Recurrent Weight Gain after Metabolic Bariatric Surgery (MBS): Emerging Insights on Kidney Function

Area of Science:

• Nephrology
• Metabolic Surgery
• Obesity Medicine

Background:

• Recurrent weight gain post-metabolic bariatric surgery (MBS) compromises long-term metabolic and renal benefits.
• The impact of weight regain on kidney function and injury pathways requires further investigation.

Purpose of the Study:

• To review and synthesize current evidence on the relationship between post-MBS weight regain and kidney function.
• To explore the mechanisms of obesity-driven kidney injury reactivation and procedural differences.

Main Methods:

• Systematic review of existing literature on weight regain after MBS and its renal consequences.
• Analysis of obesity-driven kidney injury pathways, including glomerular hyperfiltration, lipotoxicity, and NLRP3 inflammasome activation.
• Comparison of renal outcomes between different surgical procedures like Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG).

Main Results:

• Weight regain (≥20%) reactivates kidney injury pathways, leading to recurrent albuminuria (20-35%) and accelerated eGFR decline.
• RYGB demonstrates better kidney protection than SG despite varying degrees of weight regain.
• Weight recurrence triggers fibrotic signaling (TGF-β/SMAD, Wnt/β-catenin), causing renal fat accumulation and tubular injury.

Conclusions:

• Weight regain post-MBS significantly impacts kidney health by reactivating injury mechanisms and promoting fibrosis.
• Emerging therapies like GLP-1 agonists and endoscopic revisions show potential for mitigating renal sequelae.
• Personalized, multidisciplinary approaches and further research into biomarkers and antifibrotic therapies are essential for managing post-bariatric renal health.