Communicating the ocular and systemic complications of obesity to patients

Impact of Bariatric Surgery-Induced Weight Loss on Anterior Eye Health in Patients with Obesity

The aim of the present research was to assess the effect of bariatric surgery-induced weight loss on the tear film and ocular surface of patients with obesity. A total of 29 participants with obesity (aged 47.2 ± 10.1 years, 8 male) were measured at baseline and followed up one year after Roux-en-Y gastric bypass (RYGB) surgery. General anthropometric data, as well as serum lipid markers of cholesterol, were assessed in all individuals. Bilateral anterior eye measurements of tear meniscus height (TMH), non-invasive tear breakup time, bulbar and limbal redness and infrared meibography were captured using the Keratograph K5M (Oculus) and ocular surface damage was evaluated using fluorescein sodium and lissamine green staining. Bariatric surgery resulted in significant loss of weight (body mass index p < 0.001) and an improvement in the blood lipid profile (p < 0.01) in all participants. However, there were no statistically significant differences between the baseline and one-year follow-up for any of the measured clinical ocular surface and tear film variables (all p > 0.05). Although there were trends for a reduced TMH and a decrease in meibomian gland dropout after bariatric surgery, these differences were also insignificant (p > 0.05). In conclusion, weight reduction through bariatric surgery did not have an effect on the tear film or ocular surface in unselected patients with obesity.

Role of sorbitol-mediated cellular stress response in obesity-associated retinal degeneration

PURPOSE

Obesity is a global health problem associated with several diseases including ocular complications. Earlier we reported progressive retinal degeneration because of obesity in a spontaneous obese rat (WNIN/Ob) model. In the current study, we examined the molecular mechanisms leading to retinal degeneration in WNIN/Ob rat.

METHODS

Sorbitol was estimated by the fluorometric method in the retina of WNIN/Ob rats at different age (3-, 6- and 12- months), along with their respective lean rats. Immunoblotting was performed in the retina to assess the status of the insulin signaling pathway, ER stress and cellular stress (p38MAPK and ERK1/2). Human SK-N-SH cells were treated with 0.5 and 1.0 M sorbitol for 30 min to study insulin signaling, ER stress, and cellular stress. TUNEL assay was done to measure apoptosis. The retinal function in the rats was determined by electroretinogram.

RESULTS

A gradual but significantly higher intracellular sorbitol accumulation was observed in the retina of obese rats from 3- to 12-months. The cellular osmotic stress has activated the insulin signaling mechanism without activating AKT and also triggered ER stress. Both the stresses activated the ERK and p38MAPK signaling causing apoptosis in the retina leading to retinal degeneration. Retinal dysfunction was confirmed by altered scotopic and photopic electroretinogram responses. These in vivo results were mimicked in SK-N-SH cells when exposed to sorbitol in vitro.

CONCLUSIONS

These results suggest cellular stress due to sorbitol accumulation impairing the ER function, thereby leading to progressive retinal degeneration under obese conditions.

Increased risk of cataract development in WNIN-obese rats due to accumulation of intralenticular sorbitol

Epidemiological studies have reported an association between obesity and increased incidence of ocular complications including cataract, yet the underlying biochemical and molecular mechanisms remained unclear. Previously we had demonstrated accumulation of sorbitol in the lens of obese rats (WNIN/Ob) and more so in a related strain with impaired glucose tolerance (WNIN/GR-Ob). However, only a few (15-20%) WNIN/Ob and WNIN/GR-Ob rats develop cataracts spontaneously with age. To gain further insights, we investigated the susceptibility of eye lens proteins of these obese rat strains to heat- and UV-induced aggregation in vitro, lens opacification upon glucose-mediated sorbitol accumulation ex vivo, and onset and progression of cataract was followed by galactose feeding and streptozotocin (STZ) injection. The results indicated increased susceptibility toward heat- or UV-induced aggregation of lens proteins in obese animals compared to their littermate lean controls. Further, in organ culture studies glucose-induced sorbitol accumulation was found to be higher and thus the lens opacification was faster in obese animals compared to their lean littermates. Also, the onset and progression of galactose- or STZ-induced cataractogenesis was faster in obese animals compared to lean control. These results together with our previous observations suggest that obesity status could lead to hyperaccumulation of sorbitol in eye lens, predisposing them to cataract, primarily by increasing their susceptibility to environmental and/or physiological factors. Further, intralenticular sorbitol accumulation beyond a threshold level could lead to cataract in WNIN/Ob and WNIN/GR-Ob rats.

Vitamin A supplementation ameliorates obesity-associated retinal degeneration in WNIN/Ob rats

OBJECTIVE

Obesity is associated with various health afflictions, including ocular complications such as diabetic retinopathy, high intraocular pressure, cataracts, and macular degeneration. We previously reported progressive retinal degeneration after the onset of obesity in the spontaneously obese rat (WNIN/Ob) model. In the present study, we investigated vitamin A supplementation to ameliorate obesity-associated retinal degeneration in the WNIN/Ob rat.

METHODS

Five-month-old male WNIN/Ob obese (O) and lean (L) control rats were fed with vitamin A 2.6 mg (L/O-I), 26 mg (L/O-II), 52 mg (L/O-III), and 129 mg (L/O-IV) per kilogram of diet as retinyl palmitate for 4 mo 2 wk. Retinal morphology and retinal gene expression were assessed by histologic, immunohistochemical, and real-time polymerase chain reaction methods.

RESULTS

Supplementation of vitamin A at 26 or 52 mg significantly modulated the expression of retinal genes in the O but not in the L phenotype. Vitamin A supplementation significantly upregulated the expression of genes, such as rhodopsin, rod arrestin, phosphodiesterase, transducins, and fatty acid elongase-4, that were otherwise downregulated in O rat retina. The expression of glial fibrillary acidic protein was downregulated by vitamin A feeding in O rat retina. The immunohistochemical and histologic findings corroborated the gene expression data. The effects were significant at a 26- or 52-mg dose of vitamin A.

CONCLUSION

Vitamin A supplementation alleviated obesity-associated retinal degeneration in the WNIN/Ob rat.