Abstract: Objective To assess the feasibility of transferring major histocompatibility complex (MHC) gene into the thymus to mitigate xenograft rejection. Methods By molecular cloning technique, we extracted and proliferated the-H-2K d gene from donor mice (MHC class Ⅰ gene of Balb/c mice) and constructed the expression vector plasmid of pCI-H-2K d. Twenty SD rats were selected as receptors, and by using random number table, they were divided into the experimental group and the control group with equal number of rats in each group. By ultrasoundguided puncture and lipofection method, the pCI-H-2Kd was injected into thymus of SD rats in the experimental group and meanwhile, empty vector plasmid of pCIneo was injected into thymus of SD rats in the control group. Subsequently, we transplanted the donor mice myocardium xenografts into the receptor rats, and observed the xenograft rejection in both the two groups. Results The survival time of the xenotransplanted myocardium in the experimental group was significantly longer than that in the control group (14.61±2.98 d vs. 6.40±1.58 d, t=-7.619,Plt;0.05). Microtome section of transplanted myocardium in the control group showed a relatively large amount of lymphocyte infiltration and necrosis occurred to most part of the transplanted myocardium, while microtome section of experiment group showed no lymphocyte infiltration and most of the cells of the transplanted myocardium were still alive. After mixed lymphocyte culture, the reaction of receptors to donor cells in the experiment group was obviously lower than that in the control group (t=4.758, P=0.000).After the count by flow cytometer, the xenoMHC molecules were expressed in the receptors’ thymus with a transfection efficiency of 60.7%. Conclusion Our findings suggest that xenograft rejection can be mitigated substantially by donor’s MHC gene transferring into receptor’s thymus. This may provide theoretical and experimental evidence for inducing xenotransplantation tolerance.
Inherited retinal degeneration (IRD) is a group of fundus diseases characterized by a high degree of genetic heterogeneity and clinical heterogeneity, and more than 300 genetic mutations have been identified in association with IRD. Dysregulation of the intracellular second messenger cyclic guanosine monophosphate (cGMP) plays an important role in the development of IRD. cGMP participates in phototransduction process in photoreceptors. Abnormally elevated cGMP over-activate protein kinase G and cyclic nucleotide-gated channel, causing protein phosphorylation and Ca2+ overload, respectively, and these two cGMP-dependent pathways may individually or collectively drive photoreceptor degenerative lesions and death; therefore, reducing cGMP synthesis and blocking downstream signaling can be considered as treatment strategies. Investigating the molecular mechanisms of cGMP dysregulation in photoreceptor degeneration may provide a more comprehensive picture of the pathogenesis of IRD, as well as ideas for finding new therapeutic targets and designing therapeutic programs.
Mutations in the BEST1 gene are associated with a range of retinal diseases collectively referred to as "Best diseases", including Best vitelline macular dystrophy. More than 300 mutations at different sites of the BEST1 gene have been found, which may cause a series of functional disorders such as the mistransport of the calcium-activated anion channel protein-1 protein encoded by it, protein oligomerization defects, and abnormal anion channel activity, leading to different clinical phenotypes. Although it has been established that the BEST1 gene mutation is associated with at least one different type of Best disease, the relationship between the specific gene mutation site and the specific clinical phenotype has not been fully defined. For the time being. Drugs and gene therapy for the Best diseases are still in the basic research stage, which provides a broad development space for future treatment exploration. In the future, when selecting gene therapy in clinical applications, it is necessary to combine the clinical phenotype and molecular diagnosis of patients, and clearly define their mutation types and pathogenic mechanisms in order to achieve better personalized treatment effects.
Objective To introduce the method and effect of common cardiop ulmonary bypass(CPB) switched to closed extracorporeal circulation by medtronic extracorporeal membrane oxygenation(ECMO) package. Methods From Junuary 2007 to June 2008, common CPB switched to closed extracorporeal circulation by Medtronic ECMO package adding blood reservoir and artery microembolus filtrator was used to 15 patients with grave heart disease to provide CPB support during operation on heart and cardiac function support after operation. The circulation was built through femoral arteryfemoral veinsuperior vena cava intubation or aortaright auricle intubation. There were 10 male and 5 female aged from 6582 years (74.0±9.3 years) and weighed from 6389 kg (69.0±11.4 kg). There were 11 cases with old myocardial infarction, 1 case with acute myocardial infarction, 1 case with old myocardial infarction complicated with mitral stenosis and mitral incompetence, and 2 cases reopened and undergone double valve replacement. Results For all the 15 patients, the closed circulation time was 31112 min（77.3±21.5 min）. The CPB time was 51-84 min（69.7±9.8 min）. The ostoperative mechanical ventilation time was 414 h（8.3±2.9 h）. The 24 hchest drainage was 110-360 ml（227.3±80.4 ml）. All patients were cured and discharged successfully with cardiac function classification in grade ⅠⅡ. Thirteen cases were followed up. The followup time was 412 months. Their cardiac function recovered well and no complication occurred. Conclusion This method could provide effective support for heart and lung before operation，during operation and after operation. This method could save material cost. The heparin paintcoat could reduce inflammatory reaction and it is good for patients’ recovery.