Sulfatase‐mediated manipulation of the astrocyte‐Schwann cell interface

Schwann cell (SC) transplantation following spinal cord injury (SCI) may have therapeutic potential. Functional recovery is limited however, due to poor SC interactions with host astrocytes and the induction of astrogliosis. Olfactory ensheathing cells (OECs) are closely related to SCs, but intermix more readily with astrocytes in culture and induce less astrogliosis. We previously demonstrated that OECs express higher levels of sulfatases, enzymes that remove 6‐O‐sulfate groups from heparan sulphate proteoglycans, than SCs and that RNAi knockdown of sulfatase prevented OEC‐astrocyte mixing in vitro. As human OECs are difficult to culture in large numbers we have genetically engineered SCs using lentiviral vectors to express sulfatase 1 and 2 (SC‐S1S2) and assessed their ability to interact with astrocytes. We demonstrate that SC‐S1S2s have increased integrin‐dependent motility in the presence of astrocytes via modulation of NRG and FGF receptor‐linked PI3K/AKT intracellular signaling and do not form boundaries with astrocytes in culture. SC‐astrocyte mixing is dependent on local NRG concentration and we propose that sulfatase enzymes influence the bioavailability of NRG ligand and thus influence SC behavior. We further demonstrate that injection of sulfatase expressing SCs into spinal cord white matter results in less glial reactivity than control SC injections comparable to that of OEC injections. Our data indicate that sulfatase‐mediated modification of the extracellular matrix can influence glial interactions with astrocytes, and that SCs engineered to express sulfatase may be more OEC‐like in character. This approach may be beneficial for cell transplant‐mediated spinal cord repair. GLIA 2016 GLIA 2017;65:19–3

Alterations of lymphocyte subpopulations in healthy dogs with aging and in dogs with cancer

Changes in an individual\u27s immune status are considered major contributing factors towards the morbidity of cancer and mortality of aging. To evaluate age-related changes in the immune status of dogs, the immunophenotypes (CD3, CD4, CD8 and CD21) of peripheral blood lymphocytes were measured in 160 healthy dogs aged from 1 to 17 years, and in 365 dogs with various tumors and at various stages. In healthy dogs, the absolute numbers of white blood cells, lymphocytes, and CD3^+, CD4^+ and CD21^+ lymphocytes decreased significantly with age. The relative percentages of lymphocytes and CD4^+ cells decreased significantly, while CD8^+ cells increased significantly with age. The CD4:CD8 ratio showed a significant age-related decrease. In contrast, dogs with tumors possessed significantly lower absolute numbers and relative percentages of all lymphocyte phenotypes, while the CD4:CD8 ratio was significantly higher than in age-matched controls. The relative percentages of CD3^+ and CD8^+ lymphocytes were significantly lower in dogs with distant metastases compared with dogs without metastases, and the CD4:CD8 ratio increased with advanced stage. These observations illustrate the significant changes in immune status with age and the presence of marked immunological defects in a large-scale study of dogs with advanced tumors

Prognostic Utility of Apoptosis Index, Ki-67 and Survivin Expression in Dogs with Nasal Carcinoma Treated with Orthovoltage Radiation Therapy

Apoptosis, Ki-67 and survivin expression have been reported as prognostic values in human cancer treated with radiation therapy. The aim of this study was to evaluate the correlation between the outcome of canine nasal carcinomas treated with radiation therapy and these cancer markers. The apoptotic index (AI) was evaluated with TUNEL assays, and an immunohistochemical evaluation was performed on Ki-67 and survivin in 33 biopsy samples taken before treatment. Median survival times were estimated using Kaplan-Meier curves and the log-rank method. The AI ranged from 0 to 0.7%, and the percentage of Ki-67-positive cells defined as the proliferative index (PI) ranged from 0.8 to 77% in all samples. Neither the AI nor the PI had a significant relationship with survival time (P=0.056 and 0.211). Survivin expression was detected in 84.9% of samples of canine nasal carcinoma. Dogs with high survivin expression were associated with poorer response to treatment and had shorter survival times (P=0.017 and 0.031). Advanced-stage tumors were also significantly associated with a high level of survivin (P=0.026). Overexpression of survivin was shown to be an unfavorable prognostic factor in dogs with nasal carcinomas treated with radiation therapy

Peripheral Lymphocyte Subsets as a Prognostic Indicator of Mortality and Morbidity in Healthy Dogs

To evaluate the relationship among immune status and increased morbidity and mortality, peripheral blood lymphocytes (CD3+, CD4+, CD8+ and CD21+ cells) from 32 healthy dogs over 8 years of age were analyzed. Twenty-five of the 32 dogs were followed-up for 3 years after the analysis; and 14 dogs were found to be diseased, and nine dogs died. There was no notable difference between the ages of the dogs that died compared with the ones that survived. The relative percentage of CD4+ and the CD4+:CD8+ ratio decreased notably in dogs falling ill compared with healthy dogs. The relative percentage of CD3+ lymphocytes showed a notable decrease in dogs that died within 3 years in comparison with dogs that survived. In a discriminant analysis of morbidity and mortality, most patients were correctly classified as diseased or not and surviving or dead, respectively. These results indicate that the immunophenotypes of peripheral blood lymphocytes in older dogs offer promise as parameters for evaluating mortality and morbidity