Lucia Salvemini

Serum Resistin, Cardiovascular Disease and All-Cause Mortality in Patients with Type 2 Diabetes

Background High serum resistin has been associated with increased risk of cardiovascular disease in the general population, Only sparse and conflicting results, limited to Asian individuals, have been reported, so far, in type 2 diabetes. We studied the role of serum resistin on coronary artery disease, major cardiovascular events and all-cause mortality in type 2 diabetes. Methods We tested the association of circulating resistin concentrations with coronary artery disease, major cardiovascular events (cardiovascular death, non-fatal myocardial infarction and non-fatal stroke) and all-cause mortality in 2,313 diabetic patients of European ancestry from two cross-sectional and two prospective studies. In addition, the expression of resistin gene (RETN) was measured in blood cells of 68 diabetic patients and correlated with their serum resistin levels. Results In a model comprising age, sex, smoking habits, BMI, HbA1c, and insulin, antihypertensive and antidyslipidemic therapies, serum resistin was associated with coronary artery disease in both cross-sectional studies: OR (95%CI) per SD increment = 1.35 (1.10–1.64) and 1.99 (1.55–2.55). Additionally, serum resistin predicted incident major cardiovascular events (HR per SD increment = 1.31; 1.10–1.56) and all-cause mortality (HR per SD increment = 1.16; 1.06–1.26). Adjusting also for fibrinogen levels affected the association with coronary artery disease and incident cardiovascular events, but not that with all cause-mortality. Finally, serum resistin was positively correlated with RETN mRNA expression (rho = 0.343). Conclusions This is the first study showing that high serum resistin (a likely consequence, at least partly, of increased RETN expression) is a risk factor for cardiovascular disease and all-cause mortality in diabetic patients of European ancestry.

Circulating high molecular weight adiponectin isoform is heritable and shares a common genetic background with insulin resistance in nondiabetic White Caucasians from Italy: evidence from a family-based study.

Abstract.  Menzaghi C, Salvemini L, Paroni G, De Bonis C, Mangiacotti D, Fini G, Doria A, Di Paola R, Trischitta V (IRCCS “Casa Sollievo della Sofferenza”, San Giovanni Rotondo (FG), Italy, Joslin Diabetes Center and Harvard Medical School, Boston, MA, USA, “Sapienza” University; IRCCS Casa Sollievo della Sofferenza‐Mendel Institute, Rome, Italy). Circulating HMW adiponectin isoform is heritable and shares a common genetic background with insulin resistance in nondiabetic White Caucasians from Italy: evidence from a family‐based study. J Intern Med 2010; 267: 287–294.

Association between Resistin Levels and All-Cause and Cardiovascular Mortality: A New Study and a Systematic Review and Meta-Analysis

Context Studies concerning the association between circulating resistin and mortality risk have reported, so far, conflicting results. Objective To investigate the association between resistin and both all-cause and cardiovascular (CV) mortality risk by 1) analyzing data from the Gargano Heart Study (GHS) prospective design (n=359 patients; 81 and 58 all-cause and CV deaths, respectively); 2) performing meta-analyses of all published studies addressing the above mentioned associations. Data Source and Study Selection MEDLINE and Web of Science search of studies reporting hazard ratios (HR) of circulating resistin for all-cause or CV mortality. Data Extraction Performed independently by two investigators, using a standardized data extraction sheet. Data Synthesis In GHS, adjusted HRs per one standard deviation (SD) increment in resistin concentration were 1.28 (95% CI: 1.07-1.54) and 1.32 (95% CI: 1.06-1.64) for all-cause and CV mortality, respectively. The meta-analyses included 7 studies (n=4016; 961 events) for all-cause mortality and 6 studies (n=4,187: 412 events) for CV mortality. Pooled HRs per one SD increment in resistin levels were 1.21 (95% CI: 1.03-1.42, Q-test p for heterogeneity<0.001) and 1.05 (95% CI: 1.01-1.10, Q-test p for heterogeneity=0.199) for all-cause and CV mortality, respectively. At meta-regression analyses, study mean age explained 9.9% of all-cause mortality studies heterogeneity. After adjusting for age, HR for all-cause mortality was 1.24 (95% CI: 1.06-1.45). Conclusions Our results provide evidence for an association between circulating resistin and mortality risk among high-risk patients as are those with diabetes and coronary artery disease.

Circulating adiponectin and cardiovascular mortality in patients with type 2 diabetes mellitus: evidence of sexual dimorphism.

BackgroundThe pathogenesis of cardiovascular (CV) mortality, whose rate is increased in type 2 diabetes, is poorly understood.While high serum adiponectin is associated with increased CV mortality in the general population, no data are available in type 2 diabetes.We here investigated whether this counterintuitive association was observable also in diabetic patients and whether it was sex-specific.MethodsThree prospective cohorts were analyzed: 1) Gargano Heart Study (GHS; 359 patients, 58 events/1,934 person-years; py); 2) Health Professional Follow-up Study (HPFS; 833 men, 146 events/10,024 py); 3) Nurses’ Health Study (NHS; 902 women, 144 events/15,074 py).ResultsIn GHS serum adiponectin predicted CV mortality in men (hazard ratio, HR, and 95% CI per standard deviation, SD, increment = 1.54, 1.19-2.01), but not women (HR = 0.98, 0.48-2.01).Circulating adiponectin predicted CV mortality in men from HPFS (HR = 1.44, 1.21-1.72), but not in women from NHS (HR = 1.08, 0.86-1.35), used as replication samples. In a pooled analysis, HRs were 1.47 (1.27-1.70) in 1,075 men and 1.07 (0.86-1.33) in 1,019 women (p for HRs heterogeneity across sexes = 0.018).ConclusionsThis is the first report showing that high circulating adiponectin predicts increased CV mortality in men, but not in women with type 2 diabetes. Further studies are necessary to unravel the mechanisms through which adiponectin influences CV mortality in a sex-specific manner.

Novel Locus FER Is Associated With Serum HMW Adiponectin Levels

OBJECTIVE High molecular weight (HMW) adiponectin is a predominant isoform of circulating adiponectin and has been related to type 2 diabetes. Previous linkage studies suggest that different genetic components might be involved in determining HMW and total adiponectin levels. RESEARCH DESIGN AND METHODS We performed a genome-wide association study (GWAS) of serum HMW adiponectin levels in individuals of European ancestry drawn from the Nurses’ Health Study (NHS) (N = 1,591). The single nucleotide polymorphisms (SNPs) identified in the GWAS analysis were replicated in an independent cohort of Europeans (N = 626). We examined the associations of the identified variations with diabetes risk and metabolic syndrome. RESULTS We identified a novel locus near the FER gene (5q21) at a genome-wide significance level, best represented by SNP rs10447248 (P = 4.69 × 10−8). We also confirmed that variations near the adiponectin-encoding ADIPOQ locus (3q27) were related to serum HMW adiponectin levels. In addition, we found that FER SNP rs10447248 was related to HDL cholesterol levels (P = 0.009); ADIPOQ variation was associated with fasting glucose (P = 0.04), HDL cholesterol (P = 0.04), and a metabolic syndrome score (P = 0.002). CONCLUSIONS Our results suggest that different loci may be involved in regulation of circulating HMW adiponectin levels and provide novel insight into the mechanisms that affect HMW adiponectin homeostasis.

Serum Resistin and Kidney Function: A Family-Based Study in Non-Diabetic, Untreated Individuals

Background High serum resistin levels have been associated with kidney dysfunction. Most of these studies have been carried out in individuals with severe kidney impairment, diabetes, cardiovascular disease and related treatments. Thus, the observed association might have been influenced by these confounders. Our aim was to study the relationship between serum resistin, urinary albumin/creatinine ratio (ACR) and glomerular filtration rate (GFR) in a family-based sample, the Gargano Family Study (GFS) of 635 non diabetic, untreated Whites. Methods A linear mixed effects model and bivariate analyses were used to evaluate the phenotypic and genetic relations between serum resistin and both ACR and eGFR. All analyses were adjusted for sex, age, age squared, BMI, systolic blood pressure, smoking habits and physical exercise. Results After adjustments, resistin levels were slightly positively associated with ACR (β±SE = 0.049±0.023, p = 0.035) and inversely related to eGFR (β±SE = −1.43±0.61, p = 0.018) levels. These associations remained significant when either eGFR or ACR were, reciprocally, added as covariates. A genetic correlation (ρg = −0.31±0.12; adjusted p = 0.013) was observed between resistin and eGFR (but not ACR) levels. Conclusion Serum resistin levels are independently associated with ACR and eGFR in untreated non-diabetic individuals. Serum resistin and eGFR share also some common genetic background. Our data strongly suggest that resistin plays a role in modulating kidney function.

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

Aims/hypothesisInsulin 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.MethodsTo 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).ResultsACR was directly associated with high molecular weight (HMW) adiponectin isoform (p = 0.024). The two variables shared some genetic correlation (ρg = 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/interpretationOur 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.

The paradoxical association of adiponectin with mortality rate in patients with type 2 diabetes: evidence of synergism with kidney function.

BACKGROUND The paradoxical relationship between high adiponectin and increased mortality, described in several clinical subsets, has been reported only once in type 2 diabetes (T2D) and only in selected elderly patients. We investigated this relationship in unselected patients with T2D and, then, addressed its possible modulation by several demographic and clinical conditions, known to affect per se mortality rate. METHODS Patients from the Gargano Mortality Study (GMS; N = 897, follow-up = 10.5 ± 3.7 years; 290 events) and the Foggia Mortality Study (FMS; N = 529, follow-up = 7.1 ± 2.5 years; 143 events), were investigated. RESULTS For each SD adiponectin increase, HRs (95% CI) for all-cause mortality were 1.30 (1.19-1.43) in GMS, 1.43 (1.26-1.64) in FMS and 1.34 (1.24-1.45) in the combined studies. This association was independent of the possible confounding effect of demographics, adiposity measures, diabetes-related features, kidney function-related parameters and medications (p = 9.34 × 10(-9)). While no interaction was observed between adiponectin and sex, age, smoking habits, BMI, waist circumference, HbA1c, diabetes duration, micro-/macro-albuminuria and medications, a strong interaction was observed with GFR, with a significant adiponectin-mortality association observed in individuals with GFR ≥ but not those with GFR < 60 ml/min/1.73 m(2); p for adiponectin-by-GFR status interaction = 2.13 × 10(-6)). CONCLUSION This is the first study reporting a paradoxical association of adiponectin with all-cause mortality in a large sample of unselected diabetic patients and indicating that such counterintuitive effect is observed only among patients with preserved kidney function. Further studies are needed to address if the strong interwoven effect of adiponectin and GFR turns to be useful in improving previously validated tools for predicting mortality in T2D.

Serum Adiponectin and Glomerular Filtration Rate in Patients with Type 2 Diabetes

High serum adiponectin has been increased in several conditions of kidney disease. Only sparse and conflicting results have been reported in patients with type 2 diabetes (T2D), a subgroup of individuals who are at high risk for renal dysfunction. The aim of this study was to fill up this gap of knowledge by investigating such association in a large sample of Italian diabetic patients. The association between serum adiponectin levels and estimated glomerular filtration rate (eGFR by Chronic Kidney Disease-Epidemiology Collaboration CKD-EPI equation) was investigated in 1,243 patients with T2D from two cross-sectional Italian studies: 878 from San Giovanni Rotondo (SGR) and 365 from Foggia (FG). Serum adiponectin was inversely associated with eGFR in SGR [β (standard error, SE) for 1 standard deviation (SD) of adiponectin = -3.26 (0.64)] and in FG [β(SE)=-5.70(1.28)] sample, as well as in the two studies combined [β(SE)=-3.99(0.59)];(p<0.0001 for all). In this combined analysis, the association was still significant after adjusting for sex, smoking habits, body mass index (BMI), waist circumference, diabetes duration, glycated hemoglobin (HbA1c), albumin creatinine ratio (ACR) and anti-hyperglycemic, anti-hypertensive and anti-dyslipidemic treatments [β (SE)= -2.19 (0.59), p = 0.0001]. A stronger association between each SD adiponectin increment and low eGFR was observed among patients with micro-/macro-albuminuria, as compared to those with normo-albuminuria [adjusted β(SE)=-4.42(1.16) ml/min/1.73m2 vs. -1.50 (0.67) ml/min/1.73m2, respectively; p for adiponectin-by-albuminuric status = 0.022]. For each adiponectin SD increment, the odds of having eGFR < 60 ml/min/1.73m2 increased by 41% (odds ratio, OR = 1.41; 95% confidence interval, CI 1.21–1.64) in SGR sample, 53% (OR = 1.53; 95% CI 1.21–1.94) in FG sample, and 44% (OR = 1.44; 95%CI 1.27–1.64) in the two studies considered together (p<0.0001 for all). In the combined sample, further adjustment for the above mentioned covariates did not change the observed association (OR = 1.36; 95%CI 1.16–1.60; p<0.0001). Our study, so far the largest addressing the relationship between serum adiponectin and GFR in T2D, strongly suggests that the paradoxical inverse association, previously reported in different clinical sets, is also observed in diabetic patients. Further studies are needed to unravel the biology underlying this counterintuitive relationship.

Serum Resistin and Glomerular Filtration Rate in Patients with Type 2 Diabetes

Background High serum levels of the pro-inflammatory adipokine resistin have been associated with decreased renal function in the general population. The goal of this study was to investigate whether such association is also present among diabetic subjects, who are at increased risk of renal function loss. Methods The cross-sectional association between serum resistin levels and estimated glomerular filtration rate (eGFR) was investigated in 1,560 type 2 diabetic (T2D) patients of European ancestry comprised in two different cohorts: 762 patients from San Giovanni Rotondo (SGR; Italy) and 798 patients from Boston (US). Results Serum resistin was inversely associated with eGFR in SGR [β (SE) for one SD of resistin increment = -1.01 (0.70) ml/min/1.73m2, p = 0.019] and in Boston [β (SE) = -5.31 (0.74) ml/min/1.73m2, p < 0.001] samples, as well as in the two studies combined [β (SE) = -3.42 (0.52) ml/min/1.73m2, p < 0.001]. The association was unaffected by adjustment for smoking habits, BMI, waist circumference, diabetes duration, HbA1c, insulin treatment, hypertension and lipid-lowering therapy: β (SE) for one SD of resistin increment = -1.07 (0.70), p = 0.02; -5.50 (0.88), p < 0.001; and -2.81 (0.55) ml/min/1.73m2, p < .001, in SGR, Boston and the two studies combined, respectively. The association was significantly stronger in men than in women (p for resistin-by-gender interaction = 0.003). For each resistin SD increment, the odds of having eGFR < 0 ml/min/1.73m2 increased by 22% (OR = 1.22; 95% CI 1.02–1.44; p = 0.025) in SGR sample, 69% (OR = 1.69; 95% CI 1.38–2.07; p < 0.001) in Boston sample, and 47% (OR = 1.47; 95% CI 1.29–1.68; p < 0.001) in the two studies considered together. Similar associations were observed in the adjusted model: OR 95% CI for each SD resistin increment being 1.23 (1.03–1.46), p = 0.021; 1.52 (1.20–1.92), p < 0.001; 1.33 (1.16–1.53), p < 0.001, in SGR, Boston and the two studies combined, respectively. Conclusions This is the first report of an association between high serum resistin and low eGFR in patients with T2D of European ancestry.