👤 Maho Omori

Prognosis of heart failure with preserved ejection fraction (HFpEF) remains poor because of unknown pathophysiology and unestablished therapeutic strategy. This study aimed to identify a potential therapeutic intervention for HFpEF through metabolomics-based analysis. Metabolomics with capillary electrophoresis time-of-flight mass spectrometry was performed using plasma of Dahl salt-sensitive rats fed high-salt diet, a model of hypertensive HFpEF, and showed decreased free-carnitine levels. Reassessment with enzymatic cycling method revealed the decreased plasma and left-ventricular free-carnitine levels in the HFpEF model. Urinary free-carnitine excretion was increased, and the expression of organic cation/carnitine transporter 2, which transports free-carnitine into cells, was down-regulated in the left ventricle (LV) and kidney in the HFpEF model. L-Carnitine was administered to the hypertensive HFpEF model. L-Carnitine treatment restored left-ventricular free-carnitine levels, attenuated left-ventricular fibrosis and stiffening, prevented pulmonary congestion, and improved survival in the HFpEF model independent of the antihypertensive effects, accompanied with increased expression of fatty acid desaturase (FADS) 1/2, rate-limiting enzymes in forming arachidonic acid, and enhanced production of arachidonic acid, a precursor of prostacyclin, and prostacyclin in the LV. In cultured cardiac fibroblasts, L-carnitine attenuated the angiotensin II-induced collagen production with increased FADS1/2 expression and enhanced production of arachidonic acid and prostacyclin. L-Carnitine-induced increase of arachidonic acid was canceled by knock-down of FADS1 or FADS2 in cultured cardiac fibroblasts. Serum free-carnitine levels were decreased in HFpEF patients. L-carnitine supplementation attenuates cardiac fibrosis by increasing prostacyclin production through arachidonic acid pathway, and may be a promising therapeutic option for HFpEF. Show less

The aim of this study was to investigate the relationship between serum apolipoprotein (apo) A-IV levels and markers for atherosclerosis, including carotid intima-media thickness (CIMT) and the ankle-brachial index (ABI), in hemodialysis patients. We performed a cross-sectional study involving 116 maintenance hemodialysis patients (70 males; median age, 64 years), measuring CIMT, ABI, the usual laboratory examinations, and serum apo A-IV before the dialysis session. The apo A-IV concentration was measured by a noncompetitive ELISA. Serum apo A-IV concentrations were significantly lower in hemodialysis patients with cardiovascular disease and plaque in the carotid artery. The apo A-IV level was positively associated with urea nitrogen and creatinine, and negatively associated with age, interleukin-6, the neutrophil/lymphocyte ratio, and maximum CIMT. Moreover, serum apo A-IV concentrations were significantly lower in the low ABI group. On logistic analysis, patients with high apo A-IV levels had a lower odds ratio for atherosclerosis (maximum CIMT > 1.0) and cardiovascular disease compared to patients with low apo A-IV levels. On stepwise multivariate regression analysis, the serum apo A-IV level was independently associated with creatinine, the neutrophil/lymphocyte ratio, and the maximum CIMT. Serum apo A-IV is associated with atherosclerotic lesions in hemodialysis patients. Apo A-IV levels may be useful for estimating the risk of cardiovascular disease in dialysis patients. Show less

Organelles are frequently distributed in a nonrandom manner in a cell's cytoplasm. A particular distribution pattern often facilitates a specific function of a cell, whereas its aberrations can lead to cell death. We show that a mutation in the zebrafish mikre oko (mok) locus, which encodes dynactin 1 subunit of the dynactin complex, produces a severe displacement of the photoreceptor cell nucleus toward the synaptic terminus. Interference with the function of other dynein complex constituents, including p50/dynamitin, the Lis1 polypeptide, and the disruption of a nuclear envelope component of the syne gene family in vertebrate photoreceptors also result in the mispositioning of nuclei. Although the overall photoreceptor polarity is not affected, this phenotype is accompanied by a misdistribution of the Bardet-Biedl syndrome 4 polypeptide and a decreased photoreceptor survival. These findings reveal an important mechanism that regulates nuclear position in vertebrate neurons. Show less