Obesity and kidney disease: hidden consequences of the epidemic

Obesity Management and Chronic Kidney Disease

Obesity is one of the risk factors for the development and progression of chronic kidney disease (CKD). Several studies have shown the association between increased body mass index and kidney function decline. Obesity leads to CKD directly by acting as an independent risk factor and indirectly through increasing risks for diabetes, hypertension, and atherosclerosis, a group of well-established independent risk factors for CKD. Alterations in renal hemodynamics, inflammation, and in hormones and growth factors results in hyperfiltration injury and focal segmental glomerulosclerosis. In recent years, many studies have shown that the gut microbiome may play a role in the pathogenesis of obesity. Dysbiosis has been noted in obese subjects in both human and animal studies. Changes in the gut microbiome in obese patients promote weight gain by effectively extracting energy from diet, and induction of low-grade inflammation. Evidence also points to the role of inflammation within the adipose tissue in obesity as a key factor in the pathogenesis of obesity-related complications. Thus, obesity is the net result of complex interactions between behavioral, genetic, and environmental factors. In terms of management, conservative approaches are often the first option, but they often are unsuccessful in achieving and/or maintaining weight loss, particularly in severe obesity. Consequently, nonmedical management with bariatric surgery is the most effective treatment option for morbid obesity and has shown mitigation of multiple risk factors for the progression of CKD. The most frequently performed interventions are vertical sleeve gastrectomy and Roux-en-Y gastric bypass. Studies have shown that bariatric surgery is associated with beneficial effects on CKD by mitigating its risk factors by weight loss, reducing insulin resistance, hemoglobin A1c, and proteinuria, in addition to positive long-term outcomes. Because of the epidemic of obesity, the prevalence of obesity in kidney transplant recipients also is increasing. The maximal body mass index (BMI) threshold for kidney transplantation is not clear. The Organ Procurement Transplant Network/Scientific Registry of Transplant Recipients 2019 annual data report showed that the proportion of kidney transplant recipient candidates with a BMI of 30 kg/m² or greater is increasing steadily. Morbid obesity is linked to adverse graft outcomes including delayed graft function, primary nonfunction, and decreased graft survival. Obesity is also an independent risk factor for cardiovascular death in kidney transplant recipients, suggesting that these patients should not be excluded from transplantation based on their BMI because transplantation is associated with lower mortality compared with dialysis. However, many centers exclude obese patients (with different BMI cut-off values) from transplantation to avoid postoperative complications. To minimize the surgical complications of kidney transplantation in obese patients, our center has adopted the robot-assisted kidney transplantation procedure. Our data show that this approach is comparable with historical nonobese controls in the United Network for Organ Sharing database in terms of patient and graft survival. Another surgical option for this group of patients at our center is a combined robotic sleeve gastrectomy and robotic-assisted kidney transplant. In a recent study, this approach showed promising results in terms of weight loss, patient survival, and graft survival, and might become more common in the future.

Longitudinal study of glomerular hyperfiltration and normalization of estimated glomerular filtration in adults with sickle cell disease

Glomerular hyperfiltration is common in sickle cell disease (SCD) and precedes proteinuria and declining kidney function. We evaluated hyperfiltration in SCD patients and its "normalization." Routine visit data were collected retrospectively from adult SCD patients in a single centre from 2004 to 2013. Baseline was defined as first available serum creatinine and hyperfiltration as estimated glomerular filtration rates (eGFR) >130 ml/min/1·73 m² for women and >140 ml/min/1·73 m² for men. Normalization of hyperfiltration was eGFR reduction to 90-130 ml/min/1·73 m² for women or 90-140 ml/min/1·73 m² for men. Among 292 patients, median age was 27 years [interquartile range (IQR):20·0-38·0], and 56·8% had baseline hyperfiltration. Baseline hyperfiltration was inversely associated with age [odds ratio (OR):0·86, 95% confidence interval (CI): 0·82-0·90; P < 0·0001], male sex (OR:0·16, 95% CI: 0·07-0·41; P = 0·0001), haemoglobin (OR:0·76, 95% CI 0·61-0·94; P = 0·01), weight (OR:0·96, 95% CI: 0·93-0·99; P = 0·004), and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker (ACE-I/ARB) use (OR:0·08, 95% CI: 0·01-0·75; P = 0·03), and positively with hydroxycarbamide use (OR:2·99, 95% CI: 1·18-7·56; P = 0·02). Of 89 hyperfiltration patients without baseline proteinuria, 10 (11·2%) developed new-onset proteinuria [median 1·05 years (IQR:0·63-2·09)]. Normalization of hyperfiltration was less likely with higher baseline eGFR [hazard ratio (HR):0·90, 95% CI: 0·86-0·95; P < 0·0001] and more likely in males (HR:6·35, 95% CI:2·71-14·86, <0·0001). Hyperfiltration is common in adult SCD patients, particularly when younger. Decline to normal values is more likely in males, possibly representing kidney function loss rather than improvement in hyperfiltration.

Early triggers of moderately high-fat diet-induced kidney damage

Most of the obesity murine models inducing renal injury use calorie-enriched foods, where fat represents 60% of the total caloric supply, however, this strategy doubles the standard proportion of fat ingestion in obese patients. Therefore, it is crucial to study the impact of a high-fat intake on kidney physiology that resembles common obesity in humans to understand the trigger mechanisms of the long-term consequences of overweight and obesity. In this study, we analyzed whether chronic feeding with a moderately high fat diet (MHFD) representing 45% of total calories, may induce kidney function and structural injury compared to C57BL/6 mice fed a control diet. After 14 weeks, MHFD induced significant mice obesity. At the functional level, obese mice showed signs of kidney injury characterized by increased albuminuria/creatinine ratio and higher excretion of urinary biomarkers of kidney damage. While, at the structural level, glomerular hypertrophy was observed. Although, we did not detect renal fibrosis, the obese mice exhibited a significant elevation of Tgfb1 mRNA levels. Kidney damage caused by the exposure to MHFD was associated with greater oxidative stress, renal inflammation, higher endoplasmic reticulum (ER)-stress, and disruption of mitochondrial dynamics. In summary, our data demonstrate that obesity induced by a milder fat content diet is enough to establish renal injury, where oxidative stress, inflammation, ER-stress, and mitochondrial damage take relevance, pointing out the importance of opportune interventions to avoid the long-term consequences associated with obesity and metabolic syndrome.

Psychological Outcomes and Predictors of Weight Loss in Adolescents With Severe Obesity Following a Reversible Endoscopic Bariatric Procedure

Introduction: Adolescent and children obesity is a growing concern worldwide. Bariatric surgery is used as an effective treatment for adolescents with obesity and provides physical and mental health benefits. Application of alternative, minimally invasive, safe, and reversible endoscopic procedures, such as the Duodenojejunal bypass liner (DJBL), has been recently suggested as an effective treatment for adolescents with obesity. We explored specific psychological outcomes of adolescents with obesity during a year of follow-up after undergoing a reversible endoscopic bariatric procedure, and a year after removal. We were also interested in identifying psychological factors that could predict successful weight loss after the procedure. Methods: Nineteen adolescent with severe obesity undergoing DJBL procedure were psychologically assessed in an open-label, prospective clinical trial (NTC0218393), at the implantation of device and at the removal of device after 12 months. Control group of 26 adolescents with severe obesity were recruited from the same outpatient clinic undergoing only conservative treatment. In addition, adolescents from the intervention group were followed for 12 months after the removal of the device. The Youth Self Report (YSR) was used to assess adolescents' emotional and behavioural problems; The Multidimensional Body-Self Relations Questionnaire (MBSRQ) to assess body image and The Eating Disorder Examination Questionnaire (EDE-Q) to assess attitudes and behaviours related to eating disorder. Results: Significant improvements in somatic complain (F = 12.478, p = 0.001), emotional and behavioural problems (F = 7.169, p = 0.011) and food restraining (F = 9.605, p = 0.004) were found in the intervention group at device removal compared to the control group. Moreover, at the time of device removal compared to baseline, improvements in several psychological outcomes were found (F = 32.178 p = 0.000 for emotional and behavioural problems). Adolescents also became more satisfied with their appearance (F = 6.789, p = 0.019). Majority of observed changes remained stable at the next follow up a year after the device removal. Significant predictors of successful weight loss at device removal were fewer overeating episodes (B = 0.147, p = 0.022) and lower body satisfaction (B = 0.932, p = 0.013). Discussion: Following a reversible bariatric procedure, improvements of psychological (emotional and behavioural) factors were found in adolescents with severe obesity. Psychological predictors of successful weight loss were identified, showing the greatest importance of eating behaviour and body satisfaction in successful weight loss.

Oxalate Content and Antioxidant Activity of Different Ethnic Foods

OBJECTIVE

There is not enough information on the classification of oxalate content in several foods, particularly in ethnic foods, to recommend their consumption in subjects with urolithiasis (UL). The objective of the present study was to generate reliable information on the oxalate content and antioxidant activity in different foods and classify them by very low, low, medium, high and very high oxalate content and antioxidant activity.

METHODS

The oxalate content of 109 foods including ethnic foods was assessed by an enzymatic assay, and the antioxidant activity was measured by the oxygen radical absorbance capacity to determine the oxalate/antioxidant activity ratio. Oxalate consumption was then evaluated in 400 subjects with overweight and obesity using 24-h dietary recalls.

RESULTS

The main foods with high oxalate content were raw spinach, huanzontle, purslane, chard, almond, and toasted and sweetened roasted amaranth. The highest antioxidant activity was found in strawberries, all types of chocolates, roselle, morita peppers, and pinolillo. Subjects with overweight or obesity exceed the dietary oxalate daily intake recommendation.

CONCLUSIONS

The classification of foods by their oxalate content and antioxidant activity will be very useful to generate nutritional recommendation in different diseases, mainly UL.

Overweight among seafarers working on board merchant ships

BACKGROUND

Obesity and overweight represent a relevant risk factor for seafarer's health. The frequency and distribution of overweight and obesity among seafarers working on board of Italian flag ships were studied. Analysis was made on occupational medicine files collected, in the frame of health surveillance inspections, between 2013 and 2016 from Centro Internazionale Radio Medico (CIRM).

METHODS

The data of nationality, age, weight, height, blood glucose and blood pressure values obtained from 1155 seafarers were analyzed. Body mass index (BMI) values were calculated and compared with data reported for the general population of the same nationality of seafarers examined.

RESULTS

BMI values revealed a tendency to overweight, whereas blood glucose and systolic blood pressure values were in general in the normal range. Approximtely 40% of subjects investigated were overweight, and more than the 10% of them were obese. Underweight was noticeable only in 1.22% of crew members and 0.34% of officers. The 0.52% of subjects investigated was diabetic, and 2.68% were hypertensive. Seafarers, regardless their nationality and rank, showed a greater tendency to overweight and obesity compared with general population of the same ethnicity.

CONCLUSIONS

Due to the occurrence of overweight and obesity among seafarers, campaigns for promoting awareness of the phenomenon and on the danger of these conditions for health should be promoted. Specific initiatives to avoid the assumption of junk food and the organization of adequate spaces, times and programs for physical exercise sessions on board should be offered for keeping seafarers healthier.