Obesity-related focal and segmental glomerulosclerosis: normalization of proteinuria in an adolescent after bariatric surgery

Clinical characteristics and treatment compounds of obesity-related kidney injury

Disorders in energy homeostasis can lead to various metabolic diseases, particularly obesity. The obesity epidemic has led to an increased incidence of obesity-related nephropathy (ORN), a distinct entity characterized by proteinuria, glomerulomegaly, progressive glomerulosclerosis, and renal function decline. Obesity and its associated renal damage are common in clinical practice, and their incidence is increasing and attracting great attention. There is a great need to identify safe and effective therapeutic modalities, and therapeutics using chemical compounds and natural products are receiving increasing attention. However, the summary is lacking about the specific effects and mechanisms of action of compounds in the treatment of ORN. In this review, we summarize the important clinical features and compound treatment strategies for obesity and obesity-induced kidney injury. We also summarize the pathologic and clinical features of ORN as well as its pathogenesis and potential therapeutics targeting renal inflammation, oxidative stress, insulin resistance, fibrosis, kidney lipid accumulation, and dysregulated autophagy. In addition, detailed information on natural and synthetic compounds used for the treatment of obesity-related kidney disease is summarized. The synthesis of detailed information aims to contribute to a deeper understanding of the clinical treatment modalities for obesity-related kidney diseases, fostering the anticipation of novel insights in this domain.

Deceased donor kidneys from higher distressed communities are significantly less likely to be utilized for transplantation

The proportion of kidneys procured for transplantation but not utilized exceeds 20% in the United States. Factors associated with nonutilization are complex, and further understanding of novel causes are critically important. We used the national Scientific Registry of Transplant Recipients data (2010-2022) to evaluate associations of Distressed Community Index (DCI) of deceased donor residence and likelihood of kidney nonutilization (n = 209 413). Deceased donors from higher distressed communities were younger, had an increased history of hypertension and diabetes, were CDC high-risk, and had higher terminal creatinine and donation after brain death. Mechanisms and circumstances of death varied significantly by DCI. The proportion of kidney nonutilization was 19.9%, which increased by DCI quintile (Q1 = 18.1% to Q5 = 21.6%). The adjusted odds ratio of nonutilization from the highest quintile DCI communities was 1.22 (95% CI = 1.16-1.28; reference = lowest DCI), which persisted stratified by donor race. Donors from highly distressed communities were highly variable by the donor service area (range: 1%-51%; median = 21%). There was no increased risk for delayed graft function or death-censored graft loss by donor DCI but modest increased adjusted hazard for overall graft loss (high DCI = 1.05; 95% CI = 1.01-1.10; reference = lowest DCI). Results indicate that donor residential distress is associated with significantly higher rates of donor kidney nonutilization with notable regional variation and minimal impact on recipient outcomes.

Renoprotection by Inhibiting Connexin 43 Expression in a Mouse Model of Obesity-Related Renal Injury

Introduction

Our previous study conducted in an obesity-related renal injury rat model have established a connection between increased connexin 43 (Cx43) expression and renal injury. In this study, we investigated whether inhibiting Cx43 expression could provide renoprotection in a mouse model of obesity-related renal injury.

Methods

Five-week-old C57BL/6J mice were fed with a high-fat diet for 12 weeks to establish an obesity-related renal injury model, then they were treated with Cx43 antisense oligodeoxynucleotide (AS) or scrambled oligodeoxynucleotide (SCR) by an implanted osmotic pump for 4 weeks. Finally, the glomerular filtration function, the histological change in the glomeruli, and the markers of podocyte injury (WT-1, Nephrin) and inflammatory infiltration of renal tissue (CD68, F4/80 and VCAM-1) were examined respectively.

Results

The results showed that inhibiting Cx43 expression by AS in this mouse model of obesity-related renal injury can effectively improve glomerular filtration function, alleviate glomerular expansion and podocyte injury, and attenuate the inflammatory infiltration of renal tissue.

Conclusion

Our results demonstrated that inhibiting Cx43 expression by AS could provide renoprotection for the mouse model of obesity-related renal injury.

Obesity and chronic kidney disease

The prevalence of obesity has increased dramatically during the past decades, which has been a major health problem. Since 1975, the number of people with obesity worldwide has nearly tripled. An increasing number of studies find obesity as a driver of chronic kidney disease (CKD) progression, and the mechanisms are complex and include hemodynamic changes, inflammation, oxidative stress, and activation of the renin-angiotensin-aldosterone system (RAAS). Obesity-related kidney disease is characterized by glomerulomegaly, which is often accompanied by localized and segmental glomerulosclerosis lesions. In these patients, the early symptoms are atypical, with microproteinuria being the main clinical manifestation and nephrotic syndrome being rare. Weight loss and RAAS blockers have a protective effect on obesity-related CKD, but even so, a significant proportion of patients eventually progress to end-stage renal disease despite treatment. Thus, it is critical to comprehend the mechanisms underlying obesity-related CKD to create new tactics for slowing or stopping disease progression. In this review, we summarize current knowledge on the mechanisms of obesity-related kidney disease, its pathological changes, and future perspectives on its treatment.

The SSLepR mutant rat represents a novel model to study obesity-induced renal injury before puberty

Prepubertal obesity (PPO) has emerged as a major health problem over the past few decades and is a risk factor for the development of proteinuria. The current study investigated whether the development of renal injury in the obese SSLepR mutant strain occurs before puberty. When determining the temporal changes in serum sex hormones in female and male SS and SSLepR mutant rats between 4 and 10 wk of age, we only observed significant increases in estradiol and testosterone levels in female and male SS rats at 10 wk of age than at 4 wk of age. The results suggest that studying both strains between 4 and 8 wk of age is appropriate to study the effects of PPO on renal injury in this model. Proteinuria was significantly higher in SSLepR mutant rats as opposed to the values observed in SS rats at 8 wk of age, and we did not observe any sex differences in proteinuria in either strain. The kidneys from the SSLepR mutant rats displayed significant glomerular and tubular injury and renal fibrosis versus the values measured in SS rats without any sex differences. Overall, we observed increased immune cell infiltration in the kidneys from SSLepR mutant rats compared with SS rats. Interestingly, female SSLepR mutant rats displayed significant increases in not only M1 macrophages (proinflammatory) but also M2 macrophages (anti-inflammatory) versus male SSLepR mutant rats. These results suggest the SSLepR mutant rat may be a useful model to study early progression of obesity-related renal injury before the onset of puberty.

Diabetes Mellitus and Heart Failure With Preserved Ejection Fraction: Role of Obesity

Heart failure with preserved ejection fraction is a growing epidemic and accounts for half of all patients with heart failure. Increasing prevalence, morbidity, and clinical inertia have spurred a rethinking of the pathophysiology of heart failure with preserved ejection fraction. Unlike heart failure with reduced ejection fraction, heart failure with preserved ejection fraction has distinct clinical phenotypes. The obese-diabetic phenotype is the most often encountered phenotype in clinical practice and shares the greatest burden of morbidity and mortality. Left ventricular remodeling plays a major role in its pathophysiology. Understanding the interplay of obesity, diabetes mellitus, and inflammation in the pathophysiology of left ventricular remodeling may help in the discovery of new therapeutic targets to improve clinical outcomes in heart failure with preserved ejection fraction. Anti-diabetic agents like glucagon-like-peptide 1 analogs and sodium-glucose co-transporter 2 are promising therapeutic modalities for the obese-diabetic phenotype of heart failure with preserved ejection fraction and aggressive weight loss via lifestyle or bariatric surgery is still key to reverse adverse left ventricular remodeling. This review focuses on the obese-diabetic phenotype of heart failure with preserved ejection fraction highlighting the interaction between obesity, diabetes, and coronary microvascular dysfunction in the development and progression of left ventricular remodeling. Recent therapeutic advances are reviewed.

The Renal Pathology of Obesity: Structure-Function Correlations

The kidney is one of the target organs that may show health disorders as a result of obesity. Obesity-related glomerulopathy (ORG) is a kidney disease category based on a biopsy diagnosis that may occur secondary to obesity. Detailed clinicopathologic observations of ORG have provided significant knowledge regarding obesity-associated renal complications. Glomerulomegaly with focal segmental glomerulosclerosis of perihilar locations is a typical renal histopathologic finding in ORG, which has long been considered to represent a state of single-nephron glomerular hyperfiltration. This hypothesis was recently confirmed in ORG patients by estimating single-nephron glomerular filtration rate using a combined image analysis and biopsy-based stereology. Overshooting in glomerulotubular and tubuloglomerular interactions may lead to glomerular hyperfiltration/hypertension, podocyte failure, tubular protein-traffic overload, and tubulointerstitial scarring, constituting a vicious cycle of a common pathway to the further loss of functioning nephrons and the progression of kidney functional impairment.

Can childhood obesity influence later chronic kidney disease?

Childhood overweight and obesity affects more and more children. Whilst associations of childhood overweight with later outcomes such as hypertension, diabetes and cardiovascular disease have been well documented, less is known about the association of childhood overweight and obesity with kidney disease. We review the existing evidence for the association of childhood obesity with markers of childhood and adult kidney disease. Whilst there is some evidence for an association, studies have not been able to distinguish between childhood being a sensitive time to develop later kidney problems, or whether observed associations of childhood obesity with poor outcomes are driven by greater lifelong exposure to obesity.

Laparoscopic sleeve gastrectomy versus laparoscopic Roux-en-Y gastric bypass in the pediatric population: a MBSAQIP analysis

BACKGROUND

The growing prevalence of childhood obesity has resulted in an increased number of children and adolescents who undergo bariatric surgery. The safety of laparoscopic sleeve gastrectomy (LSG) and laparoscopic Roux-en-Y gastric bypass (LRYGB) remains controversial in the pediatric population.

OBJECTIVE

To assess the safety of LSG compared with LRYGB in patients aged ≤21 years.

SETTING

A retrospective analysis of the 2016 to 2017 Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program database.

METHODS

Patients aged ≤21 years who underwent LSG or LRYGB were identified in the 2016 to 2017 Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program database. A logistic regression model was used to create a 1:1 propensity-score matched cohort adjusting for age, sex, body mass index, and obesity-related co-morbidities. Unmatched and propensity-score matched analyses were performed to compare baseline characteristics and outcome data between LSG and LRYGB procedure groups. Primary outcomes of interest included 30-day major complications, such as death, reoperation, and anastomotic leak.

RESULTS

Of 3571 patients included in our study, 2911 (81.52%) underwent LSG and 660 (18.48%) underwent LRYGB. Patients who underwent LRYGB had an increased body mass index and a higher rate of obesity-related co-morbidities. The LRYGB group had a significantly increased rate of major complications within the first 30 days in both the unmatched cohort (4.55% versus 1.34%, P < .001) and the propensity-score matched cohort (4.57% versus .91%, P < .001).

CONCLUSIONS

LSG and LRYGB are both relatively safe to perform in the pediatric population with acceptable complication rates and low mortality. However, LSG demonstrated a significantly decreased rate of major complications in the first 30 days compared with LRYGB.

The spectrum of kidney biopsy findings in patients with morbid obesity

Morbid obesity, defined as body mass index (BMI) ≥40 kg/m², affects approximately 8% of United States adults and is a recognized risk factor for chronic kidney disease (CKD). We present the first focused biopsy-based study exploring the range of kidney diseases in this population. Among 3263 native kidney biopsies interpreted at Columbia University in 2017, we identified 248 biopsies from morbidly obese patients. In this cohort with median age of 53.5 years, 56% were female and median BMI was 44.0 kg/m². Diabetes and hypertension were present in 47% and 81% of patients, respectively. Median estimated glomerular filtration rate (eGFR) was 30 ml/min/1.73 m², and most patients had nephrotic range proteinuria. Obesity related glomerulopathy (ORG), defined as focal segmental glomerulosclerosis with glomerulomegaly or glomerulomegaly alone, was detected in 73 patients, including 29 with ORG alone and 44 with ORG plus another kidney disease. In contrast, 167 patients had other kidney diseases alone, without ORG, most commonly (in descending order) diabetic nephropathy, acute tubular necrosis, hypertensive nephrosclerosis, IgA nephropathy, membranous nephropathy, and lupus nephritis. In 49% of patients, kidney biopsy yielded a diagnosis predicted to change patient management. The strongest predictor of non-ORG lesions was eGFR <30 ml/min per 1.73 m², and presentation with nephrotic syndrome or acute kidney injury (with or without background CKD) was more common in non-ORG than ORG. The findings reveal an unexpectedly broad spectrum of kidney pathology beyond metabolic syndrome-associated disorders and highlight the importance of kidney biopsy to guide management and prognosis in the morbidly obese population.

Do effects of sodium-glucose cotransporter-2 inhibitors in patients with diabetes give insight into potential use in non-diabetic kidney disease?

PURPOSE OF REVIEW

Our aim was to review the rationale for the role of sodium-glucose cotransporter-2 inhibitors (SGLT-2i) as renoprotective therapy in patients with and without diabetes.

RECENT FINDINGS

SGLT-2i are antihyperglycemic agents, approved for treating type 2 diabetes to reduce glycosylated hemoglobin, type A1c. Primary glucoregulatory effects occur through selective inhibition of SGLT-2 at the renal proximal tubule promoting glucosuria leading to blood glucose lowering. From a hemodynamic perspective, SGLT-2 inhibition is also associated with decreased glomerular hyperfiltration, an effect that is mediated through natriuresis and tubuloglomerular feedback. With renal injury and progressive nephron loss, diabetic kidney disease, and nondiabetic chronic kidney diseases share overlapping phenotypes exhibiting single nephron hyperfiltration, along with increased proteinuria. Importantly, the impact of SGLT-2 inhibition on renal and systemic hemodynamic function, including effects on lowering blood pressure, hyperfiltration, and plasma volume, are independent of blood glucose lowering and instead are because of natriuresis. Accordingly, large clinical trials with SGLT-2i investigating the potential use of SGLT-2i in patients without diabetes are now underway.

SUMMARY

Based on prominent nonglycemic effects, the clinical use of SGLT-2i as renoprotective therapy may extend to nondiabetic chronic kidney diseases subtypes, which could help to address a large, unmet clinical need.

Molecular Mechanisms of Proteinuria in Focal Segmental Glomerulosclerosis

Focal segmental glomerulosclerosis (FSGS) is the most common primary glomerular disease resulting in end-stage renal disease in the USA and is increasing in prevalence worldwide. It is a diverse clinical entity with idiopathic, genetic, metabolic, infectious, and other causes that culminate in a characteristic histologic pattern of injury. Proteinuria is a hallmark of FSGS as well as other primary and secondary glomerular disorders. The magnitude of proteinuria at disease onset and during treatment has prognostic implications for renal survival as well as associated cardiovascular morbidity and mortality. Significant advances over the last two decades have shed light on the molecular architecture of the glomerular filtration barrier. The podocyte is the target cell for injury in FSGS. A growing list of disease-causing gene mutations encoding proteins that regulate podocyte survival and homeostasis has been identified in FSGS patients. Several pathogenic and regulatory pathways have been uncovered that result in proteinuria in rodent models and human FSGS. The recurrence of proteinuria and FSGS after kidney transplantation is supporting evidence for the role of a circulating permeability factor in disease pathogenesis. These advances reviewed herein have significant implications for disease classification and therapeutic drug development for FSGS.

Effect of bariatric surgery on urinary sphingolipids in adolescents with severe obesity

BACKGROUND

Untreated severe obesity of adolescents is associated with abnormal kidney function and development of chronic kidney disease. Lipotoxicity due to lipid accumulation in glomeruli might be an important mechanism in the progression of kidney disease in obesity.

OBJECTIVE

To assess subclinical glomerular injury by measuring urinary sphingolipids in adolescents with severe obesity before and after weight loss surgery. We hypothesized that the levels of urinary sphingolipids would be elevated at baseline and improve after weight reduction.

SETTING

Cincinnati Children's Hospital Medical Center, University of Cincinnati.

METHODS

Ten adolescents undergoing bariatric surgery with no microalbuminuria and normal kidney function were selected. Urinary sphingolipids (ceramides, glycosphingolipids, and sphingomyelins) were quantified using ultra performance liquid chromatography electrospray ionization tandem mass spectrometry at baseline and 1 year postoperatively. The levels of sphingolipids were compared with lean and moderately obese controls.

RESULTS

Participants with severe obesity had a mean baseline body mass index of 50 kg/m² that decreased to 36 kg/m² at 1 year postsurgery (28% reduction). Almost all urinary ceramides, glycosphingolipids, and sphingomyelin species were significantly elevated in participants with severe obesity compared with controls at baseline (P<.01). One year after weight loss surgery, levels of urinary sphingolipids improved but were still significantly elevated compared with controls.

CONCLUSIONS

Our study indicates that severe obesity is associated with increased urinary excretion of sphingolipids despite the absence of microalbuminuria or decreased kidney function. Urinary sphingolipids may therefore represent a marker of early (subclinical) glomerular injury in adolescents with severe obesity.

Bariatric Surgery and Kidney-Related Outcomes

The prevalence of severe obesity in both the general and the chronic kidney disease (CKD) populations continues to rise, with more than one-fifth of CKD patients in the United States having a body mass index of ≥35 kg/m². Severe obesity has significant renal consequences, including increased risk of end-stage renal disease (ESRD) and nephrolithiasis. Bariatric surgery represents an effective method for achieving sustained weight loss, and evidence from randomized controlled trials suggests that bariatric surgery is also effective in improving blood pressure, reducing hyperglycemia, and even inducing diabetes remission. There is also observational evidence suggesting that bariatric surgery may diminish the long-term risk of kidney function decline and ESRD. Bariatric surgery appears to be relatively safe in patients with CKD, with postoperative complications only slightly higher than in the general bariatric surgery population. The use of bariatric surgery in patients with CKD might help prevent progression to ESRD or enable selected ESRD patients with severe obesity to become candidates for kidney transplantation. However, there are also renal risks in bariatric surgery, namely, acute kidney injury, nephrolithiasis, and, in rare cases, oxalate nephropathy, particularly in types of surgery involving higher degrees of malabsorption. Although bariatric surgery may improve long-term kidney outcomes, this potential benefit remains unproved and must be balanced with potential adverse events.

Obesity-related glomerulopathy: clinical and pathologic characteristics and pathogenesis

The prevalence of obesity-related glomerulopathy is increasing in parallel with the worldwide obesity epidemic. Glomerular hypertrophy and adaptive focal segmental glomerulosclerosis define the condition pathologically. The glomerulus enlarges in response to obesity-induced increases in glomerular filtration rate, renal plasma flow, filtration fraction and tubular sodium reabsorption. Normal insulin/phosphatidylinositol 3-kinase/Akt and mTOR signalling are critical for podocyte hypertrophy and adaptation. Adipokines and ectopic lipid accumulation in the kidney promote insulin resistance of podocytes and maladaptive responses to cope with the mechanical forces of renal hyperfiltration. Although most patients have stable or slowly progressive proteinuria, up to one-third develop progressive renal failure and end-stage renal disease. Renin-angiotensin-aldosterone blockade is effective in the short-term but weight loss by hypocaloric diet or bariatric surgery has induced more consistent and dramatic antiproteinuric effects and reversal of hyperfiltration. Altered fatty acid and cholesterol metabolism are increasingly recognized as key mediators of renal lipid accumulation, inflammation, oxidative stress and fibrosis. Newer therapies directed to lipid metabolism, including SREBP antagonists, PPARα agonists, FXR and TGR5 agonists, and LXR agonists, hold therapeutic promise.

Zinc delays the progression of obesity-related glomerulopathy in mice via down-regulating P38 MAPK-mediated inflammation

OBJECTIVE

Obesity, particularly child obesity, is one of the most common public health problems in the world and raises the risk of end-stage renal disease. Zinc (Zn) is essential for multiple organs in terms of normal structure and function; however, effects of Zn deficiency or supplementation among young individuals with obesity have not been well studied.

METHODS

Weaned mice were fed high-fat diets (HFD) with varied contents of Zn (Zn deficient, adequate, and supplemented) for 3 or 6 months. This study examined associations between renal pathogenesis and dietary Zn levels, specifically assessing inflammatory pathways by utilizing P38 MAPK inhibitor SB203580.

RESULTS

HFD feeding induced typical syndromes of obesity-related renal disorders, which worsened by Zn marginal deficiency. The progression of obesity-related renal disorders was delayed by Zn supplementation. HFD induced renal inflammation, reflected by increased P38 MAPK phosphorylation along with increases of inflammatory cytokines MCP-1, IL-1β, IL-6, and TNF-α. P38 MAPK inhibition prevented renal pathological changes in mice fed with HFD and HFD/Zn deficiency.

CONCLUSIONS

P38 MAPK mediated the renal inflammatory responses, which played a central role in the pathogenesis of HFD-induced renal disorders. Zn could delay the progression of obesity-related kidney disease by down-regulating P38 MAPK-mediated inflammation.

Secondary Focal Segmental Glomerulosclerosis: From Podocyte Injury to Glomerulosclerosis

Focal segmental glomerulosclerosis (FSGS) is a common cause of proteinuria and nephrotic syndrome leading to end stage renal disease (ESRD). There are two types of FSGS, primary (idiopathic) and secondary forms. Secondary FSGS shows less severe clinical features compared to those of the primary one. However, secondary FSGS has an important clinical significance because a variety of renal diseases progress to ESRD thorough the form of secondary FSGS. The defining feature of FSGS is proteinuria. The key event of FSGS is podocyte injury which is caused by multiple factors. Unanswered questions about how these factors act on podocytes to cause secondary FSGS are various and ill-defined. In this review, we provide brief overview and new insights into FSGS, podocyte injury, and their potential linkage suggesting clues to answer for treatment of the disease.

Cardiovascular and renal effects of weight reduction in obesity and the metabolic syndrome

Obesity is a critical public health issue worldwide. Patients with obesity have markedly increased morbidity and mortality compared to the general population. The increased health risks of obesity in part are due to its close association with each of the other components of the metabolic syndrome, including hypertension, dyslipidemia, and insulin resistance. Accordingly, obese individuals are at particularly increased risk of cardiovascular disease and chronic kidney disease. Modest weight loss results in improvements in serum cholesterol levels, blood pressure, and glycemic profiles. Lifestyle interventions for weight loss have long been the mainstay of treatment in obesity. However, the existing literature demonstrates limited weight loss sustainability and inconsistent cardiovascular and renal benefits using these modalities. In addition to improvements in intermediate risk factors, surgical interventions provide a more lasting impact on long-term cardiovascular and renal outcomes, though carry higher short-term risks due to perioperative complications.

Proteinuria rebound in IgA nephropathy associated with obesity-related glomerulopathy

IgA nephropathy (IgAN), the most prevalent primary chronic glomerulonephritis worldwide, has three major risk factors: hypertension, proteinuria >1 g/day, and severe renal lesions. Obesity also portends a poor prognosis. A Japanese boy with IgAN showed nephrotic syndrome at presentation. Pathological features resembled those of membranoproliferative glomerulonephritis (MPGN), although IgA deposition differed from MPGN and IgAN. Combination therapy improved renal lesions, but rebound deterioration of proteinuria occurred in this patient, who had marked obesity and hypertension. Serial kidney biopsy specimens were compatible with obesity-related glomerulopathy (ORG). Rebound proteinuria was apparently attributable to ORG rather than relapse and flaring up of IgAN.

Tools for Successful Weight Management in Primary Care

Obesity is one of the most pervasive and costly public health problems. Clinicians need effective tools to address weight management in primary care, including evaluation and communication methods, guideline-based weight management interventions and safe and effective weight loss medications and surgery. The objective of this Grand Rounds presentation is to provide practicing clinicians with the latest information regarding effective ways to care for and communicate with patients about weight loss; evidence-based guidelines for selecting weight management therapies and safety, efficacy and adverse effects of weight loss medications and surgery.

Focal segmental glomerulosclerosis: molecular genetics and targeted therapies

Recent advances show that human focal segmental glomerulosclerosis (FSGS) is a primary podocytopathy caused by podocyte-specific gene mutations including NPHS1, NPHS2, WT-1, LAMB2, CD2AP, TRPC6, ACTN4 and INF2. This review focuses on genes discovered in the investigation of complex FSGS pathomechanisms that may have implications for the current FSGS classification scheme. It also recounts recent recommendations for clinical management of FSGS based on translational studies and clinical trials. The advent of next-generation sequencing promises to provide nephrologists with rapid and novel approaches for the diagnosis and treatment of FSGS. A stratified and targeted approach based on the underlying molecular defects is evolving.

The effects of weight change on glomerular filtration rate

BACKGROUND

Little is known about the effect of weight loss/gain on kidney function. Analyses are complicated by uncertainty about optimal body surface indexing strategies for measured glomerular filtration rate (mGFR).

METHODS

Using data from the African-American Study of Kidney Disease and Hypertension (AASK), we determined the association of change in weight with three different estimates of change in kidney function: (i) unindexed mGFR estimated by renal clearance of iodine-125-iothalamate, (ii) mGFR indexed to concurrently measured BSA and (iii) GFR estimated from serum creatinine (eGFR). All models were adjusted for baseline weight, time, randomization group and time-varying diuretic use. We also examined whether these relationships were consistent across a number of subgroups, including tertiles of baseline 24-h urine sodium excretion.

RESULTS

In 1094 participants followed over an average of 3.6 years, a 5-kg weight gain was associated with a 1.10 mL/min/1.73 m(2) (95% CI: 0.87 to 1.33; P < 0.001) increase in unindexed mGFR. There was no association between weight change and mGFR indexed for concurrent BSA (per 5 kg weight gain, 0.21; 95% CI: -0.02 to 0.44; P = 0.1) or between weight change and eGFR (-0.09; 95% CI: -0.32 to 0.14; P = 0.4). The effect of weight change on unindexed mGFR was less pronounced in individuals with higher baseline sodium excretion (P = 0.08 for interaction).

CONCLUSION

The association between weight change and kidney function varies depending on the method of assessment. Future clinical trials should examine the effect of intentional weight change on measured GFR or filtration markers robust to changes in muscle mass.

Long-Term Normal Renal Function after Drastic Weight Reduction in Patients with Obesity-Related Glomerulopathy

AIMS

No long-term studies of renal function evolution in morbidly obese (MO) patients after weight loss are available. The aim of our work was to ascertain the long-term influence of drastic weight reduction on renal function in MO patients with obesity-related glomerular lesions.

METHODS

92 MO patients with normal renal function and biopsy evidence of mild obesity-related glomerulopathy underwent bariatric surgery (BS) and subsequent drastic weight loss. A long-term prospective follow-up (mean duration: 76 ± 42 months) was carried out. Basal renal biopsies and basal and long-term metabolic and renal function studies were performed in all cases. Linear mixed models were applied.

RESULTS

Blood pressure dropped early after BS and remained stable thereafter. Creatinine clearance and BMI fell in the first 2 years, rose slightly after 5 years and then remained stable. Serum creatinine and albuminuria decreased throughout the follow-up period. Renal function and albuminuria evolution showed non-significant differences in relation to the number of glomerular lesions.

CONCLUSIONS

Drastic weight loss in BS-treated MO patients with pre-surgical normal renal function and mild obesity-related glomerular lesions is associated with short- and long-term maintenance of normal renal function and improvement in both arterial hypertension and albuminuria.

Impact of obesity on kidney function and blood pressure in children

In recent years, obesity has become an increasingly important epidemic health problem in children and adolescents. The prevalence of the overweight status in children grew from 5% to 11% from 1960s to 1990s. The epidemic of obesity has been paralleled by an increase in the incidence of chronic kidney disease (CKD) and hypertension. Results of several studies have demonstrated that obesity and metabolic syndrome were independent predictors of renal injury. The pathophysiology of obesity related hypertension is complex, including activation of sympathetic nervous system, renin angiotensin aldosterone system, hyperinsulinemia and inflammation. These same mechanisms likely contribute to the development of increased blood pressure in children. This review summarizes the recent epidemiologic data linking obesity with CKD and hypertension in children, as well as the potential mechanisms.

Causes and pathogenesis of focal segmental glomerulosclerosis

Focal segmental glomerulosclerosis (FSGS) describes both a common lesion in progressive kidney disease, and a disease characterized by marked proteinuria and podocyte injury. The initial injuries vary widely. Monogenetic forms of FSGS are largely due to alterations in structural genes of the podocyte, many of which result in early onset of disease. Genetic risk alleles in apolipoprotein L1 are especially prevalent in African Americans, and are linked not only to adult-onset FSGS but also to progression of some other kidney diseases. The recurrence of FSGS in some transplant recipients whose end-stage renal disease was caused by FSGS points to circulating factors in disease pathogenesis, which remain incompletely understood. In addition, infection, drug use, and secondary maladaptive responses after loss of nephrons from any cause may also cause FSGS. Varying phenotypes of the sclerosis are also manifest, with varying prognosis. The so-called tip lesion has the best prognosis, whereas the collapsing type of FSGS has the worst prognosis. New insights into glomerular cell injury response and repair may pave the way for possible therapeutic strategies.

Kidney function in severely obese adolescents undergoing bariatric surgery

OBJECTIVE

Determine objective measures of kidney function and analyze factors associated with kidney dysfunction in severely obese adolescents undergoing weight loss surgery were described.

METHODS

Cross-sectional data from 242 adolescent participants in the Teen-Longitudinal Assessment of Bariatric Surgery (Teen-LABS) study before weight loss surgery were analyzed. Kidney status was assessed by measuring urine albumin creatinine ratio to determine microalbuminuria and by calculating serum cystatin C-based estimated glomerular filtration rate (eGFR) to assess kidney function.

RESULTS

Mean age and median body mass index (BMI) were 17.1 years and 50.5 kg/m(2) , respectively; 76% were females and 65% were non-Hispanic white race. Fourteen percent of the cohort had microalbuminuria, and 3% had macroalbuminuria; 3% had eGFR < 60 ml/min/1.73 m(2) , and 7.1% had eGFR > 150 ml/min/1.73 m(2) . In adjusted analyses, female gender and increasing ferritin levels were significantly associated with the presence of microalbuminuria/macroalbuminuria. Increasing BMI and homeostasis model assessment of insulin resistance values were significantly associated with lower eGFR.

CONCLUSIONS

A significant number of severely obese adolescents undergoing weight loss surgery have evidence of early kidney dysfunction. Longitudinal studies following weight loss surgery in these individuals are needed to determine whether these kidney abnormalities are reversible following weight loss therapy.

Metabolic syndrome in children with chronic kidney disease and after renal transplantation

Visceral obesity and metabolic abnormalities typical for metabolic syndrome (MS) are the new epidemic in adolescence. MS is not only the risk factor for cardiovascular disease but also for chronic kidney disease (CKD). Thus, there are some reasons to recognize MS as a new challenge for pediatric nephrologists. First, hypertensive and diabetic nephropathy, the main causes of CKD in adults, both share the same pathophysiological abnormalities associated with visceral obesity and insulin resistance and have their origins in childhood. Secondly, as the obesity epidemic also affects children with CKD, MS emerges as the risk factor for progression of CKD. Thirdly, metabolic abnormalities typical for MS may pose additional risk for cardiovascular morbidity and mortality in children with CKD. Finally, although the renal transplantation reverses uremic abnormalities it is associated with an exposure to new metabolic risk factors typical for MS and MS has been found to be the risk factor for graft loss and cardiovascular morbidity after renal transplantation. MS is the result of imbalance between dietary energy intake and expenditure inducing disproportionate fat accumulation. Thus, the best prevention and treatment of MS is physical activity and maintenance of proper relationship between lean and fat mass.

Is obesity a risk factor for chronic kidney disease in children?

There is a rapid increase worldwide in the prevalence of obesity in adults and children. Obesity is not only a comorbidity for chronic kidney disease (CKD) but may also be a risk factor for CKD. Epidemiological correlations and pathophysiological changes have been observed associating obesity with CKD. Low birth weight may be associated with both obesity and low nephron mass, leading to CKD later in life. Elevated levels of adipokines, such as leptin and adiponectin, in obesity may be factors in CKD pathogenesis and progression. Furthermore, various other factors, such as hypertension, increased cardiovascular morbidity, insulin resistance, dyslipidemia, and lipotoxicity, may play significant roles in the pathogenesis of CKD in obesity. Reduction in obesity, which is a potentially modifiable risk factor, might help decrease the burden of CKD in the population. Apart from individualized options, community-based interventions have the potential to create a strong impact in this condition.

Obesity-related glomerulopathy and the nephron complement

Obesity-related glomerulopathy (ORG) is a secondary form of glomerular disease that can occur in individuals with obesity. However, the absolute risk for an obese individual to develop progressive renal deterioration is low. Therefore, obesity alone appears to be insufficient to develop such severe renal injury, and there are likely other factors that contribute to the development of this entity. The glomerular hyperfiltration found in patients with ORG has been postulated to lead to structural abnormalities in glomeruli, such as glomerulomegaly and focal segmental glomerular sclerosis, in a manner analogous to that described in patients with reduced renal mass. In fact, recent studies suggest that a reduction in nephron mass is implicated in patients with ORG and synergistically contributes to the development of this renal complication together with obesity-induced changes in renal hemodynamics.

Structural renal changes in obesity and diabetes

Overweight, obesity, and associated diseases represent an emerging problem, not only in Western countries but also in the developing world. They are now characterized as epidemic diseases. Obesity is particularly serious because its incidence in children and adolescents increased dramatically: it is estimated that in the United States every eighth adolescent suffers from obesity, which in the long run may reduce life expectancy in the population. Apart from cardiovascular disease (ie, blood pressure, stroke, and coronary heart disease), kidney diseases also have been shown to be associated with obesity. Epidemiologic studies have indicated that obesity can be a risk factor of chronic kidney disease irrespective of the presence or absence of diabetes, arterial hypertension, and other comorbidities. More evidence is accumulated on the link between chronic kidney disease in obesity and abnormalities in adipokine secretion (hyperleptinemia, lack of adiponectin), activation of the renin-angiotensin system, chronic inflammation, endothelial dysfunction, lipid accumulation, impaired renal hemodynamics, and diminished nephron number related to body mass. In general, obesity is known to aggravate the course of many primary renal diseases such as glomerulonephritides, but also impairs renal function after kidney transplantation. Microalbuminuria, proteinuria, hyperfiltration, and impaired renal function are associated with obesity. Histologically, secondary focal segmental sclerosis has been shown to be caused particularly by obesity. Of practical purpose for clinical nephrology, loss of body weight either by lifestyle modification or bariatric surgery improves albuminuria and hyperfiltration in obese patients, making renal disease in obesity accessible for prevention programs. This review specifically addresses the pathogenesis and morphology of renal functional and particularly structural changes in obesity and associated renal disease such as diabetic nephropathy.

[Primary focal segmental glomerular sclerosis in children: epidemiology and prognosis]

Focal segmental glomerulosclerosis (FSGS) is the morphologic description of a glomerular lesion which is "focal", meaning a few but not all of the total sampled glomeruli have and "segmental" solidification of the tuft that is an accumulation of extracellular matrix with obliteration of the capillary lumina (sclerosis). It represents 20% of nephrotic syndrome in children and adults. To study the role of epidemiology, clinical presentation, histology, and treatment in the prognosis of HSF child, we retrospectively analyzed 23 children with primary focal segmental glomerulosclerosis (FSGS) hospitalized in pediatric nephrology unit of Children's Hospital Harrouchi Abderrahim, CHU Ibn Rochd Casablanca from January 2000 to December 2012. The main age at onset was 7.5 years with a male predominance. Hematuria was seen in 22% of patients, hypertension in 48% of patients, and moderate renal insufficiency in one patient at presentation. According to the histological classification of Columbia, 40% of patients have a non-specific HSF (NOS), including six patients who have responded to treatment and one patient progressed to renal failure, 13% have a perihilar HSF (PH) with a good prognosis, 8% have a HSF cell (CELL), which evolved to renal failure, 35% of HSF was a tubular pole (TIP) including five patients responded to treatment and 4% was a HSF collapsing (COL) having a renal failure at admission. The FSGS's prognosis is related to several predictive factors.

Adiponectin promotes functional recovery after podocyte ablation

Low levels of the adipocyte-secreted protein adiponectin correlate with albuminuria in both mice and humans, but whether adiponectin has a causative role in modulating renal disease is unknown. Here, we first generated a mouse model that allows induction of caspase-8-mediated apoptosis specifically in podocytes upon injection of a construct-specific agent. These POD-ATTAC mice exhibited significant kidney damage, mimicking aspects of human renal disease, such as foot process effacement, mesangial expansion, and glomerulosclerosis. After the initial induction, both podocytes and filtration function recovered. Next, we crossed POD-ATTAC mice with mice lacking or overexpressing adiponectin. POD-ATTAC mice lacking adiponectin developed irreversible albuminuria and renal failure; conversely, POD-ATTAC mice overexpressing adiponectin recovered more rapidly and exhibited less interstitial fibrosis. In conclusion, these results suggest that adiponectin is a renoprotective protein after podocyte injury. Furthermore, the POD-ATTAC mouse provides a platform for further studies, allowing precise timing of podocyte injury and regeneration.

Bariatric surgery and the kidney-much benefit, but also potential harm

Bariatric surgery is increasingly performed on overweight individuals. A significant benefit with respect to cardiovascular (CV) events and survival has been documented. After weight loss, reduction of albuminuria/proteinuria is almost consistently seen; small studies documented retardation of the glomerular filtration rate (GFR) loss after bariatric surgery; reduction of blood pressure (BP) is less consistent. It has been known for a long time that the frequency of oxalate stones is increased after bariatric surgery. The main renal threat of hyperoxaluria is renal oxalosis, often irreversible, causing persisting renal failure. The causes are reduced oxalate binding by calcium due to saponification of calcium causing fat malabsorption, increased permeability for oxalate because of increased permeability of colon mucosa triggered by increased bile salts and reduced colonization of the colon by oxalobacter formigenes. These mechanisms are susceptible to treatment.

Bariatric surgery and renal function

Obesity causes a significant healthcare burden and has been shown to be an important risk factor in the development of cardiovascular disease, type 2 diabetes, and increasingly chronic kidney disease. Bariatric surgery is the most effective treatment for obesity and has been shown to drastically improve both blood pressure and diabetic control. However, the interaction of bariatric surgery and renal function is less clear. This review focuses on the effect of bariatric surgery on renal function both in the acute situation, with respect to acute kidney injury, and also on changes in renal function parameters post-bariatric surgery weight loss. The interaction of obesity, bariatric surgery, and nephrolithiasis as a precipitant of acute kidney injury will also be considered. The role of bariatric surgery in pre- and post-renal transplant recipients is discussed as well as possible mechanisms underlying the improvement in renal function.

Clinicopathological characteristics of obesity-associated focal segmental glomerulosclerosis

Obesity-related glomerulopathy (ORG) is a secondary form of focal segmental glomerulosclerosis (FSGS) occurring in obese patients with a body-mass index higher than 30 kg/m(2). It is typically manifested by nephrotic-range proteinuria without full nephrotic syndrome, and progressive renal insufficiency. Characteristic morphologic features include the consistent presence of glomerulomegaly, predominance of perihilar variant of FSGS, and the relatively mild fusion of visceral epithelial cell foot processes. The concept of podocyte depletion as a driver of the glomerular scarring in obesity-associated FSGS is well documented. The underlying mechanisms are likely to be related in part to the oxidative stress and the impairment of the integrity of the slit diaphragm and cell adhesion resulting mainly from angiotensin II and transforming growth factor-β. These proapoptotic cytokines are upregulated in obesity in response to insulin resistance, compensatory hyperinsulinemia and glomerular hyperfiltration-hypertension mediated mechanical stress. This review is designed to discuss the clinicopathologic features of obesity-associated FSGS, with a focus on the podocyte injury, which is involved in the onset and progression of the glomerulosclerotic process. Ultrastructural glomerular lesions are documented.

Effectiveness and cost-effectiveness of paediatric bariatric surgery: a systematic review

Strong evidence for successful and cost-effective obesity management strategies is still generally lacking, leading the medical profession to rely increasingly on surgical options to treat obesity in children and adolescents. We performed a systematic review to examine the effectiveness of surgical interventions to treat obese children and adolescents, and whether they are cost-effective. We searched PubMed, ISI Web of Science, Embase and the Cochrane Library to 6 September 2010, and hand-searched bibliographies. We included articles with English abstracts if they examined subjects ≤19 years of age, reported at least one postoperative weight loss measure and at least 1 year of postoperative follow-up. Thirty-seven relevant papers on bariatric surgery effectiveness in 831 children or adolescents were included, spanning 36 years. Thirteen studies examined gastric banding, with mean body mass index (BMI) reductions ranging from 8.5 to 43 kg m(-2) . Weight gain was reported in one case study. Eight papers examined Roux-en-Y gastric bypass, with mean BMI reductions ranging from 9 to 25 kg m(-2) . Fourteen publications studied other forms of bariatric surgery: sleeve gastrectomies, vertical banded gastroplasty, biliopancreatic diversion or a combination of procedures. Mean BMI reductions ranged from 9 to 24 kg m(-2) . Three surgery-related mortalities were reported, as was weight regain in several cases. The majority of studies reported resolution or improvement of comorbid conditions. A range of postoperative complications were identified across surgery types, including: ulcers, intestinal leakage, wound infection, anastomotic stricture, nutritional deficiencies, bowel obstruction, pulmonary embolism, disrupted staple lines, band slippage, psychological intolerance and repeated vomiting. Evidence on cost-effectiveness was limited to one Australian modelling project, which deemed laparoscopic adjustable gastric banding cost-effective for adolescents. Existing evidence - although based generally on underpowered, retrospective studies - suggests that bariatric surgery in older children results in significant weight loss and improvements in comorbidities and quality of life. However, postoperative complications, compliance and follow-up may be more problematic in adolescents than adults, and availability of long-term data on safety, effectiveness and cost-effectiveness remains largely unknown. Pending an improvement in the quality of available evidence, a cautious approach to child and adolescent bariatric surgery is warranted, and reversible techniques are advisable compared to approaches that permanently alter anatomy.

[Renal consequences of obesity]

The steady increase in the prevalence of obesity contributes to the increase in the prevalence of chronic kidney disease, through renal damages associated with type-2 diabetes and hypertension. Obesity is also an independent risk factor for the kidney, since it is associated with an increased risk of albuminuria and glomerulosclerosis, and worsens the course of chronic kidney disease regardless of the primary renal disease. The existence of a metabolic syndrome, constant in type-2 diabetes, and associated with abdominal obesity, is not the only requirement for renal anomalies of which the translation is a functional hyperfiltration, a clinical microalbuminuria and histologically a glomerulomegaly and glomerulosclerosis. The estimated glomerular filtration rate (GFR) in obese patients is strongly influenced by the weight or indexation to body surface area, and it is logical to take into account the value of non-indexed GFR to assess renal risk and treatment effects, especially if they lead to weight loss. Hypertension is promoted by salt sensitivity, potentially reversible, and overactivity of the renin-angiotensin system (RAS) in part due to adipose tissue. The cytokines secreted by adipose tissue (adipokines), induce sympathetic hyperactivity through leptin, and low-grade inflammatory state that contributes to the development of glomerular sclerosis lesions, especially because a resistance to adiponectin. The treatment relies on weight loss, possibly through bariatric surgery, and antagonists of the RAS.

Scope and mechanisms of obesity-related renal disease

PURPOSE OF REVIEW

Obesity is established as an important contributor of increased diabetes mellitus, hypertension, and cardiovascular disease, all of which can promote chronic kidney disease (CKD). Recently, there is a growing appreciation that, even in the absence of these risks, obesity itself significantly increases CKD and accelerates its progression.

RECENT FINDINGS

Experimental and clinical studies reveal that adipose tissue, especially visceral fat, elaborates bioactive substances that contribute to the pathophysiologic renal hemodynamic and structural changes leading to obesity-related nephropathy. Adipocytes contain all the components of the renin-angiotensin-aldosterone system, plasminogen activator inhibitor, as well as adipocyte-specific metabolites such as free fatty acids, leptin, and adiponectin, which affect renal function and structure. In addition, fat is infiltrated by macrophages that can alter their phenotype and foster a proinflammatory milieu, which advances pathophysiologic changes in the kidney associated with obesity.

SUMMARY

Obesity is an independent risk factor for development and progression of renal damage. Although the current therapies aimed at slowing progressive renal damage include reduction in weight and rely on inhibition of the renin-angiotensin system, the approach will likely be supplemented by interventions aimed at obesity-specific targets including adipocyte-driven cytokines and inflammatory factors.

Obesity-related glomerulopathy: body mass index and proteinuria

BACKGROUND AND OBJECTIVES

Obesity-related glomerulopathy (ORG) is an increasing cause of end-stage renal disease, but evidence concerning the effects of treatments is rather limited. This study was aimed at exploring the renoprotective effects of weight loss on patients with ORG.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A total of 63 patients with renal biopsy-proven ORG had food and exercise intervention in the physician-supervised weight loss program and were divided into three groups on the basis of the percentage of weight change from baseline to follow-up: significant weight loss (>3% reduction in body mass index [BMI]), stable weight, or significant weight gain (>3% increase). Metabolic parameters and renal lesions were evaluated regularly for 2 years.

RESULTS

After 6 months, 27 patients lost weight by 8.29 +/- 4.00%, with a mean decrease in proteinuria of 35.3%, whereas 24 months later, 27 patients achieved a 9.20 +/- 3.78% reduction in BMI and a 51.33% reduction in urine protein secretion. The levels of serum triglyceride, serum uric acid, and BP were also decreased. Contrarily, in patients with increased BMI, urine protein was increased by 28.78%. Correlation analysis showed proteinuria was associated with BMI, serum triglyceride, and uric acid, and multivariate regression analysis indicated the changes in BMI were the only predictor of proteinuria (P < 0.01).

CONCLUSIONS

Weight loss intervention benefited remission of proteinuria in patients with ORG, whose function could not be replaced by conventional pharmacotherapy.

Therapeutic potential of endothelin receptor antagonists for chronic proteinuric renal disease in humans

Diabetes and arterial hypertension continue to be the main causes of chronic renal failure in 2010, with a rising prevalence in part due to the worldwide obesity epidemic. Proteinuria is a main feature of chronic renal disease and mediated by defects in the glomerular filtration barrier and is as a good predictor of cardiovascular events. Indeed, chronic renal disease due to glomerulosclerosis is one of the important risk factors for the development of coronary artery disease and stroke. Glomerulosclerosis develops in response to inflammatory activation and increased growth factor production. Preclinical and first preliminary clinical studies provide strong evidence that endogenous endothelin-1 (ET-1), a 21-amino-acid peptide with strong growth-promoting and vasoconstricting properties, plays a central role in the pathogenesis of proteinuria and glomerulosclerosis via activation of its ET(A) subtype receptor involving podocyte injury. These studies have not only shown that endothelin participates in the disease processes of hypertension and glomerulosclerosis but also that features of chronic renal disease such as proteinuria and glomerulosclerosis are reversible processes. Remarkably, the protective effects of endothelin receptors antagonists (ERAs) are present even on top of concomitant treatments with inhibitors of the renin-angiotensin system. This review discusses current evidence for a role of endothelin for proteinuric renal disease and podocyte injury in diabetes and arterial hypertension and reviews the current status of endothelin receptor antagonists as a potential new treatment option in renal medicine.

Exercise counters diet-induced obesity, proteinuria, and structural kidney alterations in rat

We studied the effects of exercise training in treating renal impairment due to hypertension and obesity in rats. Diet-induced obese and non-obese Wistar rats were assigned to four groups: Sed-Ob, Ex-Ob, Sed-C, and Ex-C (motor treadmill for 13 weeks; Ex=exercise-trained, C=control, Ob=obese, Sed=sedentary). Creatinine, proteinuria, and kidney structure were evaluated. Sed-C rats had normal and stable blood pressure (BP), while Sed-Ob rats developed hypertension. After 4 weeks of exercise, BP decreased in exercise-trained groups (less than 25% at the end of the experiment in obese rats, and less than 10% in non-obese rats). Both the body mass and retroperitoneal fat mass were lower in the exercise-trained groups than in the sedentary ones. Serum creatinine was not different among the groups, but the urinary protein excretion was significantly higher in the Sed-Ob group than in the matched non-obese group. Compared to the non-obese animals the mean glomerular volume increased by 45% in Sed-Ob rats and by 30% in Ex-Ob rats. Obese animals also showed increased mesangial volume density compared to non-obese animals. The present findings allow us to conclude that the exercise training could be an auxiliary practice to attenuate renal alterations seen in diet-induced obesity.

Baseline BMI is a strong predictor of nadir BMI after adolescent gastric bypass

OBJECTIVE

Surgical treatment of extreme obesity may be appropriate for some adolescents. We hypothesized that surgical weight loss outcomes may differ by preoperative level of extreme obesity (body mass index [BMI] > or=99th percentile).

STUDY DESIGN

A longitudinal assessment of clinical characteristics from 61 adolescents who underwent laparoscopic Roux-en-Y gastric bypass at a single pediatric center from 2002 until 2007 was performed. Patients were categorized into 1 of 3 preoperative BMI groups: group 1, BMI = 40.0 to 54.9 (n = 23); group 2, BMI = 55.0 to 64.9 (n = 21); group 3, BMI = 65.0 to 95.0 (n = 17). Changes in BMI and cardiovascular risk factors between baseline and year 1 were evaluated using repeated-measures mixed linear modeling.

RESULTS

BMI in the overall cohort at baseline (60.2 +/- 11 kg/m(2)) decreased by 37.4% at 1 year after surgery (P < .001). Percent BMI change varied little by preoperative BMI groups (-37.2%, -36.8%, and -37.7% for groups 1, 2, and 3 respectively; P = .8762). The rate of change in absolute BMI units significantly varied by preoperative BMI class (group x time interaction, P < .0001), with 1-year nadir BMI values for groups 1, 2, and 3 falling to 31 +/- 4 kg/m(2), 38 +/- 5 kg/m(2), and 47 +/- 9 kg/m(2), respectively. One year after surgery, only 17% of patients achieved a nonobese BMI (<30 kg/m(2)). Significant improvements in systolic and diastolic blood pressure (P < .0001), fasting insulin (P < .0001), total cholesterol (P = .0007), and triglyceride levels (P < .0001) were seen after surgery irrespective of baseline BMI class. Mean albumin levels remained normal despite significant caloric restriction and weight loss.

CONCLUSIONS

Laparoscopic gastric bypass resulted in improvement or reversal of cardiovascular risk factors and resulted in a decrease in BMI of approximately 37% in all patients, regardless of starting BMI, 1 year after surgery. The timing of surgery for adolescent extreme obesity is an important consideration, because "late" referral for bariatric surgery at the highest of BMI values may preclude reversal of obesity.

Glomerulonephritis and managing the risks of chronic renal disease

The rising global burden of chronic renal disease, the high cost of providing renal replacement therapies, and renal disease also being a risk factor for cardiovascular disease is increasing focus on renal disease prevention. This article focuses on the aspects of renal disease (specifically poststreptococcal glomerulonephritis [PSGN] and chronic kidney disease [CKD]) in Indigenous populations in Australia, New Zealand, Canada, and the United States that diverge from those typically seen in the general population of those countries. The spectrum of renal and many other diseases seen in Indigenous people in developed countries is similar to that seen in developing countries. Diseases like PSGN that have largely disappeared in developed countries still occur frequently in Indigenous people. CKD during the childhood years is due to congenital anomalies of the kidney and urinary tract in up to 70% of cases and occurs later in polycystic kidney disease and childhood-onset diabetes. Several risk factors for CKD in adulthood are already present in childhood.

How young for bariatric surgery in children?

Obesity affects 50% of adults and 18% of children in the USA. It has wide-ranging comorbidities with clinical, psychosocial, and economic ramifications. Obesity refers to a condition of excess body fat. The basis for weight gain is a fundamental imbalance between caloric intake and output, but individual variation based on genetics, metabolism, and diverse environmental triggers is seen. Although modifications to our obesogenic society and education about the risks in our environment may lead to a decrease in the incidence of obesity through prevention, treatment for those already obese is critically important. In adults, the most successful treatment programs for obesity include a surgical procedure. This article discusses the problems obesity presents to children and their families, highlights the unique aspects of treating obesity in children, reviews the currently utilized bariatric surgical procedures, and introduces those bariatric procedures that are under development. When considering whether to use bariatric surgical procedures in a multidisciplinary weight management program for children, the special needs and characteristics of children with a severe weight problem must be considered. Development of bariatric surgical techniques and devices and implementation of these tools in multidisciplinary weight management programs need greater attention. This will require the combined efforts of the pediatric health care providers from many specialties and partnerships with industry to facilitate discovery and implementation.