Role of Presurgical Gut Microbial Diversity in Roux-en-Y Gastric Bypass Weight-Loss Response: A Cohort Study.

INTRODUCTION: Roux-en-Y gastric bypass (RYGB) substantially alters the gut microbial composition which could be associated with the metabolic improvements seen after surgery. Few studies have been conducted in Latin American populations, such as Mexico, where obesity prevalence is above 30% in the adult population. Thus, the aim of this study was to characterize the changes in the gut microbiota structure in a Mexican cohort before and after RYGB and to explore whether surgery-related changes in the microbial community were associated with weight loss. METHODS: Biological samples from patients who underwent RYGB were examined before and 12 months after surgery. Fecal microbiota characterization was performed through 16S rRNA sequencing. RESULTS: Twenty patients who underwent RYGB showed a median excess weight loss of 66.8% 12 months after surgery. Surgery increased alpha diversity estimates (Chao, Shannon index, and observed operational taxonomic units, p < 0.05) and significantly altered gut microbiota composition. Abundance of four genera was significantly increased after surgery: Oscillospira, Veillonella, Streptococcus, and an unclassified genus from Enterobacteriaceae family (PFDR < 0.1). The change in Veillonella abundance was associated with lower excess weight loss (rho = -0.446, p = 0.063) and its abundance post-surgery with a greater BMI (rho = 0.732, p = 5.4 × 10-4). In subjects without type 2 diabetes, lower bacterial richness and diversity before surgery were associated with a greater Veillonella increase after surgery (p < 0.05), suggesting that a lower bacterial richness before surgery could favor the bloom of certain oral-derived bacteria that could negatively impact weight loss. CONCLUSION: Presurgical microbiota profile may favor certain bacterial changes associated with less successful results.

Intraoperative parathyroid hormone levels dynamics of cured patients with impaired renal function following parathyroidectomy for primary hyperparathyroidism.

BACKGROUND: Intraoperative parathyroid hormones have been used to establish operative success in patients with primary hyperparathyroidism. This study's aim was to assess the impact of estimated glomerular filtration rate and serum creatinine levels on the fulfillment of >50% drop and normalization of intraoperative parathyroid hormone levels. METHODS: Patients successfully treated for primary hyperparathyroidism were analyzed. The samples for parathyroid hormone were collected at baseline, 5-, 10-, and 30-minutes postexcision. The patients were classified as follows: (1) estimated glomerular filtration rate >60 mL/min, (2) estimated glomerular filtration rate <60 mL/min and serum creatinine levels <1.2 mg/dL, and (3) estimated glomerular filtration rate <60 mL/min and serum creatinine levels >1.2 mg/dL. Comparative analysis of patients achieving the >50% parathyroid hormone drop criterion and normalization of intraoperative parathyroid hormone was performed. RESULTS: One hundred-fourteen patients were distributed as follows: 88 patients (77.2%), 14 (12.3%), and 12 (10.5%) for groups 1, 2 and 3, respectively. No difference between groups in the proportion of patients fulfilling the >50% parathyroid hormone drop criterion was found. An abnormally elevated intraoperative parathyroid hormone level at 30-minute postexcision was observed in 0, 14.3, and 16.6% in groups 1, 2, and 3, respectively (P ≤ .0001). CONCLUSION: In the study, >50% parathyroid hormone drop criterion was equally achieved despite normal or reduced estimated glomerular filtration rate. When serum creatinine levels increased >1.2 mg/dL and estimated glomerular filtration rate declined <60 mL/min, the likelihood of reaching normal intraoperative parathyroid hormone levels postexcision was significantly lower.

Clinical factors associated with early and persistent hypocalcaemia after parathyroidectomy in patients on dialysis with severe hyperparathyroidism.

AIM: Severe hypocalcaemia following parathyroidectomy for secondary or tertiary hyperparathyroidism (SHPT/THPT) is scarcely studied. We aimed to describe and identify risk factors for early and persistent hypocalcaemia after parathyroidectomy. METHODS: Retrospective pair-matched cohort study. We assessed 87 dialysis patients with SHPT (n = 73) or THPT (n = 14) paired with 146 subjects with primary hyperparathyroidism (PHPT) who underwent parathyroidectomy and were followed for 12 months. Early severe hypocalcaemia was defined as a free Ca ≤0.8 mmol/L [3.2 mg/dl] or corrected Ca ≤1.87 mmol/L [7.5 mg/dl] within 48 h. After parathyroidectomy and persistent hypocalcaemia, as an elemental Ca intake >3.0 g/day to achieve corrected Ca >2 mmol/L [8.0 mg/dl]. RESULTS: Early severe hypocalcaemia occurred in 77% (67/87) versus 6.8% (10/146) of subjects with SHPT/THPT and PHPT, respectively (p < .001). In SHPT/THPT cases, persistent hypocalcaemia occurred in 77% (49/64) and 64% (35/54) after 6 and 12 months of parathyroidectomy, respectively. In PHPT cases, persistent hypocalcaemia occurred in 6.8% (10/146) after 4-12 months of parathyroidectomy. Preoperative serum alkaline phosphatase (ALP) was the only risk factor associated to early severe hypocalcaemia (OR 7.3, 95% C.I. 1.7-10.9, p = .006) and persistent hypocalcaemia (OR 7.1, 95% C.I: 2.1-14.2, p = .011). Subjects with persistently low intact parathormone (iPTH) (<5.3 pmol/L [50 ng/ml]), suggestive of adynamic bone disease) showed higher Ca increases and less oral calcium requirements compared to those who progressively increased iPTH after parathyroidectomy. CONCLUSION: Early and persistent hypocalcaemia after parathyroidectomy in severe HPT were a common event associated directly to preoperative ALP levels. Subjects with persistently low postoperative iPTH normalized serum Ca more frequently after 1 year of follow up.

Mid-Term and Long-Term Impact of Permanent Hypoparathyroidism After Total Thyroidectomy.

BACKGROUND: Permanent hypoparathyroidism (PH) is the most frequent long-term complication after total thyroidectomy. PH is related to many short-term and long-term complications, including clinical manifestations of hypocalcemia, hypercalcemia due to overtreatment, hyperphosphatemia, gastrointestinal, neuropsychiatric symptoms, decrease in renal function and infectious complications. The aim of this study was to identify the most frequent effects of PH and its associated risk factors. METHODS: We performed a retrospective analysis of a single institutional series of patients who developed PH after total thyroidectomy between 2000 and 2016. PH was defined as hypoparathormonemia (≤12 pg/mL) or the need for calcium/vitamin D supplementation to achieve normal calcium levels for more than 12 months. Descriptive and inferential statistics were employed based on the natural scaling of each included variable. RESULTS: Thirty-nine patients fulfilled the criteria for PH. Mean ± SD age was 46.26 ± 13.4 years; 6 (15.4%) were males and 33 (84.6%) females. Mean follow-up was 6.13 ± 3.25 years. Mean calcium carbonate supplementation doses per day were 18.95 ± 17.5 g and 21.4 ± 19.3 g at 1 year and last follow-up, respectively. Hypocalcemic crisis was the most common complication (66.7%), followed by neuropsychiatric (38.5%) and gastrointestinal symptoms (33.3%). Ten patients showed a decrease in renal function (eGFR drop ≥25%) and 4 developed chronic kidney disease. The amount of calcium supplementation was the most relevant related risk factor. CONCLUSIONS: PH is associated with multiple complications, including renal function impairment, gastrointestinal, neuropsychiatric and infectious complications. Lower calcium supplementation doses are related to lower complications rates.

Preoperative and Postoperative Risk Stratification of Thyroid Papillary Microcarcinoma: A Comparative Study Between Kuma Criteria and 2015 American Thyroid Association Guidelines Risk Stratification.

Background: The incidence of micropapillary thyroid carcinoma (mPTC) has increased in the last decade. Active surveillance (AS) has been proposed as an alternative management for low-risk mPTC based on preoperative Kuma criteria. Controversy still exists on how to appropriately manage this group of patients, as some low-risk mPTC may harbor some postoperative features associated with disease recurrence as described in the 2015 American Thyroid Association (ATA) guidelines. Methods: We retrospectively reviewed 108 patients with histopathologic diagnosis of mPTC after surgery at a third level hospital in Mexico City from 2000 to 2018. Demographic and clinicopathologic data were analyzed as predictors for disease recurrence and/or metastatic disease (lymph node or distant). Comparison between group stratification based on preoperative Kuma criteria and postoperative 2015 ATA guidelines risk criteria for disease recurrence was performed. Measures of diagnostic accuracy were obtained for preoperative risk features according to the Kuma criteria. Results: Of 108 patients, 79 (73%) were classified as preoperative high-risk mPTC and 29 (27%) as low risk based on the Kuma criteria. Of these 79 high-risk patients, 38 (48%) were reclassified as low risk for disease recurrence, 12 (15%) as intermediate risk, and 29 (37%) remained as high risk based on the 2015 ATA risk criteria. Of the 29 preoperative low-risk patients, 19 (65.5%) remained as postoperative low risk for disease recurrence, 2 (7%) as intermediate risk, and 8 (27.5%) as high risk. Higher accuracy of preoperative risk features was obtained for lymph node and distant metastases, 84.2% and 97.2%, respectively. After multivariate analysis, age <40 years and microscopic extrathyroidal extension (ETE) were associated with higher risk for metastatic disease (lymph node or distant) in our cohort. Conclusions: Patients with mPTC under 40 years old and microscopic ETE are more prone to develop metastatic disease (lymph node or distant). One-third of our patients stratified as low-risk mPTC according to the Kuma criteria for AS had histopathologic features associated with a more aggressive clinical behavior or structural recurrence. In addition, lymph node and distant metastases are the preoperative risk features with the highest diagnostic accuracy for preoperative risk stratification.

Transoral Endoscopic Thyroidectomy by Vestibular Approach-Initial Experience and Comparative Analysis in the First Reported Mexican Cohort.

Introduction: Transoral endoscopic thyroidectomy by vestibular approach (TOETVA) is a relatively new technique for the surgical treatment of thyroid diseases. We present the initial experience of a reference hospital of Mexico with TOETVA. Materials and Methods: This is a comparative retrospective study of cases (TOETVA) and controls (open thyroidectomy) treated by the endocrine surgeons between July 2017 and April 2019. Cases were patients of any gender, older than 18 years of age, with malignant thyroid nodules <2 cm or undetermined <5 cm without extrathyroidal extension and no lymph node or distant metastasis. Demographic, operative, and postoperative data were obtained and analyzed. Results: Twenty patients were surgically treated by TOETVA during the study period. Controls were paired based on type of surgery and dominant thyroid nodule. Ninety percent of the patients had a definitive diagnosis of malignancy. No statistically significant differences were found in age, BMI, length of stay, thyroid lobes size, and complication rates. Operative time was longer in TOETVA (216.7 ± 62.5 vs. 153.9 ± 49.25 minutes; t test P < .0001) and intraoperative blood loss was lesser for the TOETVA group (38.25 ± 38.9 vs. 101.8 ± 126.6 mL; t test P < .04). Conclusions: TOETVA is a feasible and relatively safe surgical technique for patients with benign and malignant thyroid diseases. Complication rates seem to be comparable with conventional open technique with lesser intraoperative bleeding; nevertheless, it requires longer operative times.

I. THE ROLE OF RESEARCH ETHICS COMMITTEES IN OBSERVATIONAL STUDIES: EPIDEMIOLOGICAL REGISTRIES, CASE REPORTS, INTERVIEWS, AND RETROSPECTIVE STUDIES.

It is often unclear to the clinical investigator whether observational studies should be submitted to a research ethics committee (REC), mostly because, in general, no active or additional interventions are performed. Moreover, obtaining an informed consent under these circumstances may be challenging, either because these are very large epidemiological registries, or the subject may no longer be alive, is too ill to consent, or is impossible to contact after being discharged. Although observational studies do not involve interventions, they entail ethical concerns, including threats such as breaches in confidentiality and autonomy, and respect for basic rights of the research subjects according to the good clinical practices. In this context, in addition to their main function as evaluators from an ethical, methodological, and regulatory point of view, the RECs serve as mediators between the research subjects, looking after their basic rights, and the investigator or institution, safeguarding them from both legal and unethical perils that the investigation could engage, by ensuring that all procedures are performed following the international standards of care for research. The aim of this manuscript is to provide information on each type of study and its risks, along with actions to prevent such risks, and the function of RECs in each type of study.

I. The role of research ethics committees in observational studies: epidemiological registries, case reports, interviews, and retrospective studies

Abstract It is often unclear to the clinical investigator whether observational studies should be submitted to a research ethics committee (REC), mostly because, in general, no active or additional interventions are performed. Moreover, obtaining an informed consent under these circumstances may be challenging, either because these are very large epidemiological registries, or the subject may no longer be alive, is too ill to consent, or is impossible to contact after being discharged. Although observational studies do not involve interventions, they entail ethical concerns, including threats such as breaches in confidentiality and autonomy, and respect for basic rights of the research subjects according to the good clinical practices. In this context, in addition to their main function as evaluators from an ethical, methodological, and regulatory point of view, the RECs serve as mediators between the research subjects, looking after their basic rights, and the investigator or institution, safeguarding them from both legal and unethical perils that the investigation could engage, by ensuring that all procedures are performed following the international standards of care for research. The aim of this manuscript is to provide information on each type of study and its risks, along with actions to prevent such risks, and the function of RECs in each type of study.

[Long-term efficacy of parathyroidectomy in secondary and tertiary hyperparathyroidism]. / Eficacia a largo plazo de la paratiroidectomía en hiperparatiroidismo secundario y terciario.

BACKGROUND: Secondary and tertiary hyperparathyroidism (SHPT and THPT), are complications of chronic kidney disease (CKD), characterized by high levels of serum parathormone, hyperphosphatemia or hypercalcemia, respectively. If diet and pharmacological therapies fail, clinical practice guidelines suggest parathyroidectomy (PTX). Some studies have described its effectiveness and safety, but these have not included Mexican population. OBJECTIVE: To describe long-term effectiveness of PTX in Mexican patients with SHPT or THPT. MATERIAL AND METHODS: Observational and retrospective study of patients treated with PTX between 1995 and 2014 in a third level hospital in Mexico City. The analyses included the follow-up of medical treatment and biochemical assessment every three months during the first year, and the last evaluation. Permutation and chi square tests were used. RESULTS: The study included 27 patients (14 women). The follow-up mean was 39 months; 61.5% had SHPT. All biochemical parameters, except magnesium, were reduced in the first year of follow-up. In the long term, SHPT was controlled in 80% using PTH under a 300 pg/mL criterion, and 90% in patients with THPT using calcium criterion. Persistent hypocalcemia was present in 11.5% of cases. CONCLUSION: Mexican patients with SHPT and THPT could be successfully treated with surgery with low risk of hypocalcemia.

INTRODUCCIÓN: el hiperparatiroidismo secundario (SHPT) y terciario (THPT) son complicaciones de la enfermedad renal crónica (ERC), caracterizadas por elevación de hormona paratiroidea, hiperfosfatemia o hipercalcemia. Si la terapia nutricional y farmacológica fallan, se sugiere la paratiroidectomía (PTX). Los estudios de cohorte que han descrito su efectividad no incluyen a la población mexicana. OBJETIVO: describir la efectividad a largo plazo de la PTX en pacientes mexicanos con SHPT y THPT. MATERIAL Y MÉTODOS: estudio observacional, retrospectivo de pacientes tratados con PTX entre 1995 y 2014 en un hospital de tercer nivel de la Ciudad de México. Se registraron la terapia médica, la evaluación bioquímica, cada tres meses durante un año, y la última evaluación registrada. Se utilizaron pruebas de permutación y de chi cuadrada. RESULTADOS: se incluyeron 27 pacientes (14 mujeres). El seguimiento promedio fue de 39 meses; 61.5% tuvieron SHPT. Los parámetros bioquímicos, salvo el magnesio, disminuyeron durante el primer año postquirúrgico. A largo plazo, el SHPT fue controlado en 80%, con el criterio de la PTH menor de 300 pg/mL, y el THPT en el 90% con el criterio de normocalcemia. La hipocalcemia permanente estuvo presente en 11.5% de los casos. CONCLUSIÓN: los pacientes mexicanos con SHPT y THPT pueden ser tratados exitosamente mediante cirugía con bajo riesgo de hipocalcemia.

Exercise Induces White Adipose Tissue Browning Across the Weight Spectrum in Humans.

While the effect of exercise on white adipose tissue browning and metabolic improvement in rodents is clear, there are few studies in humans with inconclusive results. Thus, the aim of the study was to assess whether an exercise intervention promotes subcutaneous adipose tissue browning in humans, and whether this response is associated with metabolic improvement in three groups of individuals defined by body mass index (BMI) (kg/m2). Sedentary adult subjects with different BMI were enrolled in a 12-week bicycle-training program (3 times per week, intensity 70-80% HRmax). Brown and beige gene expression in subcutaneous adipose tissue (scWAT) biopsies, and serum glucose, insulin, lipid, adipokine, and myokine levels were compared before and after the exercise intervention. Thirty-three non-diabetic subjects (mean age 30.4 ± 4.6 years; 57.57% female; 13 normal weight, 10 overweight and 10 with obesity) completed the exercise intervention. Without any significant change in body composition, exercise improved several metabolic parameters, most notably insulin resistance and particularly in the overweight group. Circulating adiponectin, apelin, and irisin exercise-induced changes predicted 60% of the insulin sensitivity improvement. After exercise UCP1, TBX1, CPT1B scWAT expression significantly increased, along with P2RX5 significant positive staining. These changes are compatible with scWAT browning, however, they were not associated with glucose metabolism improvement. In conclusion, 12-weeks of exercise training produced brown/beige gene expression changes in abdominal scWAT of non-diabetic individuals with different BMI, which did not contribute to the metabolic improvement. However, this result should not be interpreted as a lack of effect of browning on metabolic parameters. These findings suggest that a bigger effect is needed and should not preclude the development of more effective strategies of browning. Furthermore, exercise-induced changes in adiponectin, apelin, and irisin predicted insulin sensitivity improvement, supporting the important role of adipokines and myokines in metabolism homeostasis.

[Laparoscopic Roux-en-Y gastric bypass surgery for morbid obesity. Experience at the Nacional de Ciencias Médicas y Nutrición Salvador Zubirán]. / Bypass gástrico laparoscópico en Y de Roux y obesidad mórbida. Experiencia en el Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán.

INTRODUCTION: Morbid obesity is a serious health problem associated to a significant reduction in life expectancy. OBJECTIVE: To evaluate the anthropometric and metabolic changes observed in obese patients, 3, 6 and 12 months after laparoscopic Roux-en-Y gastric bypass surgery and the complications associated with the procedure. MATERIAL AND METHODS: Retrospective study that included 128 consecutive obese patients submitted for bariatric surgery at the INCMNSZ (2004-2006). RESULTS: Their mean age was 38 +/- 10 years, 83% were women with a BMI of 48 +/- 6 Kg/m2. 65% were hypertensives, 55% had hypertriglyceridemia and 34% diabetes. A year after surgery all patients had at least reduced 20% their body weight and the percentage of excess body weight loss was 73%. The prevalence of hypertension, hypertrigliceridemia and diabetes was reduced to 24%, 17% and 12%, respectively (p < 0.001). Four patients died (3%), all of them had a leak of the anastomosis and intra-abdominal abscess. One died because pulmonary embolism, another with a myocardial infarction (after surgical reinterventions) and the other two with sepsis. CONCLUSIONS: Laparoscopic Roux-en-Y gastric bypass surgery in morbid obese patients favors significant reductions in body weight and associated co morbidities. This surgery is not free of complications and mortality, reason why it must be done only by surgical and interdisciplinary groups with experience in these procedures.