The comorbidities of obesity

The role of pituitary adenylate cyclase-activating polypeptide neurons in the hypothalamic ventromedial nucleus and the cognate PAC1 receptor in the regulation of hedonic feeding

Obesity is a health malady that affects mental, physical, and social health. Pathology includes chronic imbalance between energy intake and expenditure, likely facilitated by dysregulation of the mesolimbic dopamine (DA) pathway. We explored the role of pituitary adenylate cyclase-activating polypeptide (PACAP) neurons in the hypothalamic ventromedial nucleus (VMN) and the PACAP-selective (PAC1) receptor in regulating hedonic feeding. We hypothesized that VMN PACAP neurons would inhibit reward-encoding mesolimbic (A10) dopamine neurons via PAC1 receptor activation and thereby suppress impulsive consumption brought on by intermittent exposure to highly palatable food. Visualized whole-cell patch clamp recordings coupled with in vivo behavioral experiments were utilized in wildtype, PACAP-cre, TH-cre, and TH-cre/PAC1 receptor-floxed mice. We found that bath application of PACAP directly inhibited preidentified A10 dopamine neurons in the ventral tegmental area (VTA) from TH-cre mice. This inhibitory action was abrogated by the selective knockdown of the PAC1 receptor in A10 dopamine neurons. PACAP delivered directly into the VTA decreases binge feeding accompanied by reduced meal size and duration in TH-cre mice. These effects are negated by PAC1 receptor knockdown in A10 dopamine neurons. Additionally, apoptotic ablation of VMN PACAP neurons increased binge consumption in both lean and obese, male and female PACAP-cre mice relative to wildtype controls. These findings demonstrate that VMN PACAP neurons blunt impulsive, binge feeding behavior by activating PAC1 receptors to inhibit A10 dopamine neurons. As such, they impart impactful insight into potential treatment strategies for conditions such as obesity and food addiction.

Modulation of the Gut Microbiota and Serum Biomarkers After Laparoscopic Sleeve Gastrectomy: a 1-Year Follow-Up Study

PURPOSE

Bariatric surgery is a treatment option for those affected by severe obesity. This study investigated changes in gut microbiota and serum biomarkers after laparoscopic sleeve gastrectomy (LSG).

MATERIALS AND METHODS

A total of 126 patients with morbid obesity who underwent LSG were enrolled in this study. Routine biochemical tests, hormonal (insulin and glucagon), and cytokine levels (IL-6, IL-1β, TNF-α, IL-10, and TGF-β 1) were measured, in addition, real-time PCR (quantitative PCR, qPCR) quantitated gut microbiota. All the parameters were measured pre-operatively, 3, and 12 months post-surgery (F0, F3, and F12, respectively).

RESULTS

At F3, the level of FBS, HbA1c, HOMA-IR, triglyceride, cholesterol, LDL, BUN, creatinine, urea, SGOT, SGPT, IL-1β, IL-6, IFNγ, insulin, glucagon, the abundance of Prevotella and Bacteroides fragilis group, as well as the concentration of Firmicutes spp. showed significant decrease (P < 0.01), and HDL level, Akkermansia muciniphila and Roseburia spp. abundance, and Bacteroidetes and Bifidobacterium spp. concentration showed significant increase (P < 0.0001). The observed pattern continued or remained stable at F12 for all of these variables. IL-10 and TGF-β1 remained unchanged until F3 and showed a significant drop at F12. At F3, Clostridium cluster IV increased significantly and remained at that level afterward. Moreover, concentration of Phylum Actinobacteria showed an initial drop at F3 and a later increase at F12 (P < 0.0001).

CONCLUSION

LSG is associated with a significant improvement in serum biomarkers, as well as significant changes in fecal microbiota. Future systems biology analyses would shed more light on the underlying interactions of these parameters, and could help in developing novel diagnostic and therapeutic strategies for obesity management.

Lifestyle correlates of anthropometric estimates of body adiposity in an Italian middle-aged and elderly population: a covariance analysis

OBJECTIVE

To study the relationship between behavioural factors, body adiposity and muscle mass.

SUBJECTS AND METHODS

A total of 1415 Italian individuals (705 men and 710 women) aged 40-74 years from a population-based survey carried out in the town of Bollate (Milan). Analysis of covariance was used to refine and improve the precision of the comparisons.

RESULTS

Men: Smoking and sedentary behaviour were related to larger waist circumference (WC) and smaller hip circumference (HC). Increased WC was also associated with high-fat diet and moderate-to-heavy drinking (compared to light drinkers). Those more educated (completed high school) were leaner and ex-smokers had higher body mass index (BMI) than non-smokers. Women: BMI was inversely related with education, the more educated having also lower muscle mass. The light drinkers were leaner and moderate-to-heavy drinkers had less muscle mass than abstainers. Moderate-to-heavy drinkers had larger WC than light drinkers. A strong negative trend was found in the relationship between dietary fibre and WC. Overall adiposity (BMI) and, more weakly, HC and peripheral subcutaneous fat increased with more TV watching, whereas BMI lowered, together with WC and muscle mass (as measured by the mid-arm circumference), with more walking/cycling.

CONCLUSIONS

Modifiable habits such as smoking (men) and moderate-to-heavy alcohol drinking are associated with a pattern that is particularly deleterious to health: increased intra-abdominal fat and less muscle mass. Prevention strategies should be simultaneously aimed at promoting physical activities and reducing sedentary behaviours. A low-fat, fibre-rich diet seems to be closely related to a healthy distribution of body fat.