Expressions of mRNA and encoded proteins of mitochondrial uncoupling protein genes (UCP1, UCP2, and UCP3) in epicardial and mediastinal adipose tissue and associations with coronary artery disease

Objective

To evaluate the expression of UCP1, UCP2, and UCP3 mRNA and encoded proteins in epicardial and mediastinal adipose tissues in patients with coronary artery disease (CAD).

Subjects and methods

We studied 60 patients with CAD and 106 patients undergoing valve replacement surgery (controls). Expression levels of UCP1, UCP2, and UCP3 mRNA and encoded proteins were measured by quantitative real-time PCR and Western blot analysis, respectively.

Results

: We found increased UCP1, UCP2, and UCP3 mRNA levels in the epicardial adipose tissue in the CAD versus the control group, and higher UCP1 and UCP3 mRNA expression in the epicardial compared with the mediastinal tissue in the CAD group. There was also increased expression of UCP1 protein in the epicardial tissue and UCP2 protein in the mediastinum tissue in patients with CAD. Finally, UCP1 expression was associated with levels of fasting plasma glucose, and UCP3 expression was associated with levels of high-density lipoprotein cholesterol and low-density cholesterol in the epicardial tissue.

Conclusion

Our study supports the hypothesis that higher mRNA expression by UCP genes in the epicardial adipose tissue could be a protective mechanism against the production of reactive oxygen species and may guard the myocardium against damage. Thus, UCP levels are essential to maintain the adaptive phase of cardiac injury in the presence of metabolic disorders.

Dual Effect of Bleomycin on Histopathological Features of Lungs and Mediastinal Fat-Associated Lymphoid Clusters in an Autoimmune Disease Mouse Model

Mediastinal fat-associated lymphoid clusters (MFALCs) are novel immune clusters that function in the pathogenesis of bleomycin (BLM)-induced pneumonitis in a C57BL/6 mouse model. However, we lack literature on the effects of BLM in an autoimmune disease mouse model (AIDM). In the present study, BLM sulfate (BLM group) or phosphate-buffered saline (PBS group) were intranasally administered in BXSB/MpJ-Yaa (Yaa) AIDM and its wild-type strains (BXSB/MpJ “BXSB”) and the histopathology of MFALCs and lungs were examined on days 7 and 21 days. Immunohistochemical analysis was performed to detect lymphatic vessels (LVs), high endothelial venules (HEVs), proliferating, and immune cells. Furthermore, the mRNA expression of Yaa locus genes (TLR7, TLR8, Arhgap6, Msl3, and Tceanc) was detected in the lung tissues. Here, we show a dual effect of BLM on intra-thoracic immune hemostasis among Yaa AIDM and its corresponding wild-type strain (BXSB mice). The BLM group of BXSB mice displayed significantly higher values of lung injury scores (LIS) and size of MFALCs as compared with the corresponding PBS group. However, an opposite effect was detected in Yaa mice. Furthermore, Yaa mice displayed decreased serum autoantibody titers and downregulated expression of TLR7, TLR8, Msl3, and Tceanc in the lungs following BLM administration, especially on day 21. Interestingly, significant positive correlations were detected in both strains between the LIS and the size of MFALCs, LVs, HEVs, and proliferating cells. Conclusively, our findings revealed a crucial function of HEVs on the extent of lung injury and the development of MFALCs in BLM-administered Yaa AIDM and control BXSB mice with dual effects. Moreover, our data suggest that down regulation of Yaa locus genes could contribute as an important attributing factor leading to decrease in the degree of autoimmunity and lung injury in AIDM. Therefore, we suggest that genetic background contributes to BLM diversity among AIDM and the wild-type strain. Targeting some genes or venules could provide novel therapeutic approaches for some autoimmune-associated respiratory diseases via controlling the MFALCs development.

Reduction of plasma angiopoietin-like 2 after cardiac surgery is related to tissue inflammation and senescence status of patients

OBJECTIVES

A strong relationship between high circulating angiopoietin-like 2 (ANGPTL2) levels, a proinflammatory adipokine, and cardiovascular diseases has been reported. Our objective was to determine whether plasma ANGPTL2 and high-sensitivity C-reactive protein (hs-CRP) levels change postoperatively in patients who underwent heart valve surgery and/or coronary artery bypass grafting. We hypothesized that a corrective cardiac surgery would decrease ANGPTL2 levels.

METHODS

In 47 prospectively recruited patients who underwent coronary artery bypass grafting (n = 16), valve replacement (n = 16), or both (n = 15), we measured plasma ANGPTL2 and hs-CRP levels preoperatively, at 24 hours, at 3 to 5 days (hospital discharge), and at 30 to 90 days (follow-up) after surgery. Mediastinal adipose tissue and distal fragments of the left internal mammary artery (IMA) were harvested during surgery and mRNA expression of inflammatory and senescence markers was assessed using real-time quantitative polymerase chain reaction.

RESULTS

ANGPTL2 and hs-CRP levels were elevated 24 hours after surgery and then returned to baseline levels. We noted, however, a dichotomy among patients: compared with baseline, plasma ANGPTL2 levels either significantly decreased (n = 21/47) or increased (n = 26/47) after surgery. In contrast, hs-CRP levels were identical between groups (P = .997). Patients in the increased group were older (P = .002) with a higher systolic blood pressure (P = .038) at baseline. Moreover, changes in ANGPTL2 levels (ΔANGPTL2 = final minus initial levels) positively correlated with mRNA expression of tumor necrosis factor α and interleukin 8 in mediastinal adipose tissue and IMA (P < .05) and with the senescence-associated marker cyclin-dependent kinase inhibitor 1 in IMA (P = .009).

CONCLUSIONS

In younger patients with lower levels of tissue inflammation and arterial senescence load, ANGPTL2, but not hs-CRP levels decreased after cardiac surgery, suggesting that circulating ANGPTL2 reflects tissue inflammation and senescence.

Histopathological Correlations between Mediastinal Fat-Associated Lymphoid Clusters and the Development of Lung Inflammation and Fibrosis following Bleomycin Administration in Mice

Bleomycin (BLM) has been reported to induce lung inflammation and fibrosis in human and mice and showed genetic susceptibility. Interestingly, the C57BL/6 (B6) mice had prominent mediastinal fat-associated lymphoid cluster (MFALCs) under healthy condition, and showed susceptibility to development of lung fibrosis following BLM administration. However, the pathogenesis of lung lesion progression, and their correlation with MFALC morphologies, remain to be clarified. To investigate the correlations between MFALC structures and lung injuries in B6 mice, histopathological examination of mediastinal fat tissues and lungs was examined at 7 and 21 days (d) following a single 50 μL intranasal (i.n.) instillation of either BLM sulfate (5 mg/kg) (BLM group) or phosphate-buffered saline (control group). The lung fibrosis was examined by Masson’s trichrome (MT) stain of paraffin sections and mRNA expression levels of Col1a1, Col3a1, and Acta2 in different frozen lung samples. Furthermore, immunohistochemistry for CD3, B220, Iba1, Gr1, BrdU, LYVE-1, and peripheral node addressin (PNAd) was performed to detect T- and B-cells, macrophages, granulocytes, proliferating cells, lymph vessels (LVs), and high endothelial venules (HEVs). We found that MFALCs were more abundant in the BLM group as compared to the control group. The lung of BLM group developed pneumonitis with severe cellular infiltrations at 7 days and significant collagen deposition (MT) and higher expression of Col1a1, and Col3a1 at 21 days post-administration. Numerous immune cells, proliferating cells, HEVs, and LVs were observed in both MFALCs and lungs of the BLM group. Interestingly, PNAd + HEVs were observed in the lungs of the BLM group, but not the control group. Moreover, numerous Gr1 + polymorphonuclear and mononuclear-like ring cells were found in the MFALCs and lungs of the BLM group. Interestingly, flow cytometric analysis revealed a significant increase of B-cell populations within the MFALCs of BLM group suggesting a potential proliferative induction of B-cells following inflammation. Furthermore, significant positive correlations were observed between quantitative parameters of these immune cells in both the lungs and MFALCs. Thus, we suggest a potentially important role for MFALCs and HEVs in the progression of lung disease, especially in inflammatory lung disease.

Comparative analysis of mediastinal fat-associated lymphoid cluster development and lung cellular infiltration in murine autoimmune disease models and the corresponding normal control strains

We previously discovered mediastinal fat-associated lymphoid clusters (MFALCs) as novel lymphoid clusters associated with mediastinal fat tissue in healthy mice. However, no data about their morphology in immune-associated disease conditions, and their relationship with lung infiltration, is available to date. In the present study, we compared the morphological features of MFALCs in 4-month-old male murine autoimmune disease models (MRL/MpJ-lpr mice and BXSB/MpJ-Yaa mice) with those of the corresponding control strains (MRL/MpJ and BXSB/MpJ, respectively). In addition, we analysed their correlation with lung infiltration. Furthermore, immunohistochemistry for CD3, B220, Iba1, Gr1 and BrdU was performed to detect T cells and B cells, macrophages, granulocytes and proliferating cells, respectively. The spleen weight to body weight ratios and anti-double-stranded DNA autoantibody titres were found to be significantly higher in the autoimmune models than in the control strains. Furthermore, the autoimmune model presented prominent MFALCs, with a significantly greater ratio of lymphoid cluster area to total mediastinal fat tissue area, and more apparent diffused cellular infiltration into the lung lobes than the other studied strains. Higher numbers of T and B cells, macrophages and proliferating cells, but fewer granulocytes, were observed in the autoimmune models than in the control strains. Interestingly, a significant positive Pearson's correlation between the size of the MFALCs and the density of CD3-, B220- and Iba1-positive cells in the lung was observed. Therefore, our data suggest a potentially important role for MFALCs in the progression of lung disease. However, further investigation is required to clarify the pathological role of MFALCs in lung disease, especially in inflammatory disorders.