Permanent phenotypic correction of hemophilia B in immunocompetent mice by prenatal gene therapy

Hemophilia B, also known as Christmas disease, arises from mutations in the factor IX (F9) gene. Its treatment in humans, by recombinant protein substitution, is expensive, thus limiting its application to intermittent treatment in bleeding episodes and prophylaxis during surgery; development of inhibitory antibodies is an associated hazard. This study demonstrates permanent therapeutic correction of his disease without development of immune reactions by introduction of an HIV-based lentiviral vector encoding the human factor IX protein into the fetal circulation of immunocompetent hemophiliac and normal outbred mice. Plasma factor IX antigen remained at around 9%, 13%, and 16% of normal in the 3 hemophilia B mice, respectively, until the last measurement at 14 months. Substantial improvement in blood coagulability as measured by coagulation assay was seen in all 3 mice and they rapidly stopped bleeding after venipuncture. No humoral or cellular immunity against the protein, elevation of serum liver enzymes, or vector spread to the germline or maternal circulation were detected.     

Endoscopic nodular gastritis: an endoscopic indicator of high-grade bacterial colonization and severe gastritis in children with Helicobacter pylori

OBJECTIVE: To investigate the significance of endoscopic nodular gastritis associated with Helicobacter pylori infection. METHODS: This prospective study included 185 children (50.8% boys) aged 1 to 12 years (mean, 6.9 +/- 3.0 years) who underwent upper intestinal endoscopy during evaluation of chronic abdominal pain. The authors assessed the endoscopic appearance of the stomach, noting those patients with endoscopic nodular gastritis. Urease activity of gastric mucosal biopsies was measured. With histologic examination, the presence and density of H. pylori organisms, the presence of follicular gastritis, the nature of inflammation, and the gastritis activity grade and overall gastritis score were assessed. RESULTS: H. pylori infection was identified in 50 children (27%). Endoscopic nodular gastritis was significantly associated with active chronic gastritis and follicular gastritis. Nodularity in the stomach showed a high specificity (98.5%) and positive predictive value (91.7%) for the diagnosis of H. pylori infection and was observed in 22 of 50 (44%) H. pylori-positive patients and in 2 of 135 (1.5%) H. pylori-negative patients. A significant association was observed between older age and the prevalence of this finding (P< 0.001). There was a significant increase in endoscopic nodular gastritis with increased H. pylori density and a positive correlation (Pearson coefficient = 0.97) with increased gastritis score on histologic examination. Increase in gastritis score was dependent on increased H. pylori density in patients with gastric nodularity; this finding was independent of age. CONCLUSIONS: Endoscopic findings of antral nodularity in children suggest the presence of H. pylori infection and follicular gastritis and may identify cases of severe gastritis and marked bacterial colonization.     

Matricellular proteins as modulators of wound healing and the foreign body response

Matricellular proteins form a group of extracellular matrix (ECM) proteins that do not subserve a primary structural role, but rather function as modulators of cell-matrix interactions. Members of the group, including thrombospondin (TSP)-1,TSP-2, SPARC, tenascin (TN)-C, and osteopontin (OPN), have been shown to participate in a number of processes related to tissue repair. Specifically, studies in knockout mice have indicated that a deficiency in one or more of these proteins can alter the course of wound healing. More recently, TSP1, TSP2, and SPARC have also been implicated in the foreign body response, an unusual reaction to injury that occurs after the implantation of biomaterials. This review will focus on the roles of these proteins in the response to injury in mice and will show how studies of this pathophysiological process can elucidate some of the intrinsic properties of these matricellular proteins.     

Ultrasound-guided percutaneous delivery of adenoviral vectors encoding the beta-galactosidase and human factor IX genes to early gestation fetal sheep in utero

In utero gene therapy may provide treatment of genetic diseases before significant organ damage, allow permanent genetic correction by reaching stem cell populations, and provide immune tolerance against the therapeutic transgenes and vectors. We have used percutaneous ultrasound-guided injection as a minimally invasive fetal procedure. First-generation adenoviruses encoding the nuclear localizing beta-galactosidase reporter gene or the human factor IX (hFIX) gene, or colloidal carbon were delivered via the umbilical vein (UV, n = 4), heart (intracardiac [IC], n = 2), liver parenchyma (intrahepatic [HE], n = 11), peritoneal cavity (intraperitoneal [IP], n = 14), skeletal musculature ([intramuscular [IM], n = 11), or the amniotic cavity (intraamniotic [IA], n = 14) to early-gestation fetal sheep (0.3 gestation = day 33-61). Postmortem analysis was performed at 2, 9, or 28 days after injection. Although fetal survival was between 77% and 91% for IP, HE, IA, and IM routes, no fetuses survived UV or IC procedures. The hFIX levels reaching 1900 and 401 ng/ml (IP), 30 ng/ml (HE), 66.5 and 39 ng/ml (IA), and 83 and 65.5 ng/ml (IM), respectively, were determined 2 days after injection and decreased at birth to 16.5 ng/ml (IP), 7 ng/ml (HE), 4.5 ng/ml (IA), and 4 and 0 ng/ml (IM). Polymerase chain reaction (PCR) and immunohistochemistry showed broadest hFIX transgene spread and highest localised beta-galactosidase expression, respectively, after IP administration. Antibodies were observed against vector but not against hFIX.     

Adult derived mononuclear bone marrow cells improve survival in a model of acetaminophen-induced acute liver failure in rats

INTRODUCTION: Acute liver failure (ALF) is characterized by a rapid loss of hepatic function, with high mortality. Acetaminophen (APAP) intoxication and viral hepatitis are common causes of ALF. Several studies have shown the capacity of adult bone marrow cells to differentiate in hepatocytes, suggesting their use for treating ALF. AIM: In the present study, we tested the use of adult derived mononuclear bone marrow fraction to improve the survival of Wistar rats with APAP-induced ALF. METHODS: Forty-eight female Wistar rats pre-induced with phenobarbital were given APAP in a single dose of 1g/kg via intraperitoneal injection. Bone marrow mononuclear cells were purified from male rats using FICOLL gradient and injected through the portal vein in a volume of 0.2mL containing 1x10(6) cells stained with DAPI. Treatment was administered 24h after APAP injection. The sham group (n=24), received 0.2mL of saline through the portal vein 24h after APAP administration. Survival, liver histology and ALT levels were observed. RESULTS: Survival 72h post-APAP administration was 33% in the sham group and 70.8% in the group receiving bone marrow cells. Liver histology in treated animals showed less intense necrosis and the presence of DAPI-positive cells. CONCLUSIONS: We have shown that bone marrow derived cells are capable of significantly increasing the survival rate of APAP-induced ALF in 37.5% (95% CI, 27.8-40.3%).     

A two-stage method for MUAP classification based on EMG decomposition

A method for the extraction and classification of individual motor unit action potentials (MUAPs) from needle electromyographic signals is presented. The proposed method automatically decomposes MUAPs and classifies them into normal, neuropathic or myopathic using a two-stage feature-based classifier. The method consists of four steps: (i) preprocessing of EMG recordings, (ii) MUAP clustering and detection of superimposed MUAPs, (iii) feature extraction and (iv) MUAP classification using a two-stage classifier. The proposed method employs Radial Basis Function Artificial Neural Networks and decision trees. It requires minimal use of tuned parameters and is able to provide interpretation for the classification decisions. The approach has been validated on real EMG recordings and an annotated collection of MUAPs. The success rate for MUAP clustering is 96%, while the accuracy for MUAP classification is about 89%.     

Widespread distribution and muscle differentiation of human fetal mesenchymal stem cells after intrauterine transplantation in dystrophic mdx mouse

Duchenne muscular dystrophy (DMD) is a common X-linked disease resulting from the absence of dystrophin in muscle. Affected boys suffer from incurable progressive muscle weakness, leading to premature death. Stem cell transplantation may be curative, but is hampered by the need for systemic delivery and immune rejection. To address these barriers to stem cell therapy in DMD, we investigated a fetal-to-fetal transplantation strategy. We investigated intramuscular, intravascular, and intraperitoneal delivery of human fetal mesenchymal stem cells (hfMSCs) into embryonic day (E) 14-16 MF1 mice to determine the most appropriate route for systemic delivery. Intramuscular injections resulted in local engraftment, whereas both intraperitoneal and intravascular delivery led to systemic spread. However, intravascular delivery led to unexpected demise of transplanted mice. Transplantation of hfMSCs into E14-16 mdx mice resulted in widespread long-term engraftment (19 weeks) in multiple organs, with a predilection for muscle compared with nonmuscle tissues (0.71% vs. 0.15%, p < .01), and evidence of myogenic differentiation of hfMSCs in skeletal and myocardial muscle. This is the first report of intrauterine transplantation of ontologically relevant hfMSCs into fully immunocompetent dystrophic fetal mice, with systemic spread across endothelial barriers leading to widespread long-term engraftment in multiple organ compartments. Although the low-level of chimerism achieved is not curative for DMD, this approach may be useful in other severe mesenchymal or enzyme deficiency syndromes, where low-level protein expression may ameliorate disease pathology.     

Loss of metabolic flexibility as a result of overexpression of pyruvate dehydrogenase kinases in muscle,liver and the immune system: Therapeutic targets in metabolic diseases

Good health depends on the maintenance of metabolic flexibility, which in turn is dependent on the maintenance of regulatory flexibility of a large number of regulatory enzymes, but especially the pyruvate dehydrogenase complex (PDC), because of its central role in carbohydrate metabolism. Flexibility in regulation of PDC is dependent on rapid changes in the phosphorylation state of PDC determined by the relative activities of the pyruvate dehydrogenase kinases (PDKs) and the pyruvate dehydrogenase phosphatases. Inactivation of the PDC by overexpression of PDK4 contributes to hyperglycemia, and therefore the serious health problems associated with diabetes. Loss of regulatory flexibility of PDC occurs in other disease states and pathological conditions that have received less attention than diabetes. These include cancers, non-alcoholic fatty liver disease, cancer-induced cachexia, diabetes-induced nephropathy, sepsis and amyotrophic lateral sclerosis. Overexpression of PDK4, and in some situations, the other PDKs, as well as under expression of the pyruvate dehydrogenase phosphatases, leads to inactivation of the PDC, mitochondrial dysfunction and deleterious effects with health consequences. The possible basis for this phenomenon, along with evidence that overexpression of PDK4 results in phosphorylation of “off-target” proteins and promotes excessive transport of Ca²⁺ into mitochondria through mitochondria-associated endoplasmic reticulum membranes are discussed. Recent efforts to find small molecule PDK inhibitors with therapeutic potential are also reviewed.