Objective: Creatine, energy buffer in high energy demanding systems including muscle and brain, may play a beneficial role against neuroinflammation in Alzheimer’s disease (AD), and thus be a potential biomarker. This study aimed to compare the levels of plasma creatine between persons with and without AD and investigate associations of plasma creatine levels with cognitive function and blood-based inflammatory markers. Methods: We classified elderly participants by cognitive statuses: normal cognition (NC, n=17), mild cognitive impairment (MCI,n=21), and AD (n=21). To assess cognitive function and inflammatory condition, we performed neuropsychological tests and mea-sured plasma C-reactive protein (CRP) levels, respectively. Results: Plasma creatine levels were comparable among participants with AD, MCI, and NC. In overall participants, plasma cre-atine levels were not associated with neuropsychological test scores, but negatively associated with plasma CRP levels. In AD group, plasma creatine levels were negatively associated with neuropsychological test scores and, although not significant, CRP levels (p=0.086). In participants without AD (NC plus MCI), these associations disappeared. Conclusion Plasma creatine levels may not be useful as a biomarker indicating cognitive statuses. However, our results suggest that, in AD, plasma levels of creatine might reflect the extent of neuroinflammation as well as cognitive deterioration.

A subset of spondyloarthritis (SpA) called ‘reactive arthritis’ is triggered by causal pathogens, usually bacteria related to venereal disease or gastrointestinal infection. During the outbreak of coronavirus disease 2019 (COVID-19), there have been case reports about SpA after COVID-19, but the causality is still elusive. We described cases of 23-year-old monozygotic twins both diagnosed with SpA after COVID-19. The probable linkage between SpA and COVID-19 was elaborated with our cases as well as literature reviews. Of note, shared genetic traits by monozygotic twins, particularly HLA-B27 positivity, might have contributed to their susceptibility to COVID-19-induced SpA. Moreover, single-cell transcriptome analysis revealed that the transcriptomic profile of peripheral compartment of SpA after COVID-19 was distinctive from that of typical radiographic axial SpA as shown by differential expression of ribosomal protein S26 (RPS26) and small nucleolar RNA host gene 5 (SNHG5) in nearly all subsets of peripheral blood mononuclear cells.

PURPOSE: The host immune responses to skin xenografts are known to be much stronger than those to allografts. The possible reasons for that, however, are unclear. We hypothesized that chemokines trafficking leukocytes may be involved in stronger xenograft rejection process as compared to allograft rejection. METHODS: Thus, we evaluated the profiles of chemokine expression and cellular infiltration in the skin xenografts and compared to those in fully allogeneic skingrafts. RESULTS: At day 5, post-transplantation the heavier cellular infiltration of CD4+, CD8+ T cells and neutrophils into xenografts was found as compared to allografts. Similarly, more CD8+ T, CD11b+ and MOMA-2+ cells were found to infiltrate into xenografts than allografts at day 7. The xenograft showed earlier and stronger mRNA expression of chemokines such as MCP-1, IP-10 and MIG. In the late phase of xenograft rejection, strong expression of RANTES and MIP-1a was noted. In xenografts, the time of expression of IP-10 and MIG was correlated with the time of infiltration of CD4+, CD8+ cells and neutrophils whereas, the expression patterns of RANTES and MIP-1a were similar to the infiltration patterns of CD11b+ and MOMA-2+ cells. CONCLUSION: These results suggest that the prompt xenograft cellular rejection as compared to the allograft rejection may be related to the rapid induction of pro-inflammatory chemokines such as MCP-1, IP-10 and MIG in the early phase and resultant significant infiltration of CD4+ and CD8+ T cells and neutrophils.
Allografts ; Chemokine CCL5 ; Chemokines ; Heterografts* ; Leukocytes ; Neutrophils ; RNA, Messenger ; Skin* ; T-Lymphocytes ; Transplantation, Heterologous

PURPOSE: Human embryonic stem (ES) cell is pluripotent cell derived from a group of cells called the inner cell mass and has the ability to reproduce itself for long periods and give rise to types of cells that develop from the three germ layers. Due to its pluripotency, ES cell holds the promise of being able to replace cells that are damaged or destroyed by many devastating diseases. However, the potential for the recipient of an ES cell transplant to reject this cell as foreign is very high. Thus, it is essential to determine whether human ES cells express MHC antigens. The purpose of this study is to characterize the stem cell properties of our cell line (SNUhES1) and the expression profile of MHC antigens on the surface of these cells and their differentiated derivatives, embryoid bodies (EBs). METHODS: The ES cells were grown on STO fibroblast in DMEM-F12. The EBs were grown in the same medium with exception that it lacked LIF and bFGF. The expression of self-renewal-associated genes and three germ layer cell-specific genes in ES cells and EBs were measured by RT-PCR at varying time point of incubation (1, 7, 14 and 28 day). The expression of MHC molecules were measured by RT-PCR and FACS analysis. RESULTS: The SNUhES1 cells expressed all self-renewal- associated genes (Fgf4, FoxD3, Oct4, Sox2 and TERT) we tested. During the differentiation three germ layer cell-specific genes in EBs were expressed as following order: ecto-, meso- and endodermal cell-specific genes. MHC class I proteins (HLA-ABC and beta2m) on the surfaces of ES cells and EBs were expressed in very low levels. MHC class II proteins (HLA-DP, -DQ and -DR) and HLA-G were not expressed on the surface of these cells. However, the expression of MHC class II proteins were detected in 1% more or less cells of 28-day-old EBs which were hardly detected in the population of 1-day-old EBs. CONCLUSION: These data imply that SNUhES1 cells and EBs have stem cell properties. Although they express very low MHC antigens, further investigation determining whether the MHC expression in the ES cells and EBs may alter under inflammatory condition which can be occurred in damaged tissue or through surgical process.
Cell Line ; Embryoid Bodies* ; Embryonic Stem Cells* ; Endoderm ; Fibroblasts ; Germ Layers ; HLA-G Antigens ; Humans* ; Stem Cells ; Transplants

Background: Large-scale studies about epidemiologic characteristics of renal infarction (RI) are few. In this study, we aimed to analyze the incidence and prevalence of RI with comorbidities in the South Korean population. Methods: We investigated the medical history of the entire South Korean adult population between 2013 and 2019 using the National Health Insurance Service database (n = 51,849,591 in 2019). Diagnosis of RI comorbidities were confirmed with International Classification of Disease, Tenth Revision, Clinical Modification codes. Epidemiologic characteristics, distribution of comorbidities according to etiologic mechanisms, and trend of antithrombotic agents were estimated. Results: During the 7-years, 10,496 patients were newly diagnosed with RI. The incidence rate increased from 2.68 to 3.06 per 100,000 person-years during the study period.The incidence rate of RI increased with age peaking in the 70s with 1.41 times male predominance. The most common comorbidity was hypertension, followed by dyslipidemia and diabetes mellitus. Regarding etiologic risk factor distribution, high embolic risk group, renovascular disease group, and hypercoagulable state group accounted for 16.6%, 29.1%, and 13.7% on average, respectively. For the antithrombotic treatment of RI, the prescription of antiplatelet agent gradually decreased from 17.0% to 13.0% while that of anticoagulation agent was maintained around 35%. The proportion of non-vitamin K antagonist oral anticoagulants remarkably increased from only 1.4% to 17.6%. Conclusion Considering the progressively increasing incidence of RI and high prevalence of coexisting risk factors, constant efforts to raise awareness of the disease are necessary. The current epidemiologic investigation of RI would be the stepping-stone to establishing future studies about clinical outcomes and optimal treatment strategies.