[Renal consequences of obesity]

Polycystic Ovary Syndrome Accompanied by Hyperandrogenemia or Metabolic Syndrome Triggers Glomerular Podocyte Injury

Objective: To determine whether the urinary excretion of podocyte degradation products varies according to PCOS phenotype and metabolic syndrome (MetS). Methods: The concentrations of podocalyxin (PDX) and nephrin, chronic markers of podocyte damage, and neutrophil gelatinase-associated lipocalin (NGAL), a marker of acute glomerular damage, were analyzed in the morning urine samples of 50 PCOS patients and 50 healthy controls matched by age and BMI. Albuminuria was assessed by calculating the urine albumin-creatinine ratio (uACR). Results: The PDX, nephrin and NGAL concentrations of PCOS participants were significantly higher than those of the control group. While PDX, nephrin and NGAL levels of classic phenotypes were similar, they were higher than ovulatory and non-hyperandrogenic phenotypes. Significant increases in urinary levels of each podocyte protein were detected in PCOS patients with MetS compared to patients without MetS. A positive significant correlation between podocyte proteins and BMI, systolic blood pressure, testosterone, glucose, HOMA-IR and uACR. After adjusting for age and BMI, podocyte proteins were an independent risk factor for microalbuminuria. The incidence of microalbuminuria in PCOS increased 6-fold compared to controls. The frequency of microalbuminuria was higher in classical phenotypes than in ovulatory phenotype. The frequency of microalbuminuria in PCOS patients with MetS was 6.5 times higher than in PCOS patients without MetS. Conclusions: In PCOS accompanied by hyperandrogenemia or metabolic syndrome, leakage of acute and chronic podocyte breakdown products into the urine becomes more pronounced.

Association of antenatal corticosteroids with kidney function in adolescents born preterm with very low birth weight

OBJECTIVE

Investigate if antenatal corticosteroids (ANCS) are associated with worse kidney function in adolescence and if greater adiposity magnifies this association.

STUDY DESIGN

Prospective cohort of 162 14-year-olds born preterm with very low birth weight (<1500 g). Outcomes were estimated glomerular filtration rate (eGFR) and first-morning urine albumin-to-creatinine ratio (UACR). We used adjusted generalized linear models, stratified by waist-to-height ratio (WHR) ≥ 0.5.

RESULTS

Fifty-five percent had ANCS exposure and 31.3% had WHR ≥ 0.5. In adjusted analyses of the entire cohort, ANCS was not significantly associated with eGFR or UACR. However, the ANCS-eGFR association was greater in those with WHR ≥ 0.5 (β -16.8 ml/min/1.73 m2, 95% CL -31.5 to -2.1) vs. WHR < 0.5: (β 13.9 ml/min/1.73 m2, 95% CL -0.4 to 28.1), interaction term p = 0.02.

CONCLUSION

ANCS exposure was not associated with worse kidney function in adolescence, though ANCS may be associated with lower eGFR if children develop obesity by adolescence.

Role of TGF-β signalling in PCOS associated focal segmental glomerulosclerosis

Research on polycystic ovarian syndrome (PCOS) remains intense due to its evolving impact on metabolism, reproduction and cardiovascular function. Changes in metabolic pathways can also significantly impact renal function including the development of Focal Segmental Glomerulosclerosis (FSGS), one of the most highly investigated renal diseases. In FSGS, scarring of the glomerulus vascular tuft damages the kidneys. Onset of FSGS may either be congenital or due to other disorders that affect the metabolism and normal kidney function. Both PCOS and FSGS appear to be associated with Transforming Growth Factor-β (TGF-β) signalling. Over-expression of TGF-β may be due to the activation of the thrombospondin 1 (TSP1) gene, which increases the probability of developing renal disorders. Higher androgen levels in PCOS may also cause podocyte damage thus directly impacting development of FSGS. This article reviews the role of TGF-β's in PCOS and FSGS and explores the inter-relationship between these two disorders.

Association of body mass index and weight gain patterns with albumin excretion in pregnancy

AIM

We examined body mass index (BMI) and gestational weight gain (GWG) patterns of pregnant women and investigated the impact of these factors on the urinary albumin-creatinine ratio (ACR) during pregnancy.

METHODS

The data of 163 women whose basal BMI and ACR were measured during the first trimester were used in this study. Body weight alone between 12-16 weeks and body weight together with ACR after 37 weeks of gestation were measured.

RESULTS

Overall, 46% of women were overweight or obese, 60.7% had excessive weight gain and 16.6% had inadequate weight gain. Only 22.7% of women gained weight within the recommended range. There was no difference in weight gain patterns with respect to BMI. ACR during the third trimester was significantly higher than during the first trimester (7.08 [0.00-1180.90] mg/g vs 4.73 [0.00-275.00] mg/g, respectively; P = 0.001). The ACR of obese women was higher than in normal weight subjects during the third trimester (16.79 mg/g [0.01-1180.90] vs 8.07 mg/g [0.10-402.14] respectively; adjusted P = 0.015). Both ACR change and third trimester ACR were weakly but significantly correlated with basal BMI (r: 0.228 P: 0.003 and r: 0.301 P < 0.001, respectively) but not with GWG or GWG rate. Basal BMI was not associated with first-trimester ACR.

CONCLUSION

Obesity is associated with an increase in urinary albumin excretion during the course of pregnancy. Distinction of this relationship during pregnancy offers an opportunity for further research on pathophysiological mechanisms. The alarmingly high rate of non-compliance with IOM guidelines in pregnant women is a concern. Prompt measures for counseling of women before and during pregnancy in order to maintain healthy weight are needed.

Subclinical kidney injury before and 1 year after bariatric surgery among adolescents with severe obesity

OBJECTIVE

To assess subclinical kidney injury in adolescents with severe obesity by measuring biomarkers of early kidney disease and to assess changes in the levels of these biomarkers following bariatric procedures.

METHODS

Twenty-two adolescents undergoing bariatric surgery with no microalbuminuria and normal kidney function were selected. Urinary NGAL, IL-18, and KIM-1 were measured at baseline, 6 and 12 months postoperatively. Biomarker levels were compared to 44 age-gender-matched lean controls.

RESULTS

Subjects with obesity had a mean baseline BMI of 48 kg/m(2) that decreased by 34% at 1-year follow-up. Urine NGAL, IL-18, and KIM-1 were significantly elevated in subjects with obesity compared to lean controls at baseline. The obese cohort had a further significant increase in NGAL and KIM-1 at 6 months, followed by decline at 1 year. The overall change in levels of all three biomarkers through 1 year after surgery, however, was not significant compared to baseline.

CONCLUSIONS

Adolescent severe obesity is associated with increased urinary excretion of novel biomarkers of kidney injury, despite no microalbuminuria or decreased kidney function. This subclinical kidney injury persists 1 year after significant weight loss induced by bariatric surgery, suggesting that close, long-term follow-up of kidney status is warranted in these adolescents.

The longer-term effects of Roux-en-Y gastric bypass surgery on sodium excretion

BACKGROUND

Obesity is an independent risk factor for hypertension and chronic kidney disease. During the first months after bariatric surgery, an improvement of sodium excretion has been described. The aim of this work was to study the influence of bariatric surgery on sodium excretion at more than a year after the intervention.

METHODS

Patients who have undergone Roux-en-Y gastric bypass (RYGB) and who had collected a 24-h urine sample before surgery more than 12 months ago were asked to participate. A second 24-h urine sample was collected. Blood pressure and weight were measured. The difference in sodium excretion before and after surgery was calculated, and the relationship with blood pressure and weight loss was investigated.

RESULTS

We included 33 patients; the median follow-up time was 21 months (range 14-41). Sodium excretion was high before surgery (median 195 mmol/day, IQR range 167-247) and decreased by 18 % after surgery (median 160 mmol/day, IQR range 118-205, p = 0.015), while there were significant improvements in body weight (% EWL 80.9 ± 21.8), systolic blood pressure (126 to 120 mmHg, p = 0.02), and diastolic blood pressure (84 to 77 mmHg, p = 0.002), even with a reduced number of antihypertensive drugs.

CONCLUSIONS

After RYGB and considerable weight loss, sodium excretion remains high in the longer term. The profound improvement in blood pressure cannot be explained by reductions in sodium excretion after RYGB.

Moxonidine-based combination antihypertensive therapy in patients with metabolic syndrome

Aim.To assess the effects of moxonidine-based combination therapy on clinical status, laboratory parameters, and target organs in patients with metabolic syndrome (MS).Material and methods.In total, 60 MS patients with Stage 1-2 arterial hypertension (AH) were randomised into 3 groups. Group I was administered moxonidine (0,2-0,4 mg/d) and amlodipine (5-10 mg/d); Group II received moxonidine (0,2-0,4 mg/d) and hydrochlorothiazide (12,5 mg/d); Group III was treated with moxonidine (0,2-0,4 mg/d) and enalapril (10-20 mg/d). At baseline and after 24 weeks of treatment, the following characteristics were assessed: waist circumference (WC), body mass index (BMI), 24-hour blood pressure monitoring (BMP) parameters, left ventricular myocardial mass index (LVMMI), E/A ratio, isovolumetric relaxation time (IVRT), deceleration time (DT) of early diastolic velocity, peak Em velocity at interventricular septum and lateral wall levels, E/Em ratio (myocardial tissue Doppler echocardiography), pulse wave velocity (PWV) between descending aorta and aortic bifurcation levels (ultrasound method), and stiffness index β of ascending aorta. In addition, lipid, carbohydrate, and purine metabolism parameters were assessed; glomerular filtration rate (GFR) was calculated (MDRD method); and urine albumin levels were measured.Results.In Group I (moxonidine + amlodipine), target blood pressure (BP) levels were achieved in 70% of the patients. Systolic BP (SBP) levels, LVMMI, and DT decreased by 19,3±11,4 mm Hg, 4,4 g/m2 (p=0,09), and 10,6 ms (p<0,05), respectively. The increase in E/A ratio and Em annular velocity (Em av) reached 0,4 (p<0,05) and 1,4 cm/s (p<0,05), respectively, while E/Em av ratio decreased by 0,8 (p<0,05), and PWV decreased by 1,6 ms (p<0,05). The BMI decrease reached 0,7 kg/m2 (p<0,05). In Group II (moxonidine + hydrochlorothiazide), target BP levels were achieved in 40% of the participants, with a decrease in SBP levels by 14,7 mm Hg (p<0,05). DT was reduced by 9,4 ms (p<0,05), E/A ratio increased by 0,1 (p<0,05), while PWV, BMI, and GFR decreased by 1,3 m/s (p<0,05), 0,8 kg/m2 (p<0,05), and 5,6 ml/min/1,73 m2 (p<0,05), respectively. In Group III (moxonidine + enalapril), 60% of the patients achieved target BP levels, and SBP levels were reduced by 21,1 mm Hg (p<0,05). LVMMI decreased by 5,1 g/m2 (p<0,05), Em av increased by 0,3 cm/s (p<0,05), while the respective reduction in PWV, WC, and BMI reached 1,1 m/s (p<0,05), 1,8 cm (p<0,05), and 0,5 kg/m2 (p<0,05). All three groups demonstrated a significant reduction in urine albumin levels.Conclusion.The moxonidine-based combination therapy effectively reduced the levels of BP and urine albumin. The combination of moxonidine with amlodipine or enalapril improved cardiac structure and function, as well as renal excretory function. The combination of moxonidine and hydrochlorothiazide, however, negatively affected renal excretion. All three variants of combination therapy were metabolically neutral and demonstrated beneficial effects on visceral obesity.

Which Life Style Anthropometric Index is a Better Predictor of Renal Function?

BACKGROUND

Obesity is a risk factor that has been associated scientifically with hypertension, diabetes, hyperlipidemia, cancer and other life threatening diseases. The results of some studies have also shown that obesity is an independent risk factor for the development and progression of renal damage.

OBJECTIVES

The aim of the current study is to define which general and central obesity anthropometric indices are better predictors for ceratinine clearance (CC) in healthy, normal and obese Iranian women.

PATIENTS AND METHODS

In this case-controlled study, a total of 62 healthy, normal and obese women from 18 to 30 years of age in Zahedan City, the Islamic Republic of Iran, were studied. The subjects were classified into two groups; case group (31 subjects) of healthy obese women (30 ≤ BMI ≤ 39.9 kg/m(2)) and control group (31 subjects) of healthy normal women (18.5 ≤ BMI ≤ 24.9 kg/m(2)). An assessment of body mass index (BMI) was considered as a general obesity index and an assessment of waist circumference (WC) and waist to hip ratio (WHR) were considered as central obesity indices. A measurement of CC was considered for renal function.

RESULTS

The means of CC in subjects with increased BMI, WC, and WHR were significantly higher than those in subjects with normal BMI, WC, and WHR. Pearson correlation coefficient revealed that there was a stronger correlation between CC with WC than with WHR and BMI (r = 0.4, P = 0.009; r = 0.4, P = 0.01 in the case and control groups, respectively).

CONCLUSIONS

It is suggested that in clinical practice, WC can be used as a better predictor of CC than WHR and BMI in both normal and obese, healthy women.