Adjustment for body mass index changes inverse associations of HDL-cholesterol with blood pressure and hypertension to positive associations.

The associations between high-density lipoprotein cholesterol (HDL-C) and blood pressure (BP) or hypertension are inconsistent in previous studies. This study aimed to assess these associations in a large cohort of Chinese adults and across different age groups. This cross-sectional association study included 22,081 Chinese adults. Associations of HDL-C with BP and hypertension were analyzed using linear or logistic regression, with or without adjustment for confounding factors. HDL-C was inversely associated with BP and hypertension. These associations were still apparent after adjustment for age, sex, fasting plasma glucose, and low-density lipoprotein cholesterol. Sub-analyses revealed: (1) in the whole cohort and females alone, HDL-C was inversely associated with BP and hypertension in young and middle-aged but not older participants; (2) in males alone, HDL-C was not associated with systolic BP or hypertension. However, HDL-C was either inversely, or not, or positively associated with BP in young, middle-aged, and older males, respectively. After further adjustment for body mass index (BMI), the negative associations of HDL-C with BP and hypertension in the whole cohort became positive ones, and the positive associations only presented in males. These findings suggest that further adjustment for BMI changes inverse associations of HDL-cholesterol with BP and hypertension to positive associations in a cohort of Chinese adults.

Reduced renal function may explain the higher prevalence of hyperuricemia in older people.

This study aimed to investigate the contribution of renal dysfunction to enhanced hyperuricemia prevalence in older people. A cohort of 13,288 Chinese people aged between 40 and 95 years were recruited from January to May 2019. Serum uric acid concentration and estimated glomerular filtration rate [eGFR] were measured. The associations between age or eGFR and serum uric acid or hyperuricemia were analyzed using linear or binary logistic regression adjusting for risk factors. Uric acid concentration and prevalence of hyperuricemia were greater in older participants. Adjustment for reduced renal function (eGFR < 60 mL/min/1.73 m2) eliminated the associations between older age and higher uric acid concentration and between older age and higher prevalence of hyperuricemia diagnosis, whereas adjustment for other risk factors did not change those associations. Lower eGFR was associated with higher uric acid concentration both before (ß = - 0.296, P < 0.001) and after adjustment for age (ß = - 0.313, P < 0.001). Reduced renal function was associated with hyperuricemia diagnosis both before (odds ratio, OR, 3.64; 95% CI 3.10-4.28; P < 0.001) and after adjustment for age (adjusted OR, 3.82; 95% CI 3.22-4.54; P < 0.001). Mean serum uric acid and prevalence of hyperuricemia were higher in people with eGFR < 60 mL/min/1.73 m2 than those with eGFR ≥ 60 mL/min/1.73 m2. The prevalence of reduced renal function increased with older age (P < 0.001). This study suggests that reduced renal function can explain the increased uric acid levels and hyperuricemia diagnoses in older people.

Hyperuricemia is independently associated with hypertension in men under 60 years in a general Chinese population.

Hyperuricemia has been associated with hypertension, however, whether this association exists across all decades of adult life is unknown. This study aimed to assess the association between hyperuricemia and hypertension in relation to age. This retrospective cross-sectional study included a total of 22,556 adult Chinese people who attended Health Physical Examination in a Chinese hospital. Participants were aged between 18 and 95 years (mean [standard deviation], 45.4 [14.0]). Serum uric acid levels and blood pressure were measured. Associations between serum uric acid and blood pressure, and between hyperuricemia and hypertension diagnosis were analyzed using linear or logistic regression, adjusting for confounding risk factors including age, sex, total cholesterol, high-density lipoprotein cholesterol, and fasting blood glucose. Sub-analysis was stratified by age and sex. Before adjustment, high serum uric acid was associated with higher systolic blood pressure (ß = 0.214, P < 0.001) and higher diastolic blood pressure (ß = 0.271, P < 0.001). Hyperuricemia was associated with hypertension diagnosis (OR, 1.763; 95% CI, 1.635-1.901; P < 0.001) in an unadjusted analysis. These findings remained significant after adjusting for confounding factors. Sub-analysis suggested that the association between uric acid and blood pressure was weaker in older age groups and the association between hyperuricemia and hypertension was limited to people under 60 years. Hyperuricemia was independently associated with hypertension diagnosis in men but not in women, and the independent association between hyperuricemia and hypertension only presented in men under 60 years. This study suggests that hyperuricemia is independently associated with hypertension in Chinese men under 60 years.

Effects of rosuvastatin on atrial nerve sprouting and electrical remodeling in rabbits with myocardial infarction.

OBJECTIVE: This study is to investigate the effect of rosuvastatin on atrial nerve sprouting and electrical remodeling after myocardial infarction (MI). METHODS: Rabbit MI model was established by anterior descending branch ligation. These models were divided into the sham (n = 9), MI model (n = 7), and rosuvastatin intervention (n = 8) groups. Immunohistochemistry was used to detect the autonomic atrial nerve distribution. Real-time PCR and Western blot analysis were performed to evaluate the mRNA and protein expression levels, respectively. RESULTS: Our results from immunohistochemistry showed that, compared with the sham group, the densities of tyrosine hydroxylase (TH)- and choline acetyltransferase (CHAT)-positive nerve fibers were significantly elevated in the MI model group. However, TH- and CHAT-positive nerve fibers were significantly decreased by rosuvastatin treatment, suggesting that rosuvastatin could reduce autonomic nerve sprouting in acute MI. Moreover, rosuvastatin decreased the mRNA and protein expression levels of TH in atrial tissues following MI. Compared with the sham group, the mRNA expression level of KCND3 was significantly down-regulated in the MI model group. And, this down-regulation was restored by rosuvastatin treatment. These results suggested that rosuvastatin could inhibit the electrical remodeling in atrium after acute MI. CONCLUSION: Atrial nerve sprouting and electrical remodeling occur following MI, which could be suppressed by rosuvastatin treatment. Our findings provide insights into the understanding of the mechanism through which statins decrease the risk of atrium arrhythmia after MI.

Autonomic neural remodeling of the pulmonary vein-left atrium junction in a prolonged right atrial pacing canine model.

BACKGROUND: No evidence has been presented to show whether autonomic neural remodeling occurs in pulmonary vein-left atrium (PV-LA) junction and what an important role it may play in AF. This study aims to find out these issues in a prolonged rapid atrial pacing canine model. METHODS: Twelve healthy mongrel dogs were randomly divided into two groups, six in each: the paced group underwent rapid right atrial pacing at 400 beats per minute for 4 weeks, and the control group was not paced. The effective refractory period (ERP) of left superior pulmonary vein-left atrium (LSPV-LA) junction in all animals was determined immediately after 4 weeks. Tissues were removed from 1 cm around all PV-LA junctions. Immunohistochemical staining and western blotting were performed to examine the expression of tyrosine hydroxylase (TH) and choline acetyltransferase (ChAT). RESULTS: Compared with the control group, ERP of LSPV-LA junction of the paced group was significantly shortened ([83.33 ± 16.33] ms vs [111.67 ± 20.41] ms, P < 0.05). Spontaneous atrial fibrillation developed in two animals in the paced group, but in none of the control group. Immunohistochemistry showed that the average density and heterogeneity of both TH- and ChAT-positive nerves at LSPV-LA junction in the paced group were significantly higher compared to the control group (P < 0.01). Western blotting showed that the expression of TH and ChAT at four PV-LA junctions in the paced group also increased markedly compared with the control group (P < 0.01). CONCLUSION: Autonomic neural remodeling did exist in PV-LA junction after prolonged atrial pacing, which may contribute to the initiation of atrial fibrillation and be significant in its treatment by radiofrequency catheter ablation.