Atherosclerosis, inflammation and lipoprotein glomerulopathy in kidneys of apoE-/-/LDL-/- double knockout mice

Association of triglycerides to high-density lipoprotein cholesterol ratio with incident cardiovascular disease but not end-stage kidney disease among patients with biopsy-proven diabetic nephropathy

Increased triglycerides (TG) and decreased high-density lipoprotein cholesterol (HDL-C) are dyslipidemias characteristic of diabetes. Here, we aimed to examine associations of TG/HDL-C ratio with cardiovascular disease (CVD) and kidney dysfunction among patients with diabetic nephropathy. This retrospective observational study consists of patients with biopsy-proven diabetic nephropathy at Nara Medical University Hospital. Exposure of interest was TG/HDL-C ratio measured at kidney biopsy. Outcome variables were kidney histological findings, incident CVD and end-stage kidney disease (ESKD). Multivariable logistic regression models and Cox proportional hazard models were used to examined these associations. A total of 353 subjects were divided into quartiles based on TG/HDL-C ratio: Quartile 1 (reference), <1.96; Quartile 2, 1.96-3.10; Quartile 3, 3.11-4.55; and Quartile 4, ≥4.56. TG/HDL-C ratio was not a predictor of any histological findings in fully adjusted models. During median follow-up periods of 6.2 and 7.3 years, 152 and 90 subjects developed CVD and ESKD, respectively. Higher TG/HDL-C ratio was independently associated with higher incidences of CVD even after adjustments for potential confounders (hazard ratio [95% confidence interval] for Quartile 3 vs. reference; 1.73 [1.08-2.79] and Quartile 4 vs. reference; 1.86 [1.10-3.17]). Although there was a weak association between TG/HDL-C ratio and ESKD in the univariable model, the association was not significant in fully adjusted models. In conclusion, among patients with biopsy-proven diabetic nephropathy, higher TG/HDL-C ratio was independently associated with higher incidences of CVD but not with kidney outcomes, suggesting different impact of TG/HDL-C ratio on cardiorenal outcomes.

Lipoprotein Glomerulopathy-Like Lesions in Atherosclerotic Mice Defected With HDL Receptor SR-B1

High-density lipoprotein (HDL) homeostasis is important in maintaining both cardiovascular and renal health. Scavenger receptor class B type 1 (SR-B1), the major HDL receptor in mammals, plays a crucial role in reverse cholesterol transport and HDL metabolism. Evidence from mouse study has well demonstrated that HDL disorders caused by Srb1 inactivation accelerate atherosclerosis and even induce lethal cardiovascular diseases. However, the renal consequences of Srb1 dysfunction are still unknown. Here we explored this issue in both Srb1 knockout (Srb1-/-) mice and atherosclerotic low-density lipoprotein receptor knockout (Ldlr-/-) mice with Srb1 deletion. Our data showed that no apparent renal damage was observed in 5-month-old Srb1-/- mice fed on standard rodent chow diet as well as Srb1-/- mice fed on a high-fat diet (HFD) for 12 weeks. However, 5-month-old Srb1/Ldlr-/- mice fed on rodent chow had increased urinary albumin excretion and developed spontaneous intraglomerular Oil-red O (ORO)-positive lipoprotein deposition that is similar to lesions observed in human lipoprotein glomerulopathy (LPG). HFD feeding accelerated LPG-like lesions in Srb1/Ldlr-/- mice, inducing severe proteinuria and significantly promoting intraglomerular ORO-positive lipoprotein deposition. Interestingly, probucol reversed HFD-induced HDL disorders and almost fully abrogated LPG-like lesions in Srb1/Ldlr-/- mice. In conclusion, the present study demonstrates that SR-B1 dysfunction leads to LPG-like lesions in atherosclerotic mice, which could be rescued by probucol. SR-B1 loss-of-function mutant carriers therefore might be susceptible to developing metabolic nephropathy in addition to cardiovascular diseases, and probucol might be a potential therapeutics.

Relation between carotid vulnerable plaques and peripheral leukocyte: a case-control study of comparison utilizing multi-parametric contrast-enhanced ultrasound

Background

This study evaluates carotid vulnerable plaques using contrast-enhanced ultrasound (CEUS) and explores the relationship between vulnerable plaques and leukocytes.

Methods

Sixty-two symptomatic and 54 asymptomatic patients underwent CEUS. The images were analyzed using time-intensity and fitting curves, and peak (P_TIC), mean (M_TIC), peak (P_FC), sharpness (S_FC), and area under the curve (AUC_FC) were obtained. The relations between CEUS parameters and leukocytes were analyzed.

Results

In the symptomatic group, total leukocytes and neutrophils were higher, while lymphocyte was decreased; P_TIC, M_TIC, P_FC, S_FC, and AUC_FC were significantly higher; M_TIC and AUC_FC were negatively correlated with lymphocytes, and M_TIC was positively correlated with neutrophils. Classification and regression tree analysis showed that M_TIC at a cutoff of 20.8 and AUC_FC at a cutoff of 8.8 resulted in a predictive of acute cerebral infarction, accuracy of 84.3%, sensitivity of 87.1%, and specificity of 81.5%.

Conclusions

The variation in the perivascular leucocyte is significantly related to intraplaque inflammatory activities, CEUS is a feasible monitor of intraplaque neovascularization, so CEUS combined with perivascular leucocyte could be helpful as a warning for vulnerable plaques.

Angiopoietin-like protein 3 markedly enhanced in the hyperlipidemia related proteinuria

BACKGROUND

Angiopoietin-like protein 3(ANGPTL3) is well acknowledged as a key regulator of lipid metabolism. Now, there have not been enough data to explain the mechanism of hyperlipidemia related proteinuria. In this study, we hoped to investigate the changes of Angiopoietin-like protein 3(ANGPTL3) levels in hyperlipidemia patients with different proteinuria levels.

METHODS

Seventy-one patients with hyperlipidemia were selected, who were hospitalized in Gansu Provincial People's Hospital from September 2016 to September 2017, and 20 healthy people in the physical examination center were selected. We combed through medical history and conducted clinical biochemical indicators of blood urea nitrogen (BUN), serum creatinine (SCr), 24 h urine protein quantitation (24hUPro), cholesterol (TC), triglyceride (TG), high density lipoprotein (HDL) and low detection of density lipoproteins (LDL-C). The concentration of serum ANGPTL3 was measured by ELISA.

RESULTS

1. Serum ANGPTL3 in patients with hyperlipidemia related proteinuria was higher than that in the control group, and the difference was statistically significant (p < 0.05); 2. 24hUPro and BMI (r = 0.321, P = 0.002), TC (r = 0.465, P = 0.000), TG (r = 0.281, P = 0.007), LDL (r = 0.478, P = 0.000) in patients with hyperlipidemia related proteinuria are positively correlated, suggesting that dyslipidemia is related to the occurrence of proteinuria; 3. BMI, TC, TG and LDL in patients with hyperlipidemia related proteinuria were positively correlated with serum ANGPTL3. 4. The 24hUPro of patients with hyperlipidemia related proteinuria was positively correlated with serum ANGPTL3 levels, and BUN and SCr were not associated with serum ANGPTL3 level. 5. There was no significant difference in TC, TG, BMI, 24hUPro and serum ANGPTL3 between the statin-treated and the untreated groups in patients with hyperlipidemia related proteinuria.

CONCLUSIONS

Angiopoietin-like protein 3 markedly enhanced in the hyperlipidemia related proteinuria.

Pathogenesis, histopathologic findings and treatment modalities of lipoprotein glomerulopathy: A review

Lipoprotein glomerulopathy (LPG) is an uncommon cause of nephrotic syndrome and/or kidney failure. At microscopy, LPG is characterized by the presence of lipoprotein thrombi in dilated glomerular capillaries due to different ApoE mutations. ApoE gene is located on chromosome 19q13.2, and can be identified in almost all serum lipoproteins. ApoE works as a protective factor in atherosclerosis due its interaction with receptor-mediated lipoprotein clearance and cholesterol receptor. Most common polymorphisms include ApoE2/2, ApoE3/2, ApoE3/3, ApoE4/2, ApoE4/3, and ApoE4/4. All age-groups can be affected by LPG, with a discrete male predominance. Compromised patients typically reveal dyslipidemia, type III hyperlipoproteinemia, and proteinuria. LPG treatment includes fenofibrate, antilipidemic drugs, steroids, LDL aphaeresis, plasma exchange, antiplatelet drugs, anticoagulants, urokinase, and renal transplantation. Recurrence in kidney graft suggests a pathogenic component(s) of extraglomerular humoral complex resulting from abnormal lipoprotein metabolism and presumably associated to ApoE.

Magnetic Nanoparticles Conjugated with Peptides Derived from Monocyte Chemoattractant Protein-1 as a Tool for Targeting Atherosclerosis

Atherosclerosis is a multifactorial inflammatory disease that may progress silently for long period, and it is also widely accepted as the main cause of cardiovascular diseases. To prevent atherosclerotic plaques from generating, imaging early molecular markers and quantifying the extent of disease progression are desired. During inflammation, circulating monocytes leave the bloodstream and migrate into incipient lipid accumulation in the artery wall, following conditioning by local growth factors and proinflammatory cytokines; therefore, monocyte accumulation in the arterial wall can be observed in fatty streaks, rupture-prone plaques, and experimental atherosclerosis. In this work, we synthesized monocyte-targeting iron oxide magnetic nanoparticles (MNPs), which were incorporated with the peptides derived from the chemokine receptor C-C chemokine receptor type 2 (CCR2)-binding motif of monocytes chemoattractant protein-1 (MCP-1) as a diagnostic tool for potential atherosclerosis. MCP-1-motif MNPs co-localized with monocytes in in vitro fluorescence imaging. In addition, with MNPs injection in ApoE knockout mice (ApoE KO mice), the well-characterized animal model of atherosclerosis, MNPs were found in specific organs or regions which had monocytes accumulation, especially the aorta of atherosclerosis model mice, through in vivo imaging system (IVIS) imaging and magnetic resonance imaging (MRI). We also performed Oil Red O staining and Prussian Blue staining to confirm the co-localization of MCP-1-motif MNPs and atherosclerosis. The results showed the promising potential of MCP-1-motif MNPs as a diagnostic agent of atherosclerosis.

Low testosterone in ApoE/LDL receptor double-knockout mice is associated with rarefied testicular capillaries together with fewer and smaller Leydig cells

The testis as a site for atherosclerotic changes has so far attracted little attention. We used the apolipoprotein E (ApoE)/low density lipoprotein (LDL) receptor deficient mouse model (KO) for atherosclerosis (20, 40, 60 and 87-week-old) to investigate whether Leydig cells or the capillary network are responsible for reduced serum testosterone levels previously observed in extreme ages of this model. In KO mice, overall testosterone levels were reduced whereas the adrenal gland-specific corticosterone was increased excluding a general defect of steroid hormone production. In addition to micro-CT investigations for bigger vessels, stereology revealed a reduction of capillary length, volume and surface area suggesting capillary rarefaction as a factor for diminished testosterone. Stereological analyses of interstitial cells demonstrated significantly reduced Leydig cell numbers and size. These structural changes in the testis occurred on an inflammatory background revealed by qPCR. Reduced litter size of the KO mice suggests hypo- or infertility as a consequence of the testicular defects. Our data suggest reduced testosterone levels in this atherosclerosis model might be explained by both, rarefication of the capillary network and reduced Leydig cell number and size. Thus, this study calls for specific treatment of male infertility induced by microvascular damage through hypercholesterolemia and atherosclerosis.

Vasa vasorum in atherosclerosis and clinical significance

Atherosclerosis is a chronic inflammatory disease that leads to several acute cardiovascular complications with poor prognosis. For decades, the role of the adventitial vasa vasorum (VV) in the initiation and progression of atherosclerosis has received broad attention. The presence of VV neovascularization precedes the apparent symptoms of clinical atherosclerosis. VV also mediates inflammatory cell infiltration, intimal thickening, intraplaque hemorrhage, and subsequent atherothrombosis that results in stroke or myocardial infarction. Intraplaque neovessels originating from VV can be immature and hence susceptible to leakage, and are thus regarded as the leading cause of intraplaque hemorrhage. Evidence supports VV as a new surrogate target of atherosclerosis evaluation and treatment. This review provides an overview into the relationship between VV and atherosclerosis, including the anatomy and function of VV, the stimuli of VV neovascularization, and the available underlying mechanisms that lead to poor prognosis. We also summarize translational researches on VV imaging modalities and potential therapies that target VV neovascularization or its stimuli.

Macrophage-derived apoESendai suppresses atherosclerosis while causing lipoprotein glomerulopathy in hyperlipidemic mice

Lipoprotein glomerulopathy (LPG) is a renal disease often accompanied by dyslipidemia and increased serum apoE levels. apoESendai (Arg145Pro), a rare mutant based on the apoE3 sequence carrying an apoE2 charge, causes LPG in humans and transgenic mice, but its effects on the artery wall are unknown. Macrophage expression of apoESendai may also directly influence renal and arterial homeostasis. We investigated the effects of macrophage-expressed apoESendai in apoE(-/-) mice with or without LDL receptor (LDLR). Murine bone marrow transduced to express apoE2, apoE3, or apoESendai was transplanted into lethally irradiated mice. Macrophage apoESendai expression reduced aortic lesion size and inflammation by 32 and 28%, respectively, compared with apoE2 in apoE(-/-) recipients. No differences in lesion size or inflammation were found between apoESendai and apoE3 in apoE(-/-) recipients. Macrophage apoESendai expression also reduced aortic lesion size by 18% and inflammation by 29% compared with apoE2 in apoE(-/-)/LDLR(-/-) recipients. Glomerular lesions compatible with LPG with increased mesangial matrix, extracellular lipid accumulation, and focal mesangiolysis were only observed in apoE(-/-)/LDLR(-/-) mice expressing apoESendai. Thus, macrophage expression of apoESendai protects against atherosclerosis while causing lipoprotein glomerulopathy. This is the first demonstration of an apoprotein variant having opposing effects on vascular and renal homeostasis.