Coconut atrium in long-standing rheumatic valvular heart disease.

BACKGROUND: Complete calcification of the left atrium (LA) is called "coconut atrium", which decreases the compliance of LA, leading to the elevation of LA pressure that is transmitted to the right-side of the heart. The pathogenesis of LA calcification in patients with rheumatic heart disease is unknown; however, possible mechanisms include chronic strain force in the atrial wall and inflammation. We report here a patient with long-standing rheumatic valvular heart disease with coconut atrium. CASE REPORT: A 76-year-old man presented with breathlessness and leg edema due to right-sided heart failure. He was diagnosed with rheumatic fever at 8 years of age. Mitral commissurotomy and the mitral and aortic valve replacement were previously performed to treat mitral and aortic valvular stenosis. The profile view of the chest X-ray indicated a diffuse calcified outline of the LA wall. A transthoracic echocardiogram revealed pulmonary hypertension and dilatation of both atria. Moreover, computed tomography showed nearly circumferential calcification of the LA wall. Despite intense medical treatment, he succumbed to heart failure. An autopsy demonstrated that the LA was markedly dilated, its wall was calcified, and its appearance was similar to the surface of an atherosclerotic aorta. Microscopic examination revealed intensive calcification in the endocardium. Minimal accumulation of inflammatory cells was noted. Although slight fibrosis was observed, the cardiac musculature was preserved. CONCLUSIONS: To the best of our knowledge, this is the first report that identifies the histological changes of LA calcification associated with long-standing rheumatic valvular heart disease.

A super-elderly case of abdominal aortic aneurysm associated with chronic disseminated intravascular coagulation.

Chronic disseminated intravascular coagulation (DIC) is a well-known complication of aortic aneurysm. A 91-year-old Japanese woman was admitted to our hospital because of massive purpura of the lower limbs. The presence of abdominal aortic aneurysm (AAA) had been pointed out from the age of 80 years, and its diameter had gradually increased. The AAA was composed of two portions, that is, a large upper and a small lower portion, and a large mural thrombosis was observed in the lower portion. The laboratory data led to the diagnosis of DIC, and AAA was the only identifiable cause of coagulopathy. The time course of exacerbation of AAA was consistent with the progression of thrombocytopenia and purpura. Therefore, we concluded that AAA was the underlying cause of DIC. Since DIC in aortic aneurysms is associated with excessive fibrinolysis, tranexamic acid was administered as anti-fibrinolytic therapy. After that, coagulopathy was drastically improved. Our patient responded successfully to anti-fibrinolytic therapy for coagulopathy. The present case illustrates the importance of evaluation of the diameter of an aneurysm as well as intraluminal thrombosis, which may play an important role in coagulopathy including DIC. It is necessary to monitor coagulation and fibrinolysis for the follow-up of patients with AAA. .

Chylomicron remnants regulate early growth response factor-1 in vascular smooth muscle cells.

Early growth response factor-1 (Egr-1) is a zinc-finger transcription factor that induces genes that promote atherosclerosis. The goal of the present study was to determine whether Egr-1 expression is modulated by atherogenic, triglyceride rich lipoproteins known as chylomicron remnants. Chylomicron remnants induced Egr-1 mRNA and protein expression in rat cultured vascular smooth muscle cells (VSMCs) and activated extracellular signal-regulated kinase (ERK) 1/2 in VSMCs. Further, chylomicron remnant-induced Egr-1 expression was inhibited by PD98059, a selective inhibitor of MAPK kinase (MEK), suggesting that the action of chylomicron remnants on Egr-1 was dependent on the ERK/MEK pathway. Chylomicron remnants also induced mRNA expression of the pro-inflammatory cytokines, IL-2 and IFN-gamma in VSMCs. We conclude that chylomicron remnants act as atherogenic lipoproteins via induction of Egr-1 expression and via cytokine-mediated inflammation.

Chylomicron remnants induce monocyte chemoattractant protein-1 expression via p38 MAPK activation in vascular smooth muscle cells.

Chylomicron remnants, major lipoproteins at postprandial hyperlipidemia, have been considered to be proatherogenic lipoproteins. However, the mechanisms by which chylomicron remnants enhance atherosclerosis have not been fully understood. Monocyte chemoattractant protein-1 (MCP-1) is a chemokine which stimulates migration of monocytes and plays a critical role in the development of atherosclerosis. In this study, we investigated the effect of chylomicron remnants on MCP-1 expression in cultured vascular smooth muscle cells (VSMCs). We prepared chylomicrons from the lymph of gastrostomized rats fed with egg solution and obtained chylomicron remnants from the plasma of hepatectomized rats which were injected with chylomicrons. Treatment of VSMC with chylomicron remnants resulted in a significant increase of the expression of MCP-1 mRNA and protein in a time-and a dose-dependent manner. Further, chylomicron remnants activated p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase (ERK1/2). Pretreatment of VSMCs with p38 MAPK inhibitors, SB203580 and SB202190, resulted in a dose-dependent inhibition of chylomicron remnants-induced MCP-1 mRNA and protein expression, whereas a MAPK kinase inhibitor, PD98059, had no effect on these responses. MCP-1 secretion by chylomicron remnants was much more pronounced than those by chylomicrons, oxidized low-density lipoproteins, or lysophosphatidylcholine. These results indicated that chylomicron remnants stimulated MCP-1 expression in VSMCs, and suggested that chylomicron remnants might contribute to the formation of atherosclerosis through this proinflammatory effect.