TLR4 mediates lung injury and inflammation in intestinal ischemia-reperfusion.

BACKGROUND: Splanchnic ischemia is common in critically ill patients, and it can result in injury not only of the intestine but also in distant organs, particularly in the lung. Local inflammatory changes play a pivotal role in the development of acute lung injury after intestinal ischemia, but the underlying molecular mechanisms are not fully understood. We sought to examine the role of Toll-like receptor 4 (TLR4) in the mouse model of intestinal ischemia-reperfusion (I/R)-induced lung injury and inflammation. MATERIALS AND METHODS: Adult male TLR4 mutant (C3H/HeJ) mice and TLR4 wild-type (WT) (C3H/HeOuJ) mice were subjected to 40 min of intestinal ischemia by clamping the superior mesenteric artery followed by 6 h of reperfusion. Lung histology was assessed and parameters of pulmonary microvascular permeability, inflammatory cytokine expression, and neutrophil infiltration were measured. Activation of mitogen-activated protein kinases (MAPKs) and the transcription factors nuclear factor κB (NF-κB) and activator protein-1 (AP-1) in the lungs were also detected. RESULTS: After intestinal I/R, lungs from TLR4 mutant mice demonstrated a significantly lower histological injury, a marked reduction of epithelial apoptosis associated with the decreased level of cleaved caspase-3 and the increased ratio of Bcl-xL to Bax proteins, and a large reduction in pulmonary vascular permeability and myeloperoxidase (MPO) activity in comparison with WT mice. TLR4 mutant mice also displayed marked decreases in tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and macrophage inflammatory protein-2 (MIP-2) expression. Following intestinal I/R, phosporylation of p38 MAPK and activation of NF-κB and AP-1 were significantly inhibited in lung tissue from TLR4 mutant mice compared with WT controls. CONCLUSIONS: These data suggest that TLR4 plays an important role in the pathogenesis of intestinal I/R-induced acute lung injury and inflammation and that p38 kinase and NF-κB may be involved in TLR4 signaling-mediated lung inflammatory processes during intestinal I/R.

[Reoperative valve replacement in patients undergoing cardiac reoperation: a report of 104 cases].

OBJECTIVE: To review the experience of reoperative valve replacement for 104 patients. METHODS: From January 2002 to December 2009, 104 patients underwent heart valve replacement in reoperations, accounting for 2.92% of the total patient population (3557 cases) who had valve replacement during this period. In this group, 53 male and 51 female patients were included with a median age of 46 years (ranged from 13 to 72 years). The reasons of reoperation included 28 cases suffered from another valve lesion after valve replacement, 10 cases suffered from valve lesion after mitral valvuloplasty, 19 cases suffered from perivalvular leakage after valve replacement, 18 cases suffered from valve lesion after previous correction of congenital heart defect, 7 cases suffered from bioprosthetic valve decline, 10 cases suffered from prosthetic valve endocarditis, 9 cases suffered from dysfunction of machine valve, and 3 cases suffered from other causes. The re-operations were mitral and aortic valve replacement in 2 cases, mitral valve replacement in 59 cases, aortic valve replacement in 24 cases, tricuspid valve replacement in 16 cases, and Bentall's operation in 3 cases. The interval from first operation to next operation was 1 month-19 years. RESULTS: There were 8 early deaths from heart failure, renal failure and multiple organ failure (early mortality 7.69%). Major complications were intraoperative hemorrhage in 2 cases, re-exploration for mediastinal bleeding in 2 cases and sternotomy surgical site infection in 1 case. Complete follow-up (3 months-7 years and 2 months) was available for all patients. Two patients died, one patient died of intracranial hemorrhage, and another cause was unknown. CONCLUSION: Satisfactory short-term and long-term results can be obtained in reoperative valve replacement with appropriate timing of operation control, satisfactory myocardial protection, accurate surgical procedure and suitable perioperative treatment.

Ebstein's anomaly of the tricuspid valve with rheumatic mitral stenosis and aortic incompetence.

The case is reported of Ebstein's anomaly of the tricuspid valve with rheumatic mitral stenosis and aortic incompetence. In this extremely rare clinical entity, right ventricular dysfunction and respiratory dysfunction occur due to severe mitral stenosis and tricuspid regurgitation. The present case was managed with aortic and mitral valve replacement and Danielson's repair of the tricuspid valve. The general management issues of the condition are also discussed in detail.

LncRNA-LINC00472 contributes to the pathogenesis of atrial fibrillation (Af) by reducing expression of JP2 and RyR2 via miR-24.

BACKGROUND: Dysregulated methylation of the promoter of lncRNA LINC00472 reduces the expression of LINC00472 and subsequently up-regulates the expression of its competing endogenous RNA miR-24. In addition, JP2 can stabilize the expression of RyR2, whereas the deregulation of RyR2 expression may contribute to the pathogenesis of atrial fibrillation (AF). In this study, we aimed to study the role of LINC00472 in the pathogenesis of AF. METHODS: 125 AF patients and 168 healthy controls were enrolled to compare their expression of miR-24, LINC00472, JP2 and RyR2. A dual-luciferase reporter gene assay accompanied by real-time PCR, Western blot and IHC assay was subsequently conducted to evaluate the regulatory relationship among miR-24, LINC00472, JP2 and RyR2 in HCM and H9C2 cells. RESULTS: AF patients were associated with an increased level of miR-24 expression and reduced level of LINC00472 expression. Also, the level of DNA methylation in LINC00472 was increased in AF patients. MiR-24 could negatively regulate the expression of LINC00472 and JP2 by directly binding to them. CONCLUSIONS: LINC00472 could regulate the progression of AF via modulating the LINC00472/miR-24/JP2/RyR2 signaling pathway.

Does PGA external stenting reduce compliance mismatch in venous grafts?

BACKGROUND: Autogenous vein grafting is widely used in regular bypassing procedures. Due to its mismatch with the host artery in both mechanical property and geometry, the graft often over expands under high arterial blood pressure and forms a step-depth where eddy flow develops, thus causing restenosis, fibrous graft wall, etc. External stents, such as sheaths being used to cuff the graft, have been introduced to eliminate these mismatches and increase the patency. Although histological and immunochemical studies have shown some positive effects of the external stent, the mechanical mismatch under the protection of an external stent remains poorly analyzed. METHODS: In this study, the jugular veins taken from hypercholesterolemic rabbits were transplanted into the carotid arteries, and non-woven polyglycolic acid (PGA) fabric was used to fabricate the external stents to study the effect of the biodegradable external stent. Eight weeks after the operation, the grafts were harvested to perform mechanical tests and histological examinations. An arc tangent function was suggested to describe the relationship between pressure and cross-sectional area to analyse the compliance of the graft. RESULTS: The results from the mechanical tests indicated that grafts either with or without external stents displayed large compliance in the low-pressure range and were almost inextensible in the high-pressure range. This was very different from the behavior of the arteries or veins in vivo. The data from histological tests showed that, with external stents, collagen fibers were more compact, whilst those in the graft without protection were looser and thicker. No elastic fiber was found in either kind of grafts. Furthermore, grafts without protection were over-expanded which resulted in much bigger cross-sectional areas. CONCLUSION: The PGA external extent contributes little to the reduction of the mechanical mismatch between the graft and its host artery while remodeling develops. For the geometric mismatch, it reduces the cross-section area, therefore matching with the host artery much better. Although there are some positive effects, conclusively the PGA is not an ideal material for external stent.

Effect of external stents on prevention of intimal hyperplasia in a canine vein graft model.

BACKGROUND: External stents have been used to reduce intimal hyperplasia of vein grafts. The aim of the present study was to define the size of an external stent appropriate for a particular graft by comparing vein grafts with different sizes of external stents. METHODS: A series of paired trials was performed to compare femoral vein grafts with different sizes of external stents, where 30 modeled canines were equally divided into three groups: 6-mm external stent vs non-stent control, 4-mm vs 6-mm external stent, and 4-mm vs 8-mm external stent. At day 3 after operation, color Doppler flow imaging (CDFI) was done to observe blood flow in the lumen. Four weeks later, CDFI was re-checked and the veins were harvested, stained and measured. RESULTS: All grafts were patent without formation of thrombosis. External stents significantly reduced intimal thickness of the vein grafts with a 6-mm external stent compared with the vein grafts without external stents (P < 0.05). The vein grafts with the 4-mm external stent had similar intimal, medial and adventitial thicknesses compared with those with the 6-mm external stent and the 8-mm external stent. CONCLUSIONS: External stents can reduce intimal hyperplasia of vein grafts. Stents of different diameters exert the similar effect on prevention of intimal hyperplasia.

Risk factors for postoperative recurrence of cardiac myxoma and the clinical managements: a report of 5 cases in one center and review of literature.

BACKGROUND: Recurrence or metastasis of myxomas is not rare and can lead to malignancy. We aimed to analyze the risk factors for postoperative cardiac myxoma recurrence and to summarize its clinical characteristics, treatments and classification. METHODS: The clinical data of 5 patients with recurrent cardiac myxoma were retrospectively analyzed and our clinical experience was summarized. Moreover, the relevant literatures were reviewed. RESULTS: All the five cases of primary myxomas were derived from atypical positions. One patient had early distant metastasis, one had family history, and two suffered malignant recurrence. The recurrence interval was (2.30 ± 2.16) years and the recurrent tumors were all found in different chambers from those of the corresponding primary tumors. Re-operation was performed after recurrence. One patient died of heart failure after malignant recurrence, and the other 4 cases had satisfactory therapeutic outcomes after re-operations. Our experience advocated a clinical classification of "typical" and "atypical" cardiac myxoma, the typical myxomas referred to the tumors locating at the left atria, with single pedicle, rooted at or around the fossa ovalis, involving no genetic causes, and the atypical myxomas included the familial tumors, tumors stemming from multiple chambers, rooted in abnormal positions of the left atrium, with evident genetic mutation, or with malignant tendency. CONCLUSIONS: Postoperative follow-up is of vital importance for patients with myxomas characterized by multi-chamber distribution, early distant metastasis, atypical origin, and family history. Once recurs, re-operation is necessary and should be performed immediately.