Redox-regulated mechanisms in asthma

Homeostasis of the reduction-oxidation (redox) state is critical to protection from oxidative stress in the lungs. Therefore, the lungs have high levels of antioxidants, including glutathione, heme oxygenase, and superoxide dismutase. The numbers of inflammatory cells -- particularly eosinophils -- are increased in the airways of asthma patients, and these pulmonary inflammatory cells release large amounts of harmful reactive oxygen species and reactive nitrogen species. Human thioredoxin 1 (TRX1) is a redox-active protein of approximately 12 kDa that contains a (32)Cys-Gly-Pro-(35)Cys sequence necessary for its activity. The strong reducing activity of the sequence results from the cysteine residues acting as proton donors and cleaving disulfide (S-S) bonds in the target protein. Endogenous or exogenous TRX1 or both protect the lungs against ischemia-reperfusion injury, influenza infection, bleomycin-induced injury, or lethal pulmonary inflammation caused by interleukin-2 and interleukin-18. We showed that exogenous TRX1 inhibits airway hyperresponsiveness and pulmonary inflammation accompanied by eosinophilia in mouse models of asthma. Recently, we reported that exogenous TRX1 improves established airway remodeling in a prolonged antigen-exposure mouse asthma model. Exogenous and endogenous TRX1 also prevents the development of airway remodeling. Here, we discuss the role and clinical benefits of TRX1 in asthma.     

Human dental pulp-derived stem cells promote locomotor recovery after complete transection of the rat spinal cord by multiple neuro-regenerative mechanisms

Spinal cord injury (SCI) often leads to persistent functional deficits due to loss of neurons and glia and to limited axonal regeneration after injury. Here we report that transplantation of human dental pulp stem cells into the completely transected adult rat spinal cord resulted in marked recovery of hind limb locomotor functions. Transplantation of human bone marrow stromal cells or skin-derived fibroblasts led to substantially less recovery of locomotor function. The human dental pulp stem cells exhibited three major neuroregenerative activities. First, they inhibited the SCI-induced apoptosis of neurons, astrocytes, and oligodendrocytes, which improved the preservation of neuronal filaments and myelin sheaths. Second, they promoted the regeneration of transected axons by directly inhibiting multiple axon growth inhibitors, including chondroitin sulfate proteoglycan and myelin-associated glycoprotein, via paracrine mechanisms. Last, they replaced lost cells by differentiating into mature oligodendrocytes under the extreme conditions of SCI. Our data demonstrate that tooth-derived stem cells may provide therapeutic benefits for treating SCI through both cell-autonomous and paracrine neuroregenerative activities.     

Immunohistochemical and immunoblotting detection of cytokeratin in smooth muscle tumors.

Forty-six smooth muscle tumors, including 35 of gastrointestinal origin, were studied immunohistochemically for the localization of cytokeratin using a variety of monoclonal antibodies. In formalin-fixed, paraffin-embedded material, six of 40 leiomyomas, two of five leiomyosarcomas and one leiomyoblastoma were immunoreactive for cytokeratin in a few tumor cells. A proportion of non-neoplastic smooth muscle cells also exhibited a positive reaction. In fresh frozen sections of one gastric leiomyosarcoma, a high percentage of tumor cells were reactive with nine of the eleven anti-cytokeratin monoclonal antibodies examined. Cytokeratin-positive cytoplasmic filaments were further demonstrated by immunoelectron microscopy. By immunoblot analysis, an extract of this immunohistochemically cytokeratin-positive leiomyosarcoma showed a distinct band at the same position as an extract of pancreas, whereas no bands were seen in an extract of a cytokeratin-negative esophageal leiomyosarcoma. These immunohistochemical and immunoblotting findings indicate that a certain subset of smooth muscle neoplasms express genuine cytokeratin filaments.     

A new subpopulation of intestinal intraepithelial lymphocytes expressing high level of T cell receptor gamma delta.

The murine intestinal epithelium contains T cell receptor (TcR) gamma delta-bearing T cells in high frequency. In the present report, we showed that TcR gamma delta-bearing intestinal intraepithelial lymphocytes (IEL) from C3H/He (H-2k) mice can be divided into two subpopulations based on TcR expression level; a subpopulation with a remarkably high level of TcR expression and a subpopulation with a moderate level of TcR expression, designated as TcR gamma delta hi IEL and TcR gamma delta mod IEL, respectively. In flow cytometric analysis, the TcR gamma delta hi IEL expressed a high level of TcR (mean fluorescence channel 518) when compared with the TcR level of TcR gamma delta+ T cells in other lymphoid organs (mean fluorescence channel 88). The TcR gamma delta hi IEL were detected in IEL from mice of H-2k and H-2k/b haplotypes but not in H-2b and H-2d haplotypes. V delta 4, which was reported to be frequently expressed in IEL of H-2k mice, was preferentially expressed by TcR gamma delta hi IEL. These results suggested that the existence of the TcR gamma delta hi population is related to the high frequency of V delta 4 in H-2k mice.     

Morphometric studies on the age changes of autofluorescent granules and lysosomes in the epithelial cells of rat kidneys

Morphometric analysis of the lysosomal system in the proximal convoluted tubules of the kidney of rats of different ages was studied, with special regard to the accumulation of autofluorescent pigment in the epithelial cells. After maturity, the lysosomal amount in the epithelial cells was significantly increased in the 25-29-month-old group; however, the amount of autofluorescent pigment granules was not significantly increased.     

Early detection of the PAX3‐FOXO1 fusion gene in circulating tumor‐derived DNA in a case of alveolar rhabdomyosarcoma

Cell‐free DNA (cfDNA), which are small DNA fragments in blood derived from dead cells including tumor cells, could serve as useful biomarkers and provide valuable genetic information about the tumors. cfDNA is now used for the genetic analysis of several types of cancers, as a surrogate for tumor biopsy, designated as “liquid biopsy.” Rhabdomyosarcoma (RMS), the most frequent soft tissue tumor in childhood, can arise in any part of the body, and radiological imaging is the only available method for estimating the tumor burden, because no useful specific biological markers are present in the blood. Because tumor volume is one of the determinants of treatment response and outcome, early detection at diagnosis as well as relapse is essential for improving the treatment outcome. A 15‐year‐old male patient was diagnosed with alveolar RMS of prostate origin with bone marrow invasion. The PAX3‐FOXO1 fusion was identified in the tumor cells in the bone marrow. After the diagnosis, cfDNA was serially collected to detect the PAX3‐FOXO1 fusion sequence as a tumor marker. cfDNA could be an appropriate source for detecting the fusion gene; assays using cfDNA have proved to be useful for the early detection of tumor progression/recurrence. Additionally, the fusion gene dosage estimated by quantitative polymerase chain reaction reflected the tumor volume during the course of the treatment. We suggest that for fusion gene‐positive RMSs, and other soft tissue tumors, the fusion sequence should be used for monitoring the tumor burden in the body to determine the diagnosis and treatment options for the patients.     

Pericardio-peritoneal drainage using a subcostal approach

A 56-year-old man admitted to our hospital for cardiac tamponade due to dilated cardiomyopathy did not respond to treatment by usual medical means or surgery. Pericardio-peritoneal drainage was conducted using a subcostal approach. Seven months later, the patient remains well and free of signs of pericardial tamponade. This method has proved to be safe and effective in patients with persistent massive pericardial effusion.