Mouse Regenerating Myofibers Detected as False-Positive Donor Myofibers with Anti-Human Spectrin

Stem cell transplantation is being tested as a potential therapy for a number of diseases. Stem cells isolated directly from tissue specimens or generated via reprogramming of differentiated cells require rigorous testing for both safety and efficacy in preclinical models. The availability of mice with immune-deficient background that carry additional mutations in specific genes facilitates testing the efficacy of cell transplantation in disease models. The muscular dystrophies are a heterogeneous group of disorders, of which Duchenne muscular dystrophy is the most severe and common type. Cell-based therapy for muscular dystrophy has been under investigation for several decades, with a wide selection of cell types being studied, including tissue-specific stem cells and reprogrammed stem cells. Several immune-deficient mouse models of muscular dystrophy have been generated, in which human cells obtained from various sources are injected to assess their preclinical potential. After transplantation, the presence of engrafted human cells is detected via immunofluorescence staining, using antibodies that recognize human, but not mouse, proteins. Here we show that one antibody specific to human spectrin, which is commonly used to evaluate the efficacy of transplanted human cells in mouse muscle, detects myofibers in muscles of NOD/Rag1nullmdx5cv, NOD/LtSz-scid IL2Rγnull mice, or mdx nude mice, irrespective of whether they were injected with human cells. These “reactive” clusters are regenerating myofibers, which are normally present in dystrophic tissue and the spectrin antibody is likely recognizing utrophin, which contains spectrin-like repeats. Therefore, caution should be used in interpreting data based on detection of single human-specific proteins, and evaluation of human stem cell engraftment should be performed using multiple human-specific labeling strategies

Epidemiology and outcome of Clostridium difficile infections in patients hospitalized in Internal Medicine: findings from the nationwide FADOI-PRACTICE study.

BACKGROUND: Clostridium difficile (CD) is a leading cause of diarrhoea among hospitalized patients. The objective of this study was to evaluate the rate, the optimal diagnostic work-up, and outcome of CD infections (CDI) in Internal Medicine (IM) wards in Italy. METHODS: PRACTICE is an observational prospective study, involving 40 IM Units and evaluating all consecutive patients hospitalized during a 4-month period. CDI were defined in case of diarrhoea when both enzyme immunoassay for GDH, and test for A/B toxin were positive. Patients with CDI were followed-up for recurrences for 4 weeks after the end of therapy. RESULTS: Among the 10,780 patients observed, 103 (0.96 %) showed CDI, at admission or during hospitalization. A positive history for CD, antibiotics in the previous 4 weeks, recent hospitalization, female gender and age were significantly associated with CDI (multivariable analysis). In-hospital mortality was 16.5 % in CD group vs 6.7 % in No-CD group (p\u2009<\u20090.001), whereas median length of hospital stay was 16 (IQR\u2009=\u200913) vs 8 (IQR\u2009=\u20098) days (p\u2009<\u20090.001) among patients with or without CDI, respectively. Rate of CD recurrences was 14.6 %. As a post-hoc evaluation, 23 out of 34 GDH+/Tox- samples were toxin positive, when analysed by molecular method (a real-time PCR assay). The overall CD incidence rate was 5.3/10,000 patient-days. CONCLUSIONS: Our results confirm the severity of CDI in medical wards, showing high in-hospital mortality, prolonged hospitalization and frequent short-term recurrences. Further, our survey supports a 2-3 step algorithm for CD diagnosis: EIA for detecting GDH, A and B toxin, followed by a molecular method in case of toxin-negative samples

Successful bone marrow transplantation in a patient with Diamond-Blackfan anemia with co-existing Duchenne muscular dystrophy: a case report

<p>Abstract</p> <p>Introduction</p> <p>Diamond-Blackfan anemia and Duchenne muscular dystrophy are two rare congenital anomalies. Both anomalies occurring in the same child is extremely rare. Allogeneic hematopoietic stem cell transplantation is a well-established therapy for Diamond-Blackfan anemia. However, in patients with Duchenne muscular dystrophy, stem cell therapy still remains experimental.</p> <p>Case presentation</p> <p>We report the case of a nine-year-old boy of north Indian descent with Diamond-Blackfan anemia and Duchenne muscular dystrophy who underwent successful allogeneic hematopoietic stem cell transplantation. He is transfusion-independent, and his Duchenne muscular dystrophy has shown no clinical deterioration over the past 45 months. His creatine phosphokinase levels have significantly decreased to 300 U/L from 14,000 U/L pre-transplant. The patient is 100% donor chimera in the hematopoietic system, and his muscle tissue has shown 8% to 10.4% cells of donor origin.</p> <p>Conclusion</p> <p>Our patient's Diamond-Blackfan anemia was cured by allogeneic hematopoietic stem cell transplantation. The interesting clinical observation of a possible benefit in Duchenne muscular dystrophy cannot be ruled out. However, further clinical follow-up with serial muscle biopsies and molecular studies are needed to establish this finding.</p

Incidence of thrombotic complications in patients with haematological malignancies with central venous catheters : A prospective multicentre study

This prospective, observational and multicentre study assessed the incidence of, and risk factors for, symptomatic venous thrombotic complications after central venous catheter (CVC) positioning in patients with haematological malignancies. A total of 458 consecutive CVC insertions were registered in 416 patients (81-2% of whom had severe thrombocytopenia). Over the observation period (3 months or up to catheter removal), the incidence of events was: CVC-related deep vein thrombosis (DVT), 1.5%; lower limb DVT, 0.4%; pulmonary embolism (PE), 1.3%; fatal PE, 0.6%; CVC-related superficial thrombophlebitis, 3.9%; CVC-occlusion/malfunction of thrombotic origin, 6.1%; major arterial events, 1.1%. Severe bleeding and CVC-related infections were observed in 3.5% and 4.6% of cases respectively. A composite end point (any venous thromboembolism or superficial thrombophlebitis or CVC occlusion/malfunction) was defined in order to consider venous thrombotic events with a significant impact on clinical practice. With this criterion, the overall incidence was 12.0% (2.54 cases/1000 catheter days). No factor helped to predict venous thrombotic complications: only thrombocytopenia was associated with a weak trend for a reduced risk (odds ratio 0.52; 95% confidence interval 0.26-1.07). No severe bleeding was observed in those patients who received antithrombotic prophylaxis. This study shows that the impact on clinical practice of symptomatic CVC-related thrombotic complications is not negligible in patients with haematological malignancies. (copyright) 2005 Blackwell Publishing Ltd

Cooperation of Mtmr8 with PI3K Regulates Actin Filament Modeling and Muscle Development in Zebrafish

It has been shown that mutations in at least four myotubularin family genes (MTM1, MTMR1, 2 and 13) are causative for human neuromuscular disorders. However, the pathway and regulative mechanism remain unknown.Here, we reported a new role for Mtmr8 in neuromuscular development of zebrafish. Firstly, we cloned and characterized zebrafish Mtmr8, and revealed the expression pattern predominantly in the eye field and somites during early somitogenesis. Using morpholino knockdown, then, we observed that loss-of-function of Mtmr8 led to defects in somitogenesis. Subsequently, the possible underlying mechanism and signal pathway were examined. We first checked the Akt phosphorylation, and observed an increase of Akt phosphorylation in the morphant embryos. Furthermore, we studied the PH/G domain function within Mtmr8. Although the PH/G domain deletion by itself did not result in embryonic defect, addition of PI3K inhibitor LY294002 did give a defective phenotype in the PH/G deletion morphants, indicating that the PH/G domain was essential for Mtmr8's function. Moreover, we investigated the cooperation of Mtmr8 with PI3K in actin filament modeling and muscle development, and found that both Mtmr8-MO1 and Mtmr8-MO2+LY294002 led to the disorganization of the actin cytoskeleton. In addition, we revealed a possible participation of Mtmr8 in the Hedgehog pathway, and cell transplantation experiments showed that Mtmr8 worked in a non-cell autonomous manner in actin modeling.The above data indicate that a conserved functional cooperation of Mtmr8 with PI3K regulates actin filament modeling and muscle development in zebrafish, and reveal a possible participation of Mtmr8 in the Hedgehog pathway. Therefore, this work provides a new clue to study the physiological function of MTM family members

Diseased muscles that lack dystrophin or laminin-α2 have altered compositions and proliferation of mononuclear cell populations

BACKGROUND: Multiple types of mononucleate cells reside among the multinucleate myofibers in skeletal muscles and these mononucleate cells function in muscle maintenance and repair. How neuromuscular disease might affect different types of muscle mononucleate cells had not been determined. In this study, therefore, we examined how two neuromuscular diseases, dystrophin-deficiency and laminin-α2-deficiency, altered the proliferation and composition of different subsets of muscle-derived mononucleate cells. METHODS: We used fluorescence-activated cell sorting combined with bromodeoxyuridine labeling to examine proliferation rates and compositions of mononuclear cells in diseased and healthy mouse skeletal muscle. We prepared mononucleate cells from muscles of mdx (dystrophin-deficient) or Lama2(-/- )(laminin-α2-deficient) mice and compared them to cells from healthy control muscles. We enumerated subsets of resident muscle cells based on Sca-1 and CD45 expression patterns and determined the proliferation of each cell subset in vivo by BrdU incorporation. RESULTS: We found that the proliferation and composition of the mononucleate cells in dystrophin-deficient and laminin-α2-deficient diseased muscles are different than in healthy muscle. The mdx and Lama2(-/- )muscles showed similar significant increases in CD45(+ )cells compared to healthy muscle. Changes in proliferation, however, differed between the two diseases with proliferation increased in mdx and decreased in Lama2(-/- )muscles compared to healthy muscles. In particular, the most abundant Sca-1(-)/CD45(- )subset, which contains muscle precursor cells, had increased proliferation in mdx muscle but decreased proliferation in Lama2(-/- )muscles. CONCLUSION: The similar increases in CD45(+ )cells, but opposite changes in proliferation of muscle precursor cells, may underlie aspects of the distinct pathologies in the two diseases

Autologous bone marrow stem cell intralesional transplantation repairing bisphosphonate related osteonecrosis of the jaw

<p>Abstract</p> <p>Purpose</p> <p>Bisphosphonate - related osteonecrosis of the JAW (BRONJ) is a well known side effect of bisphosphonate therapies in oncologic and non oncologic patients. Since to date no definitive consensus has been reached on the treatment of BRONJ, novel strategies for the prevention, risk reduction and treatment need to be developed. We report a 75 year old woman with stage 3 BRONJ secondary to alendronate and pamidronate treatment of osteoporosis. The patient was unresponsive to recommended treatment of the disease, and her BRONJ was worsening. Since bone marrow stem cells are know as being multipotent and exhibit the potential for differentiation into different cells/tissue lineages, including cartilage, bone and other tissue, we performed autologous bone marrow stem cell transplantation into the BRONJ lesion of the patient.</p> <p>Methods</p> <p>Under local anesthesia a volume of 75 ml of bone marrow were harvested from the posterior superior iliac crest by aspiration into heparinized siringes. The cell suspension was concentrated, using Ficoll - Hypaque^®centrifugation procedures, in a final volume of 6 ml. Before the injection of stem cells into the osteonecrosis, the patient underwent surgical toilet, local anesthesia was done and spongostan was applied as a carrier of stem cells suspension in the bone cavity, then 4 ml of stem cells suspension and 1 ml of patient's activated platelet-rich plasma were injected in the lesion of BRONJ.</p> <p>Results</p> <p>A week later the residual spongostan was removed and two weeks later resolution of symptoms was obtained. Then the lesion improved with progressive superficialization of the mucosal layer and CT scan, performed 15 months later, shows improvement also of bone via concentric ossification: so complete healing of BRONJ (stage 0) was obtained in our patient, and 30 months later the patient is well and without signs of BRONJ.</p> <p>Conclusion</p> <p>To our knowledge this is the first case of BRONJ successfully treated with autologous stem cells transplantation with a complete response.</p

Eccentric Exercise Facilitates Mesenchymal Stem Cell Appearance in Skeletal Muscle

Eccentric, or lengthening, contractions result in injury and subsequently stimulate the activation and proliferation of satellite stem cells which are important for skeletal muscle regeneration. The discovery of alternative myogenic progenitors in skeletal muscle raises the question as to whether stem cells other than satellite cells accumulate in muscle in response to exercise and contribute to post-exercise repair and/or growth. In this study, stem cell antigen-1 (Sca-1) positive, non-hematopoetic (CD45-) cells were evaluated in wild type (WT) and α7 integrin transgenic (α7Tg) mouse muscle, which is resistant to injury yet liable to strain, 24 hr following a single bout of eccentric exercise. Sca-1+CD45− stem cells were increased 2-fold in WT muscle post-exercise. The α7 integrin regulated the presence of Sca-1+ cells, with expansion occurring in α7Tg muscle and minimal cells present in muscle lacking the α7 integrin. Sca-1+CD45− cells isolated from α7Tg muscle following exercise were characterized as mesenchymal-like stem cells (mMSCs), predominantly pericytes. In vitro multiaxial strain upregulated mMSC stem cells markers in the presence of laminin, but not gelatin, identifying a potential mechanistic basis for the accumulation of these cells in muscle following exercise. Transplantation of DiI-labeled mMSCs into WT muscle increased Pax7+ cells and facilitated formation of eMHC+DiI− fibers. This study provides the first demonstration that mMSCs rapidly appear in skeletal muscle in an α7 integrin dependent manner post-exercise, revealing an early event that may be necessary for effective repair and/or growth following exercise. The results from this study also support a role for the α7 integrin and/or mMSCs in molecular- and cellular-based therapeutic strategies that can effectively combat disuse muscle atrophy

Understanding hereditary diseases using the dog and human as companion model systems

Animal models are requisite for genetic dissection of, and improved treatment regimens for, human hereditary diseases. While several animals have been used in academic and industrial research, the primary model for dissection of hereditary diseases has been the many strains of the laboratory mouse. However, given its greater (than the mouse) genetic similarity to the human, high number of naturally occurring hereditary diseases, unique population structure, and the availability of the complete genome sequence, the purebred dog has emerged as a powerful model for study of diseases. The major advantage the dog provides is that it is afflicted with approximately 450 hereditary diseases, about half of which have remarkable clinical similarities to corresponding diseases of the human. In addition, humankind has a strong desire to cure diseases of the dog so these two facts make the dog an ideal clinical and genetic model. This review highlights several of these shared hereditary diseases. Specifically, the canine models discussed herein have played important roles in identification of causative genes and/or have been utilized in novel therapeutic approaches of interest to the dog and human