Negative legacy of obesity

Area of Science:

• Immunology
• Metabolic Disease Research
• Cellular Biology

Background:

• Obesity triggers inflammation, senescence in visceral adipose tissue (VAT), and increases risks for type 2 diabetes (T2DM) and cardiovascular diseases.
• Senescent CD4+ T cells (CD44hi CD62Llo, PD-1+, CD153+) in VAT produce osteopontin, exacerbating inflammation.
• Weight loss benefits T2DM and cardiovascular risk factors, but long-term effects on events and longevity remain unclear.

Purpose of the Study:

• To investigate the long-term impact of weight reduction on obesity-associated T-cell senescence and VAT inflammation.
• To elucidate the mechanisms by which senescent T cells contribute to persistent inflammation despite weight loss.

Main Methods:

• Obese mice on a high-fat diet (HFD) were switched to a control diet to induce weight reduction.
• VAT analysis compared macrophage infiltration and crown-like structures in weight-reduced mice versus continuously HFD-fed obese mice.
• Characterization of senescent CD4+ T cells (CD153+ PD-1+) and their role in maintaining inflammation.

Main Results:

• Weight reduction normalized body weight and visceral fat mass to lean levels.
• VAT in weight-reduced mice showed increased macrophage infiltration and crown-like structures compared to obese mice.
• Persistent CD153+ PD-1+ CD4+ T cells, resistant to elimination, maintained chronic inflammation via osteopontin production.

Conclusions:

• T-cell senescence is a long-lived, detrimental legacy of obesity.
• The persistence of senescent T cells creates a self-sustaining inflammatory loop, undermining the benefits of weight loss.
• Targeting T-cell senescence may be crucial for mitigating long-term obesity-related health risks.