The metabolic syndrome and risk of chronic kidney disease: pathophysiology and intervention strategies

Association between preterm delivery and the risk of maternal renal disease: A systematic review and meta‑analysis

The present systematic review and meta-analysis aimed to generate high-quality evidence on the association between preterm delivery (PTD) and subsequent risk of renal disease in the mother. A literature search was conducted on PubMed, Embase, CENTRAL and Scopus until the 15th of May 2023 for studies reporting an adjusted association between PTD and the risk of maternal renal disease. A total of seven studies were eligible. The pooled analysis found that women with PTD had a statistically significant increased risk of chronic kidney disease in the long term [hazard ratio (HR): 1.82 95% confidence interval (CI): 1.38, 2.40; I2=85%]. Similarly, the meta-analysis also found a statistically significant increased risk of end-stage renal disease (ESRD) amongst women with PTD as compared with those without PTD (HR: 2.22 95% CI: 1.95, 2.53; I2=0%). Overall, the pooled analysis showed a significantly higher incidence of renal disorders with PTD (HR: 1.98; 95% CI: 1.57, 2.50; I2=88%). The results were unchanged on sensitivity analysis. Women with PTD could be at increased risk of future chronic kidney disease and ESRD. The small number of studies and retrospective nature of data are important limitations. Further studies are needed to supplement the available evidence.

Association of metabolic syndrome and chronic kidney disease

The prevalence of kidney disease is increasing rapidly worldwide, reflecting rising rates of obesity, diabetes, and associated metabolic syndrome (MetS). Chronic kidney disease and related comorbidities such as obesity, diabetes, and hypertension place a significant financial burden on healthcare systems. Despite the widespread use of RAAS inhibitors, intensive blood pressure and glycemic control, and newer therapeutic options consisting of sodium/glucose cotransporter-2 (SGLT-2) inhibitors or glucagon-like peptide-1 (GLP-1) receptor agonists, a significant risk of progression to end-stage renal disease remains in the high-risk obese and diabetic population. The MetS is a cluster of cardiovascular risk factors that adversely affect the development and progression of chronic kidney failure. According to the criteria of the World Health Organization, it is defined by visceral adiposity, impaired glucose tolerance or insulin resistance, atherogenic dyslipidemia, raised blood pressure, and microalbuminuria with a albumin-to-creatinine ratio ≥30 mg/g. At molecular level MetS is marked by a proinflammatory state and increased oxidative stress leading to various pathophysiological changes causing endothelial dysfunction and a hypercoagulable state. Because the kidney is a highly vascularized organ, it is especially susceptible for those microvascular changes. Therefore, the MetS and its individual components are associated with the premature development, acceleration, and progression of chronic kidney disease. Therefore, it is becoming increasingly important to elucidate the underlying mechanisms of MetS-associated chronic kidney disease in order to develop new strategies for preventing and slowing the progression of renal disease. In this review, we will elucidate (i) the renal structural, hemodynamic, and metabolic changes that occur in obesity and obesity-related kidney injury; (ii) the clinicopathological characteristics of obesity-related kidney injury, primarily focusing on obesity-associated glomerulopathy; (iii) the potential additional factors or predisposing factors that may turn patients more susceptible to renal structural or functional compensatory failure and subsequent injury.

Food Emulsifiers and Metabolic Syndrome: The Role of the Gut Microbiota

The use of emulsifiers in processed foods and the rapid epidemic development of metabolic syndrome in Western countries over the past 20 years have generated growing interest. Evidence for the role of emulsifiers in metabolic syndrome through gut microbiota has not been clearly established, thus making it challenging for clinical nutritionists and dietitians to make evidence-based associations between the nature and the quantity of emulsifiers and metabolic disorders. This narrative review summarizes the highest quality clinical evidence currently available about the impact of food emulsifiers on gut microbiota composition and functions and the potential development of metabolic syndrome. The state-of-the-art of the different common emulsifiers is performed, highlighting where they are present in daily foods and their roles. Recent findings of in vitro, in vivo, and human studies assessing the effect of different emulsifiers on gut microbiota have been recently published. There is some progress in understanding how some food emulsifiers could contribute to developing metabolic diseases through gut microbiota alterations while others could have prebiotic effects. However, there are still many unanswered questions regarding daily consumption amounts and the synergic effects between emulsifiers' intake and responses by the microbial signatures of each individual.

Association of Evaluated Glomerular Filtration Rate and Incident Diabetes Mellitus: A Secondary Retrospective Analysis Based on a Chinese Cohort Study

Background

Previous studies have revealed that chronic kidney disease (CKD) is a significant risk factor for insulin resistance and diabetes. However, few studies are on the association between estimated glomerular filtration rate (eGFR) and incident diabetes, especially in the Chinese population with eGFR>60 mL/min·1.73 m2. This study explored the relationship between eGFR and incident diabetes in a large cohort in the Chinese community.

Methods

This study was a retrospective cohort study. A total of 1,99,435 adults from Rich Healthcare Group in China were studied, including all medical records for participants who received a health check from 2010 to 2016. The target-independent and target-dependent variables were eGFR measured at baseline, and incident diabetes mellitus appeared during the follow-up. After testing the proportion hypothesis, Cox proportional hazards regression was used to investigate the association between eGFR and incident diabetes. A Cox proportional hazards regression with cubic spline functions and smooth curve fitting (the cubic spline smoothing) was used to identify non-linear relationships between eGFR and the risk of diabetes. Additionally, we also performed subgroup analysis and a series sensitivity analysis. It was stated that the data had been uploaded to the DATADRYAD website.

Result

After adjusting gender, body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), fasting plasma glucose (FPG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglyceride (TG), alanine aminotransferase (ALT), aspartate aminotransferase (AST), smoking and drinking status, and family history of diabetes, the result showed that eGFR was negatively associated with incident diabetes [HR = 0.986, 95% CI (0.984, 0.988)]. A non-linear relationship was detected between eGFR and incident diabetes, with an inflection point of eGFR of 98.034 mL/min·1.73 m2. The effect sizes and the confidence intervals (Cis) on the left and right sides of the inflection point were 0.998 (0.993, 1.003) and 0.976 (0.972, 0.980), respectively. Subgroup analysis showed a stronger association in the population with FPG <6.1 mmol/L, BMI <24 kg/m2, SBP <140 mmHg, DBP <90 mmHg and family history without diabetes. The same trend was also seen in women and the population who never smoke.

Conclusion

Estimated glomerular filtration rate is independently associated with incident diabetes. The relationship between eGFR and incident diabetes is also non-linear. eGFR is strongly related to incident diabetes when eGFR was above 98.034 mL/min·1.73 m2.

Risk of chronic kidney disease in women with a history of preterm delivery: Tehran Lipid and Glucose Study

BACKGROUND

Preterm delivery (PTD) may predict the risk of long-term maternal complications. Little is known about the association between preterm delivery and maternal risk of chronic kidney disease (CKD).This study aimed to explore whether a history of preterm delivery is associated with the risk of maternal CKD.

METHODS

In this population-based cohort study within the framework of the Tehran Lipid and Glucose Study (TLGS), a total of 3035 women with at least one delivery met our eligibility criteria. A time-dependent Cox proportional-hazards regression model was used to measure the hazard ratios (HRs) and 95% confidence intervals (CIs) for evaluating the association between history of preterm delivery and risk of CKD, adjusted for smoking, parity, age at first delivery, body mass index, educational level, preeclampsia, and gestational diabetes mellitus.

RESULTS

A total of 212 women with a history of at least one preterm delivery and 2823 women with term delivery were included. The median (interquartile range) follow-up in the preterm and term delivery groups was 16 (13.0-17.0) and 16 (14.0-17.0) years, respectively. The results of multivariate Cox regression model, adjusted for confounders, showed that the risk of CKD significantly increased by 46% in women with a history of preterm delivery. Moreover, according to the time-dependent Cox regression analysis, the risk of CKD in women with a history of preterm delivery was 2.68 (95% CI 1.02, 7.05, P = 0.04) fold higher than among those with no history of  preterm delivery.

CONCLUSION

Pregnancy if complicated by preterm delivery, may increase the risk of future maternal morbidities. Our findings suggest that a history of preterm delivery was associated with an increased maternal risk of CKD in the long term. Further longitudinal studies are needed to confirm our findings.

Incident Type 2 Diabetes Among Individuals With CKD: Findings From the Chronic Renal Insufficiency Cohort (CRIC) Study

RATIONALE & OBJECTIVE

Few studies have examined incident type 2 diabetes mellitus (T2DM) in chronic kidney disease (CKD). Our objective was to examine rates of and risk factors for T2DM in CKD, using several alternative measures of glycemic control.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

1,713 participants with reduced glomerular filtration rates and without diabetes at baseline, enrolled in the Chronic Renal Insufficiency Cohort (CRIC) Study.

PREDICTORS

Measures of kidney function and damage, fasting blood glucose, hemoglobin A1c (HbA1c), HOMA-IR (homeostatic model assessment of insulin resistance), demographics, family history of diabetes mellitus (DM), smoking status, medication use, systolic blood pressure, triglyceride level, high-density lipoprotein cholesterol level, body mass index, and physical activity.

OUTCOME

Incident T2DM (defined as fasting blood glucose ≥ 126mg/dL or prescription of insulin or oral hypoglycemic agents).

ANALYTICAL APPROACH

Concordance between fasting blood glucose and HbA1c levels was assessed using κ. Cause-specific hazards modeling, treating death and end-stage kidney disease as competing events, was used to predict incident T2DM.

RESULTS

Overall T2DM incidence rate was 17.81 cases/1,000 person-years. Concordance between fasting blood glucose and HbA1c levels was low (κ for categorical versions of fasting blood glucose and HbA1c = 13%). Unadjusted associations of measures of kidney function and damage with incident T2DM were nonsignificant (P ≥ 0.4). In multivariable models, T2DM was significantly associated with fasting blood glucose level (P = 0.002) and family history of DM (P = 0.03). The adjusted association of HOMA-IR with T2DM was comparable to that of fasting blood glucose level; the association of HbA1c level was nonsignificant (P ≥ 0.1). Harrell's C for the models ranged from 0.62 to 0.68.

LIMITATIONS

Limited number of outcome events; predictors limited to measures taken at baseline.

CONCLUSIONS

The T2DM incidence rate among individuals with CKD is markedly higher than in the general population, supporting the need for greater vigilance in this population. Measures of glycemic control and family history of DM were independently associated with incident T2DM.

Study on the correlation between KCNJ11 gene polymorphism and metabolic syndrome in the elderly

The aim of the study was to examine the correlation between KCNJ11 gene polymorphism and metabolic syndrome in elderly patients. From January 2014 to January 2015, 54 elderly patients with metabolic syndrome were enrolled in this study as the observation group. During the same period, 46 healthy elderly individuals were enrolled in this study as the control group. KCNJ11 gene polymorphism (rs28502) was analyzed using polymerase chain reaction-restriction fragment length polymorphism. The expression levels of mRNA in different genotypes were detected using FQ-PCR. ELISA was used to evaluate the KCNJ11 protein expression in different genotypes. KCNJ11 gene polymorphism and metabolic syndrome was studied by measuring the blood pressure levels in patients with different genotypes. Three genotypes of KCNJ11 gene in rs28502 were CC, CT and TT. The CC, CT and TT genotype frequencies in healthy population were 8.5, 9.2 and 82.2%, respectively, while the genotype frequencies in patients with metabolic syndrome were 42.4, 49.8 and 7.8%, respectively. There were significant differences between groups (P≤0.05). However, the genotype frequencies of C/T in healthy individuals and metabolic syndrome patients were 35.3 and 38.3%, respectively. There were no significant differences between groups (P>0.05). FQ-PCR results showed that the KCNJ11 mRNA expression levels in the control and observation groups had no significant differences (P>0.05). However, the results obtained from ELISA analysis revealed that KCNJ11 protein expression level in the observation group was significantly higher than that in the control group (P<0.05). In conclusion, KCNJ11 gene polymorphism is associated with metabolic syndrome in the elderly. Elderly patients with the CC and TT genotypes are more likely to develop metabolic syndrome.

Daily Intake of Grape Powder Prevents the Progression of Kidney Disease in Obese Type 2 Diabetic ZSF1 Rats

Individuals living with metabolic syndrome (MetS) such as diabetes and obesity are at high risk for developing chronic kidney disease (CKD). This study investigated the beneficial effect of whole grape powder (WGP) diet on MetS-associated CKD. Obese diabetic ZSF1 rats, a kidney disease model with MetS, were fed WGP (5%, w/w) diet for six months. Kidney disease was determined using blood and urine chemical analyses, and histology. When compared to Vehicle controls, WGP intake did not change the rat bodyweight, but lowered their kidney, liver and spleen weight, which were in parallel with the lower serum glucose and the higher albumin or albumin/globin ratio. More importantly, WGP intake improved the renal function as urination and proteinuria decreased, or it prevented kidney tissue damage in these diabetic rats. The renal protection of WGP diet was associated with up-regulation of antioxidants (Dhcr24, Gstk1, Prdx2, Sod2, Gpx1 and Gpx4) and downregulation of Txnip (for ROS production) in the kidneys. Furthermore, addition of grape extract reduced H₂O₂-induced cell death of cultured podocytes. In conclusion, daily intake of WGP reduces the progression of kidney disease in obese diabetic rats, suggesting a protective function of antioxidant-rich grape diet against CKD in the setting of MetS.

Effect of maternal chronic disease on obstetric complications in twin pregnancies in a United States cohort

OBJECTIVE

To evaluate the effect of maternal chronic disease on obstetric complications among twin pregnancies.

DESIGN

Multicenter, retrospective, observational study.

SETTING

Clinical centers (19 hospitals).

PATIENT(S)

Twin pregnancies (n = 4,821) delivered ≥ 23 weeks of gestation and classified by maternal chronic disease (either none or any of the following: asthma, depression, hypertension, diabetes, and heart, thyroid, gastrointestinal or renal disease).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Gestational age at delivery, gestational hypertension, pre-eclampsia, gestational diabetes, placental abruption, placenta previa, hemorrhage, chorioamnionitis, maternal postpartum fever, premature rupture of membranes, labor onset (spontaneous vs. nonspontaneous), route of delivery, and maternal admission to intensive care unit.

RESULT(S)

Women with chronic disease delivered earlier (mean gestational length, 34.1 vs. 34.6 weeks) and were less likely to have term birth (risk ratio 0.80; 95% confidence interval 0.70-0.90). Cesarean delivery after spontaneous labor (risk ratio 1.20; 95% confidence interval 1.05-1.37) was also increased with chronic disease. No statistically significant effects were observed for other complications studied. Women who used assisted reproductive technology were more likely to hemorrhage, independent of chronic disease, but other findings were generally similar to the non-assisted reproductive technology sample.

CONCLUSION(S)

Chronic disease was associated with additional risk of earlier delivery and cesarean section after spontaneous labor in a nationwide sample of US twin pregnancies.