Trimethylamine N-oxide levels are associated with NASH in obese subjects with type 2 diabetes

AIMS

Trimethylamine N-oxide (TMAO), choline and betaine serum levels have been associated with metabolic diseases including type 2 diabetes (T2D) and non-alcoholic fatty liver disease (NAFLD). These associations could be mediated by insulin resistance. However, the relationships among these metabolites, insulin resistance and NAFLD have not been thoroughly investigated. Moreover, it has recently been suggested that TMAO could play a role in NAFLD by altering bile acid metabolism. We examined the association between circulating TMAO, choline and betaine levels and NAFLD in obese subjects.

METHODS

Serum TMAO, choline, betaine and bile acid levels were measured in 357 Mexican obese patients with different grades of NAFLD as determined by liver histology. Associations of NAFLD with TMAO, choline and betaine levels were tested. Moreover, association of TMAO levels with non-alcoholic steatohepatitis (NASH) was tested separately in patients with and without T2D.

RESULTS

TMAO and choline levels were significantly associated with NAFLD histologic features and NASH risk. While increased serum TMAO levels were significantly associated with NASH in patients with T2D, in non-T2D subjects this association lost significance after adjusting for sex, BMI and HOMA2-IR. Moreover, circulating secondary bile acids were associated both with increased TMAO levels and NASH.

CONCLUSIONS

In obese patients, circulating TMAO levels were associated with NASH mainly in the presence of T2D. Functional studies are required to evaluate the role of insulin resistance and T2D in this association, both highly prevalent in NASH patients.

Dysregulated microRNAs involved in contrast-induced acute kidney injury in rat and human

BACKGROUND

Contrast-induced nephropathy (CIN) is a complex syndrome of acute nephropathy that occurs following infusion of intravascular contrast agents, and is associated with an increased risk for adverse cardiovascular events. While there is no ideal biomarker for making an early diagnosis of CIN, we hypothesized that levels of specific circulating microRNA (miRNA) species might serve such a role.

METHODS

miRNA microarray assays were used to detect miRNAs in the kidney tissue of rats studied as an animal model of CIN. Real-time PCR was performed to validate results of the microarray assays. Kidney-enriched miRNAs detected in rat plasma were used as biomarkers to screen for CIN. Results obtained from the rat model of CIN were further validated in human patients with CIN.

RESULTS

Fifty-one miRNAs were aberrantly expressed in the kidney tissues between CIN and control rats; and among these, 17 miRNAs showed a >2-fold change of expression in the kidney tissues of CIN rats when compared with their expressions in non-CIN control rats. Among the 17 miRNAs aberrantly-expressed miRNAs screened from kidney tissue, only six also showed significantly different expression in the plasma of CIN rats. When compared with their levels in non-CIN control rats, the levels of three miR-30 family members (miR-30a, miR-30c, and miR-30e), as well as miR-320, were significantly increased in the plasma of CIN rats, while the plasma levels of miRNAs let-7a and miR-200a were significantly decreased. In a validation study of these results conducted with human plasma samples, only miR-30a, miR-30c, and miR-30e showed > 2-fold increases in CIN patients when compared with non-CIN patients. Receiver operating curves constructed to examine the abilities of miR-30a, miR-30c, and miR-30e to discriminate CIN patients from non-CIN patients showed AUCs of 0.954, 0.888, and 0.835, respectively.

CONCLUSIONS

Our study provides the first evidence that plasma miRNAs, and especially three miR-30 family members (miR-30a, miR-30c, and miR-30e), might serve as early biomarkers and (or) target candidates for CIN.

Laparoscopic adrenalectomy: lessons learned from an initial series of 100 patients

BACKGROUND

Laparoscopic adrenalectomy is considered the gold standard for the surgical treatment of adrenal disorders in most centers. This study analyzes the authors' experience using the lateral intraperitoneal approach with the first 100 patients. In addition to analyzing the authors' experience, this article aims to contrast it with some published series as an internal quality control.

METHODS

In a 10-year period, 138 laparoscopic adrenalectomies were performed for 100 patients. Demographics, surgical results, complications, and long-term outcomes were analyzed.

RESULTS

The participants comprised 69 women and 31 men with a mean age of 37 years. The procedures included 24 right, 38 left, and 38 bilateral adrenalectomies. The indications for surgery were Cushing's disease for 33 patients, pheochromocytoma (4 bilateral) for 23 patients, Cushing's syndrome for 18 patients, Conn's syndrome for 16 patients, and incidentaloma for 10 patients. Five procedures were converted to open surgery. Two patients with pheochromocytoma required intraoperative blood transfusion. The mean operative time was 174 min for unilateral adrenalectomies and 302 min for the bilateral procedures. The mean hospital stay was 5 days. Surgical morbidity included an abdominal wall hematoma, a small pneumothorax, and intraabominal bleeding in one patient that required reexploration. There were three operative mortalities not related to the technique. The long-term results showed control of hypercortisolism in all the patients with Cushing's disease and 82% of the patients with pheochromocytoma. Most of the patients with Conn's syndrome (91.4%) became normotensive after surgery.

CONCLUSIONS

Laparoscopic adrenalectomy is safe and effective. The complications are mild, and mortality is related more to the patient's condition than to the surgical technique.

Early-onset type 2 diabetes: metabolic and genetic characterization in the mexican population

The objective of this study was to investigate possible defects in the insulin sensitivity and/or the acute insulin response in a group of Mexican patients displaying early-onset type 2 diabetes and to evaluate the contribution of mutations in three of the genes linked to maturity-onset diabetes of the young. We studied 40 Mexican patients with an age of diagnosis between 20 and 40 yr in which the insulin sensitivity as well as the insulin secretory response were measured using the minimal model approach. A partial screening for possible mutations in 3 of the 5 genes linked to maturity-onset diabetes of the young was carried out by PCR-single strand conformation polymorphism analysis. A low insulin secretory capacity (AIRg = 68.5 +/- 5 muU/mL.min) and a near-normal insulin sensitivity (3.43 +/- 0.2 min/muU.mL x 10(4)) were found in these patients. Among this group we found two individuals carrying missense mutations in exon 4 of the hepatocyte nuclear factor-1alpha (HNF-4alpha) gene (Asp(126)-->His/Tyr and Arg(154)-->Gln, respectively) and one carrying a nonsense mutation in exon 7 of the HNF-1alpha gene (Gln(486)-->stop codon); 7.5% had positive titers for glutamic acid decarboxylase antibodies. Thirty-five percent of cases had insulin resistance; these subjects had the lipid abnormalities seen in the metabolic syndrome. A defect in insulin secretion is the hallmark in Mexican diabetic patients diagnosed between 20 and 40 yr of age. Mutations in either the HNF-1alpha or the HNF-4alpha genes are present among the individuals who develop early-onset diabetes in our population. These particular sequence changes have not been previously reported and therefore represent putative new mutations. Even in the absence of endogenous hyperinsulinemia, insulin resistance is associated with an adverse lipid profile.