ABSTRACT. Ursodeoxycholic acid (UDCA) is used to treat liver diseases and demonstrates cardioprotective effects. Accumulation of the plasma membrane sphingolipid sphingomyelin in the heart can lead to atherosclerosis and coronary artery disease. Sphingomyelinases (SMases) break down sphingomyelin, producing ceramide, and inhibition of SMases activity can promote cell survival. We hypothesized that UDCA regulates activation of ERK and Akt survival signaling pathways and SMases in protecting cardiac cells against hypoxia. Neonatal cardiomyocytes were isolated from 0-to 2-day-old Sprague Dawley rats, and given 100 µM CoCl 2 , 150 µM H 2 O 2 , or placed in a hypoxia chamber for 24 h. The ameliorative effects of 100-µM UDCA treatment for 12 h were then assessed using MTS, QuantiGene Plex (for Smpd1 and Smpd2), and SMase assays, beating rate assessment, and western blotting (for ERK and Akt). Data were analyzed by the paired Student t-tests and one-way analyses of variance. Cell viability decreased significantly after H 2 O 2 (85%), CoCl 2 (50%), and hypoxia chamber (52%) treatments compared to the untreated control (100%). UDCA significantly counteracted the effects of chamber-and CoCl 2 -induced hypoxia on viability and beating rate. However, no significant differences were observed in acid SMase gene and protein expression between the untreated, CoCl 2 , and UDCA-CoCl 2 groups. In contrast, neutral SMase gene and protein expression did significantly differ between the latter two groups. ERK and Akt phosphorylation was higher in hypoxic cardiomyocytes treated with UDCA than those given CoCl 2 alone. In conclusion, UDCA regulates the activation of survival signaling proteins and SMases in neonatal rat cardiomyocytes during hypoxia.

In hepatocytes, ursodeoxycholic acid (UDCA) activates cell signalling pathways such as p53, intracellular calcium ([Ca ] ), and sphingosine-1-phosphate (S1P)-receptor via Gα -coupled-receptor. Recently, UDCA has been shown to protect the heart against hypoxia-reoxygenation injury. However, it is not clear whether UDCA cardioprotection against hypoxia acts through a transcriptional mediator of cells stress, HIF-1α and p53. Therefore, in here, we aimed to investigate whether UDCA could protect cardiomyocytes (CMs) against hypoxia by regulating expression of HIF-1α, p53, [Ca ] , and S1P-Gα -coupled-receptor. Cardiomyocytes were isolated from newborn rats (0-2 days), and hypoxia was induced by using cobalt chloride (CoCl ). Cardiomyocytes were treated with UDCA and cotreated with either FTY720 (S1P-receptor agonist) or pertussis toxin (PTX; Gα inhibitor). Cells were subjected for proliferation assay, beating frequency, QuantiGene Plex assay, western blot, immunofluorescence, and calcium imaging. Our findings showed that UDCA counteracted the effects of CoCl on cell viability, beating frequency, HIF-1α, and p53 protein expression. We found that these cardioprotection effects of UDCA were similar to FTY720, S1P agonist. Furthermore, we observed that UDCA protects CMs against CoCl -induced [Ca ] dynamic alteration. Pharmacological inhibition of the Gα -sensitive receptor did not abolish the cardioprotection of UDCA against CoCl detrimental effects, except for cell viability and [Ca ] . Pertussis toxin is partially effective in inhibiting UDCA protection against CoCl effects on CM cell viability. Interestingly, PTX fully inhibits UDCA cardioprotection on CoCl -induced [Ca ] dynamic changes. We conclude that UDCA cardioprotection against CoCl -induced hypoxia is similar to FTY720, and its actions are not fully mediated by the Gα -coupled protein sensitive pathways. Ursodeoxycholic acid is the most hydrophilic bile acid and is currently used to treat liver diseases. Recently, UDCA is shown to have a cardioprotection effects; however, the mechanism of UDCA cardioprotection is still poorly understood. The current data generated were the first to show that UDCA is able to inhibit the activation of HIF-1α and p53 protein during CoCl -induced hypoxia in cardiomyocytes. This study provides an insight of UDCA mechanism in protecting cardiomyocytes against hypoxia.

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Traumatic diaphragmatic rupture is relatively rare, and even more difficult to diagnose. Physical examination often fails to identify this injury, and basic investigation like chest x-ray can miss this half of the time. Although not part of standard FAST (focused assessment with sonography for trauma) ultrasound scan in trauma, bedside ultrasound has the potential to pick up this pathology. This case illustrates that ultrasound in trauma can go beyond standard E-FAST (extended FAST) protocol.