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Sudden cardiac death (SCD) is an unpredictable and common mode of death in patients with heart failure (HF). Alterations in calcium handling may lead to malignant arrhythmias, resulting in SCD, and variants in calcium signaling-related genes have a significant association with SCD. Therefore, the aim of the present retrospective cohort study was to investigate the association of Ser96Ala [histidine-rich calcium-binding protein (HRC)], Ser49Gly [ß1-adrenergic receptor (ADRB1)], Arg389Gly (ADRB1) and Gly1886Ser [ryanodine receptor 2 (RYR2)] polymorphisms with serious arrhythmic events and overall mortality in patients with HF with reduced left ventricular ejection fraction of non-ischemic etiology. In total, 136 patients with HF underwent physical examination, routine laboratory tests, non-invasive assessment of cardiac function and an invasive electrophysiological study. The primary outcome was the occurrence of serious arrhythmic events, set as either SCD or appropriate implantable cardioverter-defibrillator (ICD) therapy, and the secondary outcome was all-cause death. During a median follow-up of 37 months, arrhythmic events occurred in 26 patients (19%) and 41 patients (30%) died. Patients carrying the Ser allele of the Ser96Ala polymorphism in HRC had worse survival than those with the Ala/Ala genotype (log-rank P=0.043). Despite the difference in survival time, the Ala/Ala genotype was not associated with all-cause death in the regression analysis [unadjusted hazard ratio (HR)=0.17; 95% CI, 0.02-1.21]. Regarding the Ser49Gly and Arg389Gly polymorphisms in ADRB1, homozygosity for the major alleles at both sites (Ser49Ser and Arg389Arg) was associated with a two-fold increased risk of all-cause death compared with the other genotype combinations (unadjusted HR=1.98; 95% CI, 1.02-3.82). However, this association was lost after controlling for clinical covariates. No association was observed for the Gly1886Ser polymorphism in RYR2. Overall, the present findings are concurrent with the hypothesis that the Ser96Ala (HRC), Ser49Gly (ADRB1) and Arg389Gly (ADRB1) polymorphisms may be associated with HF prognosis. In particular, the Ser96Ala polymorphism might aid in risk stratification and patient selection for ICD implantation.

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BACKGROUND: Diabetic retinopathy (DR) is characterized by ischemia, hypoxia, and angiogenesis. Erythropoietin (EPO), an angiogenic hormone, is upregulated in DR, and the association of EPO genetic variants with DR is still uncertain, as conflicting results have been reported. Therefore, we performed a case-control study followed by a meta-analysis to investigate whether the rs1617640, rs507392, and rs551238 polymorphisms in EPO gene are associated with DR. METHODS: The case-control study included 1042 Southern Brazilians with type 2 diabetes (488 without DR and 554 with DR). Eligible studies for the meta-analysis were searched from electronic databases up to June 1, 2021. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were estimated for five genetic inheritance models. RESULTS: The minor alleles of the EPO polymorphisms had nearly the same frequency in all groups of patients (35%), and no association was detected with DR in the case-control study. The meta-analysis included 14 independent sets of cases and controls with 9117 subjects for the rs1617640 polymorphism and nine independent sets with more than 5000 subjects for the rs507392 and rs551238 polymorphisms. The G allele of the rs1617640 polymorphism was suggestively associated with DR under the dominant (OR = 0.82, 95% CI: 0.68-0.98), heterozygous additive (OR = 0.82, 95% CI: 0.69-0.97), and overdominant (OR = 0.88, 95% CI: 0.79-0.97) models. In the subgroup analyses, the G allele was also suggestively associated with proliferative DR (PDR), non-proliferative DR (NPDR), and DR (PDR + NPDR) among patients with type 1 diabetes (T1DM) or non-Asian ancestry. After considering the Bonferroni correction for multiple comparisons, the G allele remained associated with NPDR and DR in T1DM. Regarding the rs507392 and rs551238 polymorphisms, no association was found between these variants and DR. CONCLUSION: Our findings provide additional support to EPO as a susceptibility gene for DR, with the rs1617640 polymorphism deserving further investigation.

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MicroRNAs (miRNAs/miRs) are involved in the pathogenesis of diabetes mellitus and its chronic complications, and their circulating levels have emerged as potential biomarkers for the development and progression of diabetes. However, few studies have examined the expression of miRNAs in diabetic retinopathy (DR) in humans. This case-control study aimed to investigate whether the plasma levels of miR-29b and miR-200b are associated with DR in 186 South Brazilians with type 2 diabetes (91 without DR, 46 with non-proliferative DR and 49 with proliferative DR). We also included 20 healthy blood donors to determine the miRNA expression in the general population. Plasma levels of miR-29b and miR-200b were quantified by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Proliferative DR was inversely associated with plasma levels of miR-29b (unadjusted OR = 0.694, 95% CI: 0.535-0.900, P = 0.006) and miR-200b (unadjusted OR = 0.797, 95% CI: 0.637-0.997, P = 0.047). However, these associations were lost after controlling for demographic and clinical covariates. In addition, patients with type 2 diabetes had lower miR-200b levels than blood donors. Our findings reinforce the importance of addressing the role of circulating miRNAs, including miR-29 and miR-200b, in DR.

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Dysregulated expression of tissue inhibitors of matrix metalloproteinases (TIMPs) is associated with systolic dysfunction and worsening heart failure (HF). However, no study has assessed the relationship between TIMP polymorphisms and chronic HF. In this study, 300 HF outpatients with reduced left ventricular ejection fraction and 304 healthy blood donors were genotyped for the 372 T > C polymorphism (Phe124Phe; rs4898) in the TIMP-1 gene and the -418 G > C polymorphism (rs8179090) in the TIMP-2 gene to investigate whether these polymorphisms are associated with HF susceptibility and prognosis. The genotype and allele frequencies of the 372 T > C polymorphism in HF patients were not significantly different from those observed among healthy subjects, and the C allele of the -418 G > C polymorphism was very rare in our population (frequency < 1%). After a median follow-up duration of 5.5 years, 121 patients (40.3%) died (67 of them from HF). Survival analysis did not show statistically significant differences in all-cause death and HF-related death between patients with and without the T allele (P > 0.05 for all comparisons). Thus, our findings do not support the hypothesis that the 372 T > C (Phe124Phe) polymorphism in the TIMP-1 gene and the -418 G > C polymorphism in the TIMP-2 gene are associated with HF susceptibility and prognosis in Southern Brazilians.

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AIM: To investigate whether the -1082A > G polymorphism (rs1800896) in the interleukin-10 (IL10) gene is associated with diabetic retinopathy (DR) in Brazilians with type 2 diabetes mellitus. METHODS: This case-control study included 847 outpatients with type 2 diabetes and 145 healthy blood donors. Four hundred and two patients had no DR, 253 had non-proliferative DR (NPDR), and 192 had proliferative DR (PDR). Genotyping was done by real-time PCR. RESULTS: Genotype and allele frequencies were similar in patients and blood donors. In relation to the presence and severity of DR, the AA genotype was overrepresented among patients with NPDR, whereas the GG genotype was more frequent among patients with PDR. Multiple logistic regression analysis showed that the AA genotype was independently associated with increased risk of NPDR, after controlling for duration of diabetes, body mass index, and insulin use (adjusted OR = 1.50; 95% CI = 1.04-2.17). The GG genotype, however, did not remain associated with increased risk of PDR (adjusted OR = 1.49; 95% CI = 0.78-2.86). CONCLUSIONS: This study identified, for the first time, an independent association of the -1082A > G polymorphism in the IL10 gene with NPDR in type 2 diabetes. This finding provides additional evidence supporting that genetic variants of IL10 are involved in the pathogenesis of DR.

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MicroRNAs are associated with myocardial damage and heart failure (HF). The present study investigated whether the plasma levels of microRNA (miR)­21, ­126 and ­423­5p alter according to the (de)compensated state of patients with HF and are associated with all­cause mortality. In 48 patients with HF admitted to the emergency room for an episode of acute decompensation, blood samples were collected to measure miR and B­type natriuretic peptide levels within 24 h of hospital admission, at the time of hospital discharge, and a number of weeks post­discharge (chronic stable compensated state). Levels of miR­21, miR­126 and miR­423­5p increased between admission and discharge, and decreased following clinical compensation. During follow­up (up to 48 months), 38 patients (79%) were rehospitalized at least once and 21 patients (44%) succumbed. Patients who had increased levels of miR­21 and miR­126 at the time of clinical compensation exhibited better 24­month survival and remained rehospitalization­free for a longer period compared with those with low levels. Additionally, patients whose levels of miR­423­5p increased between admission and clinical compensation experienced fewer hospital readmissions in the 24 months following the time of clinical compensation compared with those who had decreased levels. It was concluded that the plasma levels of miR­21, miR­126 and miR­423­5p altered during clinical improvement and were associated with the prognosis of acute decompensated HF.

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BACKGROUND/AIMS: The -1082A>G polymorphism (rs1800896) in the interleukin-10 (IL10) gene has been associated with type 2 diabetes and diabetic retinopathy, but its relationship with diabetic kidney disease (DKD) is uncertain. The aim of this case-control study was to investigate whether the -1082A>G polymorphism is associated with DKD in white Brazilians with type 2 diabetes mellitus. METHODS: Genotyping was done by real-time polymerase chain reaction for 597 type 2 diabetic outpatients. The definition of DKD was based on estimated glomerular filtration rate (eGFR) and albuminuria, and the patients were grouped in three categories: no DKD (n=249), mild to moderate DKD (n=222), and severe DKD (n=126). RESULTS: The frequency of the minor (G) allele in subjects without DKD did not differ from that observed in subjects with DKD (0.35 vs 0.39, respectively; P = 0.192). Genotype frequencies in subjects without DKD were not significantly different from those observed among patients with mild to moderate DKD or severe DKD. However, considering only the eGFR categories as an indicator of renal function, the AG genotype was independently associated with an increased risk of mildly to moderately decreased eGFR (G3a category) and GG genotype was independently associated with increased risk of kidney failure (G5 category) as compared with AA genotype. CONCLUSION: Our findings support the hypothesis that the -1082A>G polymorphism in the IL10 gene might be associated with DKD in white Brazilians with type 2 diabetes.

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AIMS: MicroRNAs (miRs) regulate processes involved in both cardiac remodeling and obesity. We investigated if the expression of selected miRs in patients with heart failure (HF) is influenced by the presence of obesity. METHODS: In this case-control study, we compared plasma levels of miR-21, -130b, -221, -423-5p, and the -221/-130b ratio in 57 age- and gender-matched subjects: 40 HF patients (20 obese HF and 20 lean HF) and 17 lean healthy controls. Body composition was estimated by bioelectrical impedance analysis. MiRs were measured by quantitative reverse transcription-PCR. Bioinformatics analysis was performed based on miRs findings to predict their putative targets and investigate their biological function. RESULTS: HF was associated with increased miR-423-5p levels in both lean and obese patients (P<0.05 vs. controls) without differences between HF groups. MiR-130b levels were reduced in obese HF patients compared with HF lean (P=0.036) and controls (P=0.025). MiR-221 levels were non-significantly increased in obese HF patients. MiR-21 levels were not different among the groups. MiR-221/-130b ratio was increased in obese HF patients, and was positively associated with body fat percentage (r=0.43; P=0.002), body mass index (r=0.44; P=0.002), and waist circumference (r=0.40; P=0.020). Computational prediction of target genes followed by functional enrichment analysis indicated a relevant role of miR-130b and miR-221 in modulating the expression of genes associated to cardiovascular and endocrine diseases, and suggested their influence in important signaling mechanisms and in numerous processes related to the circulatory and endocrine systems. CONCLUSIONS: In HF patients, the presence of obesity is associated with a differential expression of selected miRs and the miR-221/-130b ratio had significant correlations with adiposity parameters. Computational target prediction analysis identified several interrelated pathways targeted by miR-130b and miR-221 with a known relationship with endocrine and cardiovascular diseases, representing potential mechanisms to be further validated.

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CONTEXT: Matrix metalloproteinases are involved in atherosclerosis and plaque vulnerability. OBJECTIVE: To investigate serum levels and genetic polymorphisms of matrix metalloproteinases (MMPs) -1, -3 and -9 in patients submitted to carotid endarterectomy. METHODS: Genetic polymorphisms were evaluated using polymerase chain reaction (PCR-RFLP); serum levels were measured using ELISA; histological sections were stained with Picrosirius Red to analyze the fibrous cap thickness, lipid core and collagen content and with hematoxylin--eosin to detect the presence of intraplaque hemorrhage. RESULTS: MMP-9 serum levels were significantly higher in patients with a thinner fibrous cap (p = 0.033) or acute or recent intraplaque hemorrhage (p = 0.008) on histology, as well as in patients with previous stroke (p = 0.009) or peripheral vascular disease (p = 0.049). No consistent associations were observed between different MMP genotypes and fibrous cap thickness, lipid core, collagen content or intraplaque hemorrhage. CONCLUSIONS: MMP-9 serum levels were consistently associated with markers of carotid atherosclerosis and lesion vulnerability, whereas specific MMP genotypes were not.

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Diabetic retinopathy (DR) is a common chronic complication of diabetes and remains the leading cause of blindness in working-aged people. Hyperglycemia increases glucose flux through the polyol pathway, in which aldose reductase converts glucose into intracellular sorbitol, which is subsequently converted to fructose by sorbitol dehydrogenase (SDH). The accelerated polyol pathway triggers a cascade of events leading to retinal vascular endothelial dysfunction and the eventual development of DR. Polymorphisms in the gene encoding aldose reductase have been consistently associated with DR. However, only two studies have analyzed the relationship between polymorphisms in the gene encoding SDH (SORD) and DR. In this case-control study, we investigated whether the -888G > C polymorphism (rs3759890) in the SORD gene is associated with the presence or severity of DR in 446 Caucasian-Brazilians with type 2 diabetes (241 subjects with and 205 subjects without DR). The -888G > C polymorphism was also examined in 105 healthy Caucasian blood donors, and the genotyping of this polymorphism was carried out by real-time PCR. The genotype and allele frequencies of the -888G > C polymorphism in patients with type 2 diabetes were similar to those of blood donors (G allele frequency = 0.16 in both groups of subjects). Similarly, the genotype and allele frequencies in patients with DR or the proliferative form of DR were similar to those of patients without this complication (P > 0.05 for all comparisons). Thus, our findings suggest that the -888G > C polymorphism in the SORD gene is not involved in the pathogenesis of DR in type 2 diabetes.

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