Risk factors for postpartum haemorrhage in twin pregnancies and haemorrhage severity.

INTRODUCTION: This study evaluated risk factors for postpartum haemorrhage (PPH) in twin pregnancies, particularly factors associated with major PPH (blood loss of >1000 mL), to facilitate identification of high-risk twin pregnancies. METHODS: This retrospective cohort study included all women with twin pregnancies who delivered at a tertiary obstetric unit in Hong Kong from 2009 to 2018 and experienced PPH (blood loss of ≥500 mL). Postpartum haemorrhage was classified using three thresholds for blood loss volume: ≥500 mL (all PPH), >1000 mL (major PPH), and >1500 mL (severe PPH). Risk factors for each threshold of PPH were analysed. RESULTS: In total, there were 680 twin pregnancies. The overall incidence of all PPH (≥500 mL) in this cohort was 27.8%, including minor PPH (500-1000 mL, 20.1%), major but not severe PPH (1001-1500 mL, 4.4%), and severe PPH (>1500 mL, 3.2%). Logistic regression analysis showed that general anaesthesia and the use of oxytocin were significant risk factors for all PPH (≥500 mL); general anaesthesia, in vitro fertilisation, antepartum haemorrhage, placental abruption, and placenta praevia were significant risk factors for major PPH (>1000 mL); in vitro fertilisation, placenta praevia, and obesity were significant risk factors for severe PPH (>1500 mL). CONCLUSION: Women with twin pregnancies who have obesity, conception by in vitro fertilisation, or placenta praevia exhibit a high risk of severe PPH. They should deliver in obstetric units with readily available blood product transfusions and the appropriate expertise for prompt management of severe PPH.

Knowledge, attitudes, and behaviours of pregnant women towards COVID-19: a cross-sectional survey.

INTRODUCTION: This study investigated the knowledge, attitudes, and behaviours of pregnant women towards coronavirus disease 2019 (COVID-19), as well as obstetric services provided by public hospitals (eg, universal screening) during the pandemic. METHODS: This cross-sectional survey was performed in the antenatal clinics of Kowloon East Cluster, Hospital Authority. Questionnaires were distributed to pregnant women for self-completion during follow-up examinations. RESULTS: In total, 623 completed questionnaires were collected from 28 July 2020 to 13 August 2020. Within this cohort, 83.1% of the women expressed high levels of worry (41.9% very worried and 41.3% worried) about contracting COVID-19 during pregnancy, 70.5% believed that maternal COVID-19 could cause intrauterine infection of their fetuses, and 84.3% objected to banning husbands from accompanying wives during labour and delivery. Most women (80.6%) agreed with universal screening for COVID-19 at certain points during pregnancy. Logistic regression modelling showed that women who were very worried about contracting COVID-19 (P=0.005) and women in their third trimester of pregnancy (P=0.009) were more likely to agree with universal screening during pregnancy; women with higher income (P=0.017) and women who planned to deliver in a private hospital (P=0.024) were more likely to disagree with such screening. CONCLUSION: Pregnant women expressed high levels of worry about contracting COVID-19 during pregnancy; universal screening during pregnancy was acceptable to a large proportion of our participants. Efforts should be made to specifically include pregnant women when launching any population screening programme for COVID-19.

Relationship between viral load, infection-to-delivery interval and mother-to-child transfer of anti-SARS-CoV-2 antibodies.

OBJECTIVE: To investigate the association of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral load and infection-to-delivery interval with maternal and cord serum concentrations of anti-SARS-CoV-2 immunoglobulin G (IgG) antibodies and transplacental transfer ratio in pregnant women with active or recovered SARS-CoV-2 infection. METHODS: This was a prospective case series of consecutive pregnant women with laboratory-confirmed SARS-CoV-2 infection between 27 March 2020 and 24 January 2021. We collected information regarding deep throat saliva or nasopharyngeal swab (NPS) reverse transcription polymerase chain reaction (RT-PCR) test results, serial cycle threshold (Ct) values at and after diagnosis, demographic, clinical and outcome data, and neonatal NPS RT-PCR results. Qualitative and quantitative analysis of IgG and immunoglobulin M (IgM) antibodies against SARS-CoV-2 was performed in maternal and cord blood serum samples obtained at delivery. Correlation of maternal Ct values, infection-to-delivery interval, infection duration and viral load area under the curve (AUC) with gestational age (GA) at diagnosis, maternal and cord serum IgG concentrations and transplacental transfer ratio of IgG were evaluated using Pearson's correlation. RESULTS: Twenty pregnant women who consented to participate and who had delivered their babies by 31 January 2021 were included in the study, comprising 14 who had recovered from coronavirus disease 2019 (COVID-19) and six with active infection at delivery. The median GA at clinical manifestation was 32.7 (range, 11.9-39.4) weeks. The median infection-to-delivery interval and infection duration were 41.5 (range, 2-187) days and 10.0 (range, 1-48) days, respectively. The median GA at delivery was 39.1 (range, 32.4-40.7) weeks and the median seroconversion interval was 14 (range, 1-19) days. Of 13 neonates born to seropositive mothers with recovered infection at delivery, 12 tested positive for anti-SARS-CoV-2 IgG. All neonatal NPS samples were negative for SARS-CoV-2 and all cord sera tested negative for IgM. The median transplacental transfer ratio of IgG was 1.3 (interquartile range, 0.9-1.6). There was a negative correlation between infection-to-delivery interval and anti-SARS-CoV-2 IgG concentrations in maternal (r = -0.6693, P = 0.0087) and cord (r = -0.6554, P = 0.0068) serum and a positive correlation between IgG concentration in maternal serum and viral load AUC (r = 0.5109, P = 0.0310). A negative correlation was observed between transfer ratio and viral load AUC (r = -0.4757, P = 0.0409). CONCLUSIONS: In pregnant women who have recovered from COVID-19, anti-SARS-CoV-2 IgG concentrations at delivery increased with increasing viral load during infection and decreased with increasing infection-to-delivery interval. The median transplacental transfer ratio of IgG was 1.3 and it decreased with increasing viral load during infection. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Chromosomal abnormalities and neurological outcomes in fetal cerebral ventriculomegaly: a retrospective cohort analysis.

INTRODUCTION: This study investigated the incidences of chromosomal abnormalities and the neurological outcomes according to the degree of fetal cerebral ventriculomegaly. METHODS: All women with antenatal ultrasound diagnosis of fetal cerebral ventriculomegaly were retrospectively identified from two maternal-fetal medicine units in Hong Kong from January 2014 to December 2018. Degrees of fetal ventriculomegaly were classified as mild (10-11.9 mm), moderate (12-14.9 mm), or severe (≥15 mm). Genetic investigation results were reviewed, including conventional karyotyping and chromosomal microarray analysis (CMA); correlations between chromosomal abnormalities and the degree of fetal ventriculomegaly were explored. The neurological outcomes of subsequent live births were analysed to identify factors associated with developmental delay. RESULTS: Of 84 cases (ie, pregnant women and their fetuses) included, 46 (54.8%) exhibited isolated fetal ventriculomegaly, 55 (65.5%) had mild cerebral ventriculomegaly, and 29 (34.5%) had moderate or severe cerebral ventriculomegaly. Overall, 20% (14/70) of cases had chromosomal abnormalities. Moreover, 12% (3/25) of mild isolated ventriculomegaly cases had abnormal karyotype or CMA results. The CMA provided an incremental diagnostic yield of 8.6% (6/70), compared with conventional karyotyping; 4.3% exhibited pathogenic variants and 4.3% exhibited variants of uncertain significance. Among the 53 live births in the cohort, fewer cases of mild isolated ventriculomegaly were associated with developmental delay than more severe isolated ventriculomegaly (9.7% vs 41.7%, P<0.03). CONCLUSIONS: Chromosomal microarray analysis testing should be offered to all women with fetal cerebral ventriculomegaly, including women with isolated mild ventriculomegaly. The incidence of developmental delay after birth increases with the degree of prenatal cerebral ventriculomegaly.

Pathogens in preterm prelabour rupture of membranes and erythromycin for antibiotic prophylaxis: a retrospective analysis.

INTRODUCTION: Many authoritative guidelines recommend prescribing erythromycin as antibiotic prophylaxis in patients with preterm prelabour rupture of membranes (PPROM). This study evaluated the spectrum of pathogens in PPROM and assessed the effectiveness of erythromycin prophylaxis. METHODS: This retrospective study enrolled pregnant patients who were diagnosed with PPROM and who delivered at ≥24 weeks of gestation in an obstetric unit from 2013 to 2017. Pathogens isolated from maternal, placental, and neonatal specimens were analysed; their sensitivity profiles to various antibiotics were recorded. Neonatal outcomes were also evaluated. RESULTS: The overall incidence of PPROM was 2.63%. Gram-positive bacteria were cultured in 18.4% of PPROM patients (most frequent: Group B Streptococcus [GBS; 14.6%]); Gram-negative bacteria were cultured in 12.8% of PPROM patients (most frequent: Escherichia coli [8.0%]). Both Gram-positive and Gram-negative bacteria were significantly associated with early-onset neonatal sepsis (P=0.036 and P=0.001). In analyses stratified by bacterial species, E coli was significantly associated with early-onset neonatal sepsis (P=0.004), whereas GBS was not (P=0.39). Gram-positive bacteria had high rates of resistance to common antibiotics: 42.2% of GBS and 50.0% of Enterococcus and other Streptococcus bacteria were resistant to erythromycin. Escherichia coli had high rates of resistance to ampicillin (70.3%) and gentamicin (33.3%); rates of resistance to co-amoxiclav (3.6%) and intravenous cefuroxime (14.0%) were low. CONCLUSION: Gram-positive and Gram-negative bacteria were found in 29.1% of PPROM patients. Administration of erythromycin alone was insufficient to control these bacteria in 67.7% of patients with positive cultures.

Prevalence of chromosomal abnormalities and 22q11.2 deletion in conotruncal and non-conotruncal antenatally diagnosed congenital heart diseases in a Chinese population.

INTRODUCTION: The aim of the present study was to calculate the prevalence of chromosomal abnormalities among antenatally diagnosed congenital heart diseases (CHDs), and the prevalence of 22q11.2 deletion in those with conotruncal CHDs versus isolated non-conotruncal CHDs. METHODS: All patients with antenatal ultrasound finding of fetal CHDs in two obstetric units in a 5-year period were retrospectively reviewed. Detected CHDs were classified as conotruncal if the malformation involved either the aortic outflow tract or the pulmonary outflow tract; otherwise they were classified as non-conotruncal. Karyotyping, fluorescence in situ hybridisation for 22q11.2 deletion (22q11FISH), and array comparative genomic hybridisation (aCGH) results were retrieved from patient medical records. The primary outcome was prevalence of chromosomal abnormalities in CHDs. The secondary outcomes were prevalence of 22q11.2 deletion and its prevalence in conotruncal versus non-conotruncal CHDs. RESULTS: A total of 254 Chinese patients were diagnosed to have fetal CHDs. In all, 50 (19.7%) were found to have chromosomal abnormalities with seven (2.8%) patients having 22q11.2 deletion, of whom all seven had conotruncal CHDs and none had non-conotruncal CHDs (P<0.05). Conventional karyotyping detected 35 (70%) cases of the chromosomal abnormalities. The 22q11FISH detected three cases of 22q11.2 deletion; aCGH was performed to detect four cases of 22q11.2 deletion and eight other cases of copy number variations. CONCLUSION: Our results suggest that invasive testing for karyotyping is recommended for fetal CHDs. Although the prevalence of 22q11.2 deletion was low, testing for 22q11.2 deletion should be offered for conotruncal CHDs.

Secular trends in caesarean section rates over 20 years in a regional obstetric unit in Hong Kong.

INTRODUCTION: Although caesarean section rates have been increasing over the years in both public and private sectors in Hong Kong, there has been a paucity of formal surveys on local trends in such rates. This study aimed to examine the trends in caesarean section rates over a 20-year period at a public regional obstetric unit in Hong Kong using the Robson's Ten-group Classification System. METHODS: All deliveries in a single obstetric unit during a 20-year period (1995-2014) were classified into 10 subgroups according to the Robson's classification. The annual caesarean section rate for each subgroup was calculated and then stratified into 5-year intervals to analyse any significant trends. RESULTS: The caesarean section rates in a total of 86 262 births with complete data were analysed. The overall caesarean section rate increased modestly from 15.4% to 24.6% during the study period. There was an obvious increasing trend for caesarean section in those with previous caesarean section (Robson's category 5), breech presentation at delivery (category 6 and 7), multiple pregnancy (category 8), and preterm labour (category 10). A gradual fall in caesarean section rate from 14.4% to 10.8% was seen in primiparous women with term spontaneous labour (category 1). Statistically significant differences (P<0.001) in these trends were confirmed when the data were stratified into 5-year intervals for comparison. CONCLUSION: The rising caesarean section rate may be associated with clinical management policies that allow women with relative risk factors (such as breech, previous caesarean section, or multiple pregnancy) to opt for caesarean section. This rise was counterbalanced by a decrease in primary caesarean section rate in primiparous women with spontaneous labour. The trend for caesarean section was more in line with patient expectations rather than evidence-based practice.

Nitric Oxide-cGMP-PKG Pathway Acts on Orai1 to Inhibit the Hypertrophy of Human Embryonic Stem Cell-Derived Cardiomyocytes.

Cardiac hypertrophy is an abnormal enlargement of heart muscle. It frequently results in congestive heart failure, which is a leading cause of human death. Previous studies demonstrated that the nitric oxide (NO), cyclic GMP (cGMP), and protein kinase G (PKG) signaling pathway can inhibit cardiac hypertrophy and thus improve cardiac function. However, the underlying mechanisms are not fully understood. Here, based on the human embryonic stem cell-derived cardiomyocyte (hESC-CM) model system, we showed that Orai1, the pore-forming subunit of store-operated Ca(2+) entry (SOCE), is the downstream effector of PKG. Treatment of hESC-CMs with an α-adrenoceptor agonist phenylephrine (PE) caused a marked hypertrophy, which was accompanied by an upregulation of Orai1. Moreover, suppression of Orai1 expression/activity using Orai1-siRNAs or a dominant-negative construct Orai1(G98A) inhibited the hypertrophy, suggesting that Orai1-mediated SOCE is indispensable for the PE-induced hypertrophy of hESC-CMs. In addition, the hypertrophy was inhibited by NO and cGMP via activating PKG. Importantly, substitution of Ala for Ser(34) in Orai1 abolished the antihypertrophic effects of NO, cGMP, and PKG. Furthermore, PKG could directly phosphorylate Orai1 at Ser(34) and thus prevent Orai1-mediated SOCE. Together, we conclude that NO, cGMP, and PKG inhibit the hypertrophy of hESC-CMs via PKG-mediated phosphorylation on Orai1-Ser-34. These results provide novel mechanistic insights into the action of cGMP-PKG-related antihypertrophic agents, such as NO donors and sildenafil.

Impact of nuchal cord on fetal outcomes, mode of delivery, and management: a questionnaire survey of pregnant women.

OBJECTIVES: To explore pregnant women's views on the impact of nuchal cord on fetal outcomes, mode of delivery, and management. DESIGN: Questionnaire survey. SETTING: Antenatal clinic of two regional hospitals in Hong Kong. PARTICIPANTS: A questionnaire survey of all pregnant women at their first visit to the antenatal clinic of United Christian Hospital and Tseung Kwan O Hospital in Hong Kong was conducted between August and October 2012. RESULTS: Most participants (71.8%) were worried about nuchal cord, and 78.3% and 87.7% of them thought that nuchal cord could cause intrauterine death and fetal death during labour, respectively. Approximately 87.5% of participants thought that nuchal cord would reduce the chance of successful vaginal delivery and 56.4% thought that it would increase the chance of assisted vaginal delivery. Most (94.1%) participants thought that it was necessary to have an ultrasound scan at term to detect nuchal cord. In addition, 68.8% thought that it was necessary to deliver the fetus early and 72.8% thought that caesarean section must be performed in the presence of nuchal cord. Participants born in Mainland China were significantly more worried about the presence of nuchal cord than those born in Hong Kong. However, there was no difference between participants with different levels of education. CONCLUSION: Most participants were worried about the presence of nuchal cord. Many thought that nuchal cord would lead to adverse fetal outcomes, affect the mode of delivery, and require special management. These misconceptions should be addressed and proper education of women is needed.

Prevalence of Hepatitis B Carrier Status and Its Negative Association with Hypertensive Disorders in Pregnancy.

RESULTS: In a total cohort of 87889 deliveries over a period of 20 years, the prevalence rate of HBV fell from around 10-11% to around 6-7% in the last 5 years of the study. A negative association between chronic HBV carrier status and all gestational hypertensive disorders could be demonstrated. An apparent protective effect of HBV carrier status was apparently more robust against preeclampsia than gestational hypertension, as the negative association with preeclampsia was consistently observed throughout the study period. A logistic regression model showed that advanced maternal age, multiple pregnancies, obesity, and significant medical disorders were positively correlated with gestational hypertensive disorders, while multiparity and positive HBV carrier status were negatively correlated. CONCLUSION: Chronic HBV carrier status appeared to have a protective effect against the development of preeclampsia and gestational hypertension in an endemic area with high HBV prevalence rates.

Comparison of modeling accuracy between Radixact®and CyberKnife®Synchrony®respiratory tracking system.

Synchrony Respiratory Tracking system adapted from CyberKnife has been introduced in Radixact to compensate the tumor motion caused by respiration. This study aims to compare the modeling accuracy of the Synchrony system between Radixact and CyberKnife. Two Synchrony plans based on fiducial phantoms were created for CyberKnife and Radixact, respectively. Different respiratory motion traces were used to drive a motion platform to move along the superoinferior and left-right direction. The cycle time and the amplitude of target/surrogate motion of one selected motion trace were scaled to investigate the dependence of modeling accuracy on the motion characteristic. The predicted target position, the correlation error, potential difference (Radixact only) and standard error (CyberKnife only) were extracted from raw data or log files of the two systems. The modeling accuracy was evaluated by calculating the root-mean-square (RMS) error between the predicted target positions and the input motion trace. A threshold T95 within which 95% of the potential difference or the standard error lay was defined and evaluated. Except for the motion trace with a small amplitude and a good (linear) correlation between target and surrogate motion, Radixact showed smaller RMS errors than CyberKnife. The RMS error of both systems increased with the motion amplitude and showed a decreasing trend with the increasing cycle time. No correlation was found between the RMS error and the amplitude of surrogate motion. T95 could be a good estimator of modeling accuracy for CyberKnife rather than Radixact. The correlation error defined in Radixact were largely affected by the number of fiducial markers and the setup error. In general, the modeling accuracy of the Radixact Synchrony system is better than that of the CyberKnife Synchrony system under unfavorable conditions.

A local risk score model for venous thromboembolism prophylaxis for caesarean section in Chinese women and comparison with international guidelines.

OBJECTIVE: Recommendations for venous thromboembolism (VTE) prophylaxis from authoritative guidelines for women undergoing caesarean delivery differed significantly and may not be applicable to Chinese populations. We aim to formulate a local risk model for VTE prophylaxis for caesarean section women. MATERIAL AND METHODS: A local risk score model based on demographic, obstetric and medical parameters was used to assess the risk of VTE in women undergoing caesarean delivery from May 2017 to April 2018 in a regional obstetric unit. Women with increased risk (VTE Score ≥ 2) are given mechanical prophylaxis with pneumatic cuff and those with high risk (VTE Score ≥ 3) are additionally prescribed low molecular weight heparin (LMWH) as pharmacological prophylaxis in the early postpartum period. The risk scores obtained by applying other major guidelines were then compared. RESULTS: Of 859 patients were included for analysis, overweight (15.3%), advanced maternal age (9.7%), multiple pregnancy (5.1%), obesity (4.7%), and primary postpartum haemorrhage (4.1%) were the most common risk factors. Overall, 109 (12.7%) patients required mechanical prophylaxis and 28 (3.3%) patients required additional pharmacological prophylaxis. No patient had postpartum VTE events nor serious haemorrhage after receiving LMWH prophylaxis. In contrast, applying the Royal College of Obstetricians and Gynaecologists guidelines to our cohort, 649 (75.6%) patients would receive LMWH after caesarean section, compared with no patients under the American College of Obstetrics and Gynaecology guidelines. CONCLUSIONS: Our local risk score model avoided the need for large proportions of women to be subjected to pharmacological prophylaxis, and appeared safe and practical.

Deleterious effects of short-term, high-intensity exercise on immune function: evidence from leucocyte mitochondrial alterations and apoptosis.

BACKGROUND: Although moderate exercise can benefit health, acute and vigorous exercise may have the opposite effect. Strenuous exercise can induce alterations in the physiology and viability of circulating leucocytes, which have a causal relationship with exercise-induced immune distress. OBJECTIVES: To investigate the use of mitochondrial transmembrane potential (MTP), a functional marker of the energy and viability status of leucocytes, for monitoring the immunomodulating effects of short-term, high-intensity exercise. METHODS: 12 healthy volunteers with a mean Vo(2)max of 70.4 ml/kg/min carried out 3 consecutive days of high-intensity exercise (85% of Vo(2)max for 30 min every day). Blood samples were collected at multiple time points immediately before and after each exercise session and at 24 and 72 h after the completion of exercise. Leucocyte MTP, apoptosis and circulatory inflammation markers were measured by flow cytometry and enzyme-linked immunosorbent assays. RESULTS: MTP of peripheral blood leucocytes had declined immediately after the first exercise session and remained subnormal 24 h later. It did not normalise until 72 h after exercise. The sequential changes in MTP were consistent among the three leucocyte subpopulations (polymorphonuclear neutrophils, lymphocytes and monocytes) and were significant (p<0.05). Leucocytes displayed a gradual and incremental change in their propensity for apoptosis during and after exercise. Similarly, plasma concentrations of tumour necrosis factor-alpha and soluble Fas ligand were raised during the exercise sessions and had not normalised by 72 h after the completion of exercise. Correlation between changes in leucocyte MTP and plasma concentrations of tumour necrosis factor-alpha and soluble Fas ligand was variable, but significant for polymorphonuclear neutrophils and lymphocytes (p<0.05). CONCLUSIONS: Short-term, high-intensity exercise can lead to a significant and prolonged dysfunction of the mitochondrial energy status of peripheral blood leucocytes, which is accompanied by an increased propensity for apoptosis and raised pro-inflammatory mediators. These results support the immunosuppressive effects of excessive exercise and suggest that MTP is a useful marker of these effects.

Prevention of early onset group B streptococcal disease by universal antenatal culture-based screening in all public hospitals in Hong Kong.

OBJECTIVES: To determine the prevalence of maternal colonization with group B streptococcus (GBS), and early onset GBS disease (EOGBSD) after implementation of universal screening. METHODS: This was a three-year retrospective cohort study on universal antenatal rectovaginal culture-based screening and intrapartum antimicrobial prophylaxis (IAP) to colonized women in the public sector in Hong Kong. Routinely collected data including maternal colonization and EOGBSD were retrieved. RESULTS: Of 113,989 GBS screening performed, 21.8% were positive. The colonization rate was higher in the public hospitals (higher risk) than in the Maternal and Child Health Centers (lower risk) (23.7% vs 18.1%, p < .001), while their false negative rates were not greater than expected. Majority of eligible women opted for screening, and colonized women received IAP. There were 29 cases of EOGBSD with clinical signs and a positive blood or cerebrospinal fluid culture. Compared to clinical risk-based screening, EOGBSD incidence decreased after universal screening (1 vs 0.24 per 1000 births, p < .001). Although EOGBSD occurred at a higher rate in preterm than term infants, 86.7% occurred in the latter, and were associated with a false negative screening result (41.3%), lack of screening (20.7%) or unavailability of a colonization result at labour (13.8%). CONCLUSIONS: Maternal GBS colonization rate was higher than previously reported, and varied with different risk populations. EOGBSD reduced after universal screening.

Maturation of human embryonic stem cell-derived cardiomyocytes (hESC-CMs) in 3D collagen matrix: Effects of niche cell supplementation and mechanical stimulation.

Cardiomyocytes derived from human embryonic stem cells (hESC-CMs) are regarded as a promising source for regenerative medicine, drug testing and disease modeling. Nevertheless, cardiomyocytes are immature in terms of their contractile structure, metabolism and electrophysiological properties. Here, we fabricate cardiac muscle strips by encapsulating hESC-CMs in collagen-based biomaterials. Supplementation of niche cells at 3% to the number of hESC-CMs enhance the maturation of the hESC-CMs in 3D tissue matrix. The benefits of adding mesenchymal stem cells (MSCs) are comparable to that of adding fibroblasts. These two cell types demonstrate similar effects in promoting the compaction and cell spreading, as well as expression of maturation markers at both gene and protein levels. Mechanical loading, particularly cyclic stretch, produces engineered cardiac tissues with higher maturity in terms of twitch force, elastic modulus, sarcomere length and molecular signature, when comparing to static stretch or non-stretched controls. The current study demonstrates that the application of niche cells and mechanical stretch both stimulate the maturation of hESC-CMs in 3D architecture. Our results therefore suggest that this 3D model can be used for in vitro cardiac maturation study. STATEMENT OF SIGNIFICANCE: Cardiomyocytes derived from human embryonic stem cells (hESC-CMs) are regarded as being a promising source of cells for regenerative medicine, drug testing and disease modeling. Nevertheless, cardiomyocytes are immature in terms of their contractile structure, metabolism and electrophysiological properties. In the current study, we have fabricated cardiac muscle strips by encapsulating hESC-CMs in collagen-based biomaterials and demonstrated that supplementation of mesenchymal niche cells as well as provision of mechanical loading particularly stretching have significantly promoted the maturation of the cardiomyocytes and hence improved the mechanical functional characteristics of the tissue strips. Specifically, with 3% niche cells including both fibroblasts and mesenchymal stem cells, a more mature hESC-CMs derived cardiac strip was resulted, in terms of compaction and spreading of cells, and upregulation of molecular signature in both gene and protein expression of maturation. Mechanical loading, particularly cyclic stretch, produces engineered cardiac tissues with higher maturity in terms of molecular signature markers and functional parameters including twitch force, elastic modulus and sarcomere length, when comparing with static stretch or non-stretched controls. The current study demonstrates that the application of niche cells and mechanical stretch both stimulate the maturation of hESC-CMs in 3D architecture, resulting in more mature cardiac strips. Our results contribute to bioengineering of functional heart tissue strips for drug screening and disease modeling.

Leukocyte mitochondria depolarization and apoptosis in advanced heart failure: clinical correlations and effect of therapy.

OBJECTIVES: The purpose of this study was to examine the changes in leukocyte mitochondrial transmembrane potential (MTP) and its association with apoptosis in congestive heart failure (CHF). BACKGROUND: Congestive heart failure is a heterogeneous syndrome with multiple hemodynamic, neuroendocrine and immune abnormalities. Although edematous CHF may be associated with endotoxemia and increased cytokine production, peripheral blood leukocyte functions in advanced CHF remain unclear. METHODS: Thirty patients with acute decompensated CHF (mean age [+/- SEM] 74.9 +/- 3.1 years) and 20 healthy controls underwent determination of MTP, intracellular oxidants and apoptosis in three subsets of peripheral blood leukocytes. The measurements were repeated after the time of recompensation. RESULTS: Patients with acute CHF showed marked MTP reduction and increased intracellular oxidant formation in three subsets of leukocytes upon entry into the study. These changes were more prominent in patients with peripheral edema. The decline in MTP was correlated with the severity of the peripheral edema and plasma concentration of cortisol, nitrogen metabolites and tumor necrosis factor-alpha (p < 0.01). After clinical stabilization, MTP gradually recovered. Leukocytes underwent increased propensity of apoptosis one week after the time of recompensation. CONCLUSIONS: The mitochondrial depolarization and apoptosis of leukocytes in decompensated heart failure suggest that CHF is associated with severity-dependent impairments in leukocyte function. Accentuated hormonal and cytokine abnormalities and increased circulating oxidants may contribute to these changes. Early and aggressive management of advanced heart failure is helpful in the recovery of these immune abnormalities.

The influence of verapamil and nifedipine on hepatic indocyanine green clearance in patients with HBsAg-positive cirrhosis and ascites.

The influence of verapamil and nifedipine on hepatic indocyanine green kinetics was studied in 12 patients with HBsAg-positive cirrhosis and ascites. Hepatic clearance and its two biologic determinants, hepatic blood flow and metabolic activity (intrinsic clearance [maximum velocity/metabolite elimination rate constant, or Vmax/km]), were determined from hepatic indocyanine green elimination at steady state in patients with cirrhosis. Acute intravenous administration 10 mg verapamil significantly increased the hepatic indocyanine green blood flow (p less than 0.05), but significantly decreased the hepatic clearance (p less than 0.05), extraction ratio (p less than 0.05) and Vmax/km (p less than 0.05). However, acute sublingual administration of 10 mg nifedipine resulted in no significant change in any parameters of hepatic elimination function. These results show that verapamil, but not nifedipine, might impair the transhepatic extraction activity of hepatocytes in patients with HBsAg-positive cirrhosis and ascites.