Obesity-related glomerulopathy (ORG) is a silent comorbidity associated with obesity whose incidence is increasing in parallel to the obesity epidemic. ORG is associated with serious health consequences including chronic kidney disease, end-stage renal disease, and increased mortality. Unfortunately, ORG has an absence of targeted therapy (except for the use of drugs blocking the renin-angiotensin system), and therefore the prognosis of this disease may be seriously compromised. Some previous studies have shown that weight loss could be effective to decrease albuminuria and reduce the declining in kidney function in subject with obesity. In line with this, in this study the investigators will evaluate the efficacy of two different dietary strategies for ORG, given the current lack of therapies for this condition. Thus, the investigators will conduct an open-label randomized controlled trial comparing a hypocaloric Mediterranean diet with a very-low calorie diet (VLCD), evaluating the efficacy on albuminuria reduction and changes in renal function. Also, the investigators will assess changes on body composition, blood pressure, markers of renal damage and inflammation, gut microbiota, and on renal ultrasound elastography.
Our hypothesis is that a dietary strategy based on a very low calorie diet (VLCD) will produce a greater reduction in albuminuria than a hypocaloric Mediterranean diet in subjects with ORG. This improvement will be achieved through weight loss and changes in body composition, the reduction of blood pressure, the decrease in inflammatory, tubular and podocyte damage markers, modifications in adipokine concentrations, changes in the intestinal microbiota and in renal elastography. The main objective of this clinical trial is to evaluate which dietary strategy (VLCD diet or Mediterranean hypocaloric diet) is more effective in reducing albuminuria and preserving renal function in patients with ORG.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
60
Patients randomized to this group will receive a VLCD, which consists of a replacement diet based on a liquid enteral formula (46% carbohydrates, 19% fat and 32% protein; 654 Kcal/day): OPTISOURCE® PLUS, taken as 3 shakes a day. In addition, participants may consume 2 pieces of fruit/day (about 250 g/day) and up to 300 g/day of non-starchy vegetables according to the list of foods that will be provided to patients; this will constitute a total daily energy intake of about 800 Kcal. In addition, protein intake (0.8 to 1.3 g/kg/day of adjusted weight) will be adjusted by adding Resource® Instant Protein individually, depending on the anthropometry and the renal function of the patients (to preserve fat free mass, whose loss has been correlated with subsequent weight recovery)
Randomized participants in this group will be recommended to follow a Mediterranean Diet, based on the use of olive oil as the main source of visible fat and regular consumption of vegetables (≥2 servings/day), fruits (≥3 servings/day), legumes (≥3 servings/week) and fish (≥3 times a week), reducing the consumption of red meat or sausages (\<2 times a week) and eliminating the consumption of sugary drinks, pastries or industrial pastries. In this Mediterranean Diet, an energy restriction of 30% of the estimated energy needs (Harris-Benedict equation) will be established.
Hospital Regional Universitario de Málaga.
Málaga, Spain
RECRUITINGChanges in albuminuria
Albuminuria in mg/g
Time frame: From baseline to 6 months
Changes in glomerular filtration (kidney function)
Calculated with the formula CKD-EPI and measured in ml/min/1,73 m2
Time frame: From baseline to 6 months
Cystatin C levels (kidney function)
Cystatin C in ng/ml
Time frame: From baseline to 6 months
BMI (body mass index)
kg/m2
Time frame: From baseline to 6 months
Changes in total body water (TBW)
Measured in liters
Time frame: From baseline to 6 months
Changes in extracellular water (ECW)
Measured in liters
Time frame: From baseline to 6 months
Changes in intracellular water (ICW)
Measured in liters
Time frame: From baseline to 6 months
Changes in fat free mass (FFM)
Measured in kilograms
Time frame: From baseline to 6 months
Changes in fat free mass index (FFMI)
Measured in Kg/m2
Time frame: From baseline to 6 months
Changes in fat mass (FM)
Measured in Kilograms
Time frame: From baseline to 6 months
Changes in fat mass index (FMI)
Measured in Kg/m2
Time frame: From baseline to 6 months
Changes in body cell mass (BCM)
Measured in kilograms
Time frame: From baseline to 6 months
Changes in body cell mass index (BCMI)
Measured in Kg/m2
Time frame: From baseline to 6 months
Changes in appendicular skeletal muscle mass (ASMM)
Measured in kilograms
Time frame: From baseline to 6 months
Changes in blood pressure
We will perform a 24-hour Ambulatory Blood Pressure Measurement (ABPM) with the SpaceLab © OnTrak meter (Spacelabs Healthcare, Washington, USA), the newest ABPM meter from this recognized manufacturer. This ABPM meter is a clinically validated device with high precision and reliability.
Time frame: From baseline to 6 months
Changes in inflammatory biomarkers (assess kidney failure)
Measured as Fetuin A, FGF-21 and TGF-β1 by ELISA (ng/ml)
Time frame: From baseline to 6 months
Changes in tubular and podocyte damage markers (assess kidney failure)
Measured as KIM-1 y NGAL by ELISA (ng/ml)
Time frame: From baseline to 6 months
Changes in adipokines
Measured as leptin, adiponectin and resistin by ELISA (ng/ml)
Time frame: From baseline to 6 months
Modifications in gut microbiota richness and diversity
Differences in α- and β-diversities between study groups will be analyzed with the open-source Quantitative Insights into Microbial Ecology (QIIME2) software, through the diversity plugin
Time frame: From baseline to 6 months
Modifications in gut microbiota abundance and composition
Differences between the study groups at different taxa levels (phyla, family, genus and species) will be evaluated with the QIIME2 software
Time frame: From baseline to 6 months
Modifications in gut microbiota functionality
We will evaluate the differences between sudy groups in microbial functions, analyzed with the Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt2) software, within the QIIME2 environment
Time frame: From baseline to 6 months
Modifications in shear-wave renal elastography
Changes in kilopascals (kPA) in renal sinus
Time frame: From baseline to 6 months
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