WT Sham Research Articles

Abstract 521: Cardiovascular Phenotype in Mice with Renovascular Hypertension and Type II Diabetes

Background: Combined renovascular hypertension (RVH) and type II diabetes (DM II) are a major health problem. Both share common risk factors and contribute to cardiovascular morbidity and mortality. We recently observed a high mortality rate in DM II mice (dbdb) with RVH. Purpose: We sought to determine the interactions between renovascular hypertension and DM II on the cardiovascular phenotype in dbdb mice with RVH. Methods and Materials: RVH was established by placing a polytetrafluoroethylene cuff on the right renal artery of C57BL/KS (wild type, WT) or dbdb mice. We divided the mice into four groups: WT sham, WT type RAS, dbdb sham, dbdb RAS. We examined the blood pressure, plasma angiotensin I, renin, heart weight and myocyte diameter. Histologic parameters including inflammation, necrosis and fibrosis were assessed semiquantitively. Results: Blood pressure, Renin, Plasma angiotensin I: RAS produced a similar elevation in systolic blood pressure (SBP), renin mRNA expression, and plasma angiotensin I content in WT and dbdb mice with RAS. Heart weight: Despite similar elevation in SBP, db/db RAS mice showed a greater increase in heart weight than WT RAS mice (163.7 +/- 6.4 mmHg vs 145.7 +/- 2.3; n=23).. Similar trends were observed on normalization of the heart weight to tibial length. Cardiac myocyte diameter: Cardiac myocyte diameter in WT RAS (n=26) was significantly higher than in WT sham (n=15; 16.4 ± 0.3 vs. 15.0 ± 0.3 μm, p=0.0031). Myocyte diameter was higher in dbdb RAS mice (n=19, 14.76 ± 0.35) than dbdb sham (15.94 ± 0.29 μm, p= 0.0126). However, myocyte diameter was similar in dbdb RAS and WT RAS mice (16.4 ± 0.3 vs. 15.9 ± 0.3 μm, p=0.3). Histology: Sham groups had no inflammation (INF) or necrosis (NEC). Interstitial fibrous tissue was increased in dbdb RAS mice (28% by area) vs WT RAS (19% by area). Dbdb RAS mice had more severe INF (severe in 18%, mild in 82%) than WT RAS (severe in 0%, jild in 12%). Severe NEC was found in 32.1% of dbdb compared to 11.5% of WT RAS. Conclusion: The histologic changes and hypertrophy of the heart superimpose in dbdb RAS compared to WT RAS. This indicates that the risk of cardiovascular morbidity and mortality increases synergisticly in the presence of DM II and RVH.

MicroRNAs are dysregulated in the cerebral microvasculature of CKD mice

Vascular calcification arises during chronic kidney disease (CKD), and increases the risk of cardiovascular mortality. In CKD, alterations of cerebral circulation were linked with an increase in ischemic strokes and behavioral troubles. Studying pathophysiological mechanisms of calcifications and detecting new biomarkers in the cerebral circulation is thus an important issue. microRNAs are small non-coding, single-stranded RNAs that regulate messenger RNAs at the post-transcriptional level. They are involved in numerous pathologies and represent new opportunities to develop disease predictors. We used RT-qPCR to quantify endothelial-specific microRNAs in cerebral arterioles from WT mice and from pathological models of CKD. We used four mice groups: WT SHAM, WT CKD, Apolipoprotein E Knock-Out (ApoE-KO) SHAM, ApoE-KO CKD. Brains were removed after two and ten weeks of uremia and RNA from cerebral arterioles was extracted. miR-17 and miR-126 were the most dysregulated in the pathological conditions, at both the second week and tenth week of uremia. Our results suggest that miR-17 and miR-126 are potential new biomarkers of cerebral troubles of CKD patients and new therapeutic targets for innovative treatments.

Hepcidin and Ferroportin in Different Murine Models of Obesity Challenged with Polymicrobial Sepsis

Sepsis is a leading cause of mortality in non‐coronary intensive care units. Obesity has been on the rise over the past decades. Hepcidin diminishes ferroportin expression and decreases ferritin levels. In both obesity and sepsis hepcidin is increased causing lower serum iron levels. The changes of hepcidin expression in murine obesity and sepsis are unknown. The objective of this study was to compare hepcidin, ferroportin and ferritin levels in murine models of obesity (ob/ob and db/db) challenged with cecal ligation and puncture (CLP) to values in corresponding shams. RT‐PCR and ELISAs were used to quantify the expression of hepcidin and ferroportin in hepatic and subcutaneous fat tissue, and serum levels of hepcidin and ferritin in WT, ob/ob and db/db mice 6 hours following CLP. CLP led to increased hepatic expression of hepcidin in WT and ob/ob, but not db/db, mice. Hepcidin expression in subcutaneous fat was elevated solely in db/db sham mice. Ferroportin expression was unchanged in septic obese mice. Serum levels of hepcidin were significantly decreased in ob/ob and db/db CLP mice and their corresponding shams compared with WT sham and CLP mice. Ferritin levels were unchanged in all groups. The elevated tissue expression of hepcidin following CLP does not appear to exert a systemic impact, as indicated by the unchanged serum levels of hepcidin and ferritin (supported by the FWF Austrian Science Fund, P22567, Government of Styria).

UP-REGULATING HO-1 IMPROVES POST-INFARCTION HEART FUNCTION OF SPONTANEOUS HYPERTENSIVE RATS VIA ANTI-INFLAMMATION, ANTI-OXIDATION, LOWERING BLOOD GLUCOSE AND IMPROVING ENDOTHELIAL FUNCTION

ObjectivesOur previous results showed that hame oxygenase 1 (HO-1) is involved in the regulation of endothelial function by the modulation of NOS isoforms and control of oxidative stress. HO-1, in...

Gamma delta (γδ) T-cells are critical in the up-regulation of inducible nitric oxide synthase at the burn wound site

BackgroundThe high incidence of morbidity and mortality following major burn can in part be attributed to immune derangements and wound healing complications. Inflammation plays an important role in wound healing, of which inducible nitric oxide synthase (iNOS) derived nitric oxide is a central mediator. T-cells of the γδ TCR lineage have also been shown to be important in healing of the burn wound site. Nonetheless, the role of γδ T-cells in the regulation of the burn wound iNOS expression is unknown. MethodsWildtype (WT) and δ TCR−/− male C57BL/6 mice were subjected to burn (3rd degree, 12.5% TBSA) or sham treatment. Three days after injury, skin samples from non-injured and the burn wound were collected and analyzed for the expression of iNOS and cytokines and chemokine levels. In a second series of experiments, WT mice were subjected to burn and left untreated or treated with the iNOS inhibitor, L-Nil. Skin cytokine and chemokine levels were assessed 3days thereafter. ResultsBurn induced an 18-fold increase in iNOS expression at the wound site as compared to the uninjured skin of WT sham mice. In δ TCR−/− mice iNOS expression at the wound site was significantly lower than that of the WT group. Burn also induced increased levels of IL-1β, IL-6, G-CSF, TNF-α, KC, MCP-1, MIP-1α and MIP-1β at the wound site in WT and δ TCR−/− mice, but G-CSF, TNF-α, and MIP-1β levels were greater in δ TCR−/− mice. Inhibition of iNOS activity in WT mice with L-Nil suppressed burn wound levels of IL-1β, G-CSF, and MIP-1α, whereas IL-6, TNF-α, KC, MCP-1 and MIP-1β were unaffected. ConclusionsT-cells of the γδ TCR lineage significantly contribute to the up-regulation of iNOS expression which contributes to wound inflammation.

Intrahippocampal Transplantation of Transgenic Neural Precursor Cells Overexpressing Interleukin-1 Receptor Antagonist Blocks Chronic Isolation-Induced Impairment in Memory and Neurogenesis

The proinflammatory cytokine interleukin-1 (IL-1) within the brain is critically involved in mediating the memory impairment induced by acute inflammatory challenges and psychological stress. However, the role of IL-1 in memory impairment and suppressed neurogenesis induced by chronic stress exposure has not been investigated before now. We report here that mice that were isolated for 4 weeks displayed a significant elevation in hippocampal IL-1beta levels concomitantly with body weight loss, specific impairment in hippocampal-dependent memory, and decreased hippocampal neurogenesis. To examine the causal role of IL-1 in these effects, we developed a novel approach for long-term delivery of IL-1 receptor antagonist (IL-1ra) into the brain, using transplantation of neural precursor cells (NPCs), obtained from neonatal mice with transgenic overexpression of IL-1ra (IL-1raTG) under the glial fibrillary acidic protein promoter. Four weeks following intrahippocampal transplantation of IL-1raTG NPCs labeled with PKH-26, the transplanted cells were incorporated within the dentate gyrus and expressed mainly astrocytic markers. IL-1ra levels were markedly elevated in the hippocampus, but not in other brain regions, by 10 days and for at least 4 weeks post-transplantation. Transplantation of IL-1raTG NPCs completely rescued the chronic isolation-induced body weight loss, memory impairment, and suppressed hippocampal neurogenesis, compared with isolated mice transplanted with WT cells or sham operated. The transplantation had no effect in group-housed mice. These findings elucidate the role of IL-1 in the pathophysiology of chronic isolation and suggest that transplantation of IL-1raTG NPCs may provide a useful therapeutic procedure for IL-1-mediated memory disturbances in chronic inflammatory and neurological conditions.

Biglycan deficiency interferes with ovariectomy-induced bone loss.

Biglycan is a matrix proteoglycan with a possible role in bone turnover. In a 4-week study with sham-operated or OVX biglycan-deficient or wildtype mice, we show that biglycan-deficient mice are resistant to OVX-induced trabecular bone loss and that there is a gender difference in the response to biglycan deficiency. Biglycan (bgn) is a small extracellular matrix proteoglycan enriched in skeletal tissues, and biglycan-deficient male mice have decreased trabecular bone mass and bone strength. The purpose of this study was to investigate the bone phenotype of the biglycan-deficient female mice and to investigate the effect of estrogen depletion by ovariectomy (OVX). OVX or sham operations were performed on 21-week-old mice that were divided into four groups: wt sham (n = 7), wt OVX (n = 9), bgn-deficient sham (n = 10) and bgn-deficient OVX (n = 10). The mice were killed 4 weeks after surgery. Bone mass and bone turnover were analyzed by peripheral quantitative computed tomography (pQCT), biochemical markers, and histomorphometry. In contrast to the male mice, there were only few effects of bgn deficiency on bone metabolism in female mice, showing a clear gender difference. However, when stressed by OVX, the female bgn knockout (KO) mice were resistant to the OVX-induced trabecular bone loss. The wt mice showed a decrease in trabecular bone mineral density by pQCT measurements, a decrease in trabecular bone volume (BV/TV), and an increase in mineral apposition rate. In contrast, no significant changes were detected in bgn KO mice after OVX. In addition, analysis of the bone resorption marker deoxypyridinoline showed no significant increase in the bgn KO OVX mice compared with bgn KO sham mice. Measurements of serum osteoprotegerin (OPG) and RANKL revealed increased levels of OPG and decreased levels of RANKL in the bgn KO mice compared with wt mice. In conclusion, the bgn deficiency protects against increased trabecular bone turnover and bone loss in response to estrogen depletion, supporting the concept that bgn has dual roles in bone, where it may modulate both formation and resorption ultimately influencing the bone turnover process.