Pregnancy and its management in women with GSD type III - a single centre experience

We present a review of our experience and pregnancy outcome in patients with GSD III managed by our centre. Between 1997 and 2010 there were 15 pregnancies in seven women with GSD III. Four women had GSD IIIb (nine pregnancies) and three GSD IIIa (six pregnancies). There was a successful outcome in all 15 pregnancies with delivery of 15 liveborn infants. Four infants were of low birthweight (<2nd centile) but all have developed normally apart from one with behavioural/psychiatric problems. Three women had pre-existing cardiomyopathy prior to pregnancy. One of these women had deterioration of her cardiomyopathy during pregnancy and again in the post-partum period. Women with GSD III do not seem to have any issues with fertility. Overall the outcome of pregnancy for both mother and child is good. Care needs to be taken to avoid maternal hypoglycemia which may be associated with intrauterine growth restriction and low birth weight. Cardiac function should be monitored carefully particularly in those with pre-existing cardiomyopathy.     

Inflammatory stimuli up-regulate transient receptor potential vanilloid-1 expression in human bronchial fibroblasts

Lung fibroblasts are involved in interstitial lung disease, chronic asthma, and chronic obstructive pulmonary disease (COPD). The expanded fibroblast population in airway disease leads to airway remodeling and contributes to the inflammatory process seen in these diseases. The cation channel transient receptor potential vanilloid-1 (TRPV1) is activated by noxious stimuli, including capsaicin, protons, and high temperatures and is thought to have a role in inflammation. Although TRPV1 expression is primarily reported to be neuronal, some extraneuronal expression has been reported. The authors therefore sought to determine whether human primary bronchial fibroblasts (HPBFs) express TRPV1 and whether inflammatory mediators can induce TRPV1 expression. The authors show that fibroblasts are predominantly TRPV1 negative; however, following stimulation with 3 common inflammatory mediators, tumor necrosis factor α (TNF-α), lipopolysaccharide (LPS), and interleukin-1α (IL-1α), TRPV1 mRNA was observed at 24 and 48 hours post treatment with all 3 mediators. Using Western blotting an increase in TRPV1 expression with all 3 inflammatory mediators was detected with significant increases seen at 72 hours post LPS and IL-1α treatment. In stark contrast to the untreated fibroblasts, significant calcium signaling in response to capsaicin and resiniferatoxin in HPBFs treated for 24 and 48 hours with TNF-α, LPS, or IL-1α was also observed. These results indicate that TRPV1 can be expressed on bronchial fibroblasts in situations where an underlying inflammatory stimulus exists, as is the case in airway diseases such as asthma and COPD.     

Population pharmacokinetics of cyclophosphamide in patients with thalassemia major undergoing HSCT

CY in combination with BU is a widely used conditioning regimen for haematopoietic SCT (HSCT). The aim of this study was to evaluate the pharmacokinetics (PK) of CY and its major metabolite 4-hydroxyCY (HCY) in patients with thalassemia undergoing HSCT. A total of 55 patients received BU (16 mg/kg) followed by CY (160-200 mg/kg) both over 4 days before HSCT. A population PK model was developed to describe the disposition of CY and HCY and the inter-individual (IIV) and inter-occasion variability (IOV). The model was also used to determine the effects covariates including: demographics, Lucarelli classification and polymorphisms in enzymes involved in the metabolism or biotransformation of CY had on CY and HCY disposition. Overall, 17-114% IIV and 12-103% IOV in CY and HCY PK parameters were observed. Body weight and age were the main covariates, which explained the largest portion of the IIV. In addition, CYP2C9*2 explained a significant portion of the IIV in the clearance (P<0.002) and thus the area under the concentration curve (P<0.05) of CY. This covariate model may be used to design and plan targeted dose therapy in this group of pediatric patients, if clinical outcome association with CY PK are proved and target range established.     

Metabolite Profiles During Oral Glucose Challenge

To identify distinct biological pathways of glucose metabolism, we conducted a systematic evaluation of biochemical changes after an oral glucose tolerance test (OGTT) in a community-based population. Metabolic profiling was performed on 377 nondiabetic Framingham Offspring cohort participants (mean age 57 years, 42% women, BMI 30 kg/m²) before and after OGTT. Changes in metabolite levels were evaluated with paired Student t tests, cluster-based analyses, and multivariable linear regression to examine differences associated with insulin resistance. Of 110 metabolites tested, 91 significantly changed with OGTT (P ≤ 0.0005 for all). Amino acids, β-hydroxybutyrate, and tricarboxylic acid cycle intermediates decreased after OGTT, and glycolysis products increased, consistent with physiological insulin actions. Other pathways affected by OGTT included decreases in serotonin derivatives, urea cycle metabolites, and B vitamins. We also observed an increase in conjugated, and a decrease in unconjugated, bile acids. Changes in β-hydroxybutyrate, isoleucine, lactate, and pyridoxate were blunted in those with insulin resistance. Our findings demonstrate changes in 91 metabolites representing distinct biological pathways that are perturbed in response to an OGTT. We also identify metabolite responses that distinguish individuals with and without insulin resistance. These findings suggest that unique metabolic phenotypes can be unmasked by OGTT in the prediabetic state.Diabetes affects >1 in 10 adults 20 years of age or older in the U.S., and more than one-third of all adults have prediabetes (1). Changes in traditional measures of glucose and insulin metabolism are known to occur years before the diagnosis of diabetes is made (2). Using high-throughput profiling of metabolic status, we have shown that elevations in plasma branched-chain and aromatic amino acids are also able to predict future diabetes in otherwise normoglycemic, healthy adults (3). Similarly, lipid profiling has demonstrated novel perturbations in triacylglycerol distribution that signal future diabetes risk (4). These findings highlight how emerging technologies are able to broaden our perspective on early disease states, potentially lending insights into biological mechanisms that underlie diabetes and metabolic disease. Characterizing early metabolic changes may also lead to the early identification of at-risk individuals and may prompt the initiation of proven preventive strategies (5).The oral glucose tolerance test (OGTT) provides a dynamic view of glucose and insulin physiology and has been widely used for decades to diagnose diabetes (6,7). Therefore, we conducted a systematic evaluation of biochemical changes after OGTT in a community-based population, with the goal of providing a broad view of the metabolic response to a glucose challenge. An important advantage of profiling plasma samples before and after glucose ingestion is that each individual is able to serve as their own biological control. In addition to attenuating noise attributable to interindividual variation, this approach limits confounding effects of diet, medications, and other inputs that impact the human metabolome. We used a liquid chromatography/mass spectrometry (LC/MS)–based platform that allowed highly specific identification of small molecules in a targeted manner. In prior pilot studies, our group has shown that metabolite excursions with OGTT revealed a switch from catabolism to anabolism, largely attributable to insulin actions (8). In the current study, we sought to evaluate perturbations with OGTT in an expanded panel of metabolites and in a more comprehensive population-based sample with a high propensity for the development of diabetes, and to investigate these changes in individuals with and without insulin resistance.     

Rituximab induced pulmonary fibrosis in a patient with lupus nephritis

We describe a 26-year-old woman who was diagnosed eleven years ago with systemic lupus erythematosus and who had suffered multiple relapses. She presented with class IV lupus nephritis with thrombotic microangiopathy, for which she received three doses of rituximab along with plasmapheresis, with no response, and soon became dialysis dependent. One month after the last dose of rituximab, she presented with dyspnoea and hypoxia. A transbronchial lung biopsy revealed pulmonary fibrosis. A diagnosis of rituximab induced pulmonary fibrosis was made after excluding other causes and she was treated with intravenous methyl prednisolone with which there was marked improvement in symptoms and hypoxemia. This is the first report of rituximab induced pulmonary fibrosis in a patient with lupus nephritis.