Shedding light on eye disease in obesity: A review.

Obesity is known to be associated with numerous ocular manifestations, including but not limited to, diabetic retinopathy (DR), age-related macular degeneration (AMD), cataracts, glaucoma, and dry eye disease. This review aims to provide an overview of the ophthalmological findings in obesity. A literature search was conducted using PubMed and Cochrane databases for studies describing randomized clinical trials, meta-analyses, systematic reviews, and observational studies published from 1 January 2017 to 1 April 2023. The search terms used included relevant keywords such as 'obesity', 'body mass index', 'waist-to-hip ratio', 'bariatric', 'ophthalmology', 'eye disease', 'myopia', 'retinopathy', 'glaucoma', and 'cataract'. This literature search was performed on 1 April 2023. Obesity is associated with increased risk of developing DR, a sight-threatening complication of diabetes mellitus. Similarly, obesity has been shown to increase risk of AMD, cataracts, glaucoma, and ocular surface disease. Multiple mechanisms linking obesity to ophthalmic disease have been proposed. Adipose tissue produces various inflammatory cytokines that can affect ocular tissues, leading to disease progression. Additionally, obesity is associated with systemic metabolic changes that can influence ocular health. Bariatric surgery has been shown to be protective against development of ophthalmic disease. Obesity is a significant risk factor for several ophthalmological diseases. Healthcare providers should encourage weight loss in patients with overweight or obesity to prevent or delay the onset of ocular complications. Further research is needed to better understand the underlying mechanisms of this association, and to identify effective strategies for preventing or managing ophthalmic disease in patients with obesity.

Adipose Tissue Inflammation Is Not Related to Adipose Insulin Resistance in Humans.

The role of adipose tissue (AT) inflammation in AT function in humans is unclear. We tested whether AT macrophage (ATM) content, cytokine gene expression, and senescent cell burden (markers of AT inflammation) predict AT insulin resistance measured as the insulin concentration that suppresses lipolysis by 50% (IC50). We studied 86 volunteers with normal weight or obesity at baseline and a subgroup of 25 volunteers with obesity before and after weight loss. There was a strong positive relationship between IC50 and abdominal subcutaneous and femoral fat cell size (FCS). The positive, univariate relationships between IC50 and abdominal AT inflammatory markers CD68, CD14, CD206 ATM/100 adipocytes, senescent cells, IL-6, and TNF-α mRNA were not significant after adjustment for FCS. A 10% weight loss significantly reduced IC50; however, there was no reduction in adipose ATM content, senescent cells, or cytokine gene expression. Our study suggests that commonly used markers of AT inflammation are not causally linked to AT insulin resistance, whereas FCS is a strong predictor of AT insulin resistance with respect to lipolysis.

Senescent cells in human adipose tissue: A cross-sectional study.

OBJECTIVE: Adipose tissue (AT) senescence is associated with AT dysfunction in rodents, but little is known about human AT senescence. The study goal was to define the distribution of senescent cells in two subcutaneous depots and understand relationships with adiposity and inflammation. METHODS: Sixty-three volunteers (48 females) underwent abdominal and femoral subcutaneous fat biopsies. Fat cell size, senescent cells using senescence-associated ß-galactosidase staining per 100 nucleated cells (percentage), and mRNA expression of four cytokines were measured. RESULTS: There was a larger proportion of senescent cells in femoral than abdominal subcutaneous AT (mean difference 1.6% [95% CI: 0.98%-2.3%], p < 0.001), and the percentage of femoral AT senescent cells was greater in women than men (median 3.9% vs. 2.1%, p < 0.01). There was a positive correlation between senescence and fat cell size in abdominal (rs  = 0.44, p < 0.001) and femoral (rs  = 0.35, p = 0.007) AT depots. Abdominal AT tumor necrosis factor alpha (rs  = 0.49, p < 0.01) and interleukin-1ß (rs  = 0.44, p = 0.01) expression was positively correlated with abdominal, but not femoral, AT senescence. CONCLUSIONS: In human subcutaneous AT, there are more senescent cells in femoral than abdominal depots; abdominal AT senescent cells are more associated with inflammatory signals than femoral AT senescent cells.