Sustained over-expression of calpain-2 induces age-dependent dilated cardiomyopathy in mice through aberrant autophagy.

Calpains have been implicated in heart diseases. While calpain-1 has been detrimental to the heart, the role of calpain-2 in cardiac pathology remains controversial. In this study we investigated whether sustained over-expression of calpain-2 had any adverse effects on the heart and the underlying mechanisms. Double transgenic mice (Tg-Capn2/tTA) were generated, which express human CAPN2 restricted to cardiomyocytes. The mice were subjected to echocardiography at age 3, 6, 8 and 12 months, and their heart tissues and sera were collected for analyses. We showed that transgenic mice over-expressing calpain-2 restricted to cardiomyocytes had normal heart function with no evidence of cardiac pathological remodeling at age 3 months. However, they exhibited features of dilated cardiomyopathy including increased heart size, enlarged heart chambers and heart dysfunction from age 8 months; histological analysis revealed loss of cardiomyocytes replaced by myocardial fibrosis and cardiomyocyte hypertrophy in transgenic mice from age 8 months. These cardiac alterations closely correlated with aberrant autophagy evidenced by significantly increased LC3BII and p62 protein levels and accumulation of autophagosomes in the hearts of transgenic mice. Notably, injection of 3-methyladenine, a well-established inhibitor of autophagy (30 mg/kg, i.p. once every 3 days starting from age 6 months for 2 months) prevented aberrant autophagy, attenuated myocardial injury and improved heart function in the transgenic mice. In cultured cardiomyocytes, over-expression of calpain-2 blocked autophagic flux by impairing lysosomal function. Furthermore, over-expression of calpain-2 resulted in lower levels of junctophilin-2 protein in the heart of transgenic mice and in cultured cardiomyocytes, which was attenuated by 3-methyladenine. In addition, blockade of autophagic flux by bafilomycin A (100 nM) induced a reduction of junctophilin-2 protein in cardiomyocytes. In summary, transgenic over-expression of calpain-2 induces age-dependent dilated cardiomyopathy in mice, which may be mediated through aberrant autophagy and a reduction of junctophilin-2. Thus, a sustained increase in calpain-2 may be detrimental to the heart.

Combined antihypertensive and statin therapy for the prevention of cardiovascular events in patients with hypertension without complications: protocol for a systematic review and meta-analysis.

INTRODUCTION: High blood pressure (BP) affects over 40% of adults over the age of 25 worldwide and is the leading global risk factor for death or disability. Hypertension is also the most important risk factor for endovascular atherosclerosis, which, when combined with other cardiovascular risk factors, leads to atherosclerotic cardiovascular disease (ASCVD). Statins are one of the most widely used drugs for the prevention of ASCVD. The recently announced study of Heart Outcomes Prevention Evaluation-3 suggests that cholesterol-lowering agents combined with antihypertensive therapy can prevent cardiovascular events and reduce the combined endpoint. We plan to conduct a systematic review and meta-analysis to evaluate whether combined antihypertensive and statin therapy is more beneficial than antihypertensive therapy alone in patients with hypertension without complications. METHODS AND ANALYSIS: We will perform a comprehensive search for randomised controlled trials evaluating combined antihypertensive and statin therapy for the treatment of patients with hypertension. The following English electronic databases will be searched: The Cochrane Library, EMBASE and PubMed. Outcomes will be categorised as short-term (≤6 months) or long-term (>6 months). When evaluating the effects of combined antihypertensive and statin therapy, a short-term outcome is usually defined as a change in BP or lipid levels, while a long-term outcome is usually defined as cardiovascular benefits or risks. The data screening and extraction will be conducted by two different reviewers. The quality of the RCTs will be assessed according to the Cochrane handbook risk of bias tool. ETHICS AND DISSEMINATION: This review does not require ethics approval and the results of the meta-analysis will be submitted to a peer-review journal. PROSPERO REGISTRATION NUMBER: CRD42017071935.

False human immunodeficiency virus test results associated with rheumatoid factors in rheumatoid arthritis.

OBJECTIVE: To investigate if immunological factors associated with rheumatoid arthritis (RA) affect the result of human immunodeficiency virus (HIV) screening by electrochemiluminescence immunoassay (ECLIA) and enzyme-linked immunosorbent assay (ELISA). METHODS: 100 RA cases were enrolled from January 2012 to February 2013 into this study. HIV screening was conducted with ECLIA detecting both HIV-1 p24 antigen, HIV-1 and HIV-2 antibodies, with ELISA and colloidal gold method detecting HIV-1 and HIV-2 antibodies. The samples producing positive results were submitted to the Center for Disease Control for confirmation using Western blotting method. The antibody titers of rheumatoid factors (RF) including RF-IgG, RF-IgM, RF-IgA, and CCP-IgG were analyzed by ELISA. RESULTS: The HIV positive-rate determined by ECLIA was significantly higher than that by ELISA and colloidal gold method (P<0.01). The false-positive rate of HIV screening was associated with antibody titers of RF-IgG, RF-IgM, RF-IgA, and CCP-IgG in RA (P<0.01). CONCLUSIONS: Immunological factors, including RF and anti-CCP antibody, may influence the screening of HIV by ECLIA, producing false-positive result.

[Research on the relationship between combined detection of RF and CCP and Chinese medical syndrome patterns of RA].

OBJECTIVE: To study the objective diagnostic mechanisms on Chinese medical (CM) syndrome patterns of rheumatoid arthritis (RA), and to research different titers of rheumatoid factor (RF)/citrullinated protein antibody (CCP) in CM syndrome patterns of RA. METHODS: Totally 230 early RA patients were assigned to five CM syndrome pattern groups, i.e., the dampness-heat blockage group (50 cases), the cold-dampness blockage group (50 cases), the Shen-qi deficiency-cold group (50 cases), the Gan-Shen yin deficiency group (40 cases), and the blood stasis blockage group (40 cases). Another 100 healthy subjects were recruited as the healthy control group. RF-IGM, RF-IGA, RF-IGG, and anti-CCP antibody were detected and compared. RESULTS: The titers of RF-IGM, RF-IGA, RF-IGG, and anti-CCP antibody were higher in all groups than in the healthy control groups (P < 0.01). As for the 5 groups, RF-IGM, RF-IGA,RF-IGG, and anti-CCP antibody were higher in the RA active stage than in the nonactive stage. They were higher in the dampness-heat blockage group in the RA active stage than in the Shen-qi deficiency-cold group, the Gan-shen yin deficiency group, and the blood stasis blockage group. CONCLUSION: Titers of RF-IGM, RF-IGA, RF-IGG, and anti-CCP antibody could be taken as judging indicators for differentiating objective lab indices of CM syndromes and assessing the active stage of RA.

[Effect of IL-17 on collagen I/III expression in cardiac fibroblasts isolated from BALB/c mice].

AIM: To investigate the effect of IL-17 on the expression of collagen I/III in cardiac fibroblasts and analyze its molecular mechanism. METHODS: Cardiac fibroblasts were isolated from 7-14-day-old BALB/c mice and cultured in DMEM with 10% fetal bovine serum (FBS). The cells were collected after IL-17 treatment for 0, 24, 48, 72 h. IL-17 receptors on cardiac fibroblasts were detected by PCR; the collagen I/III expression was analyzed by immunofluorescence; the PKCß, Erk1/2, NF-κB phosphorylation were investigated by Western blotting. RESULTS: IL-17RA/C was expressed on cardiac fibroblasts; after 24 h of IL-17 stimulation, the collagen I/III expression obviously increased; Western blotting showed that PKCß, Erk1/2 and NF-κB were phosphorylated on 30, 45, 45 min, respectively. CONCLUSION: IL-17 could induce the expression of collagen I/III in cardiac fibroblasts, which might be related with PKCß-ERK1/2-NF-κB phosphorylation.

[Relationship between cutaneous glycometabolic disorders and cutaneous neuropathy in diabetic rats].

OBJECTIVE: To analyze the relationship between cutaneous glycometabolic disorders and cutaneous neuropathy in diabetic rats, and to look for the mechanism of neuropathy and impaired wound healing. METHODS: Eighty male SD rats were randomly divided into the normal control group (NC, n = 20), diabetic group (D, n = 20), aminoguanidine-interfered group (AI, n = 20), and insulin-interfered group (II, n = 20) by drawing lots. Diabetes was reproduced in rats of D, AI, and II groups with intraperitoneal injection of streptozotocin (STZ). Then, rats in AI group were fed with 100 mg×kg(-1)×d(-1) aminoguanidine, while rats in II group were subcutaneously injected with insulin for satisfactory control of blood glucose. Changes in mechanical and heat pain thresholds of pad of hind limb were measured at post injection week (PIW) 2, 4, 8. Skin specimens were collected during PIW 2-8 from pads for determination of contents of glucose, advanced glycation end product (AGE), substance P (SP), calcitonin gene-related peptide (CGRP), and observation of distribution and ultrastructure of skin nerve fibers. Data were processed with t test. RESULTS: The mechanical and heat pain thresholds in D group at PIW 2 [(6.3 ± 1.5) g, (6.0 ± 0.9) s, respectively ] were obviously lower than those in NC group [(13.0 ± 3.2) g, (10.3 ± 1.2) s, with t value respectively 2.71, 3.42, P values all below 0.05]. Contents of glucose and AGE in skin tissue in D group were significantly increased when compared with those in NC group, especially at PIW 8 [(2.85 ± 0.33) mg/g, (31.7 ± 3.2) U/mg of hydroxyproline vs. (0.82 ± 0.22) mg/g, (22.2 ± 1.9) U/mg of hydroxyproline, with t value respectively 1.65, 6.47, P values all below 0.01]. The myelinated nerve fibers were edematous and degenerated, with axons compressed, while the unmyelinated nerve fibers were vacuolated, with microfilament and microtubule disorderly arranged. Content of SP in skin tissue in D group was lower as compared with that in NC group, especially at PIW 2 [(16.8 ± 3.4) pg/g vs. (28.5 ± 5.0) pg/g, t = 2.42, P < 0.01]. There was no obvious difference in content of CGRP between NC and D groups, and also in content of glucose in skin between D and AI groups. Compared with those in D group, content of AGE in AI group at PIW 8 was decreased markedly [(27.2 ± 1.4) U/mg of hydroxyproline, t = 3.38, P < 0.05]; contents of glucose and AGE in II group at PIW 8 were significantly decreased [(1.42 ± 0.38) mg/g, (23.6 ± 1.3) U/mg of hydroxyproline, with t value respectively 1.74, 8.17, P < 0.05 or P < 0.01]. Compared with that in D group, contents of SP in AI and II groups were increased, with a delay in time of trough value. Content of CGRP showed no obvious difference among D, AI, and II groups. CONCLUSIONS: High glucose and accumulation of AGE are key mediators of cutaneous neuropathy and impaired wound healing in diabetes mellitus, which confirms that diabetic wound takes an atypical footing during wound repairing. Aminoguanidine and insulin can reduce contents of glucose and AGE in diabetic skin tissue, and ameliorate diabetic cutaneous neuropathy.

Adherence and invasion of mouse-adapted H pylori in different epithelial cell lines.

AIM: To assess the adhesion and invasion abilities of different mouse adapted H pylori strains in different cell lines in vitro and investigate their effects on the virulence factors cagA and vacA. METHODS: The adherence and invasion abilities of different H pylori strains in different epithelial cell lines were examined by the gentamycin protection assay. The null mutants of cagA and vacA were processed by direct PCR mutation method. The morphologic changes of different cell lines after H pylori attachment were examined by microscopy. RESULTS: The densities of adherence to and invasion into cells in vitro were different from those in the mouse infection experiments. 88-3887 strain could invade and adhere to cells stronger than SS1 and X47. All tested strains had better adhering and invasive abilities in SCG-7901 cell. CagA and vacA minus mutants had the same invasion and adherent abilities as their wild types. In all strains and cell lines tested, only AGS cell had the significant hummingbird phenotype after inoculation with the 88-3887 wild-type. CONCLUSION: Both the host cells and the bacteria play important parts in the invasion and adhesion abilities of H pylori. CagA and VacA are not related to the ability of invasion and adhesion of H pylori in different cell lines in vitro.