Adverse reactions and effects on renal function of COVID-19 vaccines in patients with IgA nephropathy.

BACKGROUND: Although vaccination has been reported to reduce the morbidity and severity of COVID-19 infection in patients with kidney disease, gross hematuria is frequently reported following vaccination in patients with IgA nephropathy. We investigated the frequency of gross hematuria following COVID-19 vaccination and its effect on renal function in IgA nephropathy patients. METHODS: Adverse reactions after two or more COVID-19 vaccine doses were investigated in 295 IgA nephropathy patients attending Osaka Cty general hospital from September 2021 to November 2022. We compared differences in background characteristics and other adverse reactions between groups with and without gross hematuria after vaccination, and examined changes in renal function and proteinuria. RESULTS: Twenty-eight patients (9.5%) had gross hematuria. The median age of patients with and without gross hematuria was 44 (29-48) and 49 (42-61) years, respectively, indicating a significant difference. The percentage of patients with microscopic hematuria before vaccination differed significantly between those with (65.2%) and without (32%) gross hematuria. Adverse reactions, such as fever, chills, headache and arthralgia, were more frequent in patients with gross hematuria. There was no difference in renal functional decline after approximately 1 year between patients with and without gross hematuria. We also found no significant changes in estimated glomerular filtration rate or proteinuria before and after vaccination in the gross hematuria group. However, some patients clearly had worsening of renal function. CONCLUSIONS: While COVID-19 vaccination is beneficial, care is required since it might adversely affect renal function in some patients.

Effect of a SGLT2 inhibitor on the systemic and intrarenal renin-angiotensin system in subtotally nephrectomized rats.

We aimed to examine the effects of a sodium glucose co-transporter 2 (SGLT2) inhibitor on systemic and intrarenal renin-angiotensin system (RAS) in subtotally nephrectomized non-diabetic rats, a model of chronic kidney disease (CKD). Oral administration of the selective SGLT2 inhibitor, TA-1887 (10 mg/kg/day), for 10 weeks induced glycosuria. However, plasma renin activity, plasma angiotensinogen levels, kidney angiotensin II contents and renal injury were not significantly affected by TA-1887. These data indicate that chronic treatment with an SGLT2 inhibitor does not activate the systemic and intrarenal RAS in subjects with non-diabetic CKD.

Detection of Splicing Abnormalities and Genotype-Phenotype Correlation in X-linked Alport Syndrome.

BACKGROUND: X-linked Alport syndrome (XLAS) is a progressive hereditary nephropathy caused by mutations in the COL4A5 gene. Genotype-phenotype correlation in male XLAS is relatively well established; relative to truncating mutations, nontruncating mutations exhibit milder phenotypes. However, transcript comparison between XLAS cases with splicing abnormalities that result in a premature stop codon and those with nontruncating splicing abnormalities has not been reported, mainly because transcript analysis is not routinely conducted in patients with XLAS. METHODS: We examined transcript expression for all patients with suspected splicing abnormalities who were treated at one hospital between January of 2006 and July of 2017. Additionally, we recruited 46 males from 29 families with splicing abnormalities to examine genotype-phenotype correlation in patients with truncating (n=21, from 14 families) and nontruncating (n=25, from 15 families) mutations at the transcript level. RESULTS: We detected 41 XLAS families with abnormal splicing patterns and described novel XLAS atypical splicing patterns (n=14) other than exon skipping caused by point mutations in the splice consensus sequence. The median age for developing ESRD was 20 years (95% confidence interval, 14 to 23 years) among patients with truncating mutations and 29 years (95% confidence interval, 25 to 40 years) among patients with nontruncating mutations (P=0.001). CONCLUSIONS: We report unpredictable atypical splicing in the COL4A5 gene in male patients with XLAS and reveal that renal prognosis differs significantly for patients with truncating versus nontruncating splicing abnormalities. Our results suggest that splicing modulation should be explored as a therapy for XLAS with truncating mutations.

Enhanced expression of natriuretic peptide receptor A and B in neutrophils of culprit lesions in patients with acute myocardial infarction.

Natriuretic peptides and their specific receptors have been suggested to have regulatory effects on smooth muscle cell (SMC) growth and inflammatory cell reactions. However, the roles of natriuretic peptide receptor A (NPR­A) and B (NPR­B) in unstable plaques remain to be studied in detail. Frozen sections from 82 coronary artery segments were used. These segments were obtained at autopsy from 13 patients with acute myocardial infarction (AMI; 7 ruptured and 6 eroded plaques) and from 30 patients with non­cardiovascular diseases. Antibodies against SMCs, endothelial cells, macrophages, neutrophils, NPR­A, NPR­B and neutral endopeptidase (NEP) were used. Neutrophil infiltration was identified in all lesions with plaque rupture or erosion. Double immunostaining identified that the majority of NPR­A­ or NPR­B­positive cells were neutrophils in ruptured and eroded plaques. Using morphometric analysis, no significant difference was observed in the percentage of NPR­A­ and NPR­B­positive cells between ruptured and eroded plaques, while the number of NEP­positive neutrophils in ruptured plaques was significantly higher compared with eroded plaques (P<0.0001). These results of the distinct presence of NPR­A­ and NPR­B­positive cells in unstable plaques underlying AMI suggested that natriuretic peptides serve a role in regulating plaque instability in humans.

Regression of glomerular and tubulointerstitial injuries by dietary salt reduction with combination therapy of angiotensin II receptor blocker and calcium channel blocker in Dahl salt-sensitive rats.

A growing body of evidence indicates that renal tissue injuries are reversible. We investigated whether dietary salt reduction with the combination therapy of angiotensin II type 1 receptor blocker (ARB) plus calcium channel blocker (CCB) reverses renal tissue injury in Dahl salt-sensitive (DSS) hypertensive rats. DSS rats were fed a high-salt diet (HS; 4% NaCl) for 4 weeks. Then, DSS rats were given one of the following for 10 weeks: HS diet; normal-salt diet (NS; 0.5% NaCl), NS + an ARB (olmesartan, 10 mg/kg/day), NS + a CCB (azelnidipine, 3 mg/kg/day), NS + olmesartan + azelnidipine or NS + hydralazine (50 mg/kg/day). Four weeks of treatment with HS diet induced hypertension, proteinuria, glomerular sclerosis and hypertrophy, glomerular podocyte injury, and tubulointerstitial fibrosis in DSS rats. A continued HS diet progressed hypertension, proteinuria and renal tissue injury, which was associated with inflammatory cell infiltration and increased proinflammatory cytokine mRNA levels, NADPH oxidase activity and NADPH oxidase-dependent superoxide production in the kidney. In contrast, switching to NS halted the progression of hypertension, renal glomerular and tubular injuries. Dietary salt reduction with ARB or with CCB treatment further reduced blood pressure and partially reversed renal tissues injury. Furthermore, dietary salt reduction with the combination of ARB plus CCB elicited a strong recovery from HS-induced renal tissue injury including the attenuation of inflammation and oxidative stress. These data support the hypothesis that dietary salt reduction with combination therapy of an ARB plus CCB restores glomerular and tubulointerstitial injury in DSS rats.

Positive association between plasma levels of oxidized low-density lipoprotein and myeloperoxidase after hemodialysis in patients with diabetic end-stage renal disease.

End-stage renal disease (ESRD) patients undergoing hemodialysis (HD) have a high prevalence of cardiovascular events. Low-density lipoprotein (LDL) in dialysis patients has been shown to be susceptible to in vitro peroxidation; therefore, oxidized-LDL (ox-LDL) could be generated in these patients. Moreover, myeloperoxidase (MPO) released from activated neutrophils may play a role in the induction of LDL oxidation. The purpose of this study was to investigate the relationship between plasma ox-LDL levels, plasma MPO levels, and serum high-sensitivity C-reactive protein (hs-CRP) levels during initial HD in patients with diabetic ESRD. Patients (n=28) had serial venous blood samples drawn before and after HD at the initial, second, and third sessions. Plasma ox-LDL levels were measured using a specific monoclonal antibody (DLH3), and plasma MPO levels were measured using an enzyme-linked immunosorbent assay kit. Plasma ox-LDL levels and MPO levels after a single HD session increased significantly (ox-LDL, P<0.005; MPO, P<0.0001) compared with levels before that HD session. However, the increase was transient since the levels returned to pre-HD session levels. Additionally, plasma MPO levels showed a positive correlation with plasma ox-LDL levels during HD (R=0.62, P=0.0029). No significant change was observed in serum hs-CRP levels before and after each HD session. This study demonstrates that plasma MPO levels are directly associated with plasma ox-LDL levels in diabetic ESRD patients during initial HD. These findings suggest a pivotal role for MPO and ox-LDL in the progression and acceleration of atherosclerosis in patients undergoing HD.

Angiotensin II receptor blockade reduces salt sensitivity of blood pressure through restoration of renal nitric oxide synthesis in patients with diabetic nephropathy.

INTRODUCTION: We have previously demonstrated the increased salt sensitivity of blood pressure (BP) in diabetic patients with early nephropathy. Here, we examined the effects of an angiotensin II receptor blocker (ARB) on salt sensitivity and renal oxidative stress or nitric oxide (NO) in those patients. PATIENTS AND METHODS: Type 2 diabetic patients with (n = 6) and without (n = 6) microalbuminuria were studied on a high-salt diet for one week and on a salt-restricted diet for one week. The study was repeated in the patients with microalbuminuria during treatment with an ARB, valsartan (80 mg/day). Salt sensitivity was assessed from the BP/sodium excretion curve. Urinary excretion rates of NOx, 8-hydroxy-2-deoxyguanosine as a marker of oxidative stress, and plasma tetrahydrobiopterin as a cofactor for NO synthase were measured. RESULTS: Compared with diabetic patients without microalbuminuria, patients with microalbuminuria showed greater salt sensitivity and lower urinary excretion of NOx. In the patients with microalbuminuria, treatment with valsartan reduced salt sensitivity in association with increased NOx excretion, reduced 8-hydroxy-2,-deoxyguanosine excretion, and increased plasma tetrahydrobiopterin levels. CONCLUSIONS: These data support the hypothesis that ARBs reduce the salt sensitivity of BP by decreasing renal oxidative stress and restoring NO activity in diabetic patients with microalbuminuria.

AP-VAS 2012 case report: a case of ANCA-negative pauci-immune crescentic glomerulonephritis associated with IL-6-producing adenosquamous cell carcinoma of the lung.

A 76-year-old man with lung cancer and multiple metastases was admitted for purpura and rapidly progressive glomerulonephritis. Adenosquamous cell carcinoma of the lung had been diagnosed 6 months earlier. Two anti-cancer drug regimens had no effect. At admission, his survival with his malignancy was estimated to be several months. Renal biopsy revealed pauci-immune necrotizing crescentic glomerulonephritis (CrGN). Negative results were obtained for myeloperoxidase-anti-neutrophil cytoplasmic antibody (ANCA) and proteinase-3-ANCA by enzyme-linked immunosorbent assay, and for peripheral-ANCA and cytoplasmic-ANCA by indirect immunofluorescence. He was diagnosed with ANCA-negative pauci-immune CrGN. Although steroids were initiated, the patient died of renal failure and intestinal bleeding 2 weeks later. It was later found that cancer cells were positive for interleukin (IL)-6 and that serum IL-6 levels were significantly elevated, concomitantly with increased IL-8, granulocyte-colony stimulating factor and transforming growth factor-ß levels. Some kinds of lung cancer are known to produce IL-6 that activate neutrophils and are related to ANCA-associated CrGN. It appears that IL-6 can activate neutrophils in the pathogenesis of ANCA-negative pauci-immune CrGN with lung cancer. Therapy that blocks IL-6 may prove to be effective in vasculitis and cancer-related symptoms in such cases.

Tonsillectomy has beneficial effects on remission and progression of IgA nephropathy independent of steroid therapy.

BACKGROUND: Indication of tonsillectomy in IgA nephropathy is controversial. The purpose of this study was to examine the efficacy of tonsillectomy on remission and progression of IgA nephropathy. METHODS: We conducted a single-center 7-year historical cohort study in 200 patients with biopsy-proven IgA nephropathy. Study outcomes were clinical remission defined as disappearance of urine abnormalities at two consecutive visits, glomerular filtration rate (GFR) decline defined as 30% GFR decrease from baseline and GFR slope during the follow-up. RESULTS: Seventy of the 200 patients received tonsillectomy. Tonsillectomy was associated with increased incidence of clinical remission (P+0.01, log-rank test) and decreased incidence of GFR decline (P=0.01, log-rank test). After adjustment for age and gender, hazard ratios in tonsillectomy were 3.90 (95% confidence interval 2.46-6.18) for clinical remission and 0.14 (0.02-1.03) for GFR decline. After further adjustment for laboratory (baseline mean arterial pressure, GFR, 24-h proteinuria and hematuria score), histological (mesangial score, segmental sclerosis or adhesion, endocapillary proliferation and interstitial fibrosis) or treatment variables (steroid and renin-angiotensin system inhibitors), similar results were obtained in each model. Even after exclusion of 69 steroid-treated patients, results did not change. GFR slopes in tonsillectomy and non-tonsillectomy groups were 0.60±3.65 and -1.64±2.59 mL/min/1.73 m2/year, respectively. In the multiple regression model, tonsillectomy prevented GFR decline during the follow-up period (regression coefficient 2.00, P=0.01). CONCLUSION: Tonsillectomy was associated with a favorable renal outcome of IgA nephropathy in terms of clinical remission and delayed renal deterioration even in non-steroid-treated patients.

Relationship between urinary angiotensinogen and salt sensitivity of blood pressure in patients with IgA nephropathy.

We demonstrated previously that the blood pressure of patients with IgA nephropathy becomes salt sensitive as renal damage progresses. We also showed that increased urinary angiotensinogen levels in such patients closely correlate with augmented renal tissue angiotensinogen gene expression and angiotensin II levels. Here, we investigated the relationship between urinary angiotensinogen and salt sensitivity of blood pressure in patients with IgA nephropathy. Forty-one patients with IgA nephropathy consumed an ordinary salt diet (12 g/d of NaCl) for 1 week and a low-salt diet (5 g/d of NaCl) for 1 week in random order. The salt-sensitivity index was calculated as the reciprocal of the slope of the pressure-natriuresis curve drawn by linking 2 data points obtained during consumption of each diet. The urinary angiotensinogen:creatinine ratio was significantly higher in patients who consumed the ordinary salt diet compared with the low-salt diet (17.5 µg/g [range: 7.3 to 35.6 µg/g] versus 7.9 µg/g [range: 3.1 to 14.2 µg/g] of creatinine, respectively; P<0.001). The sodium sensitivity index in our patients positively correlated with the glomerulosclerosis score (r=0.43; P=0.008) and changes in logarithmic urinary angiotensinogen:creatinine ratio (r=0.37; P=0.017) but not with changes in urinary protein excretion (r=0.18; P=0.49). In contrast, changes in sodium intake did not alter the urinary angiotensinogen:creatinine ratio in patients with Ménière disease and normal renal function (n=9). These data suggest that the inappropriate augmentation of intrarenal angiotensinogen induced by salt and associated renal damage contribute to the development of salt-sensitive hypertension in patients with IgA nephropathy.

A decline in platelet activation and inflammatory cell infiltration is associated with the phenotypic redifferentiation of neointimal smooth muscle cells after bare-metal stent implantation in acute coronary syndrome.

AIM: This immunohistochemical investigation was to analyze the relationship between platelet activation/aggregation, inflammatory cell infiltration, the differentiation state of neointimal smooth muscle cells (SMCs), expression of platelet-derived growth factor (PDGF), and endothelial cell regeneration at sites of bare-metal stents (BMS) in patients with acute coronary syndrome (ACS). METHODS: Sixteen coronary arteries after stenting were obtained at autopsy from ACS patients. Serial frozen sections were stained with antibodies against SMCs (1A4, HHF-35, CGA-7), macrophages, neutrophils, endothelial cells, GP IIb/IIIa, P-selectin, PDGF-B, and PDGF-beta receptor. RESULTS: Up to 12 days after BMS, the stent sites contained P-selectin-positive activated platelets with neutrophil infiltration. From 24 to 55 days after BMS, parts of the platelet thrombi were still positive for P-selectin, and infiltration of neutrophils and macrophages was also found. Neointimal SMCs at these stages stained positive with 1A4 but negative with CGA-7, and PDGF-B and PDGF-beta receptor were expressed in macrophages and SMCs. At sites from 3 months onward, platelet thrombi and neutrophil infiltration were not detected, and the neointima contained increased numbers of highly differentiated SMCs with CGA-7 positivity. The P-selectin-positive area was positively correlated with the neutrophil count and macrophage-positive area (neutrophils, r=0.86, p<0.0005; macrophage, r=0.66, p<0.05). In contrast, the P-selectin-positive area was negatively correlated with the HHF-35-positive area and CGA-7-positive area (HHF-35, r=-0.90, p<0.0001; CGA-7, r=-0.82, p<0.005). CONCLUSION: These observations suggest that P-selectin-positive platelet thrombi in the neointima are positively associated with the inflammatory cell infiltration and reversely associated with the phenotypic redifferentiation of neointimal SMCs after BMS in ACS patients.

Expression of LYVE-1 in sinusoidal endothelium is reduced in chronically inflamed human livers.

BACKGROUND: LYVE-1, a specific marker of lymphatics, is expressed in hepatic sinusoidal endothelium. A previous study revealed that LYVE-1 expression in sinusoidal endothelium was reduced in cirrhosis. However, it is still obscure how LYVE-1 expression in sinusoidal endothelium was reduced during the disease progression. To elucidate whether there were relationships among LYVE-1 attenuation, sinusoidal capillarization, and disease progression, we performed immunohistochemical investigations based on frozen human livers. METHODS: Frozen liver sections of chronic hepatitis (n = 8), cirrhosis (n = 13), and normal/control liver (n = 10) were examined by immunostaining for lymphatic endothelial markers (LYVE-1 and D2-40) and vascular endothelial markers (CD31 and von Willebrand factor). Computer-aided morphometry was applied to obtain objective data. The diseased liver tissues were also examined ultrastructurally. RESULTS: In controls, sinusoidal endothelium was positive for LYVE-1 and CD31, but negative for D2-40 and von Willebrand factor. In chronic hepatitis and cirrhosis, LYVE-1 expression in sinusoidal endothelium was attenuated, especially in areas adjacent to active inflammatory or fibrotic lesions, while von Willebrand factor was reciprocally expressed in sinusoidal endothelium. The morphometric analyses revealed that LYVE-1 positivity in sinusoidal endothelium was significantly (P < 0.0001) decreased in chronic hepatitis and cirrhosis compared to controls and was negatively correlated (Rs = -0.72, P < 0.0001) to von Willebrand factor positivity. Furthermore, LYVE-1 positivity was negatively correlated to inflammatory grade (Rs = -0.51, P = 0.021) and fibrosis severity (Rs = -0.46, P = 0.038). Sinusoidal endothelium in the diseased livers showing LYVE-1 attenuation had lost fenestrations. CONCLUSIONS: These findings indicated that LYVE-1 attenuation in sinusoidal endothelium was one of the manifestations of capillarization, and was associated with hepatic disease progression.

Elevated levels of neopterin are associated with carotid plaques with complex morphology in patients with stable angina pectoris.

OBJECTIVE: Neopterin is an activation marker for monocytes/macrophages, and circulating levels of neopterin are elevated in patients with coronary complex lesions in unstable angina pectoris. We investigated the possible association between neopterin and complex carotid plaques which may be associated with the risk of ischemic stroke in patients with stable angina pectoris (SAP). METHODS: We measured plasma levels of neopterin in 102 patients with SAP and carotid ultrasound was performed for evaluation of the presence of carotid plaques and plaque surface characteristics categorized as complex or noncomplex. In addition, endarterectomy specimens of extracranial high-grade carotid stenosis with complex plaques from five patients with SAP were immunohistochemically examined with antibodies to smooth muscle cells, endothelial cells, platelets, macrophages, and T cells. RESULTS: Plasma neopterin levels were significantly higher in patients with complex carotid plaques than in those with noncomplex plaques (median [interquartile range]: 24.2 [19.2-39.3]nmol/L vs. 19.4 [11.9-25.1]nmol/L; P=0.01) or without any plaques (18.8 [14.9-23.6]nmol/L; P=0.001). On multivariate logistic analyses after adjustment for traditional atherosclerotic risk factors, multi-vessel coronary disease and high sensitivity C-reactive protein, neopterin levels were independently associated with the presence of complex carotid plaques (adjusted OR 2.21 per SD increase, 95%CI 1.13-4.33, P=0.02). Immunohistochemical staining revealed abundant neopterin-positive macrophages in carotid complex lesions. CONCLUSION: These findings demonstrate that carotid plaques with complex morphology have increased circulating neopterin levels and immunohistochemical localization of neopterin in patients with SAP. Neopterin can be considered an important biomarker of plaque destabilization in carotid artery atherosclerotic lesions in this population.

Enhanced expression of haemoglobin scavenger receptor in accumulated macrophages of culprit lesions in acute coronary syndromes.

AIMS: Effective clearance of extracellular haemoglobin (Hb) is thought to limit systemic oxidative heme toxicity, which is presumed to contribute to the pathogenesis of plaque instability. We immunohistochemically examined the relationship between intraplaque haemorrhage, 4-HNE (4-hydroxy-2-nonenal), an index of lipid peroxidation, and the Hb scavenger receptor (CD163), using coronary atherectomy specimens from 74 patients with stable angina pectoris (SAP, n = 39) or unstable angina pectoris (UAP, n = 35). METHODS AND RESULTS: Atherectomy samples were stained with antibodies against glycophorin A (a protein specific to erythrocyte membranes), CD31, 4-HNE, and CD163. Quantitative analysis demonstrated that glycophorin A-positive areas, 4-HNE-positive macrophage score, and CD163-positive macrophage score in UAP patients were significantly higher (glycophorin A, P < 0.0001; 4-HNE-positive macrophage score, P < 0.0001; CD163-positive macrophage score, P < 0.0005) than in SAP patients. The percentage of the glycophorin A-positive area showed a significant positive correlation with the number of CD31-positive microvessels and the 4-HNE-positive macrophage score (microvessels, R = 0.59, P < 0.0001; 4-HNE, R = 0.59, P < 0.0001). Moreover, the CD163-positive macrophage score was positively correlated with glycophorin A-positive area and the 4-HNE-positive macrophage score (glycophorin A, R = 0.58, P < 0.0001; 4-HNE, R = 0.53, P < 0.0001). CONCLUSION: These findings suggest a positive association among intraplaque haemorrhage, enhanced expression of Hb scavenger receptor, and lipid peroxidation in human unstable plaques.

Evidence for abundant presence of chymase-positive mast cells in the kidneys of patients with immunoglobulin A nephropathy: effect of combination therapy with prednisolone and angiotensin II receptor blocker valsartan.

Several investigators have reported chymase-positive mast cells in tubulointerstitial damage. However, the significance of the presence of chymase in the pathophysiology of renal diseases is unclear. We investigated relationships among chymase, renal damage, and intra-renal circulation. The participant pool consisted of 52 patients with immunoglobulin A (IgA) nephropathy who underwent renal biopsy. Of these, 18 were examined before and 2 months after the initiation of treatment with prednisolone alone (n=9) or combined with the angiotensin II receptor blocker valsartan (n=9). Biopsied renal specimens were evaluated, and the degree of renal circulation (resistive index; RI) was calculated by measuring flow velocity using Doppler sonography. The number of chymase-positive mast cells as visualized by immunohistochemical staining correlated significantly with both tubulointerstitial damage (rho=0.69, p<0.001) and RI (r=0.52, p<0.001). Treatment with prednisolone combined with valsartan effectively decreased both chymase-positive mast cells and RI, displaying a significant correlation between these biomarkers (rho=0.85, p=0.016). However, no such effect was observed with prednisolone alone. The severity of tubulointerstitial damage and the degree of proteinuria were similar in both treatment groups throughout the study term. We concluded that the presence of chymase-positive mast cells and the associated decrease in renal circulation corresponded to disease progression in IgA nephropathy. Combination therapy using prednisolone and valsartan may lead to improvements in intra-renal circulation and to interference in the recruitment of chymase-positive mast cells.

Enhanced expressions of endothelin-converting enzyme and endothelin receptors in human colonic tissues of Crohn's disease.

Endothelin-1, a powerful vasoconstrictor, forms the endothelin system together with endothelin-converting enzyme and endothelin type A and type B receptors. These endothelin system components are considered to participate in inflammatory and wound healing responses. Previous reports have suggested a role for the endothelin-1 in the pathology of Crohn's disease. In the present study, we immunohistochemically investigated the expressions of the endothelin system components in affected human intestinal tissues of Crohn's disease. Eighteen surgical specimens of colonic tissue obtained from patients with Crohn's disease and 12 normal colonic tissues as controls were examined. Frozen tissue sections cut from the samples were subjected to the immunohistochemical single and double staining. The endothelin system components were expressed mainly in the muscular layers and blood vessels. In diseased colonic tissues, inflammatory infiltration and fibrotic tissue reactions with marked smooth muscle cell proliferation were frequently seen, and were closely associated with increased expressions of the endothelin system components. These results strongly suggest that endothelin-converting enzyme and endothelin type A and type B receptors collectively play a role in the inflammatory and fibrogenic processes of Crohn's disease. Especially, submucosal smooth muscle proliferation, a histological hallmark of strictures, may be attributable to the upregulated endothelin system.

Enhanced expression of angiotensin II type 1 receptor in usual interstitial pneumonia.

BACKGROUND: Angiotensin II, a potent vasoconstrictor, has been considered to be involved in various fibrotic disorders including idiopathic interstitial pneumonias. To clarify whether this agent contributes to the development and progression of usual interstitial pneumonia, a major entity of idiopathic interstitial pneumonias, we immunohistochemically examined expression of its specific receptor, angiotensin II type 1 receptor, in human normal and diseased lung tissues. METHODS: Video-assisted thoracoscopic lung biopsy specimens obtained from patients with usual interstitial pneumonia (n=8) were sectioned and stained using single or double immunostaining techniques with specific antibodies against angiotensin II type 1 receptor and smooth muscle actin. Lung tissues of desquamative interstitial pneumonia (n=2) and normal lung tissues (n=6) were also examined for comparative analyses. RESULTS: Expression of angiotensin II type 1 receptor was limited in vascular and bronchial smooth muscle cells in normal lungs. In contrast, the receptor-positive mesenchymal cells, most of which were also positive for smooth muscle actin and arranged like a bundle, were markedly increased in association with dense collagen deposition in thickened alveolar walls of usual interstitial pneumonia. In desquamative interstitial pneumonia, the fibroproliferative change, including angiotensin II type 1 receptor-positive mesenchymal cell proliferation, was milder than that in usual interstitial pneumonia. CONCLUSIONS: These findings suggest that angiotensin II and its type 1 receptor play a profibrogenic role in idiopathic interstitial pneumonias, particularly in usual interstitial pneumonia. Furthermore, angiotensin II type 1 receptor-positive smooth muscle cells increased in diseased lung tissues may be contractile and may contribute to reduction of airspaces in usual interstitial pneumonia.

Expression of cyclooxygenase-2 in Hodgkin's lymphoma: its role in cell proliferation and angiogenesis.

Although many studies have revealed the association between cyclooxygenase-2 (COX-2) and carcinogenesis, the association between COX-2 and Hodgkin's lymphoma (HL) remains unknown. We examined the immunohistochemical expression of COX-2, p53, bcl-2, and Ki-67 in 33 patients with HL, and counted microvessels stained with CD34. Hodgkin and Reed - Sternberg (HRS) cells with COX-2 expression were scored as 0 = no staining; 1 = <25% of cells staining; 2 = 25-49%; 3 = 50-75%; and 4 = > or =75%. COX-2 expression was observed in 15 cases of classical HL. Nevertheless, neither accumulation of p53 nor bcl-2 expression was associated with COX-2 expression. The percentage of Ki-67 positive-HRS cells and microvessel density in COX-2 score groups 2-4 were significantly higher than those in score group 0, respectively. We show that COX-2 expression is associated with cell proliferation and angiogenesis in HL. These findings suggest that COX-2 may be a target for therapy in HL.

Endothelin-converting enzyme expression in the neointima after percutaneous coronary intervention.

Smooth muscle cells (SMCs) are the major cellular component of neointimal tissues after percutaneous coronary intervension (PCI). Endothelin-1 (ET-1) is a powerful vasoconstrictor and has a mitogenic effect on SMCs. Endothelin-converting enzyme (ECE) is a key enzyme in the process of ET-1 generation. However, the expression of ECE in association with post-PCI repair processes has not been reported. Thirteen coronary sites after PCI obtained at autopsy and 6 atherectomy specimens obtained from restenotic sites were investigated. Frozen sections were stained with antibodies against ECE, SMCs, macrophages, and endothelial cells. The immunoreactivity of ECE was quantified using computer-aided planimetry. At the early stage after PCI, most neointimal SMCs expressed ECE. The ECE-positive cell area was significantly (p<0.005) larger in the sites within 3 months after PCI than in the sites from 6 months onward. In atherectomy specimens, neointimal SMCs showed distinct ECE positivity. These findings suggest that ECE is upregulated in the neointima at early stages after PCI injury. ECE may be one of the mediators in the repair processes after PCI in humans.