Irisin and Cardiometabolic Disorders in Obesity: A Systematic Review.

Background: Overweight and obesity are global health issues, impacting a significant portion of young adults. Obesity is a complex condition influenced by genetics and environmental factors, leading to increased susceptibility to cardiovascular diseases (CVDs), hypertension, dyslipidemia, and insulin resistance. Irisin, a protein derived from the cleavage of fibronectin type III domain-containing protein 5, may have relationship with these cardiometabolic diseases. Objective: This systematic review aims to examine the relationship between serum irisin levels and obesity, particularly in individuals predisposed to cardiovascular risk factors. Methods: A thorough literature search was conducted in multiple databases, including "Science Direct," "Scopus," "PubMed," and "Lilacs," from July 2020. Inclusion criteria encompassed subjects with metabolic disorders (with or without obesity, BMI ≥30 kg/m2), clinical trials, and observational studies published between 2010 and June 2020. Exclusion criteria were animal studies, meta-analyses, systematic reviews, studies evaluating only healthy subjects, and those investigating disorders beyond cardiometabolic diseases. Results: Out of 151 identified articles, 30 met the inclusion criteria. These studies, published between 2013 and 2020, assessed adults (≥21 years) and included 26 observational studies and 4 clinical trials (n = 7585 subjects). All studies examined irisin's role in obesity and CVDs, often including associated diseases such as type 2 diabetes and hypertension. Despite varying sample sizes, the samples within the articles were homogeneous. Observational studies exhibited a low risk of bias in at least 60% of the evaluated domains. Clinical trials demonstrated a low risk of bias in at least 50% of the domains. Limitations. Although the systematic review provides valuable insights, it is limited by the available literature and the varying methodologies used across studies. Conclusion: The review suggests that irisin plays a significant role as both a preventive measure and a biomarker for comorbidities linked to obesity and cardiometabolic disorders. Future research should focus on standardized irisin measurement methods and diverse populations to further elucidate its mechanisms of action.

Non-pregnant Women Have a Lower Vitamin D than Pregnant Women After Gastric Bypass.

OBJECTIVE: To compare the nutritional status of vitamin D, calcium, and serum concentrations of parathyroid hormone (PTH) between women undergoing Roux-en-Y gastric bypass (RYGB) who became pregnant and women who did not become pregnant during the same postoperative period, as well as the impact of these changes on maternal and child health. METHODS: This is a longitudinal and retrospective study of women who previously underwent RYGB, paired by age and preoperative body mass index (BMI), divided into two groups: group 1 (G1), comprising 79 women who did not become pregnant, and group 2 (G2), comprising 40 pregnant women assessed in the overall trimesters. Both groups were analyzed before surgery (T0) and in the same interval after surgery: less than or equal to 1 year (T1) or greater than 1 year (T2), with a 2-year period at the most. Serum concentrations of vitamin D, calcium, parathyroid hormone (PTH), and gestational and neonatal complications were investigated. Statistical analysis was performed by the Statistical Package for the Social Sciences 21.0 (p < 0.05). RESULTS: Despite the additional nutritional demands at pregnancy, women evaluated after 1 year of RYGB had the highest demands of vitamin D when compared with pregnant women in the second trimester(p = 0.04). Women who became pregnant within 1 year of bariatric surgery were more likely to develop a urinary tract infection which, in turn, was associated with vitamin D inadequacy (p = 0.02).In the same period, the concentrations of calcium in the second and third trimesters showed a strong correlation with the number of pregnancies (R = 0.8, p = 0.008, R = 0.8, p = 0.003) and deliveries (R = 0.7, p = 0.013, R = 0.8, p = 0.006) and its nutritional status in the first trimester also showed a strong correlation with the occurrence of small newborns for gestational age/large for gestational age (SGA/LGA) (R = 0.8, p = 0.007). CONCLUSION: Since the highest vitamin D depletions occurred in G1 when compared with G2, the study suggests that a period of time for supplementation and its adjustments in post-bariatric pregnancy may be beneficial. It also encourages further investigation on the number of pregnancies/deliveries during prenatal care, due to vitamin D influence on the nutritional status of calcium, and it points out that changes in concentrations of this vitamin in pregnant women may lead to SGA/LGA newborns' births.

Maternal Anthropometry and Its Relationship with the Nutritional Status of Vitamin D, Calcium, and Parathyroid Hormone in Pregnant Women After Roux-en-Y Gastric Bypass.

OBJECTIVE: To assess the influence of pre-pregnancy body mass index (BMI), total gestational weight gain (TGWG), and pre-pregnancy surgical success on the nutritional status of vitamin D, calcium, and parathyroid hormone (PTH) in the trimesters of pregnancy of women who previously underwent Roux-en-Y gastric bypass (RYGB). METHODOLOGY: This is an analytical, longitudinal, and retrospective study comprising 42 pregnant women who previously underwent RYGB. Concentrations of vitamin D3, calcium, and PTH were assessed in all trimesters. Anthropometric variables necessary for calculating TGWG, surgical success, and BMI were collected preoperatively and over the trimesters of pregnancy. RESULTS: A total of 97.1% had vitamin D3 inadequacy at some point in pregnancy. Pre-pregnancy BMI, even when classified as overweight, may have exacerbated the serum concentrations of this vitamin in the third trimester (p = 0.011), and it was significantly lower in women with normal weight and/or obesity (p = 0.039). It was evidenced that both pre-pregnancy BMI and TGWG above the recommended optimal weight can be associated with calcium homeostasis, especially early in pregnancy. It was also shown that surgical success in the pre-pregnancy period may have influenced the serum concentrations of vitamin D in the second trimester of pregnancy (p = 0.013). CONCLUSION: This study draws attention to the importance of monitoring the nutritional status of vitamin D3 and calcium in the prenatal period due to its relationship with pre-pregnancy BMI, TGWG, and surgical success.