DNA methylation is altered in B and NK lymphocytes in obese and type 2 diabetic human

Objective

Obesity is associated with low-grade inflammation and the infiltration of immune cells in insulin-sensitive tissues, leading to metabolic impairment. Epigenetic mechanisms control immune cell lineage determination, function and migration and are implicated in obesity and type 2 diabetes (T2D). The aim of this study was to determine the global DNA methylation profile of immune cells in obese and T2D individuals in a cell type-specific manner.

Material and methods

Fourteen obese subjects and 11 age-matched lean subjects, as well as 12 T2D obese subjects and 7 age-matched lean subjects were recruited. Global DNA methylation levels were measured in a cell type-specific manner by flow cytometry. We validated the assay against mass spectrometry measures of the total 5-methylcytosine content in cultured cells treated with the hypomethylation agent decitabine (r = 0.97, p < 0.001).

Results

Global DNA methylation in peripheral blood mononuclear cells, monocytes, lymphocytes or T cells was not altered in obese or T2D subjects. However, analysis of blood fractions from lean, obese, and T2D subjects showed increased methylation levels in B cells from obese and T2D subjects and in natural killer cells from T2D patients. In these cell types, DNA methylation levels were positively correlated with insulin resistance, suggesting an association between DNA methylation changes, immune function and metabolic dysfunction.

Conclusions

Both obesity and T2D are associated with an altered epigenetic signature of the immune system in a cell type-specific manner. These changes could contribute to the altered immune functions associated with obesity and insulin resistance.     

Importance of measuring pharmacologically active metabolites of edoxaban: development and validation of an ultra-high-performance liquid chromatography coupled with a tandem mass spectrometry method

Journal of Thrombosis and Thrombolysis - Although DOACs do not require regular measurements of their blood concentrations, clinical situations may require an assessment of their concentration....     

Novel Genetic Models of Osteoporosis by Overexpression of Human RANKL in Transgenic Mice

Receptor activator of NF‐κB ligand (RANKL) plays a key role in osteoclast‐induced bone resorption across a range of degenerative bone diseases, and its specific inhibition has been recently approved as a treatment for women with postmenopausal osteoporosis at high or increased risk of fracture in the United States and globally. In the present study, we generated transgenic mice (TghuRANKL) carrying the human RANKL (huRANKL) genomic region and achieved a physiologically relevant pattern of RANKL overexpression in order to establish novel genetic models for assessing skeletal and extraskeletal pathologies associated with excessive RANKL and for testing clinical therapeutic candidates that inhibit human RANKL. TghuRANKL mice of both sexes developed early‐onset bone loss, and the levels of huRANKL expression were correlated with bone resorption and disease severity. Low copy Tg5516 mice expressing huRANKL at low levels displayed a mild osteoporotic phenotype as shown by trabecular bone loss and reduced biomechanical properties. Notably, overexpression of huRANKL, in the medium copy Tg5519 line, resulted in severe early‐onset osteoporosis characterized by lack of trabecular bone, destruction of the growth plate, increased osteoclastogenesis, bone marrow adiposity, increased bone remodeling, and severe cortical bone porosity accompanied by decreased bone strength. An even more severe skeletal phenotype developed in the high copy Tg5520 founder with extensive soft tissue calcification. Model validation was further established by evidence that denosumab, an antibody that inhibits human but not murine RANKL, fully corrected the hyper‐resorptive and osteoporotic phenotypes of Tg5519 mice. Furthermore, overexpression of huRANKL rescued osteopetrotic phenotypes of RANKL‐defective mice. These novel huRANKL transgenic models of osteoporosis represent an important advance for understanding the pathogenesis and treatment of high‐turnover bone diseases and other disease states caused by excessive RANKL. © 2014 American Society for Bone and Mineral Research.     

Identification of prognostic markers in diffuse midline gliomas H3K27M‐mutant

Pediatric diffuse midline gliomas are devastating diseases. Among them, diffuse midline gliomas H3K27M‐mutant are associated with worse prognosis. However, recent studies have highlighted significant differences in clinical behavior and biological alterations within this specific subgroup. In this context, simple markers are needed to refine the prognosis of diffuse midline gliomas H3K27M‐mutant and guide the clinical management of patients. The aims of this study were (i) to describe the molecular, immunohistochemical and, especially, chromosomal features of a cohort of diffuse midline gliomas and (ii) to focus on H3K27M‐mutant tumors to identify new prognostic markers. Patients were retrospectively selected from 2001 to 2017. Tumor samples were analyzed by immunohistochemistry (including H3K27me3, EGFR, c‐MET and p53), next‐generation sequencing and comparative genomic hybridization array. Forty‐nine patients were included in the study. The median age at diagnosis was 9 years, and the median overall survival (OS) was 9.4 months. H3F3A or HIST1H3B mutations were identified in 80% of the samples. Within the H3K27M‐mutant tumors, PDGFRA amplification, loss of 17p and a complex chromosomal profile were significantly associated with worse survival. Three prognostic markers were identified in diffuse midline gliomas H3K27M‐mutant: PDGFRA amplification, loss of 17p and a complex chromosomal profile. These markers are easy to detect in daily practice and should be considered to refine the prognosis of this entity.     

Molecular studies of translocations and trisomy involving chromosome 13

Twenty-four cases of trisomy 13 and one case with disomy 13, but a de novo dic(13,13) (p12p12) chromosome, were examined with molecular markers to determine the origin of the extra (or rearranged) chromosome. Twenty-one of 23 informative patients were consistent with a maternal origin of the extra chromosome. Lack of a third allele at any locus in both paternal origin cases indicate a somatic duplication of the paternal chromosome occurred. Five cases had translocation trisomy: one de novo rob(13q14q), one paternally derived rob(13q14q), two de novo t(13q13q), and one mosaic de novo t(13q13q)/r(13). The patient with a paternal rob(13q14q) had a maternal meiotic origin of the trisomy; thus, the paternal inheritance of the translocation chromosome was purely coincidental. Since there is not a significantly increased risk for unbalanced offspring of a t(13q14q) carrier and most trisomies are maternal in origin, this result should not be surprising; however, it illustrates that one cannot infer the origin of translocation trisomy based on parental origin of the translocation. Lack of a third allele at any locus in one of the three t(13q13q) cases indicates that it was most likely an isochromosome of postmeiotic origin, whereas the other two cases showed evidence of recombination. One balanced (nontrisomic) case with a nonmosaic 45,−13,−13,t(13;13) karyotype was also investigated and was determined to be a somatic Robertsonian translocation between the maternal and paternal homologues, as has been found for all balanced homologous Robertsonian translocations so far investigated. Thus, it is also incorrect to assume in de novo translocation cases that the two involved chromosomes are even from the same parent. Despite a maternal origin of the trisomy, we cannot therefore infer anything about the parental origin of the chromosomes 13 and 14 involved in the translocation in the de novo t(13q14q) case nor for the two t(13;13) chromosomes showing a meiotic origin of the trisomy. © 1996 Wiley-Liss, Inc.     

Carpal tunnel syndrome due to t cell lymphoma

In 2 patients, carpal tunnel syndrome was one of the presenting manifestations of a noncutaneous T cell lymphoma. Infiltration of the carpal tunnel by neoplastic T cells was proven by biopsy in both patients. In 1 case, the carpal tunnel syndrome was associated with eosinophilic fasciitis. These observations emphasize the importance of histologic examination of annular ligaments removed during surgical decompression procedures.