Linda Morgan

Randomized, Placebo-Controlled Trial of Pioglitazone in Nondiabetic Subjects With Nonalcoholic Steatohepatitis

BACKGROUND & AIMS Nonalcoholic steatohepatitis (NASH) is a leading cause of chronic liver disease for which there is limited therapy available. Insulin sensitizing, anti-inflammatory, and antifibrotic properties of thiazolidinediones support their use in treating NASH. We have evaluated pioglitazone in the treatment of nondiabetic patients with NASH. METHODS We randomized 74 nondiabetic patients (45 men; median age, 54 y) with histologically proven NASH to 12 months of standard diet, exercise, and either placebo or pioglitazone (30 mg/day). Sixty-one patients (30 placebo, 31 pioglitazone) had liver biopsies both at the beginning and the end of the study. RESULTS Compared with placebo, pioglitazone therapy was associated with an increase in weight (mean change, -0.55 vs +2.77 kg; P = .04) and a reduction in glucose (+0.4 vs -0.1 mmol/L; P = .02), HbA1c (+0.16% vs -0.18%; P = .006), insulin C peptide level (+42 vs -78 pmol/L; P = .02), alanine aminotransferase level (-10.9 vs -36.2 u/L; P = .009), gamma-glutamyltransferase level (-9.4 vs -41.2 u/L; P = .002), and ferritin (-11.3 vs -90.5 microg/L; P = .01). Histologic features including hepatocellular injury (P = .005), Mallory-Denk bodies (P = .004), and fibrosis (P = .05) were reduced in patients treated with pioglitazone compared with those in the placebo group. CONCLUSIONS Pioglitazone therapy over a 12-month period in nondiabetic subjects with NASH resulted in improvements in metabolic and histologic parameters, most notably liver injury and fibrosis. Larger extended trials are justified to assess the long-term efficacy of pioglitazone in this patient group.

Maternal activating KIRs protect against human reproductive failure mediated by fetal HLA-C2

Many common disorders of pregnancy are attributed to insufficient invasion of the uterine lining by trophoblast, fetal cells that are the major cell type of the placenta. Interactions between fetal trophoblast and maternal uterine NK (uNK) cells--specifically interactions between HLA-C molecules expressed by the fetal trophoblast cells and killer Ig-like receptors (KIRs) on the maternal uNK cells--influence placentation in human pregnancy. Consistent with this, pregnancies are at increased risk of preeclampsia in mothers homozygous for KIR haplotype A (KIR AA). In this study, we have demonstrated that trophoblast expresses both paternally and maternally inherited HLA-C surface proteins and that maternal KIR AA frequencies are increased in affected pregnancies only when the fetus has more group 2 HLA-C genes (C2) than the mother. These data raise the possibility that there is a deleterious allogeneic effect stemming from paternal C2. We found that this effect also occurred in other pregnancy disorders (fetal growth restriction and recurrent miscarriage), indicating a role early in gestation for these receptor/ligand pairs in the pathogenesis of reproductive failure. Notably, pregnancy disorders were less frequent in mothers that possessed the telomeric end of the KIR B haplotype, which contains activating KIR2DS1. In addition, uNK cells expressed KIR2DS1, which bound specifically to C2+ trophoblast cells. These findings highlight the complexity and central importance of specific combinations of activating KIR and HLA-C in maternal-fetal immune interactions that determine reproductive success.

Searching for genetic clues to the causes of pre-eclampsia

Pre-eclampsia and its related syndromes are significant causes of maternal and fetal death, but much remains unclear about the underlying disease mechanisms. Epidemiological research has consistently demonstrated a familial predisposition to pre-eclampsia, which has encouraged genetic research in this area. The goal is the discovery of susceptibility genes which will inform understanding of the pathophysiology of pre-eclampsia, and may prove to be targets for therapeutic or preventative strategies. This review examines the application of molecular technologies to the search for genetic clues in pre-eclampsia and emphasizes the importance of integrative approaches. The results of recent genome-wide linkage studies have been particularly encouraging, identifying a number of loci which merit closer examination. Candidate gene studies have proved less fruitful, generating conflicting and inconclusive results. Possible explanations and remedies for this deficiency are discussed with a view to stimulating closer collaboration between researchers in this field.

Pre‐eclampsia and the angiotensinogen gene

It is widely recognised that pre-eclampsia, one of the commonest and most serious complications of pregnancy, has an inherited component. Alterations in the reninangiotensin system in pregnancy suggest that genes encoding components of this system may be implicated. Recently, this suggestion has received support from genetic studies. In one study of affected siblings, there was distortion of allele sharing at a highly polymorphic dinucleotide repeat region close to the angiotensinogen gene (Arngrimsson et al. 1993). Another study demonstrated an association between an angiotensinogen gene variant and the disease (Ward et al. 1993). The second exon of the angiotensinogen gene, located on chromosome 1, encodes the signal peptide and the first 252 amino acids of the protein. Near the 3’ end of exon 2, a single base mutation (T-C) results in the substitution of threonine for methionine at amino acid 235. An association between the T235 variant and pre-eclampsia was described by Ward et al. (1993) in Caucasian women from Utah in the United States and in Japanese women. In these women possession of the T235 allele was also associated with higher plasma angiotensinogen concentrations. In our population, the frequency of the T235 allele among 137 healthy nonpregnant women (0.41) was found to correspond closely to that previously reported for a Caucasian population (Jeunemaitre et al. 1992). In this preliminary study we have now determined the frequency with which the T235 allele was found in 30 nulliparous pregnant Caucasian women in whom plasma angiotensinogen concentrations were also measured. Fifteen women were normotensive throughout pregnancy and the puerperium (median blood pressure 115/70 mmHg). Fifteen women developed pre-eclampsia according to strict criteria (median blood pressure 143/95 mmHg; minimum proteinuria 0.3 g/l). All women had been normotensive before

Angiotensin-converting enzyme insertion-deletion polymorphism in normotensive and pre-eclamptic pregnancies

OBJECTIVE To investigate the hypothesis that pre-eclampsia is associated with a common insertion-deletion polymorphism in the angiotensin-converting enzyme gene. DESIGN Seventy-two women with pre-eclampsia and 83 normotensive pregnant women participated in the study. Pre-eclampsia was defined as a blood pressure exceeding 140/90 mm Hg in a previously normotensive woman, associated with proteinuria in excess of 300 mg/l in a 24 h collection. Samples for fetal genotyping were available from 66 pregnancies complicated by pre-eclampsia and 79 normotensive pregnancies. METHODS Maternal and fetal samples were genotyped at the insertion-deletion (I-D) polymorphism in intron 16 of the angiotensin-converting enzyme gene by the polymerase chain reaction followed by agarose electrophoresis. RESULTS Neither the I-D genotype distributions nor the allele frequencies differed significantly between pre-eclamptic and normotensive pregnancies in maternal or fetal samples (phi2 <0.3, not significant). The odds ratio for pre-eclampsia in women with the DD genotype, compared with the ID and II genotype, was 1.09 (95% confidence interval 0.55-2.16). The odds ratio associated with the DD genotype in the fetus was 1.14 (0.56-2.32). CONCLUSION This study has found no evidence that the insertion-deletion polymorphism in the angiotensin-converting enzyme gene is associated with pre-eclampsia.

Maternal and fetal angiotensinogen gene allele sharing in pre-eclampsia

Objective To compare the angiotensinogen genotypes in normotensive and pre‐eclamptic pregnancies in maternal and fetal samples.

Functional and genetic studies of the angiotensin II type 1 receptor in pre-eclamptic and normotensive pregnant women

Objective To examine and compare angiotensin II type 1 receptor genotype and its relationship to platelet angiotensin II binding for pre-eclamptic and normotensive pregnant women. Design In a case‐control study, 43 pre-eclamptic women and 83 normotensive women were genotyped at the angiotensin II type 1 receptor gene locus. Platelet angiotensin II binding was measured for a subset of 11 pre-eclamptic and 57 normotensive pregnant women. We genotyped 162 healthy blood donors also, to examine the allelic background and patterns of linkage disequilibrium in the Nottingham population. Methods Patients were recruited during pregnancy using a rigorous definition of pre-eclampsia. DNA was extracted from peripheral venous blood and genotyped at six previously described diallelic polymorphisms in the angiotensin II type 1 receptor gene, using competitive allele-specific oligonucleotide hybridization, and at a dinucleotide repeat polymorphism in the 3′ flanking region of the gene. Platelet angiotensin II binding and plasma angiotensin II concentrations were determined for peripheral venous blood. Results Normotensive pregnant women homozygous for cytosine at nucleotide 573 had significantly higher levels of platelet angiotensin II binding than did heterozygous women and women homozygous for thymidine at this site. Pre-eclamptic women had significantly higher levels of platelet angiotensin II binding than did normotensive pregnant women. The frequencies of allelic variants did not differ significantly between normotensive and pre-eclamptic women. Conclusion The physiological regulation of platelet angiotensin II type 1 receptor expression in normal pregnancy is determined in part by angiotensin II type 1 receptor genotype. There was no evidence that the polymorphisms in the angiotensin II type 1 receptor gene were associated with pre-eclampsia.

DNA polymorphisms and linkage disequilibrium in the angiotensinogen gene

A number of recent studies have implicated the angiotensinogen gene in the aetiology of essential hypertension in Caucasian, Japanese and African Caribbean subjects. We have genotyped 153 healthy white Caucasian subjects at a dinucleotide repeat polymorphism and seven diallelic sites in the coding or flanking regions of the angiotensinogen gene, including one polymorphism not previously studied. We have also documented patterns of linkage disequilibrium between polymorphisms. There is evidence of variation in the frequency of several mutations when compared with published results from other Caucasian control populations, possibly due to cryptic ethnic differences between these groups. This should be considered in the design and interpretation of studies of the angiotensinogen gene.

Variants in the fetal genome near FLT1 are associated with risk of preeclampsia

Preeclampsia, which affects approximately 5% of pregnancies, is a leading cause of maternal and perinatal death. The causes of preeclampsia remain unclear, but there is evidence for inherited susceptibility. Genome-wide association studies (GWAS) have not identified maternal sequence variants of genome-wide significance that replicate in independent data sets. We report the first GWAS of offspring from preeclamptic pregnancies and discovery of the first genome-wide significant susceptibility locus (rs4769613; P = 5.4 × 10−11) in 4,380 cases and 310,238 controls. This locus is near the FLT1 gene encoding Fms-like tyrosine kinase 1, providing biological support, as a placental isoform of this protein (sFlt-1) is implicated in the pathology of preeclampsia. The association was strongest in offspring from pregnancies in which preeclampsia developed during late gestation and offspring birth weights exceeded the tenth centile. An additional nearby variant, rs12050029, associated with preeclampsia independently of rs4769613. The newly discovered locus may enhance understanding of the pathophysiology of preeclampsia and its subtypes.

The role of genetics in pre-eclampsia and potential pharmacogenomic interventions

The pregnancy-specific condition pre-eclampsia not only affects the health of mother and baby during pregnancy but also has long-term consequences, increasing the chances of cardiovascular disease in later life. It is accepted that pre-eclampsia has a placental origin, but the pathogenic mechanisms leading to the systemic endothelial dysfunction characteristic of the disorder remain to be determined. In this review we discuss some key factors regarded as important in the development of pre-eclampsia, including immune maladaptation, inadequate placentation, oxidative stress, and thrombosis. Genetic factors influence all of these proposed pathophysiological mechanisms. The inherited nature of pre-eclampsia has been known for many years, and extensive genetic studies have been undertaken in this area. Genetic research offers an attractive strategy for studying the pathogenesis of pre-eclampsia as it avoids the ethical and practical difficulties of conducting basic science research during the preclinical phase of pre-eclampsia when the underlying pathological changes occur. Although pharmacogenomic studies have not yet been conducted in pre-eclampsia, a number of studies investigating treatment for essential hypertension are of relevance to therapies used in pre-eclampsia. The pharmacogenomics of antiplatelet agents, alpha and beta blockers, calcium channel blockers, and magnesium sulfate are discussed in relation to the treatment and prevention of pre-eclampsia. Pharmacogenomics offers the prospect of individualized patient treatment, ensuring swift introduction of optimal treatment whilst minimizing the use of inappropriate or ineffective drugs, thereby reducing the risk of harmful effects to both mother and baby.