Melatonin Protects Chronic Kidney Disease Mesenchymal Stem/Stromal Cells against Accumulation of Methylglyoxal via Modulation of Hexokinase-2 Expression

Treatment options for patients with chronic kidney disease (CKD) are currently limited; therefore, there has been significant interest in applying mesenchymal stem/stromal cell (MSC)-based therapy to treat CKD. However, MSCs harvested from CKD patients tend to show diminished viability and proliferation due to sustained exposure to uremic toxins in the CKD environment, which limits their utility for cell therapy. The application of melatonin has been demonstrated to improve the therapeutic efficacy of MSCs derived from and engrafted to tissues in patients suffering from CKD, although the underlying biological mechanism has not been elucidated. In this study, we observed overexpression of hexokinase-2 (HK2) in serum samples of CKD patients and MSCs harvested from an adenine-fed CKD mouse model (CKD-mMSCs). HK2 upregulation led to increased production levels of methylglyoxal (MG), a toxic metabolic intermediate of abnormal glycolytic processes. The overabundance of HK2 and MG was associated with impaired mitochondrial function and low cell proliferation in CKD-mMSCs. Melatonin treatment inhibited the increases in HK2 and MG levels, and further improved mitochondrial function, glycolytic metabolism, and cell proliferation. Our findings suggest that identifying and characterizing metabolic regulators such as HK2 in CKD may improve the efficacy of MSCs for treating CKD and other kidney disorders.

Pretreatment with Lycopene Attenuates Oxidative Stress-Induced Apoptosis in Human Mesenchymal Stem Cells

Human mesenchymal stem cells (MSCs) have been used in cell-based therapy to promote revascularization after peripheral or myocardial ischemia. High levels of reactive oxygen species (ROS) are involved in the senescence and apoptosis of MSCs, causing defective neovascularization. Here, we examined the effect of the natural antioxidant lycopene on oxidative stress-induced apoptosis in MSCs. Although H2O2 (200 muM) increased intracellular ROS levels in human MSCs, lycopene (10 muM) pretreatment suppressed H2O2-induced ROS generation and increased survival. H2O2-induced ROS increased the levels of phosphorylated p38 mitogen activated protein kinase (MAPK), Jun-N-terminal kinase (JNK), ataxia telangiectasia mutated (ATM), and p53, which were inhibited by lycopene pretreatment. Furthermore, lycopene pretreatment decreased the expression of cleaved poly (ADP ribose) polymerase-1 (PARP-1) and caspase-3 and increased the expression of B-cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein (Bax), which were induced by H2O2 treatment. Moreover, lycopene significantly increased manganese superoxide dismutase (MnSOD) expression and decreased cellular ROS levels via the PI3K-Akt pathway. Our findings show that lycopene pretreatment prevents ischemic injury by suppressing apoptosis-associated signal pathway and enhancing anti-oxidant protein, suggesting that lycopene could be developed as a beneficial broad-spectrum agent for the successful MSC transplantation in ischemic diseases.

The Effect of Amniotic Membrane Transplantation on the Treatment of Necrotizing Scleritis after Pterygium Excision

PURPOSE: To investigate the efficacy of amniotic membrane transplantation (AMT) in patients who were diagnosed with necrotizing scleritis after pterygium excision and who were refractory to systemic corticosteroid and immunosuppressive therapy. METHODS: Six patients who had persistent scleral melting with systemic corticosteroid or immunosuppressive agents underwent double AMT as a permanent patch graft and temporary overlying barrier. Postoperatively, the symptom improvements, reepithelization times and visual acuity changes were evaluated. RESULTS: Choroidal detachment was detected in two patients preoperatively. In all patients, ocular pain improved at 4.7 +/- 3.1 days, and reepithelization of the scleral lesions was completed at 13.2 +/- 8.1 days postoperatively. Choroidal detachment in two patients disappeared at postoperative 2 and 8 days. Complete remission was found in 5 of the 6 eyes (83.3%). One eye which achieved full epithelization in the necrotic area experienced recurrent nodular scleritis in another quadrant, resulting in remission after changing the regimen of immunosuppressive agents. Mean values of initial and final visual acuities were 0.898 logMAR and 0.428 logMAR, respectively, and the visual acuities improved in all patients. CONCLUSIONS: AMT is effective in promoting reepithelization of the necrotic area, resulting in complete remission of necrotizing scleritis in patients who were refractory to systemic corticosteroid or immunosuppressive therapy.

Association between Low-Density Lipoprotein Subclasses and Lipoprotein Lipase Gene Polymorphisms in Coronary Artery Disease / 대한진단검사의학회지

BACKGROUND: A preponderance of small low-density lipoproteins (LDL subclass phenotype B) has been closely associated with a high-risk for coronary artery disease. Lipoprotein lipase (LPL) gene polymorphisms have been found to be associated with coronary artery disease and lipid levels; but their impact on LDL particle size is less clearly established. METHODS: The LDL subclass phenotype was analyzed in 114 normal controls and 131 patients with coronary artery disease using the LipoPrint LDL system (Quantimetrix Co., Redondo Beach, CA, USA). HindIII and PvuII polymorphisms of LPL genes were analyzed using PCR-RFLP. Ser447 -Ter polymorphisms of LPL gene were analyzed using the PCR-based method and using mismatched primer and restriction digestion. The analysis of their associations with the LDL subclass phenotype and the LDL score was investigated. RESULTS: No statistical differences in the allelic frequencies of HindIII, PvuII and Ser447 -Ter poly-morphisms were observed between the control and patient groups. The G allelic frequency of Ser447 -Ter polymorphism was significantly higher in phenotype B than in the phenotype AandI group (P=0.043). HindIII, PvuII and Ser447 -Ter sites were in strong linkage disequilibrium. CONCLUSIONS: HindIII, PvuII and Ser447 -Ter polymorphisms were not directly linked with coronary artery disease. However, the Ser447 -Ter polymorphism is associated with the small LDL particle, which results in a change in lipid metabolism and might have an effect on the development of coronary artery disease.

Plasminogen activator inhibitor-1 4G/5G promoter polymorphism and coagulation factor VII Arg353-->Gln polymorphism in Korean patients with coronary artery disease

An increased risk for arterial thrombosis is associated with high plasma levels of coagulation and fibrinolytic factors such as PAI-1 and FVII. In this study, the 4G/5G polymorphism in the promoter of PAI-1 gene and Arg353-->Gln polymorphism in the FVII gene were analysed in 139 normal adults and 158 patients with coronary artery disease (CAD), and their association with plasma lipid traits was investigated. There were no significant differences in the allele frequencies of PAI-1 and FVII polymorphisms between control and patient groups. The allelic distributions of both polymorphisms in Koreans were similar to those in Japanese but significantly different from those in Caucasians. In the CAD group, the 4G homozygotes of PAI-1 polymorphism showed significantly higher levels of total (p=0.0250) and LDL cholesterol (p=0.0335) with individuals having other genotypes. However, FVII polymorphism showed no association with lipid levels. In conclusion, the 4G/5G PAI-1 promoter polymorphism and Arg353-->Gln FVII polymorphism are not major genetic risk factors for CAD in Koreans. However, 4G allele of PAI-1 polymorphism revealed to be associated with the levels of cholesterol, especially LDL cholesterol levels in CAD patients.