Bariatric endocrinology: principles of medical practice

Fetal programming of human energy homeostasis brain networks: Issues and considerations

In this paper, we present a transdisciplinary framework and testable hypotheses regarding the process of fetal programming of energy homeostasis brain circuitry. Our model proposes that key aspects of energy homeostasis brain circuitry already are functional by the time of birth (with substantial interindividual variation); that this phenotypic variation at birth is an important determinant of subsequent susceptibility for energy imbalance and childhood obesity risk; and that this brain circuitry exhibits developmental plasticity, in that it is influenced by conditions during intrauterine life, particularly maternal-placental-fetal endocrine, immune/inflammatory, and metabolic processes and their upstream determinants. We review evidence that supports the scientific premise for each element of this formulation, identify future research directions, particularly recent advances that may facilitate a better quantification of the ontogeny of energy homeostasis brain networks, highlight animal and in vitro-based approaches that may better address the determinants of interindividual variation in energy homeostasis brain networks, and discuss the implications of this formulation for the development of strategies targeted towards the primary prevention of childhood obesity.

The predictive role of parathyroid hormone for non-alcoholic fatty liver disease based on invasive and non-invasive findings in candidates of bariatric surgery

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH) and hepatic fibrosis are the most detrimental hepatic abnormalities associated with increased body weight with devastating clinical outcomes. Therefore, there is a substantial necessity for efficient management strategies, including significant weight reduction. Bariatric surgery has been used as a therapeutic approach in a selected obese patient with NAFLD/NASH and other cardiometabolic comorbidities.

PURPOSE

The study is focused on the predictive role of PTH with the indices of hepatic steatosis/NAFLD and NASH based on liver biopsy, elastography, and sonography in morbidly obese patients.

METHODS

Ninety patients with BMI between 35 and 40 kg/m2 with more than two comorbidities who referred to Imam Reza outpatient clinic from December 2016 to September 2017 were recruited and underwent initial assessments, including demographic profiles, psychological assessment, anthropometric measurements, hepatic biopsy, and basic laboratory tests. Liver stiffness was evaluated using two-dimensional shear wave elastography (2D-SWE) at least two weeks before liver biopsy. The histological analysis of the liver was performed using biopsy samples which obtained from left hepatic lobe during bariatric surgery under direct surgeon observation using a 16-gauge Tru-cut needle. The study was approved by the ethical committee (IR.MUMS.fm.REC.1396.312).

RESULTS

The level of PTH was significantly high in patients with positive histology for hepatic fibrosis, steatosis, and NASH/NAFLD compared to patients with negative histology (p = 0.005, p = 0.009, and p = 0.013, respectively). Also, patients with liver fibrosis confirmed by elastography had significantly higher serum PTH concentration than patients without fibrosis (p = 0.011). PTH was also positively correlated with hepatic fibrosis, NASH, and steatosis (p = 0.007, p = 0.012, p = 0.023, respectively).

CONCLUSION

High levels of PTH was significantly associated with histological indices of (hepatic fibrosis, steatosis, NAFLD and NASH) and elasticity indices. Therefore, it is imperative to assess for high levels of PTH in the morbidly obese population pre-and post-bariatric surgery. However, for a more robust and comprehensive assessment, a randomized controlled trial is needed. The study was conducted in accordance with the practice guidance in the diagnosis and management of NAFLD from the American association for the study of liver disease (AASLD) 2018.

LEVEL III

Evidence obtained from well-designed cohort or case-control analytic studies.

High Incidence of Secondary Hyperparathyroidism in Bariatric Patients: Comparing Different Procedures

BACKGROUND

Bariatric surgery is an effective therapy for morbid obesity but may reduce calcium absorption and significantly decrease the bone mineral density. This study examined the prevalence of secondary hyperparathyroidism (SHPT) in obese subjects during follow-up after different bariatric surgeries. We investigated predictors of SHPT.

METHODS

We enrolled 1470 obese subjects undergoing bariatric/metabolic surgery with at least 1-year follow-up, including 322 patients undergoing Roux-en-Y gastric bypass (RYGB), 695 undergoing single anastomosis (mini-) gastric bypass (SAGB), 93 undergoing laparoscopic adjustable gastric banding (LAGB), and 360 undergoing sleeve gastrectomy (SG). Five years of data were available for 215 patients. Patients were instructed to supplement their diet according to the guideline. Calcium, parathyroid hormone (PTH), and vitamin D levels were measured before surgery and at 1 and 5 years after surgery. SHPT was defined as PTH > 69 pg/mL.

RESULTS

The overall prevalence of SHPT was high, 21.0% before surgery and was not different between patients with different bariatric procedures. Pre-operative PTH correlated with age, BMI, and vitamin D levels. Multi-variate analysis confirmed that vitamin D level was the only independent predictor of SHPT before surgery. The prevalence of SHPT increased to 35.4% at 1 year after surgery and 63.3% at 5 years after surgery. SAGB had the highest prevalence of SHPT (50.6%) followed by RYGB (33.2%), LAGB (25.8%), and SG (17.8%) at 1 year after surgery. At 5 years after surgery, SAGB still had the highest prevalence of SHPT (73.6%), followed by RYGB (56.6%), LAGB (38.5%), and SG (41.7%). Serum PTH at 1 year after surgery correlated with decreased BMI and weight loss. Multi-variate analysis confirmed that age, sex, calcium level, and bypass procedure were independent predictor of SHPT after surgery.

CONCLUSIONS

The prevalence of SHPT is high in morbidly obese patients before bariatric surgery which is related to vitamin D deficiency. The prevalence of SHPT increased continually along with the time after bariatric surgery, especially in patients receiving SAGB, followed by RYGB. The supplementation of vitamin D and calcium have to be higher in bypass procedure, especially in malabsorptive procedure.

BARIATRIC ENDOCRINOLOGY AND VERY-LOW-CALORIE MEAL PLANS

ABBREVIATIONS

PSMF = protein-sparing modified fast; VLCMP = very-low-calorie meal plans.

Determinants of Secondary Hyperparathyroidism in Bariatric Patients after Roux-en-Y Gastric Bypass or Sleeve Gastrectomy: A Pilot Study

Objective. Nutritional deficiencies are common after bariatric surgery. We aimed to assess the prevalence and possible predictors of secondary hyperparathyroidism (SHPT) in bariatric patients. Methods. A total of 95 patients who had undergone Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) were assessed after a median of 3 years after surgery. Anthropometric/demographic and weight-loss parameters were compared according to the presence of SHPT, independently for men/premenopausal women and postmenopausal women. Results. SHPT was highly prevalent (men/premenopausal women, 52.1%; postmenopausal women, 31.9%). Among men/premenopausal women, multivariate analysis indicated that SHPT was predicted by (a) 25-hydroxyvitamin D levels (Exp(B) = 0.869, P-value = 0.037), independently of age, sex, smoking; (b) calcium (Exp(B) = 0.159, P-value = 0.033) and smoking, independently of age and sex; (c) magnesium (Exp(B) = 0.026, P-value = 0.046) and smoking, independently of age and sex. Among postmenopausal women, SHPT was predicted by menopausal age independently of age, smoking, and levels of 25-hydroxyvitamin D or calcium. The development of SHPT was not associated with the type of surgery. Conclusions. RYGB and SG exhibited similar effects regarding the regulation of the hypothalamus-pituitary-parathyroid axis after surgery. Vitamin D status and menopausal age appear to determine SHPT on the long term. SHPT should be sought and vigorously treated with calcium and vitamin D supplementation.