The protective effect of ursodeoxycholic acid in an in vitro model of the human fetal heart occurs via targeting cardiac fibroblasts

From dried bear bile to molecular investigation of differential effects of bile acids in ex vivo and in vitro models of myocardial dysfunction: Relevance for neuroinflammation

Bile acids have been known to have both beneficial and detrimental effects on heart function, and as a consequence this can affect the brain. Inflammation is a key factor linking the heart and the brain, bile acids can reduce inflammation in the heart and, as a consequence, neuroinflammation, which may be due to the activation of different peripheral and central cellular and molecular mechanisms. Herein, we compile data published so far and summarise evidence demonstrating the effects of bile acids on myocardial cell viability and function, and its related mechanisms, in ex vivo and in vitro studies conducted in homeostatic state or in models of cardiovascular diseases. Studies show that ursodeoxycholic acid (UDCA) and tauroursodeoxycholic acid (TUDCA) do not affect the viability or contraction of cardiomyocytes in homeostatic state, and while UDCA has the capability to prevent the effect of hypoxia on reduced cell viability and beating rate, TUDCA can protect endoplasmic reticulum (ER) stress-induced apoptosis and cardiac contractile dysfunction. In contrast, deoxycholic acid (DCA) decreases contraction rate in homeostatic state, but it also prevents hypoxia-induced inflammation and oxidative stress, whereas lithocholic acid (LCA) can rescue doxazosin-induced apoptosis. Moreover, glycodeoxycholic acid (GDCA), cholic acid (CA), chenodeoxycholic acid (CDCA), glycocholic acid (GCA), taurocholic acid (TCA), taurochenodeoxycholic acid (TCDCA) and taurodeoxycholic acid (TDCA) decrease contraction, whereas CDCA decreases cell viability in homeostatic conditions. The mechanisms underlying the aforementioned contrasting effects involve a differential regulation of the TGR5, M2R and FXR receptors, as well as the cAMP signalling pathway. Overall, this review confirms the therapeutic potential of certain types of bile acids: UDCA, TUDCA, and potentially LCA, in cardiovascular diseases. By reducing inflammation in the heart, bile acids can improve heart-brain communication and promote overall health. Additional investigations are required to better elucidate mechanisms of action and more personalized clinical therapeutic doses.

Intrahepatic cholestasis of pregnancy and fetal cardiac dysfunction: a systematic review and meta-analysis

OBJECTIVE

Intrahepatic cholestasis of pregnancy is associated with adverse perinatal outcomes. Fetal cardiac dysfunction may be 1 part of the pathophysiology of pregnancies complicated by intrahepatic cholestasis of pregnancy. This systematic review and meta-analysis aimed to evaluate the association between intrahepatic cholestasis of pregnancy and fetal cardiac dysfunction.

DATA SOURCES

Systematic searches were performed on the databases of Medline, Embase, and Cochrane Library (up to March 2, 2023) for studies evaluating fetal cardiac function in pregnancies complicated by intrahepatic cholestasis of pregnancy in addition to the reference lists of included studies.

STUDY ELIGIBILITY CRITERIA

Studies were eligible for inclusion if they assessed the fetal cardiac function by fetal echocardiography in women with intrahepatic cholestasis of pregnancy (mild or severe) and compared with fetuses of healthy pregnant women. The studies published in English were included.

METHODS

The quality of the retrieved studies was assessed using the Newcastle-Ottawa Scale. Data on fetal myocardial performance index, E wave/A wave peak velocities ratio, and PR interval were pooled for the meta-analysis using random-effects models. The results were presented as weighted mean differences and 95% confidence intervals. This meta-analysis was registered with the International Prospective Register of Systematic Reviews (registration number: CRD42022334801).

RESULTS

A total of 14 studies were included in this qualitative analysis. Of note, 10 studies that reported data on fetal myocardial performance index, E wave/A wave peak velocities ratio, and PR interval were included in the quantitative analysis and showed a significant association between intrahepatic cholestasis of pregnancy and fetal cardiac dysfunction. Significantly higher fetal left ventricular myocardial performance index values (weighted mean difference, 0.10; 95% confidence interval, 0.04-0.16) and longer fetal PR intervals (weighted mean difference, 10.10 ms; 95% confidence interval, 7.34-12.86) were revealed in pregnancies complicated by intrahepatic cholestasis of pregnancy. Compared with the situation in pregnancies complicated by mild intrahepatic cholestasis of pregnancy, PR intervals were even longer in pregnancies complicated by severe intrahepatic cholestasis of pregnancy (weighted mean difference, 5.98 ms; 95% confidence interval, 0.20-11.77). There was no significant difference in fetal E wave/A wave peak velocities ratio between the group with intrahepatic cholestasis of pregnancy and the healthy pregnant group (weighted mean difference, 0.01; 95% confidence interval, -0.03 to 0.05).

CONCLUSION

Our findings supported the idea that intrahepatic cholestasis of pregnancy is associated with overall impaired fetal myocardial performance and impaired fetal cardiac conduction system. However, current evidence about the association between fetal cardiac dysfunction and intrahepatic cholestasis of pregnancy-induced stillbirth is lacking. Further studies are needed to reveal the relationship between fetal cardiac dysfunction and adverse perinatal outcomes in pregnancies complicated by intrahepatic cholestasis of pregnancy.

Gastrointestinal disorders in post-COVID syndrome. Clinical guidelines

Summary Post- COVID syndrome refers to the long-term consequences of a new coronavirus infection COVID-19, which includes a set of symptoms that develop or persist after COVID-19. Symptoms of gastrointestinal disorders in post- COVID syndrome, due to chronic infl ammation, the consequences of organ damage, prolonged hospitalization, social isolation, and other causes, can be persistent and require a multidisciplinary approach. The presented clinical practice guidelines consider the main preventive and therapeutic and diagnostic approaches to the management of patients with gastroenterological manifestations of postCOVID syndrome. The Guidelines were approved by the 17th National Congress of Internal Medicine and the 25th Congress of Gastroenterological Scientifi c Society of Russia.

Effects of elevated bile acid levels on fetal myocardium in intrahepatic cholestasis of pregnancy, a retrospective study from a neonatal perspective

AIM

Intrahepatic cholestasis of pregnancy (ICP) is a liver disease which may lead to a sudden fetal death.Previous studies have suggested that the fetal accident may be related to their cardiac dysfunction.However,the relationship between fetal cardiac dysfunction and their maternal bile acid levels is not clear.This objective was to clarify the relationship from a neonatal perspective and to furtherly make clear the aftereffect by analyzing the cardiac parameters of the older neonates.

METHODS

In this case-control study,patients and their neonates,managed between 10 September 2018 and 30 June 2021 at a Chinese university hospital center,were divided into severe ICP group,mild ICP group and control gestational group.The maternal bile acid levels and the cardiac paramerers of one-day-old neonates and five-day-old neonates were analyzed,respectively.

RESULTS

The specific-myocardial enzyme(CK-MB) and left ventricular fraction shortening(FS) of neonates showed significant difference between ICP group and control group, and were meaningfully correlated with maternal bile acid levels.However,There was no significant difference in cardiac injury parameters of older neonates between the ICP group and control group.

CONCLUSIONS

The elevated maternal bile acid levels can lead to fetal myocardial injury and the injury can be recovered after removel from high concentrations of bile acid.

The Role of Bile Acids in the Human Body and in the Development of Diseases

Bile acids are specific and quantitatively important organic components of bile, which are synthesized by hepatocytes from cholesterol and are involved in the osmotic process that ensures the outflow of bile. Bile acids include many varieties of amphipathic acid steroids. These are molecules that play a major role in the digestion of fats and the intestinal absorption of hydrophobic compounds and are also involved in the regulation of many functions of the liver, cholangiocytes, and extrahepatic tissues, acting essentially as hormones. The biological effects are realized through variable membrane or nuclear receptors. Hepatic synthesis, intestinal modifications, intestinal peristalsis and permeability, and receptor activity can affect the quantitative and qualitative bile acids composition significantly leading to extrahepatic pathologies. The complexity of bile acids receptors and the effects of cross-activations makes interpretation of the results of the studies rather difficult. In spite, this is a very perspective direction for pharmacology.

Fetal cardiac dysfunction in pregnancies affected by intrahepatic cholestasis of pregnancy: A cohort study

AIM

To analyze the presence of fetal myocardial dysfunction in intrahepatic cholestasis of pregnancy (ICP) at diagnosis.

METHODS

This prospective cohort study included 49 pregnant participants with ICP at diagnosis and 49 nonaffected controls from a single public hospital. ICP was diagnosed based on clinical symptoms after excluding other causes of pruritus and presence of autoimmune diseases. Total bile acids were not obtained in this cohort. ICP pregnancies were assessed with a functional echocardiography at diagnosis including PR-interval, isovolumetric contraction time (ICT), ejection time (ET), and isovolumetric relaxation time (IRT) for electrical, systolic, and diastolic function, respectively. Controls were assessed at recruitment. Perinatal outcomes were obtained from delivery books. The main outcome was the presence of PR-interval prolongation or first-degree fetal heart block, and echographic signs of diastolic and systolic dysfunction.

RESULTS

Compared to controls, ICP were above upper limit in conjugated bilirubin (2.0% vs. 20.4%; p = 0.008), aspartate aminotransferase (2.0% vs. 24.5%; p = 0.002), and alanine aminotransferase (4.1% vs. 28.6%; p = 0.002). ICP was associated with a higher PR-interval (130 ± 12 ms vs. 121 ± 6 ms; p < 0.0001) with five first-degree fetal heart blocks. IRT was significantly higher in ICP (42 ± 6 ms vs. 37 ± 5 ms; p = 0.0001), with no differences in ICT and ET. PR-interval trend was only positively correlated with IRT in ICP pregnancies (p = 0.04 and p = 0.34, in ICP and controls, respectively).

CONCLUSIONS

Our study demonstrates that fetuses affected by maternal ICP are associated with electrical and diastolic myocardial dysfunction. More studies focused on antenatal and postnatal functional echocardiography are necessary to validate our results and consider these markers in the clinical management of ICP pregnancies.

Gut Microbiome and Organ Fibrosis

Fibrosis is a pathological process associated with most chronic inflammatory diseases. It is defined by an excessive deposition of extracellular matrix proteins and can affect nearly every tissue and organ system in the body. Fibroproliferative diseases, such as intestinal fibrosis, liver cirrhosis, progressive kidney disease and cardiovascular disease, often lead to severe organ damage and are a leading cause of morbidity and mortality worldwide, for which there are currently no effective therapies available. In the past decade, a growing body of evidence has highlighted the gut microbiome as a major player in the regulation of the innate and adaptive immune system, with severe implications in the pathogenesis of multiple immune-mediated disorders. Gut microbiota dysbiosis has been associated with the development and progression of fibrotic processes in various organs and is predicted to be a potential therapeutic target for fibrosis management. In this review we summarize the state of the art concerning the crosstalk between intestinal microbiota and organ fibrosis, address the relevance of diet in different fibrotic diseases and discuss gut microbiome-targeted therapeutic approaches that are current being explored.

The Role of Bile Acids in Cardiovascular Diseases: from Mechanisms to Clinical Implications

Bile acids (BAs), key regulators in the metabolic network, are not only involved in lipid digestion and absorption but also serve as potential therapeutic targets for metabolic disorders. Studies have shown that cardiac dysfunction is associated with abnormal BA metabolic pathways. As ligands for several nuclear receptors and membrane receptors, BAs systematically regulate the homeostasis of metabolism and participate in cardiovascular diseases (CVDs), such as myocardial infarction, diabetic cardiomyopathy, atherosclerosis, arrhythmia, and heart failure. However, the molecular mechanism by which BAs trigger CVDs remains controversial. Therefore, the regulation of BA signal transduction by modulating the synthesis and composition of BAs is an interesting and novel direction for potential therapies for CVDs. Here, we mainly summarized the metabolism of BAs and their role in cardiomyocytes and noncardiomyocytes in CVDs. Moreover, we comprehensively discussed the clinical prospects of BAs in CVDs and analyzed the clinical diagnostic and application value of BAs. The latest development prospects of BAs in the field of new drug development are also prospected. We aimed to elucidate the underlying mechanism of BAs treatment in CVDs, and the relationship between BAs and CVDs may provide new avenues for the prevention and treatment of these diseases.

Molecular Pathogenesis of Intrahepatic Cholestasis of Pregnancy

Intrahepatic cholestasis of pregnancy (ICP) is a pregnancy-specific liver disease. The maternal symptoms are characterized by skin pruritus and elevated bile acids, causing several adverse outcomes for fetuses, including an increased risk of preterm birth, meconium-stained amniotic fluid, neonatal depression, respiratory distress syndrome, and stillbirth. Genetic, hormonal, immunological, and environmental factors contribute to the pathogenesis of ICP, and the estrogen-bile acid axis is thought to play a dominant role. The advances in the past 10 years uncover more details of this axis. Moreover, dysregulation of extracellular matrix and oxygen supply, organelle dysfunction, and epigenetic changes are also found to cause ICP, illuminating more potential drug targets for interfering with. Here, we summarize the molecular pathogenesis of ICP with an emphasis on the advancement in the past 10 years, aiming to give an updated full view of this field.

Management of patients with digestive diseases during the COVID-19 pandemic. Clinical Practice Guidelines by the Russian scientific medical society of internal medicine (RSMSIM) and the Gastroenterological Scientific Society of Russia (2nd edition)

The presented clinical practice guidelines of the Gastroenterological Scientific Society of Russia (GSSR), diagnostic, and therapeutic approaches for patients with digestive diseases during the COVID-19 pandemic. The guidelines were approved by the XXIII Congress of the GSSR and the 22nd International Slavonic-Baltic Scientifi c Forum “St. Petersburg - Gastro-2020 ON-LINE” (St. Petersburg, June 11, 2020). The presented clinical practice guidelines of the Russian Scientific Medical Society of Internal Medicine (RSMSIM) and the Gastroenterological Scientific Society of Russia (GSSR), diagnostic, and therapeutic approaches for patients with digestive diseases during the COVID-19 pandemic. The recommendations were approved at the XV National Congress of Internal Medicine, XXIII Congress of NOGR on the basis of the 1st edition, adopted at the 22nd International Slavic- Baltic Scientific Forum “St. Petersburg - Gastro-2020 ON-LINE”.

Fetal cardiac dysfunction in intrahepatic cholestasis of pregnancy is associated with elevated serum bile acid concentrations

BACKGROUND & AIMS

Intrahepatic cholestasis of pregnancy (ICP) is associated with an increased risk of stillbirth. This study aimed to assess the relationship between bile acid concentrations and fetal cardiac dysfunction in patients with ICP who were or were not treated with ursodeoxycholic acid (UDCA).

METHODS

Bile acid profiles and NT-proBNP, a marker of ventricular dysfunction, were assayed in umbilical venous serum from 15 controls and 76 ICP cases (36 untreated, 40 UDCA-treated). Fetal electrocardiogram traces were obtained from 43 controls and 48 ICP cases (26 untreated, 22 UDCA-treated). PR interval length and heart rate variability (HRV) parameters were measured in 2 behavioral states (quiet and active sleep).

RESULTS

In untreated ICP, fetal total serum bile acid (TSBA) concentrations (r = 0.49, p = 0.019), hydrophobicity index (r = 0.20, p = 0.039), glycocholate concentrations (r = 0.56, p = 0.007) and taurocholate concentrations (r = 0.44, p = 0.039) positively correlated with fetal NT-proBNP. Maternal TSBA (r = 0.40, p = 0.026) and alanine aminotransferase (r = 0.40, p = 0.046) also positively correlated with fetal NT-proBNP. There were no significant correlations between maternal or fetal serum bile acid concentrations and fetal HRV parameters or NT-proBNP concentrations in the UDCA-treated cohort. Fetal PR interval length positively correlated with maternal TSBA in untreated (r = 0.46, p = 0.027) and UDCA-treated ICP (r = 0.54, p = 0.026). Measures of HRV in active sleep and quiet sleep were significantly higher in untreated ICP cases than controls. HRV values in UDCA-treated cases did not differ from controls.

CONCLUSIONS

Elevated fetal and maternal serum bile acid concentrations in untreated ICP are associated with an abnormal fetal cardiac phenotype characterized by increased NT-proBNP concentration, PR interval length and HRV. UDCA treatment partially attenuates this phenotype.

LAY SUMMARY

The risk of stillbirth in intrahepatic cholestasis of pregnancy (ICP) is linked to the level of bile acids in the mother which are thought to disrupt the baby's heart rhythm. We found that babies of women with untreated ICP have abnormally functioning hearts compared to those without ICP, and the degree of abnormality is closely linked to the level of harmful bile acids in the mother and baby's blood. Babies of women with ICP who received treatment with the drug UDCA do not have the same level of abnormality in their hearts, suggesting that UDCA could be a beneficial treatment in some ICP cases, although further clinical trials are needed to confirm this.

Channelling the Force to Reprogram the Matrix: Mechanosensitive Ion Channels in Cardiac Fibroblasts

Cardiac fibroblasts (CF) play a pivotal role in preserving myocardial function and integrity of the heart tissue after injury, but also contribute to future susceptibility to heart failure. CF sense changes to the cardiac environment through chemical and mechanical cues that trigger changes in cellular function. In recent years, mechanosensitive ion channels have been implicated as key modulators of a range of CF functions that are important to fibrotic cardiac remodelling, including cell proliferation, myofibroblast differentiation, extracellular matrix turnover and paracrine signalling. To date, seven mechanosensitive ion channels are known to be functional in CF: the cation non-selective channels TRPC6, TRPM7, TRPV1, TRPV4 and Piezo1, and the potassium-selective channels TREK-1 and KATP. This review will outline current knowledge of these mechanosensitive ion channels in CF, discuss evidence of the mechanosensitivity of each channel, and detail the role that each channel plays in cardiac remodelling. By better understanding the role of mechanosensitive ion channels in CF, it is hoped that therapies may be developed for reducing pathological cardiac remodelling.

Management of patients with digestive diseases during the COVID-19 pandemic: Clinical Practice Guidelines by the Gastroenterological Scientific Society of Russia

The presented clinical practice guidelines of the Gastroenterological Scientific Society of Russia (GSSR), diagnostic, and therapeutic approaches for patients with digestive diseases during the COVID-19 pandemic. The guidelines were approved by the XXIII Congress of the GSSR and the 22nd International Slavonic-Baltic Scientific Forum “St. Petersburg — Gastro-2020 ON-LINE” (St. Petersburg, June 11, 2020).

Prolonged ursodeoxycholic acid administration reduces acute ischaemia-induced arrhythmias in adult rat hearts

Acute myocardial ischaemia and reperfusion (I-R) are major causes of ventricular arrhythmias in patients with a history of coronary artery disease. Ursodeoxycholic acid (UDCA) has previously been shown to be antiarrhythmic in fetal hearts. This study was performed to investigate if UDCA protects against ischaemia-induced and reperfusion-induced arrhythmias in the adult myocardium, and compares the effect of acute (perfusion only) versus prolonged (2 weeks pre-treatment plus perfusion) UDCA administration. Langendorff-perfused adult Sprague-Dawley rat hearts were subjected to acute regional ischaemia by ligation of the left anterior descending artery (10 min), followed by reperfusion (2 min), and arrhythmia incidence quantified. Prolonged UDCA administration reduced the incidence of acute ischaemia-induced arrhythmias (p = 0.028), with a reduction in number of ventricular ectopic beats during the ischaemic phase compared with acute treatment (10 ± 3 vs 58 ± 15, p = 0.036). No antiarrhythmic effect was observed in the acute UDCA administration group. Neither acute nor prolonged UDCA treatment altered the incidence of reperfusion arrhythmias. The antiarrhythmic effect of UDCA may be partially mediated by an increase in cardiac wavelength, due to the attenuation of conduction velocity slowing (p = 0.03), and the preservation of Connexin43 phosphorylation during acute ischaemia (p = 0.0027). The potential antiarrhythmic effects of prolonged UDCA administration merit further investigation.

Enzymatic quantification of total serum bile acids as a monitoring strategy for women with intrahepatic cholestasis of pregnancy receiving ursodeoxycholic acid treatment: a cohort study

OBJECTIVE

To evaluate enzymatic total serum bile acid quantification as a monitoring strategy for women with intrahepatic cholestasis of pregnancy (ICP) treated with ursodeoxycholic acid (UDCA).

DESIGN

Cohort.

SETTING

One UK university hospital.

POPULATION

29 ICP cases treated with UDCA.

METHODS

Serial samples were collected prospectively throughout gestation. Total serum bile acids were measured enzymatically and individual bile acids by high-performance liquid chromatography-tandem mass spectrometry. Data were log-transformed and analysed with random effects generalised least square regression.

MAIN OUTCOME MEASURES

The relationship between enzymatic total bile acid measurements and individual bile acid concentrations after UDCA treatment.

RESULTS

In untreated women, cholic acid was the principal bile acid (51%) and UDCA concentrations were <0.5%, whereas UDCA constituted 60% (IQR 43-69) of serum bile acids following treatment and cholic acid fell to <20%. Changes in the total bile acid measurement reflected similar alterations in the concentrations of the pathologically elevated bile acids, e.g. a two-fold increase in enzymatic total bile acids is accompanied by approximately a two-fold increase in cholic acid and chenodeoxycholic acid at most UDCA doses (P < 0.001). Most of the effects of UDCA on cholic acid occur in the first week of treatment (60% relative reduction, P = 0.025, 95% CI 0.2-0.9, from 10 micromol/l (4.7-17.6) to 3.5 micromol/l (1.4-7.5).

CONCLUSION

Ursodeoxycholic acid becomes the main component of the bile acid measurement after treatment. Enzymatic total bile acid assays are good predictors of both cholic acid and chenodeoxycholic acid, the primary bile acids that are raised prior to treatment.

TWEETABLE ABSTRACT

Ursodeoxycholic acid constitutes approximately 60% of the bile acid measurement and reduces pathological cholic acid in treated women.

Ursodeoxycholic acid versus placebo in women with intrahepatic cholestasis of pregnancy (PITCHES): a randomised controlled trial

BACKGROUND

Intrahepatic cholestasis of pregnancy, characterised by maternal pruritus and increased serum bile acid concentrations, is associated with increased rates of stillbirth, preterm birth, and neonatal unit admission. Ursodeoxycholic acid is widely used as a treatment without an adequate evidence base. We aimed to evaluate whether ursodeoxycholic acid reduces adverse perinatal outcomes in women with intrahepatic cholestasis of pregnancy.

METHODS

We did a double-blind, multicentre, randomised placebo-controlled trial at 33 hospital maternity units in England and Wales. We recruited women with intrahepatic cholestasis of pregnancy, who were aged 18 years or older and with a gestational age between 20 weeks and 40 weeks and 6 days, with a singleton or twin pregnancy and no known lethal fetal anomaly. Participants were randomly assigned 1:1 to ursodeoxycholic acid or placebo, given as two oral tablets a day at an equivalent dose of 500 mg twice a day. The dose could be increased or decreased at the clinician's discretion, to a maximum of four tablets and a minimum of one tablet a day. We recommended that treatment should be continued from enrolment until the infant's birth. The primary outcome was a composite of perinatal death (in-utero fetal death after randomisation or known neonatal death up to 7 days after birth), preterm delivery (<37 weeks' gestation), or neonatal unit admission for at least 4 h (from birth until hospital discharge). Each infant was counted once within this composite. All analyses were done according to the intention-to-treat principle. The trial was prospectively registered with the ISRCTN registry, number 91918806.

FINDINGS

Between Dec 23, 2015, and Aug 7, 2018, 605 women were enrolled and randomly allocated to receive ursodeoxycholic acid (n=305) or placebo (n=300). The primary outcome analysis included 304 women and 322 infants in the ursodeoxycholic acid group, and 300 women and 318 infants in the placebo group (consent to use data was withdrawn for 1 woman and 2 infants). The primary composite outcome occurred in 74 (23%) of 322 infants in the ursodeoxycholic acid group and 85 (27%) of 318 infants in the placebo group (adjusted risk ratio 0·85 [95% CI 0·62-1·15]). Two serious adverse events were reported in the ursodeoxycholic acid group and six serious adverse events were reported in the placebo group; no serious adverse events were regarded as being related to treatment.

INTERPRETATION

Treatment with ursodeoxycholic acid does not reduce adverse perinatal outcomes in women with intrahepatic cholestasis of pregnancy. Therefore, its routine use for this condition should be reconsidered.

FUNDING

National Institute for Health Research Efficacy and Mechanism Evaluation Programme.

Cardiomyocyte-myofibroblast contact dynamism is modulated by connexin-43

Healthy cardiomyocytes are electrically coupled at the intercalated discs by gap junctions. In infarcted hearts, adverse gap-junctional remodeling occurs in the border zone, where cardiomyocytes are chemically and electrically influenced by myofibroblasts. The physical movement of these contacts remains unquantified. Using scanning ion conductance microscopy, we show that intercellular contacts between cardiomyocytes and myofibroblasts are highly dynamic, mainly owing to the edge dynamics (lamellipodia) of the myofibroblasts. Decreasing the amount of functional connexin-43 (Cx43) at the membrane through Cx43 silencing, suppression of Cx43 trafficking, or hypoxia-induced Cx43 internalization attenuates heterocellular contact dynamism. However, we found decreased dynamism and stabilized membrane contacts when cellular coupling was strengthened using 4-phenylbutyrate (4PB). Fluorescent-dye transfer between cells showed that the extent of functional coupling between the 2 cell types correlated with contact dynamism. Intercellular calcein transfer from myofibroblasts to cardiomyocytes is reduced after myofibroblast-specific Cx43 down-regulation. Conversely, 4PB-treated myofibroblasts increased their functional coupling to cardiomyocytes. Consistent with lamellipodia-mediated contacts, latrunculin-B decreases dynamism, lowers physical communication between heterocellular pairs, and reduces Cx43 intensity in contact regions. Our data show that heterocellular cardiomyocyte-myofibroblast contacts exhibit high dynamism. Therefore, Cx43 is a potential target for prevention of aberrant cardiomyocyte coupling and myofibroblast proliferation in the infarct border zone.-Schultz, F., Swiatlowska, P., Alvarez-Laviada, A., Sanchez-Alonso, J. L., Song, Q., de Vries, A. A. F., Pijnappels, D. A., Ongstad, E., Braga, V. M. M., Entcheva, E., Gourdie, R. G., Miragoli, M., Gorelik, J. Cardiomyocyte-myofibroblast contact dynamism is modulated by connexin-43.

Heart and bile acids - Clinical consequences of altered bile acid metabolism

Cardiac dysfunction has an increased prevalence in diseases complicated by liver cirrhosis such as primary biliary cholangitis and primary sclerosing cholangitis. This observation has led to research into the association between abnormalities in bile acid metabolism and cardiac pathology. Approximately 50% of liver cirrhosis cases develop cirrhotic cardiomyopathy. Bile acids are directly implicated in this, causing QT interval prolongation, cardiac hypertrophy, cardiomyocyte apoptosis and abnormal haemodynamics of the heart. Elevated maternal serum bile acids in intrahepatic cholestasis of pregnancy, a disorder which causes an impaired feto-maternal bile acid gradient, have been associated with fatal fetal arrhythmias. The hydrophobicity of individual bile acids in the serum bile acid pool is of relevance, with relatively lipophilic bile acids having a more harmful effect on the heart. Ursodeoxycholic acid can reverse or protect against these detrimental cardiac effects of elevated bile acids.

Bile acids and cardiovascular function in cirrhosis

Cirrhotic cardiomyopathy and the hyperdynamic syndrome are clinically important complications of cirrhosis, but their exact pathogenesis is still partly unknown. Experimental models have proven the cardiotoxic effects of bile acids and recent studies of their varied receptor-mediated functions offer new insight into their involvement in cardiovascular dysfunction in cirrhosis. Bile acid receptors such as farnesoid X-activated receptor and TGR5 are currently under investigation as potential therapeutic targets in a variety of pathological conditions. These receptors have also recently been identified in cardiomyocytes, vascular endothelial cells and smooth muscle cells where they seem to play an important role in cellular metabolism. Chronic cholestasis leading to abnormal levels of circulating bile acids alters the normal signalling pathways and contributes to the development of profound cardiovascular disturbances. This review summarizes the evidence regarding the role of bile acids and their receptors in the generation of cardiovascular dysfunction in cirrhosis.

Ursodeoxycholic acid prevents ventricular conduction slowing and arrhythmia by restoring T-type calcium current in fetuses during cholestasis

Background

Increased maternal serum bile acid concentrations in intrahepatic cholestasis of pregnancy (ICP) are associated with fetal cardiac arrhythmias. Ursodeoxycholic acid (UDCA) has been shown to demonstrate anti-arrhythmic properties via preventing ICP-associated cardiac conduction slowing and development of reentrant arrhythmias, although the cellular mechanism is still being elucidated.

Methods

High-resolution fluorescent optical mapping of electrical activity and electrocardiogram measurements were used to characterize effects of UDCA on one-day-old neonatal and adult female Langendorff-perfused rat hearts. ICP was modelled by perfusion of taurocholic acid (TC, 400μM). Whole-cell calcium currents were recorded from neonatal rat and human fetal cardiomyocytes.

Results

TC significantly prolonged the PR interval by 11.0±3.5% (P<0.05) and slowed ventricular conduction velocity (CV) by 38.9±5.1% (P<0.05) exclusively in neonatal and not in maternal hearts. A similar CV decline was observed with the selective T-type calcium current (I_Ca,T) blocker mibefradil 1μM (23.0±6.2%, P<0.05), but not with the L-type calcium current (I_Ca,L) blocker nifedipine 1μM (6.9±6.6%, NS). The sodium channel blocker lidocaine (30μM) reduced CV by 60.4±4.5% (P<0.05). UDCA co-treatment was protective against CV slowing induced by TC and mibefradil, but not against lidocaine. UDCA prevented the TC-induced reduction in the I_Ca,T density in both isolated human fetal (−10.2±1.5 versus −5.5±0.9 pA/pF, P<0.05) and neonatal rat ventricular myocytes (−22.3±1.1 versus −9.6±0.8 pA/pF, P<0.0001), whereas UDCA had limited efficacy on the I_Ca,L.

Conclusion

Our findings demonstrate that I_Ca,T plays a significant role in ICP-associated fetal cardiac conduction slowing and arrhythmogenesis, and is an important component of the fetus-specific anti-arrhythmic activity of UDCA.

Pregnancy and bile acid disorders

During pregnancy, extensive adaptations in maternal metabolic and immunological physiology occur. Consequently, preexisting disease may be exacerbated or attenuated, and new disease susceptibility may be unmasked. Cholestatic diseases, characterized by a supraphysiological raise in bile acid levels, require careful monitoring during pregnancy. This review describes the latest advances in the knowledge of intrahepatic cholestasis of pregnancy (ICP), the most common bile acid disorder specific to pregnancy, with a focus on the disease etiology and potential mechanisms of ICP-associated adverse pregnancy outcomes, including fetal demise. The course of preexisting cholestatic conditions in pregnancy is considered, including primary sclerosing cholangitis, primary biliary cholangitis, biliary atresia, and Alagille syndrome. The currently accepted treatments for cholestasis in pregnancy and promising new therapeutics for the condition are described.

Bile acids and gestation

There are numerous profound maternal physiological changes that occur from conception onwards and adapt throughout gestation in order to support a healthy pregnancy. By the time of late gestation, when circulating pregnancy hormones are at their highest concentrations, maternal adaptations include relative hyperlipidemia, hypercholanemia and insulin resistance. Bile acids have now been established as key regulators of metabolism, and their role in gestational changes in metabolism is becoming apparent. Bile acid homeostasis is tightly regulated by the nuclear receptor FXR, which has been shown to have reduced activity during pregnancy. This review focuses on the gestational alterations in bile acid homeostasis that occur in normal pregnancy, which in some women can become pathological, leading to the development of intrahepatic cholestasis of pregnancy. As well as their important role in maternal metabolic health, we will review bile acid metabolism in the feto-placental unit.

Evaluating the effectiveness and safety of ursodeoxycholic acid in treatment of intrahepatic cholestasis of pregnancy: A meta-analysis (a prisma-compliant study)

BACKGROUND

Intrahepatic cholestasis of pregnancy (ICP) is a specific pregnancy-related disorder without standard medical therapies. Ursodeoxycholic acid (UDCA) is the most used medicine, but the efficacy and safety of UDCA remain uncertain. Several meta-analyses had been made to assess the effects of UDCA in ICP. However, the samples were not large enough to convince obstetricians to use UDCA. We conducted a meta-analysis to evaluate the effects and safety of UDCA in patients with ICP, which included only randomized controlled trials (RCTs).

METHODS

Six databases were searched. The search terms were "ursodeoxycholicacid," "therapy," "management," "treatment," "intrahepatic cholestasis of pregnancy," "obstetric cholestasis," "recurrent jaundice of pregnancy," "pruritus gravidarum," "idiopathic jaundice of pregnancy," "intrahepatic jaundice of pregnancy," and "icterus gravidarum."Randomized controlled trials of UDCA versus control groups (included using other medicines) among patients with ICP were included. The primary outcomes were improved pruritus scores and liver function. Secondary outcomes were the maternal and fetal outcomes in patients with ICP.Data were extracted from included RCTs. The Mantel-Haenzel random-effects model or fixed-effects model was used for meta-analysis.

RESULTS

A total of 12 RCTs involving 662 patients were included in the meta-analysis. In pooled analyses that compared UDCA with all controls, UDCA was associated with resolution of pruritus (risk ratio [RR], 1.68; 95% confidence interval [CI],1.12-2.52; P = 0.01),decrease of serum levels of alanine aminotransferase (ALT) (standardized mean difference (SMD), -1.36; 95% CI, -2.08 to -0.63; P <0.001), reduced serum levels of bile acid (SMD, -0.68; 95% CI, -1.15 to -0.20; P <0.001), fewer premature births (RR, 0.56; 95% CI, 0.43-0.72; P <0.001),reduced fetal distress (RR, 0.68; 95% CI, 0.49-0.94; P = 0.02), high Apgar scores at 5 minutes (RR, 0.44; 95% CI, 0.24-0.82; P = 0.009), less frequent respiratory distress syndrome (RDS) (RR, 0.33; 95% CI, 0.13-0.86; P = 0.02), and fewer neonates in the intensive care unit (NICU) (RR, 0.55; 95% CI, 0.35-0.87; P <0.05), increased gestational age (SMD,0.44; 95% CI, 0.26-0.63; P <0.001), and birth weight (SMD, 0.21; 95% CI, 0.02-0.40; P = 0.03). There were no differences in meconium staining and intrauterine growth retardation (IUGR) between the groups (P >0.05). No trials reported adverse effects on mothers and fetuses except nausea and emesis.

CONCLUSION

UDCA is effective and safe to improve pruritus and liver function in ICP. UDCA also reduced adverse maternal and fetal outcomes in pregnant women with ICP.

The Popeye domain containing protein family--A novel class of cAMP effectors with important functions in multiple tissues

Popeye domain containing (Popdc) proteins are a unique family, which combine several different properties and functions in a surprisingly complex fashion. They are expressed in multiple tissues and cell types, present in several subcellular compartments, interact with different classes of proteins, and are associated with a variety of physiological and pathophysiological processes. Moreover, Popdc proteins bind the second messenger cAMP with high affinity and it is thought that they act as a novel class of cAMP effector proteins. Here, we will review the most important findings about the Popdc family, which accumulated since its discovery about 15 years ago. We will be focussing on Popdc protein interaction and function in striated muscle tissue. However, as a full picture only emerges if all aspects are taken into account, we will also describe what is currently known about the role of Popdc proteins in epithelial cells and in various types of cancer, and discuss these findings with regard to their relevance for cardiac and skeletal muscle.

A review of the literature on cardiac electrical activity between fibroblasts and myocytes

Myocardial injuries often lead to fibrotic deposition. This review presents evidence supporting the concept that fibroblasts in the heart electrically couple to myocytes.