesterol, LDL-cholesterol and triglyceride lowering effect of atorvastatin was dependent on dose. Log dose-response data was linear over the commonly prescribed dose range. Manufacturer-recommended atorvastatin doses of 10 to 80 mg/day resulted in 36% to 53% decreases of LDL-cholesterol. The review did not provide a good estimate of the incidence of harms associated with atorvastatin because of the short duration of the trials and the lack of reporting of adverse effects in 37% of the placebo-controlled trials.

Adiponectin gene therapy ameliorates high-fat, high-sucrose diet-induced metabolic perturbations in mice

BACKGROUND AND DESIGN

Adiponectin is an adipokine secreted primarily from adipose tissue that can influence circulating plasma glucose and lipid levels through multiple mechanisms involving a variety of organs. In humans, reduced plasma adiponectin levels induced by obesity are associated with insulin resistance and type 2 diabetes, suggesting that low adiponectin levels may contribute the pathogenesis of obesity-related insulin resistance.

METHODS AND RESULTS

The objective of the present study was to investigate whether gene therapy designed to elevate circulating adiponectin levels is a viable strategy for ameliorating insulin resistance in mice fed a high-fat, high-sucrose (HFHS) diet. Electroporation-mediated gene transfer of mouse adiponectin plasmid DNA into gastrocnemius muscle resulted in elevated serum levels of globular and high-molecular weight adiponectin compared with control mice treated with empty plasmid. In comparison to HFHS-fed mice receiving empty plasmid, mice receiving adiponectin gene therapy displayed significantly decreased weight gain following 13 weeks of HFHS diet associated with reduced fat accumulation, and exhibited increased oxygen consumption and locomotor activity as measured by indirect calorimetry, suggesting increased energy expenditure in these mice. Consistent with improved whole-body metabolism, mice receiving adiponectin gene therapy also had lower blood glucose and insulin levels, improved glucose tolerance and reduced hepatic gluconeogenesis compared with control mice. Furthermore, immunoblot analysis of livers from mice receiving adiponectin gene therapy showed an increase in insulin-stimulated phosphorylation of insulin signaling proteins.

CONCLUSION

Based on these data, we conclude that adiponectin gene therapy ameliorates the metabolic abnormalities caused by feeding mice a HFHS diet and may be a potential therapeutic strategy to improve obesity-mediated impairments in insulin sensitivity.

Low pre-transplant adiponectin multimers are associated with adverse allograft outcomes in kidney transplant recipients a 3-year prospective study

BACKGROUND

In kidney transplant recipients endothelial dysfunction is almost a universal risk factor for allograft failure. Adiponectin, an adipocyte derived hormone, has endothelial-protective properties and the high-molecular weight (HMW) multimer is the major active form, exerting anti-inflammatory and anti-apoptotic effects on endothelial cells. This study evaluated, whether pre-transplant total and HMW multimer adiponectin levels are associated with markers of endothelial dysfunction and arteriosclerosis and predict long-term graft survival in patients after kidney transplantation.

METHODS

In 206 renal transplant recipients pre-transplant total and HMW adiponectin levels were measured in serum by ELISA and Western blot, respectively. During the 36 months active follow up (median [interquartile range] 1249 [1020; 1445] days) 13 patients died (94% patient survival) and renal allograft failure was reported in 18 patients (91% graft survival).

RESULTS

Pre-transplant total and HMW adiponectin levels were significantly associated with lipid and glucose parameters at baseline. After 3 years follow-up pre-transplant total and HMW adiponectin levels were significantly inversely associated with the incidence of allograft failure (adiponectin: r=-0.216; p=0.002: HMW: r=-0.218; p=0.002). In multivariable adjusted Cox proportional hazard regression models patients in the lowest total and HMW adiponectin quartile had a significantly increased risk for allograft failure within 3 years post-transplantation: odds ratio [95%CI]: total adiponectin: 4.25 [1.27-14.24; p=0.019], and HMW multimers: 3.35 [1.04-10.76; p=0.042], respectively.

CONCLUSION

Low pre-transplant levels of total and HMW adiponectin reflect a pro-atherogenic endothelial milieu and independently predict an increased risk of allograft failure in kidney-transplant recipients. Measurement of adiponectin levels may identify patients at risk for adverse allograft outcomes after kidney transplantation.

Relationship between ADIPOQ gene, circulating high molecular weight adiponectin and albuminuria in individuals with normal kidney function: evidence from a family-based study

AIMS/HYPOTHESIS

Insulin resistance is associated with reduced serum adiponectin and increased albuminuria levels. Thus, one would anticipate an inverse relationship between circulating adiponectin and albuminuria. However, several studies have described a 'paradoxical' elevation of serum adiponectin in patients with elevated albuminuria. These findings may have been confounded by the presence of diseases and related treatments known to affect circulating adiponectin and albuminuria. We therefore studied the relationship between circulating adiponectin and albuminuria in the absence of such confounders.

METHODS

To this purpose, the relationship between adiponectin isoforms and albumin:creatinine ratio (ACR) was investigated in a family-based sample of 634 non-diabetic untreated white individuals with normal kidney function. We also investigated whether the two variables share a common genetic background and addressed the specific role of the gene encoding adiponectin on that background by genotyping several ADIPOQ single nucleotide polymorphisms (SNPs).

RESULTS

ACR was directly associated with high molecular weight (HMW) adiponectin isoform (p = 0.024). The two variables shared some genetic correlation (ρ(g) = 0.38, p = 0.04). ADIPOQ promoter SNP rs17300539 was associated with HMW adiponectin (p = 4.8 × 10(-5)) and ACR (p =0.0027). The genetic correlation between HMW adiponectin and ACR was no longer significant when SNP rs17300539 was added to the model, thus reinforcing the role of this SNP in determining both traits.

CONCLUSIONS/INTERPRETATION

Our study shows a positive, independent correlation between HWM adiponectin and ACR. ADIPOQ variability is associated with HMW adiponectin and ACR, and explains some of the common genetic background shared by these traits, thus suggesting that ADIPOQ and HMW adiponectin modulate albuminuria levels.

Metformin and atorvastatin combination further protect the liver in type 2 diabetes with hyperlipidaemia

BACKGROUND

non-alcoholic fatty liver disease (NAFLD) and type 2 diabetes are associated with dyslipidaemia, inflammation and oxidative stress. However, the pathophysiology of NAFLD in type 2 diabetes with hyperlipidaemia is not fully known, as well as the utility of the commonly prescribed anti-diabetic and lipid-lowering drugs in ameliorating liver injury markers.

METHODS

hepatic complications of type 2 diabetes with hyperlipidaemia and the effects of atorvastatin and metformin, isolated and in association, in systemic and hepatic inflammatory and oxidative stress markers were tested using genetic type 2 diabetic Goto-Kakizaki rats fed with a high-fat diet.

RESULTS

the high-fat diet aggravated the overall metabolic state and the hepatic markers of injury. All treatments decreased fasting glycaemia, insulin resistance and free fatty acid levels. Combined treatment further decreased C-reactive protein (CRP), adiponectin, liver tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6), systemic and hepatic oxidative stress and portal inflammation.

CONCLUSIONS

our data provides evidence of a greater benefit with a combination of atorvastatin and metformin in improving liver injury in type 2 diabetes with hyperlipidaemia.

Differential metabolic effects of distinct statins

Reciprocal relationships between endothelial dysfunction and insulin resistance suggest that therapies improving endothelial dysfunction will simultaneously improve insulin sensitivity and other metabolic parameters. However, previous studies with some statins either did not alter insulin sensitivity or promoted insulin resistance despite significant improvements in endothelial dysfunction and decreases in circulating pro-inflammatory markers. This may be due to pleiotropic or off-target effects of some statins to cause insulin resistance by diverse mechanisms unrelated to endothelial dysfunction. Indeed, there is evidence of other differential metabolic actions of distinct statins including effects on hydroxymethylglutaryl-CoA reductase inhibition, isoprotenoid synthesis, calcium release, glucose transport, insulin secretion, and/or insulin resistance. Pravastatin increases expression of adiponectin mRNA, enhances adiponectin secretion, increases plasma levels of adiponectin, and enhances insulin sensitivity in mice and humans. Clinical studies including large scale randomized controlled trials demonstrate potential differences between individual statins, with pravastatin promoting risk reduction for new onset of diabetes. Conversely, other statins including atorvastatin, rosuvastatin, and simvastatin all promote significant increase in this risk. Given the frequent concordance of metabolic diseases including diabetes, obesity, and metabolic syndrome with cardiovascular diseases associated with hyperlipidemia, it is important to understand the potential metabolic risks and benefits of therapies with distinct statins. In this review, we discuss these differential effects of statins on metabolic homeostasis and insulin sensitivity.

Pharmacological effects of lipid-lowering drugs on circulating adipokines

The cardioprotective effects of lipid-lowering drugs have been primarily attributed to their effects on blood lipid metabolism. However, emerging evidence indicates that lipid-lowering drugs also modulate the synthesis and secretion of adipose tissue-secreted proteins referred to as adipokines. Adipokines influence energy homeostasis and metabolism and have also been shown to modulate the vascular inflammatory cascade. The purpose of this review will be to examine the reported effects of commonly used lipid-lowering drugs (statins, fibrates, niacin and omega-3-fatty acids) on the circulating concentrations of leptin, adiponectin, tumor necrosis-factor-α (TNF-α), Retinol binding protein 4 (RBP4) and resistin. Overall, the lipid-lowering drugs reviewed have minimal effects on leptin and resistin concentrations.Conversely, circulating adiponectin concentrations are consistently increased by each lipid-lowering drug reviewed with the greatest effects produced by niacin. Studies that have examined the effects of statins, niacin and omega-3-fatty acids on TNF-α demonstrate that these agents have little effect on circulating TNF-α concentrations. Niacin and fibrates appear to lower RBP4 but not resistin concentrations. The results of the available studies suggest that a strong relationship exists between pharmacological reductions in blood lipids and adiponectin that is not obvious for other adipokines reviewed.

Increment and impairment of adiponectin in renal failure

AIMS

Patients with chronic renal failure are at high risk of cardiovascular diseases. Previous studies in healthy population showed that hypoadiponectinemia was associated with high cardiovascular disease risk. However, plasma adiponectin (APN) levels are increased in renal dysfunction. Therefore, the clinical significance of plasma APN level in patients with moderate renal dysfunction is controversial. The aim of this study was to determine the change of plasma APN levels in a mouse model of renal failure and the loss of vasculo-protective function of APN in the presence of high cystatin C levels.

METHODS AND RESULTS

Subtotal (5/6) nephrectomy was performed in APN-knockout (KO) mice and wild-type (WT) mice. The procedure in WT mice resulted in the significant increase of plasma APN and cystatin C levels. The clearance rate of APN was measured by injecting plasma from WT mice into KO mice. The clearance rate was significantly decreased in subtotal nephrectomized KO mice compared with sham-operated KO mice. Adiponectin protein and mRNA levels in adipose tissue were similar to subtotal nephrectomized and sham-operated mice. In cultured endothelial cells, at a high concentration corresponding to renal failure, cystatin C abolished the suppressive effects of APN on tumour necrosis factor alpha-induced expression of monocyte adhesion molecules.

CONCLUSION

Plasma APN increases in chronic renal failure, at least in part due to low clearance rate. High concentrations of cystatin C abolish the vasculo-protective effect of APN.

Urinary adiponectin excretion: a novel marker for vascular damage in type 2 diabetes

OBJECTIVE

Markers reliably identifying vascular damage and risk in diabetic patients are rare, and reports on associations of serum adiponectin with macrovascular disease have been inconsistent. In contrast to existing data on serum adiponectin, this study assesses whether urinary adiponectin excretion might represent a more consistent vascular damage marker in type 2 diabetes.

RESEARCH DESIGN AND METHODS

Adiponectin distribution in human kidney biopsies was assessed by immunohistochemistry, and urinary adiponectin isoforms were characterized by Western blot analysis. Total urinary adiponectin excretion rate was measured in 156 patients with type 2 diabetes who had a history of diabetic nephropathy and 40 healthy control subjects using enzyme-linked immunosorbent assay. Atherosclerotic burden was assessed by common carotid artery intima-media-thickness (IMT).

RESULTS

A homogenous staining of adiponectin was found on the endothelial surface of glomerular capillaries and intrarenal arterioles in nondiabetic kidneys, whereas staining was decreased in diabetic nephropathy. Low-molecular adiponectin isoforms ( approximately 30-70 kDa) were detected in urine by Western blot analysis. Urinary adiponectin was significantly increased in type 2 diabetes (7.68 +/- 14.26 vs. control subjects: 2.91 +/- 3.85 microg/g creatinine, P = 0.008). Among type 2 diabetic patients, adiponectinuria was associated with IMT (r = 0.479, P < 0.001) and proved to be a powerful independent predictor of IMT (beta = 0.360, P < 0.001) in multivariable regression analyses. In a risk prediction model including variables of the UK Prospective Diabetes Study coronary heart disease risk engine urinary adiponectin, but not the albumin excretion rate, added significant value for the prediction of increased IMT (P = 0.007).

CONCLUSIONS

Quantification of urinary adiponectin excretion appears to be an independent indicator of vascular damage potentially identifying an increased risk for vascular events.