Tenofovir alafenamide or tenofovir disoproxil fumarate in pregnancy to prevent HBV transmission: Maternal ALT trajectory and infant outcomes

BACKGROUND

The use of antiviral agents, specifically tenofovir disoproxil fumarate (TDF), in pregnant women to prevent mother-to-child HBV transmission is a key step towards hepatitis elimination. However, data on using tenofovir alafenamide (TAF) is insufficient. The frequent occurrence of postpartum ALT flares may impact the clinical implementation.

METHODS

The maternal and infant outcomes were compared in multi-centre trials of high viral load HBsAg/HBeAg+ pregnant women receiving TAF or TDF from the third trimester until 2 weeks postpartum with intensive follow-ups. To explore the dynamic pre- and postpartum changes in ALT levels, we used a group-based trajectory model for analysing data of 332 women from three prospective studies.

RESULTS

After treatment, the maternal HBV DNA levels significantly decreased from baseline to delivery: 7.87 ± 0.59 to 3.99 ± 1.07 Log10 IU/mL TAF (n = 78) and 8.30 ± 0.36 to 4.47 ± 0.86 Log10 IU/mL (TDF, n = 53), with viral load reductions of 3.87 versus 3.83 Log10 IU/mL. The HBsAg-positive rates among 12-month-old infants were 1.28% (1/78) versus 1.82% (1/55) respectively (p = 1.00). Of the TAF or TDF-treated mothers, 25.64% versus 16.98% experienced ALT > 2X ULN, and 11.54% versus 1.89% received extended antiviral treatment. Our model revealed four distinct ALT patterns: stable ALT (87.2%), moderate (8.0%) or marked (2.4%) postpartum flares, or prepartum elevations (2.4%).

CONCLUSIONS

TAF effectively reduces mother-to-child HBV transmission, but prophylaxis failure still occurred in few cases. Postpartum ALT flares are common in women receiving TAF or TDF during pregnancy. Approximately 12.8% of mothers may require extended postpartum antiviral treatment.

CLINICAL TRIAL NUMBER

NCT03695029 (ClinicalTrials.gov).

Characterization of Hepatitis B Virus in Tenofovir-Treated and Untreated Chronically Infected Mothers and Their Immunoprophylaxis Failure Infants

BACKGROUND

Maternal tenofovir disoproxil fumarate (TDF) therapy during late pregnancy can reduce mother-to-infant transmission of hepatitis B virus (HBV). We investigated HBV mutations associated with maternal TDF therapy and their role in infant immunonophylaxis failure (IPF).

METHODS

Serum samples from untreated (n = 89) and TDF-treated (n = 68), highly viremic, chronically infected mothers and their infants were analyzed for HBV DNA by nested polymerase chain reaction (PCR) and direct sequencing.

RESULTS

At delivery, compared with untreated mothers, TDF-treated mothers had a lower HBV DNA titer and a higher frequency of basal core promoter (BCP) gene mutations, but they had similar frequencies in pre-S/S and pre-core/core mutations. The 14 mothers harboring surface "a" determinant mutants did not transmit the mutants to their immunized infants. Such mutants were found in 3 of 13 IPF infants; the 13 mothers had wild-type hepatitis B surface antigen (HBsAg). In univariable analysis, maternal HBV DNA titer (odds ratio [OR]: 1.54; 95% confidence intervals [CI]: 1.02-2.33; P = .039), genotype C (OR: 4.18; 95% CI: 1.28-13.62; P = .018) and pre-S1 wild-type sequence (OR: 6.33; 95% CI: 1.85-21.68; P = .003) at delivery were associated with infant IPF. Multivariable analyses showed that maternal genotype C (OR: 3.71; 95% CI: 1.11-12.36; P = .033) and pre-S1 wild-type (OR: 6.34; 95% CI: 1.79-22.44; P = .004) were associated with infant IPF independently of maternal viremia.

CONCLUSIONS

Along with high maternal HBV DNA titer at delivery, maternal genotype C and pre-S1 wild-type sequence were potential risk factors for infant IPF, although BCP mutations were not. The offspring of pregnant women harboring "a" determinant mutants as major strains seemed to be protected by immunoprophylaxis.

CLINICAL TRIALS REGISTRATION

NCT01312012.

Kinetics of hepatitis B surface antigen in pregnant women with and without tenofovir disoproxil fumarate

Tenofovir disoproxil fumarate (TDF) is the preferred treatment to prevent mother-to-infant transmission in highly viremic HBV-infected women. Data on hepatitis B surface antigen (HBsAg) levels in pregnant women are lacking. We aimed to investigate prepartum and postpartum HBsAg kinetics and its correlation with HBV DNA in pregnant women. HBV-infected mothers with HBV DNA ≥7.5 log₁₀  IU/ml were tested for HBsAg and HBV DNA from baseline to 6 months postpartum. Of the 186 pregnant women with comparable baseline HBsAg and HBV DNA, 101 received TDF from the third trimester until 1 month postpartum. At delivery, TDF group had mildly lower HBsAg (4.32 ± 0.47 vs. 4.54 ± 0.35 log₁₀  IU/ml, p = .0004) and markedly lower HBV DNA (4.26 ± 0.97 vs. 8.11 ± 0.70 log₁₀  IU/ml, p < .0001) than the control group. In the TDF group, mean reduction of HBsAg and HBV DNA from baseline to delivery were 0.22 ± 0.38 and 3.96 ± 0.93 log₁₀  IU/ml. HBsAg reduction had a positive correlation (r = .309; p = .0017) with HBV DNA reduction, and was predictive of HBV DNA reduction ≥3 log₁₀  IU/ml (area under the receiver operating characteristic curve, 0.67; 95% confidence interval, 0.50-0.82). At 6 months postpartum, TDF and control group had comparable HBsAg and HBV DNA. In conclusion, HBsAg decreased slightly at delivery in pregnant women receiving TDF. For monitoring the effect of antiviral therapy during pregnancy, HBV DNA is a better marker than HBsAg. Our data provided valuable information regarding monitoring HBV-infected pregnant women using antiviral therapy.

Occult Hepatitis B Virus Infection in Immunized Infants Born to Untreated and Tenofovir-Treated Highly Viremic Mothers

Tenofovir disoproxil fumurate (TDF) therapy during late pregnancy in highly viremic mothers can reduce residual overt hepatitis B virus (HBV) infections of their infants that occur despite immunoprophylaxis.^1,2 Occult HBV infection (OBI) has been defined as the presence of HBV DNA in liver or sera in subjects seronegative for hepatitis B surface antigen (HBsAg).³ OBI has been found in varying proportions of immunized infants born to HBsAg-positive mothers.^4-6 We aimed to investigate the impact of maternal TDF therapy during pregnancy on vertically acquired OBI.

Long-term growth and bone development in children of HBV-infected mothers with and without fetal exposure to tenofovir disoproxil fumarate

BACKGROUND & AIMS

Tenofovir disoproxil fumarate (TDF) is the preferred treatment to prevent maternal transmission of HBV, owing to its efficacy and safety. However, data are lacking on the long-term safety outcomes in children following fetal exposure to TDF.

METHODS

Children participating in a prospective, multisite trial of maternal TDF treatment during late pregnancy were recruited for follow-up visits once a year. Growth parameters, serum biochemistry, HBV serology, and bone mineral density (BMD) by dual-energy x-ray absorptiometery scan were measured.

RESULTS

One hundred and twenty-eight children, 71 in the TDF and 57 in the control group, completed 255 follow-up visits at the age of 2 to 7 (median, 4.08) years. No differences in z-scores for weight-for-age (0.26 ± 0.90 vs. 0.22 ± 0.99, p = 0.481), z-scores for height-for-age (0.20 ± 1.02 vs. 0.25 ± 0.98, p = 0.812), and estimated glomerular filtration rate (169.12 ± 50.48 vs. 169.06 ± 34.46 ml/min/1.73m², p = 0.479) were detected. After adjustment for age, sex and HBV status by multiple linear regression, children in the TDF and control group had comparable levels of serum calcium, phosphorus, bone-specific alkaline phosphatase, calcidiol and BMD of lumbar spines (0.55 ± 0.01 vs. 0.57 ± 0.01 g/cm², p = 0.159) and left hip (0.56 ± 0.01 vs. 0.56 ± 0.01 g/cm², p = 0.926).

CONCLUSIONS

Children of HBV-infected mothers who did or did not receive tenofovir disoproxil fumarate treatment during late pregnancy had comparable long-term growth, renal function, and bone development up to 6-7 years after delivery.

CLINICAL TRIAL NUMBER

NCT01312012 (ClinicalTrials.gov) LAY SUMMARY: Currently there are insufficient long-term safety data in children born to mothers who took antiviral agents during pregnancy to prevent mother-to-infant transmission of hepatitis B virus (HBV). In this study, we found that children of HBV-infected mothers who did or did not receive tenofovir disoproxil fumarate treatment during late pregnancy had comparable long-term growth, renal function, and bone development up to 6-7 years after delivery.

Hepatitis B-management of acute infection and active inflammation in pregnancy-a hepatologist's perspective

Women at childbearing age and pregnant ladies living in the areas of high or intermediate prevalence of hepatitis B virus (HBV) remain at risk of getting the infection and passing the infections to their offspring via mother-to-child transmission (MTCT) of HBV. HBV infection may affect the mothers by active hepatitis, very occasionally liver cirrhosis and rarely fulminant hepatitis and liver failure. The virus may be transmitted to the babies despite immunoprophylaxis in the setting of very high maternal viral load. Tenofovir disoproxil fumarate (TDF) has been shown to be efficacious to reduce MTCT of HBV, which contributes to the elimination of chronic HBV infection by 2030, the goal set by World Health Organization.

Decreased neonatal hepatitis B virus (HBV) viremia by maternal tenofovir treatment predicts reduced chronic HBV infection in children born to highly viremic mothers

BACKGROUND

Maternal anti-viral treatment prevents mother-to-infant transmission of hepatitis B virus (HBV), but the role of neonatal viremia on subsequent HBV infection is not clear.

AIMS

To investigate the effect of maternal anti-viral treatment on neonatal serum HBV DNA and hepatitis B surface antigen (HBsAg) in infants born to highly viremic mothers and the roles of neonatal markers in predicting chronic HBV infection in children.

METHODS

Serum HBV DNA and HBsAg were tested in children. Of the 201 pregnant mothers, 110 received tenofovir during the third trimester. Chronic infection in children was defined by HBsAg seropositivity at 6 or 12 months lasting more than 6 months.

RESULTS

The maternal HBV viral loads from baseline to delivery were 8.25 ± 0.48 to 4.29 ± 0.98 log₁₀  IU/mL; and 8.29 ± 0.49 to 8.12 ± 0.68 log₁₀  IU/mL in the tenofovir and control group respectively. Of the 208 children, those in the tenofovir group had a lower rate of neonatal HBV DNA seropositivity at birth (5.22% vs 30.11%, P < 0.0001) and HBsAg seropositivity at 6 months (1.74% vs 11.83%, P = 0.003) and 12 months (1.74% vs 10.75%, P = 0.007). In a first multivariate analysis, maternal HBV DNA level at delivery (odds ratio = 1.70, P = 0.0172) and neonatal HBsAg positivity (odds ratio = 19.37, P < 0.0001) were significantly associated with children's chronic HBV infection. In a second model, neonatal HBV DNA positivity was a strong independent influence variable (odds ratio = 61.89, P = 0.0002).

CONCLUSIONS

Maternal tenofovir therapy decreased maternal viral load and neonatal viremia. Positive neonatal HBV DNA was highly correlated with chronic HBV infection in children. Clinical Trial Identifier: NCT01312012.

A novel near-infrared nanomaterial with high quantum efficiency and its applications in real time in vivo imaging

Fluorescence imaging signal is severely limited by the quantum efficiency and emission wavelength. To overcome these challenges, novel NIR-emitting K₅NdLi₂F₁₀ nanoparticles under NIR excitation was introduced as fluorescence imaging probe for the first time. The photostability of K₅NdLi₂F₁₀ nanoparticles in the water, phosphate buffer saline, fetal bovine serum and living mice was investigated. The fluorescence signal was detected with depths of 3.5 and 2.0 cm in phantom and pork tissue, respectively. Fluorescence spectrum with a significant signal-to-background ratio of 10:1 was captured in living mice. Moreover, clear NIR images were virtualized for the living mice after intravenous injection. The imaging ability of nanoparticles in tumor-beard mice were evaluated, the enrichment of K₅NdLi₂F₁₀ nanoparticles in tumor site due to the enhanced permeability and retention effect was confirmed. The systematic studies of toxicity, bio-distribution and in-vivo dynamic imaging suggest that these materials give high biocompatibility and low toxicity. These NIR-emitting nanoparticles with high quantum efficiency, high penetration and low toxicity might facilitate tumor identification in deep tissues more sensitively.

Management of Pregnant Women and Children: Focusing on Preventing Mother-to-Infant Transmission

Hepatitis B virus (HBV) immunization has been effectively preventing chronic HBV infection with >90% efficacy in countries with universal neonatal immunization. Perinatal mother-to-infant transmission of HBV remains the major cause of chronic HBV infection despite immunization. Maternal hepatitis B e-antigen (HBeAg) and high viral load have been noted to be the most important risk factors for transmission. In recent years, short-term antiviral therapy for pregnant women in the third trimester has been shown to be highly effective in reducing 90% of vaccine failure in children. It is important to monitor maternal aminotransferase elevations postpartum. Long-term outcome of mothers and children is needed and awaits further investigations. Despite the above-mentioned preventive measures, it is also important to monitor high-risk children at 1 year of age with hepatitis B surface antigen and anti-hepatitis B to identify those with chronic HBV infection. Most of the children with chronic HBV infection were in the immune-tolerant phase. The goals for antiviral treatment in children are to reduce severity of liver injury, achieve HBeAg seroconversion, and prevent development of liver fibrosis and cancer. Studies on antiviral therapy are undergoing to elucidate the optimal indication and drug treatment for children. The ideal future goal of treatment is to eradicate chronic HBV infection globally.

A review of strategies to prevent mother-to-infant transmission of hepatitis B virus infection

Hepatitis B virus (HBV) infection causes long-term, life-threatening liver diseases worldwide. HBV is transmitted through either the horizontal or mother-to-infant route, which is the major route of transmission in endemic areas. Administration of hepatitis B immunoglobulin and hepatitis B vaccine to newborns of infected mothers prevents mother-to-infant transmission. Implementation of a universal hepatitis B vaccination program has proven successful in eliminating the infection and related complications. Nevertheless, efforts are still needed to improve global coverage of the hepatitis B vaccine. Infants born to highly viremic mothers are still at risk of infection despite current immunoprophylaxis. An increasing number of reports have shown promising efficacy and safety profiles with the use of nucleoside/nucleotide analogues in highly viremic pregnant women to prevent mother-to-infant transmission.

Quantitative maternal hepatitis B surface antigen predicts maternally transmitted hepatitis B virus infection

Despite immunoprophylaxis, hepatitis B virus (HBV) transmission in highly viremic mothers remains a global health issue. Using quantitative maternal surface antigen (HBsAg) to predict HBV infection in infants has not been investigated. We enrolled 526 mother-infant pairs with positive maternal HBsAg under current immunoprophylaxis. Maternal viral load and quantitative HBsAg were measured in the peripartum period. Infant HBsAg seropositivity for more than 6 months was defined as chronic infection. Rates of chronic infection in infants at various maternal HBsAg levels were estimated using a multivariate logistic regression model. Results showed that maternal HBsAg was positively correlated with maternal viral load (r = 0.69; P < 0.001) and accurately predicted maternal viral load above 6, 7, and 8 log₁₀ IU/mL with an area under the receiver operating characteristic curve (AUC) of 0.97, 0.98, and 0.95. Nineteen infants were chronically infected. After adjustment for the other risk factor, maternal HBsAg level was significantly associated with risk of infection (adjusted odds ratio for each log₁₀ IU/mL increase, 15.02; 95% confidence interval [CI], 3.89-57.94; P < 0.001). The AUC for predicting infection by quantitative maternal HBsAg was comparable to that by maternal viral load (0.89 vs. 0.87; P = 0.459). Estimated rates of infection at maternal HBsAg levels of 4, 4.5, and 5 log₁₀ IU/mL were 2.4% (95% CI, 0.1-4.6; P = 0.04), 8.6% (95% CI, 4.5-12.7; P < 0.001), and 26.4% (95% CI, 12.6-40.2; P < 0.001).

CONCLUSION

Quantitative maternal HBsAg predicts infection in infants as well as maternal viral load does. Antiviral therapy may be considered in pregnant women with an HBsAg level above 4-4.5 log₁₀ IU/mL to interrupt mother-to-infant transmission. (Hepatology 2016;64:1451-1461).

Mother-to-infant transmission of hepatitis B virus infection: significance of maternal viral load and strategies for intervention

BACKGROUND & AIMS

Immunoprophylaxis reduces but does not completely eradicate hepatitis B virus (HBV) transmission. This prospective study aims at assessing the rate and risk factors of maternally transmitted HBV infection.

METHODS

We enrolled 303 mother-infant pairs with positive maternal hepatitis B surface antigen (HBsAg) under current immunization program. Maternal viral load was determined by a real-time PCR-based assay. The children were tested for HBsAg at 4-8 months and/or 1-3 years of age. Rates of HBV infection were estimated using a multivariate logistic regression model.

RESULTS

HBeAg-positive mothers (81/303, 26.7%) had higher viral loads than HBeAg-negative mothers (7.4 ± 1.9 vs. 2.7 ± 1.4 log10 copies/ml, p<0.0001). Ten children, born to HBeAg-positive mothers with high viral load (median, 8.4; range, 6.5-9.5 log₁₀ copies/ml), were chronically infected. After adjustment for maternal age, birth type, factors related to maternal-fetal hemorrhage, gestational age, infant gender, birth weight, timeliness of vaccination, and feeding practice, maternal viral load was significantly associated with risk of infection (adjusted odds ratio for each log₁₀ copy/ml increase, 3.49; 95% confidence interval (CI), 1.63-7.48; p=0.001). The predictive rates of infection at maternal viral load levels of 7, 8, and 9 log₁₀ copies/ml were 6.6% (95% CI, 0.5-12.6%; p=0.033), 14.6% (95% CI, 5.6-23.6%; p=0.001), and 27.7% (95% CI, 13.1-42.4%; p<0.001), respectively.

CONCLUSIONS

Additional strategies to further reduce transmission should be considered in mothers with a viral load above 7-8 log₁₀ copies/ml.

Effects of maternal screening and universal immunization to prevent mother-to-infant transmission of HBV

BACKGROUND & AIMS

Mother-to-infant transmission is the major cause of hepatitis B virus (HBV) infection among immunized children. There has been much debate about screening pregnant women and administering hepatitis B immunoglobulin (HBIG) to newborns. We analyzed the rate of HBV infection among children born to hepatitis B surface antigen (HBsAg)-positive mothers and whether HBIG administration reduces transmission.

METHODS

We analyzed data from 2356 children born to HBsAg-positive mothers, identified through prenatal maternal screens. In addition to HBV vaccines, HBIG was given to all 583 children with hepatitis B e antigen (HBeAg)-positive mothers and to 723 of 1773 children with HBeAg-negative mothers. Serology tests for HBV were performed from 2007 to 2009, when children were 0.5-10 years old.

RESULTS

A significantly greater percentage of children with HBeAg-positive mothers tested positive for antibodies against the hepatitis B core protein (16.76%) and HBsAg (9.26%) than children with HBeAg-negative mothers (1.58% and 0.29%, respectively; P < .0001 and <.001). Among the HBV-infected children, the rate of chronicity also was higher among children with HBeAg-positive mothers than children with HBeAg-negative mothers (54% vs 17%; P = .002). Similar rates of antibodies against the hepatitis B core protein (0.99% and 1.88%; P = .19) and HBsAg (0.14% and 0.29%; P = .65) were noted in children born to HBeAg-negative mothers who were or were not given HBIG. Infantile fulminant hepatitis developed in 1 of 1050 children who did not receive HBIG (.095%).

CONCLUSIONS

Children born to HBeAg-positive mothers are at greatest risk for chronic HBV infection (9.26%), despite immunization. Administration of HBIG to infants born to HBeAg-negative mothers did not appear to reduce the rate of chronic HBV infection, but might prevent infantile fulminant hepatitis. Screening pregnant women for HBsAg and HBeAg might control mother-to-infant transmission of HBV.

Long-term effect of maternal HBeAg on delayed HBeAg seroconversion in offspring with chronic hepatitis B infection

BACKGROUND AND AIMS

This cohort study investigated the long-term effect of maternal hepatitis B virus (HBV) sero-status on the spontaneous HBeAg seroconversion in offspring with chronic HBV infection.

METHODS

A total of 185 HBeAg-positive chronic HBV-infected children, with maternal HBV seromarkers checked, were enrolled. The median age at enrolment and follow-up duration was 5.7 years (range, neonate to 16.5 years) and 20.2 years (range, 4.2-31.0 years) respectively. These children were grouped according to the initial maternal HBsAg and HBeAg status: (i) children of non-carrier mothers (n=48); (ii) children of HBeAg-negative chronic HBV-infected mothers (n=57); (iii) children of HBeAg-positive chronic HBV-infected mothers (n=80). HBV seromarkers and liver function profiles of these children were performed at 6-month intervals.

RESULTS

One hundred and twenty-one (65.4%) subjects had achieved spontaneous HBeAg seroconversion at the end of this follow-up study. Spontaneous HBeAg seroconversion was achieved in 83.3% of children with non-carrier mothers, 73.7% of children with HBeAg-negative chronic HBV-infected mothers and 48.8% of children with HBeAg-positive mothers during similar duration (P<0.001). Positive maternal HBeAg and genotype C were associated with delayed spontaneous HBeAg seroconversion in multivariate analysis (P=0.01 and P=0.002 respectively). In children of HBeAg-positive chronic HBV-infected mothers, persistent presence of maternal HBeAg showed a trend of association with delayed HBeAg seroconversion in their offspring (P=0.06). Children of late maternal HBeAg seroconversion (>40 years old) had delayed HBeAg seroconversion compared with those of early HBeAg seroconversion mothers (P=0.06).

CONCLUSIONS

Persistence of maternal HBeAg is an important risk factor for delayed spontaneous HBeAg seroconversion in children with chronic HBV infection.

Secular trend of the viral genotype distribution in children with chronic hepatitis B virus infection after universal infant immunization

Genotypes B and C are the major hepatitis B virus (HBV) genotypes in Taiwan, and genotype C is associated with more severe liver disease than genotype B. Whether the implementation of the hepatitis B immunization program has affected the secular trend of the HBV genotype distribution remains unknown. We thus investigated the HBV genotypes in hepatitis B surface antigen (HBsAg)-carrier children born before the implementation of the universal infant immunization program and in those born afterward. One hundred seven children who were infected with HBV despite appropriate immunization were enrolled as immunized cases with HBV breakthrough infection. Each case was matched with two unimmunized HBsAg carriers according to the age at enrollment. HBV genotypes were determined with molecular methods. Compared with unimmunized HBsAg carriers, more immunized children had HBsAg-positive mothers (65.9% versus 100%, P < 0.001) and were infected with genotype C (16.4% versus 42.1%, P < 0.001). Among the children born to HBsAg-positive mothers, the mothers' and children's HBV genotypes were highly concordant in both unimmunized [κ = 0.97, 95% confidence interval (CI) = 0.90-1.00] and immunized children (κ = 0.97, 95% CI = 0.92-1.00). After adjustments for gender, maternal age, and delivery mode, immunized HBsAg-carrier children born to HBsAg-positive mothers had a higher likelihood of genotype C infection than unimmunized children (odds ratio = 3.03, 95% CI = 1.62-5.65, P = 0.001). However, the increased genotype C to genotype B ratio was not seen in the HBsAg-carrier mother pool in the postimmunization era.

CONCLUSION

In the postimmunization era, most HBV breakthrough infections are due to maternal transmission, and immunized children born to genotype C mothers may have a higher rate of breakthrough infection than those born to genotype B mothers.

Fecal elastase 1, serum amylase and lipase levels in children with cholestasis

BACKGROUND/AIM

The pancreatic functions of children with cholestatic liver diseases were unclear. Due to anatomic vicinity and common ontogenic origin, hepatobiliary disorders of infancy may also affect pancreatic function. The aim of the study was to evaluate the exocrine pancreatic function and common pancreatic function tests in children with cholestatic disorders.

METHODS

In 40 children with cholestasis, fecal elastase 1 (FE1) concentrations were measured. Serum amylase and lipase values were tested. The diagnoses included 32 patients with extrahepatic cholestasis (biliary atresia (BA) and choledochal cyst), and 8 patients with intrahepatic cholestasis (progressive familial intrahepatic cholestasis and Alagille syndrome). None had renal insufficiency or clinical symptoms/signs of acute pancreatitis.

RESULTS

All the patients had normal FE1 (>200 microg/g). Nineteen percent (7/37) had elevated serum amylase levels (>100 U/l). Thirty-two percent (12/37) had elevated serum lipase levels above the normal (>120 U/l). Seventy-three percent (8/11) of BA patients with bilirubin >2 mg/dl had elevated serum lipase levels compared to 18% (3/17) with bilirubin < or = 2 mg/dl (p = 0.0036). None had detectable pancreatic abnormality on ultrasonography and magnetic resonance images.

CONCLUSIONS

None of the cholestatic children in this study had exocrine pancreatic insufficiency as detected by FE1. Hyperamylasemia and/or hyperlipasemia were frequently found. In children with BA, those with impaired biliary excretion tended to have elevated serum pancreatic enzymes as compared with those who had no jaundice. A decreased hepatic metabolism may be the cause.

The development of hepatocellular carcinoma among prospectively followed children with chronic hepatitis B virus infection

We prospectively followed 426 children with chronic hepatitis B virus infection. During 6250 person-years, 2 boys developed hepatocellular carcinoma, with an incidence of 32 per 100,000 person-years. Both had e antigen seroconversion in early childhood and cirrhosis. Early e antigen seroconversion and/or cirrhosis may be risk factors for hepatocellular carcinoma.

Correlation of p53 mutations with resistance to platinum-based chemotherapy and shortened survival in ovarian cancer

PURPOSE

The p53 tumor suppressor gene plays a central role in cell cycle regulation and induction of apoptosis. We analyzed p53 alterations and their impact on response to chemotherapy and clinical outcome in ovarian cancer patients.

EXPERIMENTAL DESIGN

One hundred seventy-eight ovarian carcinomas, snap frozen and stored at -80 degrees C, were analyzed for mutations of the p53 gene (exons 2-11) by single-strand conformation polymorphism and DNA sequencing and for p53 overexpression by immunohistochemistry (monoclonal antibody DO7).

RESULTS

p53 mutations were found in 56% (99 of 178) of the tumors, and 62% of these were located in evolutionary highly conserved domains of the gene. Time to progression and overall survival were significantly shortened in patients with p53 mutations compared with wild-type p53 (P = 0.029 and P = 0.014) and patients with mutations in highly conserved domains as opposed to nonconserved domains or wild-type p53 (P = 0.010 and P = 0.007). p53 protein overexpression (>10% positively stained nuclei) was found in 62% (110 of 178). Time to progression and overall survival were shorter in cases with p53 overexpression (cutpoint, 10%: P = 0.071 and P = 0.056) but only marginally significant. Resistance to adjuvant cisplatin or carboplatin chemotherapy was significantly more frequent in patients with p53 overexpression (P = 0.001) or p53 missense mutations (P = 0.008) than patients with normal p53.

CONCLUSIONS

p53 alterations correlate significantly with resistance to platinum-based chemotherapy, early relapse, and shortened overall survival in ovarian cancer patients in univariate analysis. In multivariable analysis though, p53 was not an independent prognostic factor.

Alternative and aberrant messenger RNA splicing of the mdm2 oncogene in invasive breast cancer

mdm2 is part of a complex mechanism that regulates the expression of p53 as well as the function of Rb, p19ARF, and other genes. In humans, mdm2 dysregulation is associated with gene amplification. This study was undertaken to characterize altered mdm2 expression in a cohort of 38 invasive breast cancers and 9 normal breast specimens. Reverse-transcription PCR with primers spanning the entire open reading frame of the mdm2 gene in breast tissue RNA samples generated PCR products of full-length mdm2 (1526 bp) as well as smaller products (653, 281, 254, and 219 bp). Sequence analysis demonstrated that the 653-bp product was an alternatively spliced product (defined as splicing at the exon/intron boundary consensus sites), whereas the 281, 254, and 219 bp mdm2 products were aberrantly spliced products (splicing at sites not considered to be exon/intron boundary sites). Reverse-transcription-PCR with normal breast tissue RNA samples yielded only the 1526-bp product in five samples and the 1526-bp product and the 653-bp product in four samples. The 653-bp alternatively spliced product was expressed in 21% of breast cancers, and the smaller, aberrantly spliced mRNA products (281 bp, 254 bp, and/or 219 bp) were expressed in 16% of breast cancers. The protein products predicted by the alternatively spliced mRNAs and the aberrantly spliced mRNAs lacked either the entire binding domain for p53 or the majority of the binding domain for p53. Immunohistochemical analysis of HER2/neu (c-erbB2), estrogen receptor, progesterone receptor, epidermal growth factor receptor, and p53 protein was performed. p53 sequence alterations were identified by mismatch detection and confirmed by p53 oligonucleotide microarray technology. An association was demonstrated between the expression of aberrantly and/or alternatively spliced mdm2 mRNAs and a lack of progesterone receptor. An association was also demonstrated between mdm2 aberrantly and/or alternatively expression products and the presence of p53 tumor suppressor gene mutations. mdm2 is transcribed from two different promoters: one, p53-dependent, and the other, p53-independent. The 5' untranslated region of the transcripts was evaluated to determine the promoter usage in each breast cancer specimen. No correlation was observed between mdm2 splice products and promoter usage. The presence of aberrant expression products of mdm2 in breast cancer specimens was correlated with a shortened overall patient survival. These observations suggest that mdm2 expression is altered in invasive breast cancer and is associated with more aggressive disease.

Conditioned nutritional deficiencies in the cardiomyopathic hamster heart

BACKGROUND

Evidence indicates that nutritional factors may be important in the maintenance of myocyte structure and energetics. The failing myocardium has been reported to exhibit a depletion of several nutrients that are important for the maintenance of intracellular calcium homeostasis and cellular energetics, and levels of oxidative stress. This nutrient depletion may contribute to the progressive deterioration in myocardial structure and function observed in heart failure.

OBJECTIVE

To examine the extent to which advanced cardiomyopathy results in a depletion of nutrients and/or metabolites and antioxidants, and whether supplementation with these nutrients may influence cellular structure or function.

SUBJECTS AND METHODS

Cardiomyopathic hamsters were randomly placed to one of the three following diet groups: chow; control gelled diet; or a supplemented gelled diet that provided taurine, carnitine, coenzyme Q10, selenium, vitamins E and C, creatine, thiamine and L-cysteine. After approximately three months of supplementation, one group of hamsters underwent functional testing using a modified Langendorff technique with biopsy samples taken for electron microscopy. Myocardial nutrient concentrations were determined in a second group of diseased and nondiseased hamsters of the same age.

RESULTS

Cardiomyopathy resulted in a depletion of vitamin E, creatine, carnitine, taurine and coenzyme Q10. Supplementation resulted in improved cardiac ultrastructure, function and contractility compared with nonsupplemented hamsters.

CONCLUSIONS

These studies suggest that heart failure results in 'condition-related nutrient deficiencies' that, once corrected, can significantly impact on heart function and structure.

Neurocutaneous melanosis with epilepsy: report of one case

Neurocutaneous melanosis is a rare congenital syndrome characterized by the association of large or multiple congenital melanocytic nevi and benign or malignant melanotic tumors in the central nervous system. Patients with neurocutaneous melanosis usually have neurological symptoms early in life that progress rapidly due to the development of increased intracranial pressure or malignant melanoma. We report a 2-month-old female infant with multiple congenital melanocytic nevi and frequent seizure attacks. Magnetic resonance imaging of the brain demonstrated several regions compatible with melanotic deposits. During follow-up for one year, she had normal development and was seizure-free under the treatment of phenobarbital and valproic acid. We suggest that infants with large or multiple congenital melanocytic nevi should receive regular clinical check-up and brain imaging to exclude the possibility of central nervous system lesions.

Effects of estrogen replacement on infarct size, cardiac remodeling, and the endothelin system after myocardial infarction in ovariectomized rats

BACKGROUND

Estrogen may increase the long-term survival of women who have suffered from a myocardial infarction (MI). We examined the acute and chronic influence of estrogen on MI in the rat left coronary artery ligation model.

METHODS AND RESULTS

Female Sprague-Dawley rats (10 to 12 weeks, n=93), divided into 3 groups (rats with intact ovaries, ovariectomized rats administered 17beta-estradiol [17beta-E(2)] replacement, and ovariectomized rats administered placebo 2 weeks before MI), were randomized to left coronary artery ligation (n=66) or sham-operated (n=27) groups. Ten to 11 weeks after MI, rats were randomly assigned to either (1) assessment of left ventricular (LV) function and morphometric analysis or (2) measurement of cardiopulmonary mRNA expression of preproendothelin-1 and endothelin A and B receptors. Acutely, estrogen was associated with a trend toward increased mortality. Infarct size was increased in the 17beta-E(2) group compared with the placebo group (42+/-2% versus 26+/-3%, respectively; P:=0.01). Chronically, wall tension was normalized through a reduction in LV cavity size with estrogen treatment (419+/-41 mm Hg/mm for 17beta-E(2) versus 946+/-300 mm Hg/mm for placebo, P:=0.039). In the LV, there was a 2.5-fold increase in endothelin B mRNA expression after MI in placebo-treated rats (P:=0.004 versus sham-operated rats) that was prevented in the 17beta-E(2) group (P:=NS versus sham-operated rats).

CONCLUSIONS

These results suggest that estrogen is detrimental at the time of MI or early post-MI period, resulting in an increased size of infarct or infarct expansion, but chronically, it can normalize wall tension and inhibit LV dilatation, which may in turn lead to increased long-term survival. Regulation of the endothelin system, particularly the expression of the endothelin B receptor, may contribute to these estrogenic effects.

Comparison of TP53 mutations identified by oligonucleotide microarray and conventional DNA sequence analysis

As the rate of gene discovery accelerates, more efficient methods are needed to analyze genes in human tissues. To assess the efficiency, sensitivity, and specificity of different methods, alterations of TP53 were independently evaluated in 108 ovarian tumors by conventional DNA sequence analysis and oligonucleotide microarray (p53 GeneChip). All mutations identified by oligonucleotide microarray and all disagreements with conventional gel-based DNA sequence analysis were confirmed by re-analysis with manual and automated dideoxy DNA sequencing. A total of 77 ovarian cancers were identified as having TP53 mutations by one of the two approaches, 71 by microarray and 63 by gel-based DNA sequence analysis. The same mutation was identified in 57 ovarian cancers, and the same wild type TP53 sequence was observed in 31 ovarian cancers by both methods, for a concordance rate of 81%. Among the mutation analyses discordant by these methods for TP53 sequence were 14 cases identified as mutated by microarray but not by conventional DNA sequence analysis and 6 cases identified as mutated by conventional DNA sequence analysis but not by microarray. Overall, the oligonucleotide microarray demonstrated a 94% accuracy rate, a 92% sensitivity, and an 100% specificity. Conventional DNA sequence analysis demonstrated an 87% accuracy rate, 82% sensitivity, and a 100% specificity. Patients with TP53 mutations had significantly shorter overall survival than those with no mutation (P = 0.02). Women with mutations in loop2, loop3, or the loop-sheet-helix domain had shorter survival than women with other mutations or women with no mutations (P = 0.01). Although further refinement would be helpful to improve the detection of certain types of TPS3 alterations, oligonucleotide microarrays were shown to be a powerful and effective tool for TP53 mutation detection.

The tyrosine kinase p56lck is essential in coxsackievirus B3-mediated heart disease

Infections are thought to be important in the pathogenesis of many heart diseases. Coxsackievirus B3 (CVB3) has been linked to chronic dilated cardiomyopathy, a common cause of progressive heart disease, heart failure and sudden death. We show here that the sarcoma (Src) family kinase Lck (p56lck) is required for efficient CVB3 replication in T-cell lines and for viral replication and persistence in vivo. Whereas infection of wild-type mice with human pathogenic CVB3 caused acute and very severe myocarditis, meningitis, hepatitis, pancreatitis and dilated cardiomyopathy, mice lacking the p56lck gene were completely protected from CVB3-induced acute pathogenicity and chronic heart disease. These data identify a previously unknown function of Src family kinases and indicate that p56lck is the essential host factor that controls the replication and pathogenicity of CVB3.

Susceptibility to myocarditis is dependent on the response of alphabeta T lymphocytes to coxsackieviral infection

Viral myocarditis is an important cause of heart failure and dilated cardiomyopathy. T lymphocytes are implicated in myocardial damage in murine models of coxsackievirus B3 (CVB3) myocarditis. We used knockout mice lacking CD4 (CD4(-/-)), CD8 (CD8(-/-)), both coreceptors (CD4(-/-)CD8(-/-)), or the T-cell receptor beta chain (TCRbeta(-/-)) to address the contribution of T-cell subpopulations to host susceptibility to CVB3 myocarditis. Severity of disease was magnified in CD8(-/-) mice but attenuated in CD4(-/-) mice, consistent with a pathogenic role for CD4(+) lymphocytes. Elimination of both CD4 and CD8 molecules from T lymphocytes by genetic knockout better protected mice from myocarditis, demonstrating that both CD4(+) and CD8(+) T cells contribute to host susceptibility. The same benefit occurred in TCRbeta(-/-) mice, with prolonged survival and minimal myocardial disease observed after CVB3 infection. Elevated interferon-gamma and decreased tumor necrosis factor-alpha expression are associated with attenuated myocardial damage in CD4(-/-)CD8(-/-) mice. These results show that the presence of TCRalphabeta(+) T cells enhances host susceptibility to myocarditis. The severity of myocardial damage and associated mortality are dependent on the predominant T-cell type available to respond to CVB3 infection. One mechanism by which CD4(+) and CD8(+) T-cell subsets influence the pathogenesis of myocarditis may involve specific cytokine expression patterns.

Cardiac function and cytotoxic aldehyde production in a murine model of chronic iron-overload

OBJECTIVES

To determine the relationship between the total chronic dose of iron administered, ex-vivo cardiac function and the concentrations of cytotoxic aldehydes in heart tissue of a murine model.

METHODS

In the first experiment, 34 male B6D2F1 mice were randomized to receive intraperitoneal injections of 5, 10 or 20 mg of iron dextran for three weeks, or a placebo control. The mice were subsequently randomized to undergo ex-vivo assessment of cardiac function. In the second experiment, free radical generation, quantified by the presence of 20 separate cytotoxic aldehydes, was assessed in heart tissue of 40 mice that were randomized to receive chronic treatment with various concentrations of iron dextran (100 mg to 300 mg total chronic dose administered), placebo treatment with saline, or no treatment at all (baseline).

RESULTS

Iron-loaded groups displayed dose-dependent depressions of heart rate, systolic pressure, developed pressure, coronary pressure, -dP/dt and +dP/dt, and increases in diastolic pressure. Monotonic dose-dependent increases in total heart aldehydes were observed in the iron-treated groups (r-0.97, p < 0.0001), whereas no significant differences were observed between baseline or time-placebo control groups.

CONCLUSIONS

While no single mechanism is likely to account for the complex pathophysiology of iron-induced heart failure, our findings show that chronic iron-loading in a murine model results in dose-dependent alterations to cardiac function; and results in free radical mediated damage to the heart, as measured by excess concentrations of cytotoxic aldehyde-derived peroxidation products. This is the first description of the effects of excess iron on cardiac function assessed by an ex-vivo Langendorff technique in a murine model of chronic iron-overload.

Tissue expression and immunolocalization of tumor necrosis factor-alpha in postinfarction dysfunctional myocardium

BACKGROUND

Tumor necrosis factor-alpha (TNF-alpha) is markedly elevated in advanced heart failure. It is not known whether tissue TNF-alpha is elevated in the common setting of myocardial infarction leading to heart failure and what the source of TNF-alpha is. To determine this, we studied the expression and protein localization of TNF-alpha and its 2 main receptors (TNF-R1/R2) in a rat model of large infarction.

METHODS AND RESULTS

Male rats were randomized to proximal left anterior descending ligation. The animals were killed on days 1, 3, 10, and 35 after ligation to examine gene expression and protein production of TNF-alpha and TNF-R1/R2 from the infarct, peri-infarct, and contralateral zones of infarcted heart. There was increased TNF-alpha mRNA production throughout the myocardium at day 1, and detectable expression persisted to day 35 after myocardial infarction. The expression of this cytokine is not confined strictly to the infarct or peri-infarct zones but is expressed by cardiac myocytes within the myocardium in the contralateral normal zone. Changes in gene expression are mirrored initially by augmented protein production within the myocytes. Levels of TNF-alpha protein in the infarct and peri-infarct zones rose early to 8- to 10-fold above normal levels and rose to 4- to 5-fold in the contralateral zone. Finally, expression of the TNF-R1 mRNA transcripts was upregulated at days 3 and 10 after ligation in the infarct and peri-infarct zones, suggesting that the signal transduction pathways necessary for TNF-alpha in the heart remain intact as TNF-alpha biosynthesis increases.

CONCLUSIONS

TNF-alpha is present early in a model of large myocardial infarction and is sustained into the later stage within the myocardium. Expression of this cytokine is not only confined strictly to the infarct or peri-infarct zone but is expressed by cardiac myocytes within the myocardium contralateral to the infarct. Therefore TNF-alpha production forms a part of an important intrinsic myocardial stress response system to injury.

p53 mutations and expression in ovarian cancers: correlation with overall survival

The p53 gene is altered in approximately 50% of all human malignancies. p53 overexpression, identified by immunohistochemistry, and p53 mutations, identified by single-strand conformational polymorphism (SSCP) and DNA sequencing, have been described in ovarian cancers. p53 overexpression has been correlated with poor outcome for women with ovarian cancer in some studies. With only limited data, the assumption has been made that p53 overexpression corresponds to p53 mutations. The purpose of this investigation was to assess p53 alterations in ovarian cancer to determine if p53 overexpression corresponds with mutations in the p53 gene, and to assess whether either predicts clinical outcome in ovarian carcinoma. Frozen ovarian carcinoma tumor specimens from 105 patients were analyzed by immunohistochemical staining for p53 expression. SSCP was used to screen for mutations and DNA sequencing was used to confirm the specific mutation in exons 2 to 11, encompassing the entire p53 open reading frame. Those ovarian carcinomas identified as wild-type p53 by SSCP were subjected to automated DNA sequence analysis of the entire open reading frame. Relative to DNA sequence analysis, the sensitivity of SSCP was 85% and the specificity was 98%. Immunohistochemical staining demonstrated that 72 of the 105 (69%) cases had positive immunostaining. SSCP and DNA sequencing identified and confirmed mutations in 60 of the 105 carcinomas (57%). Although there was a statistically significant association between p53 immunostaining and p53 mutations (p = 0.0002), false-negative and -positive results were identified. Tumor grade (p = 0.03), stage (p = 0.08), and overall survival (p = 0.15) were moderately associated with positive p53 immunostaining. Patients with p53 mutations and overexpression had shorter overall patient survival (p = 0.02). The findings demonstrated that, individually, p53 mutations and p53 overexpression were each related to shorter patient survival, but the strongest predictor of outcome was a combination of both mutations and overexpression. Comparisons of overall survival for women with mutations in loop 2, loop 3, and the loop-sheet-helix domains together showed a statistically significant difference in survival compared to survival of women whose ovarian cancers had other mutations (p = 0.046).

A serine elastase inhibitor reduces inflammation and fibrosis and preserves cardiac function after experimentally-induced murine myocarditis

In viral myocarditis, inflammation and destruction of cardiac myocytes leads to fibrosis, causing progressive impairment in cardiac function. Here we show the etiologic importance of serine elastase activity in the pathophysiology of acute viral myocarditis and the therapeutic efficacy of an elastase inhibitor. In DBA/2 mice inoculated with the encephalomyocarditis virus, a more than 150% increase in myocardial serine elastase activity is observed. This is suppressed by a selective serine elastase inhibitor, ZD0892, which is biologically effective after oral administration. Mice treated with this compound had little evidence of microvascular constriction and obstruction associated with myocarditis-induced ischemia reperfusion injury, much less inflammation and necrosis, only mild fibrosis and myocardial collagen deposition, and normal ventricular function, compared with the infected nontreated group.

Chronic endothelin-1 blockade preserves myocardial contractility in dilated cardiomyopathy

Endothelin-1 (ET-1) is known to have positive inotropic effects in isolated cardiac muscle strips. ET-1 levels are elevated in congestive heart failure (CHF). We investigated the effects of ET-1 on contractility and cardiac relaxation (lusitropy) of the intact healthy murine heart and myocarditic/cardiomyopathic heart by chronic oral treatment with a mixed ETA/ETB blocker SB217242. Chronic ET-1 blockade of normal hearts resulted in depression of contractility and lusitropy of the normal heart but preservation and enhancement of contractility and lusitropy in myocarditic animals, in which ET-1 cardiac content is elevated. This suggests that ET-1 is important in the basal contractility and relaxation of the normal heart but that its chronic elevation in CHF causes impairment of cardiac systolic and diastolic performance.

Genomic semi-automated cycle sequencing as a sensitive screening technique for p53 mutations in frozen tumor samples

Single-strand conformational polymorphism (SSCP) is the most widely used method for p53 gene mutation screening. Nucleotide sequence analysis is considered more sensitive for detection of mutations. We established a genomic semi-automated cycle sequencing protocol suitable for p53 gene mutation screening. The technique was applied to 44 SSCP-negative frozen ovarian cancer samples: Eleven mutations (11/44, 25%) were found, 6 point missense mutations, 3 silent point mutations, 1 nonsense mutation and 1 single-base deletion. Heterozygous mutations were readily detectable. Genomic semi-automated cycle sequencing is a sensitive, time-effective screening method requiring only small amounts of tumor tissue.

WAF1/Cip1 gene polymorphism and expression in carcinomas of the breast, ovary, and endometrium

The p53 gene is altered in approximately 50% of human cancers and is considered to be important in the pathogenesis of these malignancies. The p53 protein product regulates the transition from G1 to S phase of the cell cycle and entry to the DNA damage repair pathway. As alterations in this pathway appear to be important in a variety of human cancers, downstream effector proteins of p53 are potential sites for somatic alterations. WAF1/Cip1, also known as WAF1, Cip1, sdi1, or CAP20, codes for a 21-kd protein (p21WAF1/Cip1), which was recently described as a universal inhibitor of cyclins and is thus critical in cell cycle control. Mutations in WAF1/Cip1 are potentially important in human malignancies because they could affect the control of the cell cycle. To understand whether mutations of WAF1/Cip1 occur in cancer, we screened 53 cases of invasive breast carcinoma, 35 cases of ductal carcinoma in situ (DCIS), 53 ovarian carcinomas, and 47 endometrial carcinomas in the second exon of WAF1/Cip1 (90% of the open reading frame). p21WAF1/Cip1 expression was characterized with immunohistochemistry. Cells from the blood of 21 normal individuals were also characterized using single-strand conformational polymorphism analysis, DNA sequencing and restriction analysis. Single-strand conformational polymorphism analysis demonstrated an altered mobility pattern for exon 2 in 12 invasive breast cancers (22.6%), 5 DCIS of the breast (14%), 8 invasive ovarian carcinomas (15%), and 9 endometrial carcinomas (19%). In total, 209 samples were screened, and 38 cases (18.2%) had an altered codon 31. Each case with altered single-strand conformational polymorphism, analyzed by DNA sequencing and/or restriction analysis, showed the same alteration of codon 31, a C to A transversion encoding a change in amino acid sequence from serine to arginine (31Ser-->31Arg). DNA from the blood of 21 normal individuals showed the same alteration in WAF1/Cip1 in 4 cases (19%). Furthermore, paired normal tissue was available for 3 of 20 breast carcinomas with the Ser31Arg transversion. Normal DNA from all 3 cases showed the same 31Arg alteration as found in the tumor tissue. These results indicate that codon 31 is a polymorphic site and that the serine to arginine shift is a polymorphism. p21WAF1/Cip1 expression, identified by immunohistochemistry, was found to vary in a pattern that depended both on the tissue type and on the presence or absence of the codon 31 polymorphism. Using pair-wise comparisons in breast DCIS, we found higher protein expression in tumor nuclei as compared with benign stromal cell nuclei (P = 0.002) or normal ductal epithelium (P = 0.005). Invasive breast cancer specimens showed a trend in p21WAF1/Cip1 immunostaining similar to DCIS but did not reach statistical significance (P = 0.12). However, when cases with extensive desmoplastic reaction were excluded, a statistically significant association (P = 0.019) similar to that in DCIS was noted. In contrast to the breast tumors, ovarian carcinomas exhibited significantly greater p21WAF1/Cip1 expression in the benign stromal (fibroblast) nuclei surrounding the tumor than in the carcinoma cell nuclei (P = 0.016). Endometrial carcinoma revealed no difference in staining when comparing benign tissue with carcinoma (P = 0.99); however, unlike breast and ovarian carcinomas in which there was no correlation between p21WAF1/Cip1 expression and the presence or absence of the alteration at the 31st codon, endometrial carcinomas showed an increased percentage of immunopositive nuclei associated (P = 0.056) with 31Arg. These results demonstrate tissue-specific expression patterns of WAF1/Cip1 in different tumors which appears to be characteristic of the tumor type.

Favorable left ventricular remodeling following large myocardial infarction by exercise training. Effect on ventricular morphology and gene expression

Continued adverse remodeling of myocardium after infarction may lead to progressive ventricular dilation and heart failure. We tested the hypothesis that exercise training in a healed myocardial infarction-dysfunction rat model can favorably modify the adverse effects of ventricular remodeling including attenuation of abnormal myosin gene expression. Sprague-Dawley rats were subjected to either proximal LAD ligation or sham operation. At 5 wk after the operation, animals were randomly assigned to sedentary conditions or 6 wk of graduated swim training, creating four experimental groups: infarct sedentary (IS), infarct exercise (IE), sham sedentary (SS), and sham exercise (SE). At 11 wk all rats were sacrificed and analyzed. Compared to sedentary infarct controls, exercise training attenuated left ventricular (LV) dilation and allowed more hypertrophy of the non infarct wall. The exercise-trained hearts also showed a reduction in the estimated peak wall tension. Northern blot analysis showed an increase in beta-myosin heavy chain expression in the hearts of the sedentary infarction group soon after infarction when compared to sham controls. However, with exercise training, there was a significant attenuation of the beta-myosin heavy chain expression in the myocardium. Exercise training in a model of left ventricular dysfunction after healed myocardial infarction can improve the adverse remodeling process by attenuating ventricular dilation and reducing wall tension. The abnormal beta-myosin expression was also attenuated in the exercise trained group. This is evidence that abnormal gene expression following severe myocardial infarction dysfunction can be favorably modified by an intervention.

Effects of oxygen free radicals and scavengers on the cardiac extracellular collagen matrix during ischemia-reperfusion

OBJECTIVE

Collagen is lysed early during ischemia-reperfusion, but whether this is due to ischemia or reperfusion injury is not known. The effect of oxygen free radicals and free radical scavengers on left ventricular hemodynamics, myocardial morphology and collagen content were studied in an isolated, Langendorff-perfused rat heart model of regional ischemia-reperfusion.

METHODS

All hearts received left anterior descending coronary artery ischemia for 20 mins. Group 1 had ischemia only; group 2 had ischemia followed by reperfusion with oxygenated Krebs-Henseleit buffer for 20 mins; group 3 had oxygen free radicals generated by hypoxanthine and xanthine oxidase during reperfusion; group 4 had free radical scavengers with superoxide dismutase plus catalase; group 5 had both oxygen free radicals and free radical scavengers during reperfusion.

RESULTS

Left ventricular developed pressure decreased significantly in group 3 during ischemia followed by reperfusion (58 +/- 3.1 mmHg versus 42 +/- 2.4 mmHg, P = 0.004), but did not change significantly in any of the other groups. Necrosis score on pathology was highest in group 3; this score also was higher than that in group 5 with free radical scavengers added (3.0 +/- 0.3 versus 2.0 +/- 0.4, P = 0.07) and higher than that of group 2 with reperfusion with buffer only (3.0 +/- 0.3 versus 1.4 +/- 0.5, P < 0.05). Collagen content decreased significantly compared with control in group 3 only with ischemia followed by reperfusion with the addition of oxygen free radicals (18.4 +/- 1.5 versus 11.9 +/- 1.7 g/mg protein, P < 0.05). The addition of free radical scavengers in group 5 mainly attenuated the collagen loss. Scanning electron microscopy revealed profound structural changes of the extracellular collagen matrix in numerous regions of 'stunning' independent of tissue necrosis.

CONCLUSIONS

We conclude that: first, oxygen free radicals trigger significant collagen damage and left ventricular dysfunction during reperfusion; second, these changes extend beyond the ischemic damage alone; and third, free radical scavengers can effectively limit oxygen free radical-induced collagen loss and left ventricular dysfunction.

Alterations in fatty acid metabolism in adriamycin cardiomyopathy

Myocardial fatty acid metabolism may be impaired in adriamycin cardiomyopathy. In order to determine the extent of fatty acid metabolism alterations, we measured steady state [14C]palmitate oxidation and the incorporation of [14C]palmitate into the neutral lipid pool in a rat model of adriamycin cardiomyopathy. Isolated hearts from control rats and rats treated with adriamycin were perfused with 1.2 mmol/l of [14C]palmitate for 30 min to achieve steady state oxidation measured as [14C]O2 production; then perfused with 1.2 nmol/l of unlabelled palmitate. Hearts were killed early (0-5 min) or late (10-30 min) after the [14C]palmitate perfusion, to determine incorporation into the neutral lipid pool, and neutral lipid utilization. In the control group steady state oxidation was reached in 10 min ([14C]O2 production = 580 +/- 61 nmol/min/g dry wt) of perfusion. In the adriamycin treated group, mean CO2 production was significantly reduced at 10 min (329 +/- 44 nmol/min/g dry wt, P < 0.01 v control). At 30 min, [14C]O2 production in the treated group was not significantly different than controls (521 +/- 65 nmol/min/g dry wt v 617 +/- 36 nmol/min/g dry wt, P = N.S.). The incorporation of [14C]palmitate into the neutral lipid pool measured in the early subgroup was significantly reduced for adriamycin treated hearts v controls (7.2 +/- 0.6 v 12.0 +/- 1.4 mumol/g dry wt respectively, P < 0.01). In the control group 14C labelled neutral lipid reduced with time to 8.4 +/- 1.1 mumol/g dry wt (P < 0.05) in the late group. The adriamycin group demonstrated no significant change between early and late measurements. In conclusion, in adriamycin cardiomyopathy: (1) there is significant delay in achieving steady state palmitate oxidation, although the steady state rate is near normal; (2) palmitate incorporation into the neutral lipid pool is reduced; (3) neutral lipid pool utilization may also be reduced. These data suggest impaired uptake of palmitate into the cell in adriamycin cardiomyopathy, with a relatively maintained capacity for oxidative metabolism.

Are the kinetics of technetium-99m methoxyisobutyl isonitrile affected by cell metabolism and viability?

To investigate the role of cell viability and metabolism on the myocardial kinetics of a new tracer, technetium-99m-methoxyisobutyl isonitrile (Tc-99m-MIBI), 250 microCi/l Tc-99m-MIBI was infused in isolated rat hearts under constant flow conditions. The hearts were studied after inducing irreversible damage by cytochrome c oxidase inhibitor sodium cyanide (n = 8) or sarcolemmal membrane detergent Triton X-100 (n = 8). The control hearts (n = 6) received no toxins. Mean Tc-99m-MIBI peak accumulation activity was significantly reduced after cyanide (51.1 +/- 44.2% of control, p less than 0.01) and Triton (13.8 +/- 2.7% of control, p less than 0.001) administration. Kinetic studies also showed marked reduction in accumulation rates and marked increase in clearance rates for cyanide (p less than 0.01) and Triton (p less than 0.01) groups compared with controls. Potential changes in regional flow distribution were assessed using microspheres. When peak accumulation activity was corrected for these changes, there remained significant differences between the groups. In the cyanide and Triton groups, irreversible cell injury was confirmed by creatine kinase and lactate dehydrogenase release, triphenyl tetrazolium chloride staining, and electron microscopy. All the cells were viable in the control group. We conclude that the accumulation and clearance kinetics of Tc-99m-MIBI are significantly affected by cell viability. Tc-99m-MIBI kinetics appear to be dependent on sarcolemmal integrity and to a lesser extent on aerobic metabolism.

The effect of essential fatty acid deficiency on the stimulation of intestinal calcium transport by 1,25-dihydroxyvitamin D3

The effect of altering the lipid composition of the brush-border membrane on the ability of 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) to stimulate calcium transport across the intestinal mucosa was examined by raising chicks on a vitamin D, essential fatty acid-deficient diet (-DEFAD) and measuring calcium absorption from duodenal sacs in situ and calcium uptake into brush-border membrane vesicles in vitro. Administration of 1,25-(OH)2D3 to -DEFAD and to -D control chicks led to the same increase in calcium transport in situ, whereas calcium transport in isolated brush-border membrane vesicles was not stimulated in the EFAD group, but responded normally in the control group. When the incubation temperature was increased to 34 degrees C, brush-border membrane vesicles from 1,25-(OH)2D3-treated essential fatty acid-deficient (+DE-FAD) chicks accumulated calcium at a faster rate than did vesicles from -DEFAD chicks. There was a marked decrease in the linoleic acid content and an increase in the oleic acid content of both the total lipid extract of the brush-border membrane as well as the phosphatidylcholine and phosphatidylethanolamine fractions, which could explain the temperature sensitivity of the in vitro system. When the diet of the EFAD chicks was supplemented with linoleic acid, the rate of calcium uptake into subsequently isolated vesicles from +DE-FAD chicks correlated with the amount of linoleic acid in the brush-border membranes. These results support the concept that the action of 1,25-(OH)2D3 on membrane lipid turnover and structure plays a critically important role in the 1,25-(OH)2D3-mediated cellular transport responses.