Increased Tropism of Extracellular Vesicles Derived from Palmitic Acid-Treated Hepatocytes to Activated Hepatic Stellate Cells.

Myofibroblast-like activated hepatic stellate cells (aHSCs), which produce collagen, a major cause of liver fibrosis, are specific target cells for antifibrotic treatment. Recently, several reports have indicated that extracellular vesicles (EVs) play important roles in cell-to-cell communication through their tropism for specific cells or organs. Therefore, the present study aimed to identify aHSC-directed EVs by focusing on cell-to-cell interactions in the liver under pathological conditions. EVs were derived from the hepatocyte cell line AML12 treated with or without palmitic acid (PA) and evaluated for their physical properties and uptake by the aHSC cell line LX-2. AML12-derived EVs had a mean particle diameter of 110-130 nm, negative charge, and expressed the exosomal makers CD9 and CD63. PA-treated AML12 cells released larger EVs with higher protein levels than those without PA treatment. The intracellular uptake efficacy of EVs derived from PA-treated AML12 cells into activated LX-2 cells was significantly higher than those without PA treatment. Our study revealed that PA treatment induces hepatocytes to release EVs with aHSC-tropism. These findings may contribute to the development of an EV-based drug delivery system (DDS) for aHSC-targeted therapy and provide new insights into the role of steatotic hepatocyte-derived EVs in physiological or pathophysiological functions.

Quantitative real-time measurement of endothelin-1-induced contraction in single non-activated hepatic stellate cells.

Although quiescent hepatic stellate cells (HSCs) have been suggested to regulate hepatic blood flow, there is no direct evidence that quiescent HSCs display contractile abilities. Here, we developed a new method to quantitatively measure the contraction of single isolated HSCs and evaluated whether endothelin-1 (ET-1) induced contraction of HSCs in a non-activated state. HSCs isolated from mice were seeded on collagen gel containing fluorescent beads. The beads around a single HSC were observed gravitating toward the cell upon contraction. By recording the movement of each bead by fluorescent microscopy, the real-time contraction of HSCs was quantitatively evaluated. ET-1 induced a slow contraction of non-activated HSCs, which was inhibited by the non-muscle myosin II inhibitor blebbistatin, the calmodulin inhibitor W-7, and the ETA receptor antagonist ambrisentan. ET-1-induced contraction was also largely reduced in Ca2+-free conditions, but sustained contraction still remained. The tonic contraction was further diminished by the Rho-kinase inhibitor H-1152. The mRNA expression of P/Q-type voltage-dependent Ca2+ channels (VDCC), as well as STIM and Orai, constituents of store-operated channels (SOCs), was observed in mouse non-activated HSCs. ET-1-induced contraction was not affected by amlodipine, a VDCC blocker, whereas it was partly reduced by Gd3+ and amiloride, non-selective cation channel blockers. However, neither YM-58483 nor SKF-96365, which inhibit SOCs, had any effects on the contraction. These results suggest that ET-1 leads to Ca2+-influx through cation channels other than SOCs and produces myosin II-mediated contraction of non-activated HSCs via ETA receptors, as well as via mechanisms involving Ca2+-calmodulin and Rho kinase.

Caffeine-induced inversion of prostaglandin E2 effects on hepatic stellate cell activation.

BACKGROUND AND AIMS: Liver inflammation leads to the activation of hepatic stellate cells (HSCs), resulting in the development of liver fibrosis. The present study aimed to investigate the effects of prostaglandin E2 (PGE2), which is biosynthesized by Kupffer cells, hepatocytes, and HSCs during inflammation, on HSC activation, including its combinatory effect with caffeine. METHODS: HSCs isolated from mice were activated by culturing in a medium supplemented with 10% fetal bovine serum for 7 days on plastic plates. The activation of HSCs was evaluated by immunofluorescence of α-smooth muscle actin in HSCs. Comprehensive gene expression analysis was performed using mRNA-sequencing to compare HSCs cultured for 1 or 7 days, with or without PGE2, caffeine, or both. RESULTS: PGE2 (1 µM) facilitated the activation of HSCs but inhibited the HSC activation in the presence of caffeine (3 mM). Comprehensive gene expression analysis revealed that HSCs treated with PGE2 in the presence of caffeine were classified in the same class as HSCs cultured for 1 day, i.e., quiescent HSCs. In contrast, PGE2 did not exhibit an inhibitory effect on HSC activation when co-treated with any isoform-specific phosphodiesterase inhibitors. Although the adenylate cyclase inhibitor 2',5'-dideoxyadenosine suppressed the elevation of intracellular cAMP level induced by PGE2 in the presence of caffeine, it had no effect on the inhibition of HSC activation by PGE2 plus caffeine. CONCLUSION: The effect of PGE2 on HSC activation is changed from facilitatory to inhibitory when combined with caffeine, suggesting that caffeine may effectively suppress liver fibrosis during inflammation.

Effects of Pimobendan on Prolonging Time to Rehospitalization or Frequency of Rehospitalization in Patients with Heart Failure: A Retrospective Cohort Study Using a Medical Administrative Database (PREFER Study).

BACKGROUND: As approximately 24% of patients with chronic heart failure are rehospitalized within 1 year and heart failure is aggravated by repeated hospitalizations, greater importance was attached to the prevention of hospitalization. OBJECTIVE: The objective of this study was to investigate the influence of pimobendan on rehospitalization of patients with advanced heart failure using a Japanese medical administrative database. METHODS: From January 2010 to February 2018, patients hospitalized two or more times for heart failure were selected for analysis. The primary endpoint was the incidence of hospitalizations for heart failure during the follow-up period, which was compared between pimobendan prescription and non-prescription groups after propensity score matching. RESULTS: The total number of patients with heart failure included during the study period was 1 421 110 and we matched 276 patients in both groups. The incidence of rehospitalization throughout the period to completion of follow-up was 365.23/1000 people/yr (95% confidence interval [CI]: 327.78-402.69) in the pimobendan prescription group and 537.81/1000 people/yr (95% CI: 492.36-583.27) in the non-prescription group. The cumulative incidence at 365 days was significantly lower in the pimobendan prescription group (pimobendan prescription group: 35.4% (95% CI: 29.8-41.8), non-prescription group: 51.2% (95% CI: 45.1-57.7), (P < 0.001). The adjusted hazard ratio in the pimobendan prescription group was 0.556 (95% CI: 0.426-0.725, P < 0.001). CONCLUSION: Pimobendan was suggested to extend the time to rehospitalization for patients with advanced heart failure. It is necessary to verify the results of this study by performing a prospective study. In addition, the influence of pimobendan on general heart failure patients must be examined.

Mechanism of Membrane Depolarization Involved in α1A-Adrenoceptor-Mediated Contraction in Rat Tail and Iliac Arteries.

Our previous studies have shown that phenylephrine-induced contraction of cutaneous arteries is primarily mediated via α1A-adrenoceptors, but not α1D-adrenoceptors that generally mediate vascular contraction, and that the larger part of the contraction is induced in a voltage-dependent Ca2+ channel (VDCC)-independent manner. Here, we investigated the mechanism underlying the smaller part of the α1A-adrenoceptor-mediated contraction, i.e., VDCC-dependent one, in cutaneous arteries. Isometric contraction was measured with wire myograph in endothelium-denuded tail and iliac arterial rings isolated from male Wistar rats. LOE908 (10 µM), a cation channel blocker, partially inhibited the contraction induced by phenylephrine in tail and iliac arteries. Nifedipine (10 µM) further suppressed the phenylephrine-induced contraction that remained in the presence of LOE908 (10 µM) in iliac arteries but barely in tail arteries, suggesting that phenylephrine-induced depolarization in tail arteries is due to the activation of LOE908-sensitive cation channels. In iliac arteries, the contraction induced by A-61603, a specific α1A-adrenoceptor agonist, was also partially inhibited by LOE908 (10 µM); however, nifedipine had little effect on the A-61603-induced contraction that remained in the presence of LOE908 (10 µM), suggesting that depolarization mediated via α1A-adrenoceptors is due to the activation of LOE908-sensitive cation channels even in iliac arteries. These results suggest that membrane depolarization mediated via α1Α-adrenoceptors is caused by cation influx through LOE908-sensitive cation channels. Less contribution of VDCC to phenylephrine-induced contraction in tail arteries compared to in iliac arteries is likely due to that α1Α-adrenoceptor-mediated activation of VDCC is caused only by depolarization via cation influx through LOE908-sensitive cation channels.

Efficacy and Safety of Switching From Oral Bisoprolol to Transdermal Patch in Japanese Patients With Chronic Heart Failure.

BACKGROUND: TY-0201 (TY) is a transdermal formulation of bisoprolol that is the free base of bisoprolol fumarate (BO), a drug widely used to treat chronic heart failure (CHF). The objectives of this phase II study were to evaluate the efficacy and safety of TY when switching from oral BO to TY in patients with CHF whose drug therapy was optimized, and to determine the dose conversion rate of BO to TY.Methods and Results:The efficacy and safety of once daily TY patch use for 16 weeks was investigated in 40 patients with CHF who were stabilized with an optimized drug treatment, including BO, after switching from BO to TY at the dose conversion rate of 5:8. The pre-switch left ventricular ejection fraction was 50.13±11.09% (mean±SD). The post-switch value was 50.87±10.79% after 16 weeks, which was not significantly different, with similar results for other efficacy and safety parameters. The 16-week study was continued for all patients without changing doses after switching to TY. No cardiovascular deaths, hospitalizations for worsening HF, or significant safety concerns were observed. CONCLUSIONS: Efficacy was maintained without significant safety concerns in patients with CHF who were stabilized with BO treatment after switching to TY, suggesting the appropriateness of the dose conversion rate.

Cloning and characterization of the 5'-flanking region of the rat P4Halpha gene encoding the prolyl 4-hydroxylase alpha(I) subunit.

Prolyl 4-hydroxylase (P4H), an alpha(2)beta(2) tetramer, plays a crucial role in collagen synthesis. It catalyzes the hydroxylation of proline residues in X-Pro-Gly sequences to form 4-hydroxyproline. We isolated a genomic clone of the rat P4Halpha(I) gene. Approx. 0.6 kb of the fragment, which contained the 5'-flanking region, exon 1, and intron 1, was sequenced. Computer analysis revealed several motifs that may act as binding sites for basal transcription factors. To elucidate the regulation of the rat P4Halpha(I) gene expression, we assessed the 0.6 kb 5'-flanking region of the P4Halpha(I) gene for basal promoter activity. A series of deletion mutants of the 5'-flanking region linked to the luciferase gene was constructed. The basal expression level of these constructs was determined in fetal rat lung fibroblasts and Hepa-1 hepatoma cells. By measuring the luciferase activity, we found a positive-regulatory region at positions -246 to -165 bp.