Amid the excitement over the results of the BI 10773 (Empagliflozin) Cardiovascular Outcome Event Trial in Type 2 Diabetes Mellitus Patients (EMPA-REG OUTCOME) trial (1), the potential mechanisms through which empagliflozin produced a rapid and profound reduction in hospitalization for heart failure and cardiovascular (CV) death in subjects with type 2 diabetes remain entirely unexplained. Importantly, the effects of empagliflozin on objective measures of cardiac structure and function are unknown (2). We report the first systematic analysis of echocardiograms of 10 patients with type 2 diabetes and established CV disease in whom empagliflozin 10 mg/day was initiated as per approved clinical indication, without any other concurrent changes in medications. Transthoracic echocardiograms, performed before and 3 months after initiation of empagliflozin, were analyzed by an experienced cardiac echocardiographer not involved in the clinical care of the patients and blinded to identity of the patients and the study order (pre vs. post). Informed patient consent and ethics approval were obtained.Baseline patient characteristics were as follows: 80% were men, age was mean (SD) 67.6 (6.6) years, 40% had a previous myocardial infarction, 90% had undergone vascularization, and estimated glomerular filtration rate was 77.5 (21.3) mL/min/1.73 m 2 . Background medications included the following: eight patients on metformin, five patients on dipeptidyl peptidase-4 inhibitors, one patient on a sulfonylurea, three patients on insulin, nine patients on statins, six patients on ACE inhibitors or angiotensin receptor blockers, two patients on diuretics, eight patients on b-blockers, and three patients on calcium channel blockers. Mean (SD) treatment duration was 151. These observations, albeit preliminary, suggest the potential of empagliflozin to favorably promote LV reverse remodeling and improve diastolic function in subjects with type 2 diabetes and established CV disease. The rapid cardiac benefits are consistent with the early separation of the Kaplan-Meier curves for heart failure-associated hospitalization and CV mortality in the EMPA-REG OUTCOME trial (1). Whether the improvement in diastolic function is secondary to a reduction in LV mass or through another distinct mechanism remains

Nemaline myopathy (NM) is a congenital myopathy that can result in lethal muscle dysfunction and is thought to be a disease of the sarcomere thin filament. Recently, several proteins of unknown function have been implicated in NM, but the mechanistic basis of their contribution to disease remains unresolved. Here, we demonstrated that loss of a muscle-specific protein, kelch-like family member 40 (KLHL40), results in a nemaline-like myopathy in mice that closely phenocopies muscle abnormalities observed in KLHL40-deficient patients. We determined that KLHL40 localizes to the sarcomere I band and A band and binds to nebulin (NEB), a protein frequently implicated in NM, as well as a putative thin filament protein, leiomodin 3 (LMOD3). KLHL40 belongs to the BTB-BACK-kelch (BBK) family of proteins, some of which have been shown to promote degradation of their substrates. In contrast, we found that KLHL40 promotes stability of NEB and LMOD3 and blocks LMOD3 ubiquitination. Accordingly, NEB and LMOD3 were reduced in skeletal muscle of both Klhl40 -/-mice and KLHL40-deficient patients. Loss of sarcomere thin filament proteins is a frequent cause of NM; therefore, our data that KLHL40 stabilizes NEB and LMOD3 provide a potential basis for the development of NM in KLHL40-deficient patients.

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