The effect of bariatric surgery on renal function and disease: a focus on outcomes and inflammation

Abstract

Renal dysfunction and disease, including hyperfiltration, proteinuria and hypofiltration, are commonly associated with obesity. Diabetic kidney disease is also common in obese cohorts. Weight loss interventions, including bariatric surgery, can effectively reduce weight and improve renal outcomes. Some of this effect may be due to the remission of Type 2 diabetes and hypertension. However, other mechanisms, including the resolution of inflammatory processes, may also contribute. The effect of bariatric surgery on renal function has only recently become a focus of particular investigation. In this study, we will review the effects of bariatric surgery on obesity-associated kidney disease. We will discuss the pitfalls in assessing renal function in obese cohorts and will examine the effect of bariatric surgery on renal function and urinary protein excretion using different mechanisms. We will give particular attention to the evidence for bariatric surgery in cohorts with established renal disease and suggest future directions. In particular, we will outline the evidence for inflammation as an important therapeutic target, and the emerging medical therapies being considered to exploit this target in obesity- and diabetes-related kidney disease.

Estimated GFR Before and After Bariatric Surgery in CKD

“…The larger difference in the period of the first year after surgery between surgery patients and controls may be due to a number of acute factors resulting from massive weight loss (peak weight loss for RYGB and GS was at ~ 1 year after surgery), none of which we could measure in this study. These might include a decrease in serum creatinine level due to the muscle loss that accompanies massive weight loss (and thus eGFR would appear to greatly increase), 14 rapid improvement in levels of inflammatory markers, 14,41 and changes in glomerular he-modynamics. 42 To avoid the confounding nature of profound changes in body composition during the initial period of weight loss following surgery (12 months) in the interpretation of changes in serum creatinine levels, it may be best to begin the study of bariatric surgery and CKD after the first year of weight loss.…”

Predicting the Glomerular Filtration Rate in Bariatric Surgery Patients

“…Bariatric surgery is of interest to nephrologists not only because it is associated with an increased risk for both acute and chronic kidney injury [2] but also because it serves as a research model to investigate the relationship between obesity, weight reduction, and kidney health. Investigations using the bariatric surgery model suggest that weight loss in obese persons may have renoprotective effects [3,4] although the body of evidence relies primarily on estimated (eGFR) rather than directly measured GFR (mGFR). Similarly, clinical evaluations of bariatric surgery patients also depend on eGFR.…”

Obesity and kidney: The new insight

“…Može se pretpostaviti da će se to smanjenje težine reperkutovati kako na smanjenje proteinurije tako i na poboljšanje JGF, što je i pokazano u pojedinim novijim studijama (27,28). Potrebno je napomenuti da je kod ekstremno gojaznih bolesnika sa HOB barijatrična hirurgija praćena i sa više komplikacija (nefrolitijazom, oksaltnom nefropatijom, akutnom bubrežnom slabošću i posebno gubitkom gustine kosti), ali da učestalost ne prelazi 10% (29,30,31). U poslednjih godinu dana se sve više govori i o SGLT2 inhibitorima u lečenju dijabetesa, koji ne samo da redukuju telesnu težinu već dovode i do smanjene hiperfiltracije kroz glomerule inhibicijom glomerulsko-tubulske povratne sprege.…”