Effects of Elobixibat, an Inhibitor of Ileal Bile Acid Transporter, on Glucose and Lipid Metabolism: A Single-arm Pilot Study in Patients with T2DM.

PURPOSE: The ileal bile acid transporter inhibitor elobixibat was recently approved in Japan for use in the treatment of patients with chronic constipation. Elobixibat has been associated with increased plasma glucagon-like peptide 1 level through Takeda G protein receptor 5, which is a membrane receptor of bile acids. The present study assessed the metabolic effects of elobixibat in patients with type 2 diabetes mellitus (T2DM)-related constipation. METHODS: In this single-arm pilot study, 21 patients with T2DM and constipation were administered elobixibat 10 mg/d for 12 weeks (period 1). The primary end point was the change in hemoglobin (Hb) A1c at week 12. Secondary end points included physical parameters; constipation symptoms; and blood parameters, such as low-density lipoprotein cholesterol (LDL-C), arachidonic acid (AA), and fatty acid fractions. Thereafter, the study participants chose whether to continue therapy for an additional 12 weeks (period 2), at which point HbA1c and lipid levels were reevaluated. Safety information, including adverse events, discontinuation and interruption of the drug, was collected at each visit during the trial. FINDINGS: Period 1: the levels of HbA1c, LDL-C, and AA were significantly reduced after administration of elobixibat for 12 weeks (-0.2%, -21.4 mg/dL, and -16.1 µg/dL, respectively; P = 0.016, P < 0.001, and P = 0.010). Period 2: at week 24, the change from baseline in HbA1c was significantly greater among those who continued elobixibat treatment than in those who discontinued after 12 weeks (-0.23% vs +0.21%; P = 0.038). No serious or severe adverse events were observed. IMPLICATIONS: Elobixibat may benefit patients with T2DM by improving glucose metabolism and lowering serum LDL-C and AA levels, in addition to ameliorating constipation. This single-arm pilot study was of a small sample size. The findings provide a basis for designing a larger-scale study to confirm the effects of elobixibat on glucose and lipid metabolism. (UMIN Clinical Trials Registry identifier: UMIN000045508; https://www.umin.ac.jp/ctr/index.htm).

Case Report: Myxedema Coma Caused by Immunoglobulin A Vasculitis in a Patient With Severe Hypothyroidism.

Myxedema coma is a critical disorder with high mortality rates. Disruption of the compensatory mechanism for severe and long-term hypothyroidism by various causes leads to critical conditions, including hypothermia, respiratory failure, circulatory failure, and central nervous system dysfunction. Infectious diseases, stroke, myocardial infarction, sedative drugs, and cold exposure are considered the main triggers for myxedema coma. A 59-year-old Japanese woman presented with bilateral painful purpura on her lower legs. She was diagnosed with coexisting immunoglobulin A (IgA) vasculitis and severe IgA vasculitis with nephritis and was consequently treated with intravenous methylprednisolone (125 mg/day). However, she rapidly developed multiple organ failure due to the exacerbation of severe hypothyroidism, i.e., myxedema. Her condition improved significantly following oral administration of prednisolone along with thyroxine. There was a delayed increase in the serum free triiodothyronine level, while the serum free thyroxine level was quickly restored to normal. Rapid deterioration of the patient's condition after admission led us to diagnose her as having myxedema coma triggered by IgA vasculitis. Hence, clinicians should be aware of the risks of dynamic exacerbations in patients with hypothyroidism. Furthermore, our study suggested that combination therapy with thyroxine and liothyronine might prove effective for patients with myxedema coma, especially for those who require high-dose glucocorticoid administration.

[VNUT Is a Therapeutic Target for Type 2 Diabetes and NASH].

ATP, used in cells as an energy currency, also acts as an extracellular signaling molecule. Studies of purinergic receptor subtypes have revealed that purinergic chemical transmission plays important roles in various cell types. The vesicular nucleotide transporter (VNUT), the ninth transporter in the SLC17 organic anion transporter family, is essential for vesicular ATP storage and its subsequent release. The VNUT is localized on the membrane of secretory vesicles and actively transports ATP into vesicles using an electrochemical gradient of protons supplied by vacuolar proton ATPase (V-ATPase) as a driving force. ATP acts as a damage-associated molecular pattern (DAMPs), contributing to the persistence of chronic inflammation. Chronic inflammation induces systemic insulin resistance, which is the underlying pathology of type 2 diabetes and non-alcoholic fatty liver disease (NAFLD), ranging from simple steatosis to non-alcoholic steatohepatitis (NASH). We previously demonstrated that ATP transported in insulin granules via the VNUT negatively regulates insulin secretion. We also found that hepatocytes release ATP in a VNUT-dependent manner, which elicits hepatic insulin resistance and inflammation. VNUT-knockout mice exhibited improved glucose tolerance and were resistant to the development of high fat diet-induced NAFLD. In this article, we summarize recent advances in our understanding of the mechanism of the VNUT, the development of inhibitors, and its pathological involvement in type 2 diabetes and NAFLD. The pharmacological inhibition of the VNUT may represent a potential therapeutic approach for the treatment of metabolic diseases.

Clodronate, an inhibitor of the vesicular nucleotide transporter, ameliorates steatohepatitis and acute liver injury.

The vesicular nucleotide transporter (VNUT) is responsible for the vesicular storage and release of ATP from various ATP-secreting cells, and it plays an essential role in purinergic signaling. Although extracellular ATP and its degradation products are known to mediate various inflammatory responses via purinoceptors, whether vesicular ATP release affects steatohepatitis and acute liver injury is far less understood. In the present study, we investigated the effects of clodronate, a potent and selective VNUT inhibitor, on acute and chronic liver inflammation in mice. In a model of methionine/choline-deficient diet-induced non-alcoholic steatohepatitis (NASH), the administration of clodronate reduced hepatic inflammation, fibrosis, and triglyceride accumulation. Clodronate also protected mice against high-fat/high-cholesterol diet-induced steatohepatitis. Moreover, prophylactic administration of clodronate prevented D-galactosamine and lipopolysaccharide-induced acute liver injury by reducing inflammatory cytokines and hepatocellular apoptosis. In vitro, clodronate inhibited glucose-induced vesicular ATP release mediated by VNUT and reduced the intracellular level and secretion of triglycerides in isolated hepatocytes. These results suggest that VNUT-dependent vesicular ATP release plays a crucial role in the recruitment of immune cells, cytokine production, and the aggravation of steatosis in the liver. Pharmacological inhibition of VNUT may provide therapeutic benefits in liver inflammatory disorders, including NASH and acute toxin-induced injury.

Human Leukocyte Antigen (HLA) Subtype-Dependent Development of Myasthenia Gravis, Type-1 Diabetes Mellitus, and Hashimoto Disease: A Case Report of Autoimmune Polyendocrine Syndrome Type 3.

BACKGROUND Patients with type 1 diabetes mellitus, myasthenia gravis (MG), and Hashimoto disease are diagnosed as having autoimmune polyendocrine syndrome type 3 (APS3). APS3 is rare, and its pathogenesis is unclear. We describe a female patient with APS3 whose human leukocyte antigen (HLA) type could provide a clue to the pathogenesis of APS3. CASE REPORT A 40-year-old Japanese female patient who had been diagnosed with MG at 5 years of age, and which had been treated with cholinesterase inhibitors, was referred to our hospital with thirst, polydipsia, polyuria, weight loss, and hyperglycemia. She was found to have type 1 diabetes mellitus based on laboratory tests. She was also positive for anti-thyroid peroxidase antibody and was thus diagnosed with Hashimoto disease. This combination of type 1 diabetes mellitus, myasthenia gravis, and Hashimoto disease led to a diagnosis of APS3. Her HLA serotype was A24; B46/54; DR4/9; DQ8/9, and genotype was A*24: 02; B*46: 01: 01/54: 01: 01; C*01: 02; DRB1*04: 06/09: 01: 02; DQB1*03: 02: 01/03: 03: 02; and DQA1*03: 01/03: 02: 01. We subsequently reviewed 10 cases of APS3 combined with MG, including the present case and cases reported in Japanese. This review revealed that HLA-DR9/DQ9 might be a specific HLA subtype associated with APS3 with MG. Four of the 10 cases had MG diagnosed before diabetes mellitus and autoimmune thyroid disease. CONCLUSIONS The present case showed that, in people with HLA-B46 and -DR9, antibody-negative MG can precede the development of APS3 by many years. Physicians should consider the possibility of APS3 when evaluating patients with ocular-type myasthenia gravis, and screen them for type 1 diabetes.