The association of leptin and homocysteine with renal function impairment in a population of Taiwanese adults

Association of hyperhomocysteinemia and chronic kidney disease in the general population: a systematic review and meta-analysis

BACKGROUND

Increasing evidence shows that an elevated homocysteine(Hcy) level is associated with an increased risk of chronic kidney disease (CKD). This study systematically evaluated the correlation between homocysteine level and the incidence of CKD reported in cohort and cross-sectional studies.

METHODS

We searched electronic databases and reference lists for relevant articles. 4 cohort studies and 7 cross-sectional studies including 79,416 patients were analyzed in a meta-analysis. Hyperhomocysteinemia was defined as a Hcy level > 15 µmol/L, which was the criterium used in previous studies. Meta-analyses were conducted of literature searches from online databases such as PubMed, Embase, Cochrane and Scopus. Computed pooled adjusted odds ratios with corresponding 95% confidence intervals (95% CI) were used to estimate the risk of new-onset CKD according to Hcy levels in the general population.

RESULTS

People with high Hcy levels were more likely to suffer from CKD than people with normal Hcy levels (pooled OR, 2.09; 95% CI, 1.72-2.55). This positive relationship persisted across different study types such as cohort studies (summary OR, 2.2; 95% CI, 1.55-3.13) and cross-sectional studies (summary OR, 2.07; 95% CI, 1.63-2.63).

CONCLUSIONS

People with hyperhomocysteinemia have a higher incidence of CKD, Hyperhomocysteinemia may also be an independent risk factor for CKD in the general population.

Folate Deficiency Enhanced Inflammation and Exacerbated Renal Fibrosis in High-Fat High-Fructose Diet-Fed Mice

The prevalence of obesity and chronic kidney disease (CKD) is increasing simultaneously and rapidly worldwide. Our previous study showed that folate deficiency increased lipid accumulation and leptin production of adipocytes. Whether folate plays a role in CKD, particularly obesity-related nephropathy remains unclear. To investigate the effects of folate deficiency on CKD in diet-induced obese mice, four groups of male C57BL/6 mice were fed either a normal-fat diet (NF) with folate (NF+f); NF without folate (NF-f); high-fat high-fructose diet (HFF) with folate (HFF+f); or HFF without folate (HFF-f) for 12 months during the study. The results showed that HFF increased not only body weight, fasting blood glucose, total cholesterol (TC), low-density lipoprotein (LDL)-cholesterol, and blood pressure, but also cytokines levels, such as interleukin (IL)-2, interferon (IFN)-γ, IL-17A/F, IL-6, monocyte chemoattractant protein (MCP)-1, and transforming growth factor (TGF)-β1. The indicators of kidney failure including urinary protein, neutrophil gelatinase-associated lipocalin (NGAL), renal type I and IV collagen deposits and leptin content, and serum creatinine were also increased by HFF. Folate-deficient diets further elevated serum TC, LDL-cholesterol, IL-6, tumor necrosis factor (TNF)-α, MCP-1, TGF-β1, and leptin, but decreased IL-10 level, and thus exacerbated renal fibrosis. To investigate the possible mechanisms of folate deficiency on renal injury, phosphorylation of pro-fibrosis signaling molecules, including signal transducer and activator of transcription (STAT)3 and small mothers against decapentaplegic (Smad)2/3, were assayed. Both HFF and folate deficiency significantly increased the phosphorylation of STAT3 and Smad2/3, suggesting synergistic effects of HFF-f on chronic renal inflammation and fibrosis. In conclusion, the results demonstrated that folate deficiency might aggravate inflammatory status and enhance renal fibrosis.

Serum homocysteine is a valuable marker for predicting aggravation of infection in intestinal obstruction patients

The aim of this study was to investigate the expression of serum homocysteine (HCY), procalcitonin (PCT), and C-reactive protein (CRP) in abdominal infectious disease and analyze their relationship with the degree of abdominal infection. We conducted a retrospective study involving 157 patients with abdominal infections at Xuzhou Central Hospital between January 2016 and October 2019. The patients were composed of intestinal obstruction (73 cases), appendicitis (45 cases), perforation of the digestive tract (25 cases), and cholecystitis (14 cases). The HCY, PCT, and CRP levels of patients with abdominal infections were detected using enzyme-linked immunosorbent assay (ELISA), and correlation analysis between the HCY, PCT, and CRP levels and abdominal infection was performed using Pearson's correlation analysis. Compared with before treatment, the HCY, PCT, and CRP levels in the four groups decreased significantly after treatment. The levels in the patients in the intestinal obstruction group decreased more markedly than in those in the other groups. There were positive correlations among the HCY level, PCT, and CRP before treatment only in patients with intestinal obstruction (P < 0.001). The difference was statistically significant in the HCY level between the non-operation and the operation groups in patients with intestinal obstruction (P < 0.001). Serum HCY may be a valuable marker for predicting aggravation of infection in patients with intestinal obstruction.

The Controversial Role of HCY and Vitamin B Deficiency in Cardiovascular Diseases

Plasma homocysteine (HCY) is an established risk factor for cardiovascular disease CVD and stroke. However, more than two decades of intensive research activities has failed to demonstrate that Hcy lowering through B-vitamin supplementation results in a reduction in CVD risk. Therefore, doubts about a causal involvement of hyperhomocysteinemia (HHcy) and B-vitamin deficiencies in atherosclerosis persist. Existing evidence indicates that HHcy increases oxidative stress, causes endoplasmatic reticulum (ER) stress, alters DNA methylation and, thus, modulates the expression of numerous pathogenic and protective genes. Moreover, Hcy can bind directly to proteins, which can change protein function and impact the intracellular redox state. As most mechanistic evidence is derived from experimental studies with rather artificial settings, the relevance of these results in humans remains a matter of debate. Recently, it has also been proposed that HHcy and B-vitamin deficiencies may promote CVD through accelerated telomere shortening and telomere dysfunction. This review provides a critical overview of the existing literature regarding the role of HHcy and B-vitamin deficiencies in CVD. At present, the CVD risk associated with HHcy and B vitamins is not effectively actionable. Therefore, routine screening for HHcy in CVD patients is of limited value. However, B-vitamin depletion is rather common among the elderly, and in such cases existing deficiencies should be corrected. While Hcy-lowering with high doses of B vitamins has no beneficial effects in secondary CVD prevention, the role of Hcy in primary disease prevention is insufficiently studied. Therefore, more intervention and experimental studies are needed to address existing gaps in knowledge.

Factors associated with hyperhomocysteinemia in relatively healthy Taiwanese adults: A retrospective medical record study

Elevated homocysteine levels have been proposed as a risk factor for cardiovascular disease. The aim of this study was to evaluate factors associated with hyperhomocysteinemia in relatively healthy Taiwanese adults.A retrospective cross-sectional study was conducted using data from the health examination database in a medical center located in southern Taiwan. Hyperhomocysteinemia was defined as a plasma homocysteinemia level >15 μmol/L. Factors associated with hyperhomocysteinemia were evaluated using univariate and multiple stepwise logistic regression analyses.A total of 817 adults with a mean age of 55.5 years were included in the present study, and of them, 67 (8.2%) had hyperhomocysteinemia. Results from multiple logistic regression analysis showed that male sex (Odd ratio [OR] = 12.28, 95% CI = 2.94-51.27, P  = .001), advanced age (OR = 1.37 per 10 years, 95% CI = 1.06-1.77, P = .017), triglycerides (OR = 1.02 per 10 mg/dL, 95% CI = 1.01-1.04, P = .010), and uric acid (OR = 1.27, 95% CI = 1.09-1.49, P = .004) were significantly and independently associated with hyperhomocysteinemia.In this retrospective medical record study, male sex, advanced age, higher plasma level of triglyceride, and uric acid were significantly associated with hyperhomocysteinemia in relatively healthy Taiwanese adults.

Relationship between lactate dehydrogenase and albuminuria in Chinese hypertensive patients

Lactate dehydrogenase (LDH) has been reported to be positively correlated with albuminuria assessed by urinary albumin‐to‐creatinine ratio (UACR) in patients with sickle cell disease; both LDH and albuminuria are positively associated with the severity of hypertension (HTN). Here, a cross‐sectional study was performed to investigate the association between LDH and albuminuria in Chinese hypertensives. A total of 1169 Chinese individuals (aged 58.0 ± 11.5 years, 60.4% male), who were admitted to our hospital, were included in this study. Based on the level of LDH, all hypertensives (n = 802) were divided into three groups: HTN1 (lowest tertile of LDH, n = 264), HTN2 (mediate tertile of LDH, n = 268), and HTN3 (highest tertile of LDH, n = 270). Hypertensives with hyperhomocysteinemia were defined as hypertensives with homocysteine ≥15μmol/L. Meanwhile, 367 normotensives served as controls. Compared with normotensives, the levels of LDH and UACR were significantly higher in hypertensives (p < .05). There was an increasing trend of albuminuria (UACR ≥30 mg/g) from control, HTN1, HTN2 to HTN3 group (4% vs. 12.1% vs. 14.9% vs. 19.6%, χ² = 38.886, p < .001). Stepwise multiple regression analysis showed an independent association between LDH and UACR in patients with HTN (β = 0.085, p < .05), but not in normotensives. After further stratification in hypertensive patients, this correlation remained in the male (β = 0.161, p < .001), elderly (age ≥65 years, β = 0.174, p < .001) and especially hypertensives with hyperhomocysteinemia (β = 0.402, p < .001). LDH combined with white blood cell (WBC) counts was observed to have better discrimination for albuminuria than creatinine united with cystatin C in hypertensives according to receiver operation characteristic curves (area under curve: 0.637 vs. 0.535, z = 2.563, p = .0104). In conclusion, the level of LDH was associated with albuminuria in Chinese patients with HTN, particularly in hypertensives with hyperhomocysteinemia. LDH combined with WBC provided better prediction of albuminuria than routine renal function assessment in hypertensives. Further studies are needed to confirm LDH as an early marker for the risk of kidney involvement among hypertensives.

Hyperhomocysteinemia Concurrent with Metabolic Syndrome Is Independently Associated with Chronic Kidney Disease among Community-Dwelling Adults in an Urban Korean Population

Elevated homocysteine (Hcy) levels and metabolic syndrome (MetS) are associated with chronic kidney disease (CKD). We investigated the combined effects of hyperhomocysteinemia (HHcy) and MetS on CKD among community-dwelling adults in an urban area of South Korea. We also identified the combination of HHcy and individual MetS components associated with the maximal risk of CKD. A retrospective cross-sectional study involving 19,311 health examinees between 2 January 2011 and 31 December 2015 was conducted. The participants were divided into four groups—namely, the HHcy−/MetS−, HHcy−/MetS+, HHcy+/MetS−, and HHcy+/MetS+ groups. CKD was defined as a low eGFR <60 mL/min/1.73 m² or albuminuria. The HHcy+/MetS+ group had a higher risk of CKD than the HHcy−/MetS+ group (odds ratio (OR): 1.750, p = 0.002 for males; OR: 3.224, p < 0.001 for females). The HHcy+/MetS+ group had a higher CKD risk than the HHcy+/MetS− group; however, the difference was not statistically significant (OR: 1.070, p = 0.712 for males; OR: 1.847, and p < 0.074 for females). HHcy concurrent with MetS increased the CKD risk. Among the combinations of HHcy and MetS components, the coexistence of HHcy and central obesity had the greatest effect on CKD. Therefore, the timely detection and treatment of HHcy and MetS are important for preventing CKD.

Sex differences in risk factors for stroke in patients with hypertension and hyperhomocysteinemia

Data on the sex-specific differences in risk of stroke among patients with H-type hypertension are limited. We aimed to analyze interactions between sex and other risk factors on stroke, including the sex-methylenetetrahydrofolate reductase (MTHFR) interaction. A retrospective analysis of baseline data from 2040 patients with hypertension and hyperhomocysteinemia (HHcy) included demographic characteristics, biomarkers, history of chronic diseases and lifestyle factors. Polymerase chain reaction-restriction fragment length polymorphism method was used to investigate the C677T polymorphism of MTHFR gene. We examined independent effects and interactions between sex and stratified factors on the risk of stroke by logistic regression model. A total of 1412 patients suffered stroke, and the prevalence of stroke was 70.65% in men and 66.53% in women. Both men and women had independent risk factors for stroke, including diabetes mellitus, atrial fibrillation, smoking, increased level of systolic blood pressure (SBP) and plasma total homocysteine (tHcy), as well as the decreased level of high-density lipoprotein cholesterol. Diastolic blood pressure (DBP) -specific risk of stroke was unique to men. Interactions between sex and other risk factors on stroke risk were statistically significant: age, fasting plasma glucose (FPG), SBP, DBP, triglycerides (TG) and tHcy. Furthermore, tHcy interacted with age, SBP and DBP in men, and age, SBP, DBP, FPG, and TG in women to modulate the risk of stroke. Although TT genotype did not have an independent effect on stroke, it could interact with sex and FPG, TG and SBP to increase stroke. In conclusion, sex-specific differences are useful to stratify the risk of stroke and assist clinicians in the decision to select a reasonable therapeutic option for high-risk patients.

Vitamin B6 intake and incidence of diabetic retinopathy in Japanese patients with type 2 diabetes: analysis of data from the Japan Diabetes Complications Study (JDCS)

PURPOSE

Although vitamin B6 has been suspected to prevent the progression of diabetic retinopathy, evidence of this in patients with type 2 diabetes based on longitudinal studies is sparse. This study investigated the relationship between vitamin B6 intake and the incidence of diabetic retinopathy in Japanese patients with type 2 diabetes.

METHODS

The study was part of an examination of a nationwide cohort of patients with type 2 diabetes aged 40-70 years with HbA1c ≥ 48 mmol/mol. After excluding nonresponders to a dietary survey using the Food Frequency Questionnaire based on food groups, 978 patients were analyzed. Primary outcome was the 8-year risk of a diabetic retinopathy event, and Cox regression analyses estimated hazard ratios (HRs) for retinopathy according to vitamin B6 intake adjusted for age, gender, body mass index, HbA1c, smoking, energy intake, and other confounders.

RESULTS

Mean vitamin B6 intake in quartiles ranged from 1.1 to 1.6 mg/day, and half of the participants had vitamin B6 intake below the recommended daily dietary allowance according to dietary reference intakes in Japanese adults (men 1.4 mg/day; women 1.2 mg/day). After adjusting for confounders, HRs for diabetic retinopathy in the 2nd, 3rd, and 4th quartile groups of vitamin B6 intake compared with the 1st quartile group were 1.17 (95% confidence interval 0.81-1.69, p = 0.403), 0.88 (0.58-1.34, p = 0.550), and 0.50 (0.30-0.85, p = 0.010), respectively.

CONCLUSIONS

Findings suggested that high vitamin B6 intake was associated with a lower incidence of diabetic retinopathy in Japanese with type 2 diabetes.

Obesity, hyperhomocysteinaemia and risk of chronic kidney disease: a population-based study

BACKGROUND

Obesity is associated with increased risk of cardiovascular disease and chronic kidney disease (CKD). Hyperhomocysteinaemia refers to increased oxidative stress and has been associated with the risk of CKD.

OBJECTIVES

We investigated the association among body mass index (BMI), homocysteine level and impaired renal function in a Taiwanese adult population.

METHODS

This was a retrospective cross-sectional study involving 24826 subjects who underwent a health check-up from January 2013 to December 2015. A multivariate linear regression model was developed to analyse the relationship among BMI, serum homocysteine and estimated glomerular filtration rate (eGFR). A multivariate logistic regression model was used to assess the relationship among weight categories, hyperhomocysteinaemia and CKD.

RESULTS

The prevalence of CKD in the quartile groups of homocysteine were 2.5%, 2.7%, 3.4% and 5.2% (P < 0.01). For every one-unit increase in BMI (kg/m2), the eGFR decreased by 0.50 ml/min/1.73 m2. Overweight/obese subjects with high homocysteine levels had a higher odds ratio (OR) for CKD, as compared with normal weight subjects (1.84 versus 1.38, respectively; P < 0.01 versus P = 0.02, respectively). Overweight/obese female subjects with hyperhomocysteinaemia had an OR of 3.40 [P < 0.01; 95% confidence interval (CI): 2.06-5.61] for CKD; in males, the OR was 1.66 (P < 0.01; 95% CI: 1.38-1.99).

CONCLUSIONS

Patients who are overweight/obese with higher homocysteine levels have an increased risk of CKD, especially females. Additional studies exploring whether the effect of weight loss or homocysteine-lowering therapies such as folic acid, vitamin B12 supplements that may prevent or slow the progression of declining renal function, is warranted.

Association between Homocysteine Levels and All-cause Mortality: A Dose-Response Meta-Analysis of Prospective Studies

Plasma homocysteine (Hcy) levels may be associated with all-cause mortality risk. However, the results of this association are conflicting and the dose-response relationship between them has not been clearly defined. In this meta-analysis, we conducted a systematic literature search of the PubMed, Embase, Web of Science and Cochrane Library for the relevant articles dated up to February 2017. Pooled relative risks (RRs) and corresponding 95% confidence intervals (CIs) were calculated to evaluate the estimates, and the dose-response relationship was estimated using a restricted cubic spline model. Eleven prospective studies (4,110 deaths among 27,737 individuals) were included. The summary RR of all-cause mortality for the highest Hcy category vs. the lowest Hcy category was 1.80 (95% CI: 1.51, 2.14) with the random effects model. In dose-response meta-analysis, Hcy levels were significantly associated with all-cause mortality risk in a linear fashion (p_nonlinearity = 0.255), and the risk of all-cause mortality increased by 33.6% for each 5 µmol/L increase in Hcy levels (RR = 1.336, 95% CI: 1.254–1.422, p < 0.001). Findings from this dose-response meta-analysis suggest that Hcy levels are linearly and positively associated with risk of all-cause mortality.