Higher blood hematocrit predicts hyperuricemia: a prospective study of 62,897 person-years of follow-up

Preexisting Hyperuricemia Before High-Altitude Ascent is Associated with a Slower Recovery of Estimated Glomerular Filtration Rate Following Descent

Zhao, Linggong, Yujie Huang, and Xiaoling Tan. Preexisting hyperuricemia before high-altitude ascent is associated with a slower recovery of estimated glomerular filtration rate following descent. High Alt Med Biol. 25:308-318, 2024. Objectives: Hypoxia at high altitudes results in elevated uric acid (UA) and reduced estimated glomerular filtration rate (eGFR). However, the impact of a prolonged high-altitude sojourn on UA levels and renal function in patients with preexisting hyperuricemia warrants further exploration. The study was to investigate the eGFR and related factors in patients with preexisting hyperuricemia following exposure to high altitude. Methods: The study included 345 participants, who worked at a high altitude for 1 year. Anthropometric and laboratory indices were collected before ascent (i.e., baseline), as well as 20 and 80 days after descent. The participants were categorized into individuals with hyperuricemia (HUA) or normal uric acid (NUA) group based on the presence or absence of hyperuricemia at baseline. Results: No difference in baseline eGFR was observed between the two groups before ascend or on day 20 after descent (p > 0.05). However, on day 80, eGFR of the HUA group was lower compared with the NUA group (p < 0.05). Correlations existed between post-descent eGFR levels and variables, including sampling time, UA levels, total and direct bilirubin, and baseline grouping. Conclusions: After high-altitude exposure, the recovery of eGFR was delayed in participants with preexisting hyperuricemia. Preexisting hyperuricemia and high-altitude hypoxia jointly contribute to renal impairment.

Incidence density of hyperuricemia and association between metabolism-related predisposing risk factors and serum urate in Chinese adults: a cohort study

Background

Evidence regarding the association between metabolism-related indicators and serum urate (SU) is limited. We aimed to obtain the incidence density of hyperuricemia and to explore the association between metabolism-related predisposing risk factors and SU.

Methods

A total of 48,979 Chinese adults from the Beijing Physical Examination Center were included in the study. The partial least squares path model was used to explore the relationship between SU and metabolism-related risk factors. The generalized additive model was used for smooth curve fitting, showing the sex-specific associations of SU at follow-up with baseline fasting blood glucose (FBG) concentrations and age.

Results

The incidence density of hyperuricemia was 78/1000 person-years. Baseline SU, age, sex, obesity, FBG, and lipid metabolism were significantly associated with SU at follow-up (all P values <0.05). Non-linear relationships were found between the baseline FBG concentrations and SU at follow-up, while U-shaped associations were observed between baseline age and SU at follow-up.

Conclusions

The SU concentration is associated with several metabolism-related risk factors such as obesity and FBG. Recognition of these associations will aid in a deeper understanding of the multifaceted nature of SU regulation.

Altered insulin secretion dynamics relate to oxidative stress and inflammasome activation in children with obesity and insulin resistance

BACKGROUND

Insulin resistance (IR) is considered the main driver of obesity related metabolic complications, and is related to oxidative stress and inflammation, which in turn promote each other. There is currently no specific definition of IR in children, rather, that for adult population is used by pediatric endocrinologists instead. Altered insulin secretion dynamics are associated with worse metabolic profiles and type 2 diabetes mellitus development, thus we aimed to test whether insulin response relates to oxidative stress and inflammation in children.

METHODS

We conducted a case-control study, including 132 children classified as follows: 33 children without obesity (Lean); 42 with obesity but no IR according to the American Diabetes Association criteria for adults (OBIR-); 25 with obesity and IR and an early insulin response to an oral glucose tolerance test (OGTT) (EP-OBIR +); 32 with obesity, IR, and a late insulin peak (LP-OBIR +); and studied variables associated with lipid and carbohydrate metabolism, oxidative stress, inflammation and inflammasome activation.

RESULTS

The measured parameters of children with obesity, IR, and an early insulin response were similar to those of children with obesity but without IR. It was late responders who presented an impaired antioxidant system and elevated oxidative damage in erythrocytes and plasma, and inflammasome activation at their white blood cells, despite lower classical inflammation markers. Increased uric acid levels seems to be one of the underlying mechanisms for inflammasome activation.

CONCLUSIONS

It is insulin response to an OGTT that identifies children with obesity suffering oxidative stress and inflammasome activation more specifically. Uric acid could be mediating this pathological inflammatory response by activating NLRP3 in peripheral blood mononuclear cells.

A Mathematical Model for Blood Flow Accounting for the Hematological Disorders

This paper considers a mathematical model that accounts for the hematological disorders of blood in its flow in human arteries. Blood is described as a Newtonian fluid but with its viscosity as a function of the hematocrit, plasma viscosity, and shape factor of the red blood cells. The artery is modeled as a flexible circular pipe with the blood flow as oscillatory. This model is solved using HAM (Homotopy Analysis Method), an approximate analytical method, and we computed expressions for wall shear stress (WSS) and volumetric flow rate. With the help of publicly available data, blood flow in the human femoral artery for male and female populations aged 19 to 60 and above years is simulated for healthy, anemia, and polycythemia cases. The model projected a significant difference in the mean volumetric flow rates in the conditions mentioned above. Results also indicated that the mean WSS of healthy and anemic populations are not significantly different. However, a significant difference in the mean has been observed in healthy and polycythemic conditions. Furthermore, a 33.3% decrease in hematocrit value from that in the normal range (taken as 0.45) of a healthy population has increased the flow rate by 33.5%. For a value 33.3% above 0.45, there is a decrease of 42.7% in the flow rate.

Risk factors for the development of hyperuricemia: A STROBE-compliant cross-sectional and longitudinal study

Hyperuricemia has received increasing attention as a major public health problem. This study aims to investigate the risk factors for hyperuricemia and to explore the relationship between changes in biochemical variables and incident hyperuricemia.A cross-sectional and subsequently prospective study was performed among adults who took their health checkups at Zhejiang University Hospital. The participants who were free of hyperuricemia at baseline received annual follow-up examinations during a 6-year period. Cox proportional hazards regression analyses were conducted to calculate the risks for incident hyperuricemia.Of the 9238 participants enrolled, 1704 (18.4%) were diagnosed as hyperuricemia. During 21,757 person-years of follow-up, 1492 incident hyperuricemia cases were identified. The incidence of hyperuricemia was 68.58 cases per 1000 person-year of follow-up in the overall participants. The prevalence and the incidence of hyperuricemia increased greatly in female older than 50 years. High levels of BMI, SBP, FPG, TG, LDL-C, ALT, BUN, and creatinine increased the risk of hyperuricemia. Suffering fatty liver also increased the risk of hyperuricemia. Subjects with increasing DBP, TG, BUN, creatinine, or decreasing HDL-C were more likely to incident hyperuricemia.This study revealed that the change of diastolic blood pressure (DBP), serum triglycerides (TG), blood urea nitrogen (BUN), creatinine, and high-density lipoprotein cholesterol (HDL-C) level were independently associated with incident hyperuricemia.

Association of hematocrit with blood pressure and hypertension

BACKGROUND

Hypertension (HTN) is a risk factor for stroke, renal failure, and cardiovascular disease. The association between biochemical and hematological parameters with high blood pressure may provide a more precise approach to risk prediction conferred by HTN in these patients.

OBJECTIVE

The aim of current study was to explore whether biochemical and hematological parameters are associated with HTN in a cohort study with a 7-year follow-up.

MATERIALS AND METHODS

A total of 9808 individuals were enrolled and recruited as part of the Mashhad Stroke and Heart Atherosclerotic Disorders (MASHAD) cohort study, and biochemical and hematological factors were measured in all subjects. Univariate and multivariate logistic regression analysis were performed to determine the association of biochemical and hematological parameters with HTN.

RESULTS

Several biochemical parameters including fasting plasma glucose (FBG), serum high-sensitivity C-reactive protein (hs-CRP), triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and uric acid were increased in hypertensive participants. In contrast, serum high-density lipoprotein cholesterol (HDL-C) was lower in hypertensive individuals. Furthermore, we demonstrated that hematological parameters including white blood cell (WBC) count, red blood cell (RBC) count, hemoglobin (HGB), hematocrit (HCT), and mean corpuscular hemoglobin (MCH) were higher in the hypertensive group compared to the control group. But mean corpuscular volume (MCV), and red cell distribution width (RDW), were decreased in the hypertensive group. Furthermore, our results strongly suggested that among these parameters, hematocrit was the independent risk factor for hypertension in the population.

CONCLUSION

We demonstrated the association of altered biochemical and hematological factors with hypertension supporting the value of emerging markers for early prediction of high blood pressure in prone individuals.

Relationship between cigarette smoking and hyperuricemia in middle-aged and elderly population: a cross-sectional study

The aim of the study was to estimate the cross-sectional association between cigarette smoking and the prevalence of hyperuricemia (HU) in the middle-aged and elderly males and females. A total of 3415 males and 2932 females were included in this study. HU was defined as SUA≥ 416 mmol/L for males and ≥360 mmol/L for females. The smoking status was classified into four categories based on daily smoking habit: (1) 0/day; (2) 1-10/day; (3) 11-20/day; and (4) >20/day. Multivariable logistic regressions were conducted to examine the aforementioned association. The prevalence of HU in the male and female sample was 25.0 and 10.0 %, respectively. In male subjects, the prevalence of HU in smokers (22.8 %) was significantly lower than that in non-smokers (26.5 %) (p = 0.016). Meanwhile, with adjustment for potential confounding factors, the prevalence of HU in smokers was still lower (OR = 0.83, 95 % CI 0.70-0.98, P = 0.033). Furthermore, a significantly inverse association between smoking status and HU was observed in the multivariable model. The multivariable-adjusted OR (95 % CI) for HU in the second, third and fourth category of smoking status was 0.84 (95 % CI 0.66-1.06), 0.90 (95 % CI 0.69-1.18) and 0.76 (95 % CI 0.58-0.99), respectively, compared with that in the first category. A clear trend (P for trend was 0.036) was observed. However, there was no significant association between cigarette smoking and HU in female subjects (P for trend was 0.739). This study indicated an inverse association between cigarette smoking and the prevalence of HU in the middle-aged and elderly male population, independent of some major confounding factors. The findings of this study expect further prospective studies to confirm the causal relationship.

Effect of a traditional Chinese medicine prescription Quzhuotongbi decoction on hyperuricemia model rats studied by using serum metabolomics based on gas chromatography-mass spectrometry

Morbidity of hyperuricemia has constantly increased in population in decades, and hyperuricemia has proved to be an important risk factor for gout, cardiovascular diseases and others. Many urate-lowering drugs have unfavorable side effects and drug interactions. Quzhuotongbi decoction (QZTBD) is an empirical traditional Chinese medicine prescription for clinical therapy of hyperuricemia without serious adverse effects. In the study, we investigated the effects of QZTBD on urate and other metabolites in the sera of hyperuricemia model rats. Hyperuricemia model was established by orally administering yeast extract paste, and allopurinol served as a positive control drug. Serum metabolomics was performed by using a gas chromatography-mass spectrometry (GC-MS) method. Student's t-test and the principal component analysis (PCA) were employed to find the metabolic perturbations in hyperuricemia model rats. The levels of urate, lactate, pyruvate and ornithine were significantly increased, and xanthine, glyconic acids (ribonate, galactonate), amino acids (aspartate, proline, glutamine, serine, pyroglutamate, glutamate) and glucose were down-regulated greatly in the model rats. It demonstrated that nucleotide metabolism, amino acid metabolism and glycolytic pathway were disturbed by yeast administration. An orthogonal signal correction-partial least-squares discriminant analysis (OSC-PLS DA) was performed to assess the effects of yeast administering and drug treatment. 11 significantly distinctive metabolites among four groups were defined according to the variable importance for project values (VIP>1) and univariate ANOVA (p value<0.05). As compared to the model rats, the serum uric acid levels were lowered markedly under the treatment of allopurinol or QZTBD. Aspartate and glutamine involved in purine metabolism, were raised to normal level as well. The different influences on xanthine, glutamate pyroglutamate and galactonate suggested there were different mechanisms of two drugs in urate-lowering therapy. Our finding proved that QZTBD can efficiently lower the level of serum uric acid in a different way from allopurinol, which suggested that QZTBD based on the theory of TCM could be an effective therapeutic option for hyperuricemia.