Biomedical subjects
T Mitarai
Publications and source records attributed to T Mitarai.
[Granulomatous glomerulonephritis].
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Massive uncomplicated vascular immune complex deposits in the kidney of a patient with systemic lupus erythematosus.
The case of a patient with systemic lupus erythematosus (SLE) is reported which was accompanied by renal dysfunction and massive vascular immune deposits in the kidney without active glomerular lesions. The renal biopsy showed arterioles and small arteries with circumferential periodic acid-Schiff (PAS) and Masson trichrome-positive homogenous material in the subendothelial area in the absence of thrombotic, necrotizing or inflammatory lesions. Immunofluorescence and electron microscopy examination demonstrated immune deposits in the vascular walls. Glomeruli showed only minor abnormalities with a trend to collapse. There was no improvement in renal dysfunction over a 4-year period until the patient's death, despite steroid therapy producing a decrease in disease activity. The autopsy showed similar vascular changes to those seen in the biopsy, however; glomeruli were either sclerotic or showed a trend to collapse. Massive uncomplicated vascular immune complex deposition without active glomerular lesions is rare. The present case indicates that this type of lupus vasculopathy may be a prognostic factor for the loss of renal function in SLE mediated by hemodynamic glomerular injury.
A family with two sisters with collagenofibrotic glomerulonephropathy.
Collagenofibrotic glomerulonephropathy is a recently recognized disease entity. Although an autosomal recessive inheritance pattern has been suggested for this condition, there are few reports of familial cases. Only four pairs of child siblings, with histological confirmation of the glomerular lesions, have been reported. The current report describes a family including two sisters with histological evidence of collagenofibrotic glomerulonephropathy. Serum concentrations of the procollagen III peptide were elevated in the affected sisters, whereas their parents and other siblings demonstrated neither proteinuria nor increased blood levels of the procollagen III peptide. Our findings support an autosomal recessive pattern of inheritance for this type of glomerulonephropathy. They also suggest that the serum concentration of the procollagen III peptide is a useful marker for collagenofibrotic glomerulonephropathy.
Angiotensin I converting enzyme gene polymorphism in non-insulin dependent diabetes mellitus.
A total of 168 patients with non-insulin dependent diabetes (NIDDM) followed over 10 years were recruited in this study. The patients were divided into two groups: Group 1 patients had a stable renal function (N = 96) and Group 2 had a declining renal function (N = 72). Group 1 included those whose serum creatinine was normal five years ago but had increased to > or = 2 mg/dl or those who has reached end-stage renal failure (requiring dialysis) by the time of study. All patients were genotyped for the insertion/deletion (I/D) polymorphism of the ACE gene, the M235T polymorphism of the angiotensinogen (Atg) gene and the A1166C polymorphism of the angiotensin II type 1 receptor (AT1) gene. The genotype frequency distributions of M235T Atg and the A116C AT1 gene polymorphisms were not different between Group 1 versus Group 2. While the frequency of the ACE DD genotype in Group 1 (7.3%) was comparable to that of the general population, the DD frequency was significantly higher in Group 2 (26.4%) than in Group 1 (odds ratio, 4.56; 95% confidence interval, 1.80 approximately 11.56, P < 0.001). Among all 168 patients studied, the renal survival rate was significantly lower among DD than ID (P < 0.005) or II patients (P < 0.001). In patients with a declining renal function (Group 2), those with the DD genotype had a significantly shorter time interval from onset of diabetes to the initiation of dialysis (13.4 +/- 1.4 years) than those with ID (20.7 +/- 1.2 years, P < 0.01) or II genotypes (17.5 +/- 1.1 year, P < 0.01). Analysis of the clinical course of the three ACE genotypes revealed that the majority (95%) of patients with the DD genotype who had albuminuria progressed to end-stage renal disease within 10 years of diagnosis of diabetes. Our analysis also revealed that initiation and continuation of dialysis are associated with a progressive decrease in the frequency of the DD genotype. These results indicate that, in NIDDM, the ACE DD genotype has a high prognostic value for progressive deterioration of renal function. Moreover, the DD genotype appears to increase the mortality once dialysis is initiated.
Jak3 expression in glomerular epithelia of IgA nephropathy (IgA-N) patients.
Jak3 is a member of the Janus kinase family which plays an important role in cytokine signal transduction. Jak3 associates the gamma(c) chain of receptors for IL-2, IL-4, IL-7, IL-9 and IL-15, and is essential for the signal transduction of these cytokines. We have isolated Jak3 kinase from renal mesangial cells and demonstrated the constitutive expression of Jak3 in glomeruli in vivo. To investigate the physiological and pathological role of Jak3 in glomeruli, we prepared anti-Jak3 antibody and analysed the localization of Jak3 in glomeruli of renal biopsy samples from various nephritis patients and normal subjects. Among 61 nephritis patients and four normal subjects investigated in the present study, Jak3 was selectively localized to glomerular epithelia of IgA-N patients (14/34 cases) and focal glomerulosclerosis patients (1/5 cases), but not detected in minimal changes (n = 6), membranous glomerulonephropathy (n = 7), crescentic glomerulonephritis (n = 4), lupus nephritis patients (n = 5), and normal subjects (n = 4). The intense immunoreactivity for Jak3 is significantly associated with the decrease in creatinine clearance (81.5 +/- 10.4 ml/min versus 104.3 +/- 29.6 ml/min; P < 0.05, Student's t-test) and the increase in level of serum creatinine (1.13 +/- 0.33 mg/dl versus 0.75 +/- 0.23 mg/dl; P < 0.01, Student's t-test) in IgA-N patients. Furthermore, gamma(c) chain was concomitantly expressed with Jak3 in glomerular epithelia in vivo and in vitro, suggesting that signal transduction via gamma(c)-Jak3 cascade may be involved in the pathogenesis of glomerular injury of IgA-N. Taken together with the recent findings that IL-4-secreting T lymphocytes in affected glomeruli injure glomerular epithelium, the responsiveness of glomerular epithelium for IL-4 may be pathologically enhanced in IgA-N.
Macrophage-colony stimulating factor (M-CSF) enhances proteinuria and recruitment of macrophages into the glomerulus in experimental murine nephritis.
In this study, we examined the effects of macrophage-colony stimulating factor (M-CSF) on glomerular macrophages in lipopolysaccharide (LPS)-induced murine nephritis. Mice injected intraperitoneally with either M-CSF plus LPS, LPS alone, M-CSF alone or saline every day for 8 days were examined for the degree of urine albumin excretion and lymphocyte-function associated antigen-1-positive (LFA-1+) cells in peripheral blood as well as renal pathology. From our results, LPS or M-CSF combined with LPS emphasized the degree of proteinuria, glomerular deposition of immunoglobulins and mesangial proliferation, associated with accumulation of macrophages in the glomeruli. However, in immunohistological examination of kidneys from these nephritic mice, neither intercellular adhesion molecule-1 (ICAM-1), which may play an important role in the recruitment of macrophages into glomeruli, M-CSF receptor nor the number of LFA-1+ cells in peripheral blood was enhanced by M-CSF. On the other hand, M-CSF alone induced neither proteinuria nor any pathological changes and did not increase the number of glomerular Mac-1+ cells above that in saline-treated controls. These results indicate that M-CSF does not directly cause glomerulonephritis but might participate in accelerating the glomerular inflammatory process by stimulating a potent chemoattractant to recruit monocytes-macrophages into the glomeruli.
Differentiated phenotype of glomerular mesangial cells in nodular culture.
Prolonged culture of glomerular mesangial cells forms nodular structures composed of cells and surrounding extracellular matrix (ECM), which may mimic the situation in the glomerular mesangium of the kidney. The aim of this study was to investigate whether nodule-associated cells (NAC) exhibit a different phenotype to nodule-unassociated cells (NUC) in vitro. As phenotypic markers for rat mesangial cells, we examined mitogenic activity, expression of alpha-smooth muscle actin, and production of ECM constituents. Autoradiographic and immunohistochemical analyses revealed that NAC showed far less mitogenesis that NUC, like mesangial cells in the normal glomerulus. Immunofluorescence study and Northern blot analysis showed that alpha-smooth muscle actin, a marker of mesangial cell activation/dedifferentiation, was strongly expressed in NUC but faint in NAC. When nodules were dissolved by trypsinization, the dispersed NAC regained both active mitogenesis and alpha-smooth muscle actin expression, suggesting that the altered phenotype was reversible. Northern blot analysis revealed that the ratio of type IV collagen versus type I collagen expression, a marker of mesangial cell differentiation, was elevated in NAC compared with NUC. This phenotypic shift toward differentiation was associated with upregulation of transforming growth factor-beta 1. These findings demonstrate that mesangial cells in nodules exhibit a phenotype which is distinct from that of cells in two-dimensional cultures. We hypothesize that, as a differentiated feature, cultured mesangial cells have the ability to create an appropriate three-dimensional cyto-architecture that resembles the glomerular mesangium.
[Eradication of Helicobacter pylori in patients with end-stage renal disease undergoing dialysis treatment].
The aim of the present study was to examine the efficacy and safety of combination therapy with amoxicillin (AMPC), lansoprazole, and plaunotol for the eradication of H. pylori in dialysis patients. The subjects consisted of 15 dialysis patients (10 men and 5 women, mean age of 56 +/- 2.4 years) in whom H. pylori was found in the stomach. H. pylori status was evaluated by histology, culture and rapid urease test with biopsy specimens of the gastric mucosa. The patients were treated with AMPC 500 mg once a day for 3 weeks, lansoprazole 30 mg once a day for 8 weeks and plaunotol 80 mg three times a day for 24 weeks. In addition, the concentrations of serum gastrin and gastric juice ammonia were measured. Fourteen patients completed the treatment schedule, while one discontinued treatment because of nausea and diarrhea. Among the 14 patients, H. pylori was eradicated in 11 without any side effects (eradication rate 78.6%). Concentrations of gastric juice ammonia and serum gastrin were reduced significantly in patients who became H. pylori-negative. The present study indicates that combination therapy with AMPC, lansoprazole and plaunotol is safe and efficient for the eradication of H. pylori in dialysis patients. The results also suggested that elevated concentrations of gastric juice ammonia and serum gastrin in dialysis patients can be attributed, at least in part, to H. pylori infection.
Reconstitution of SCID mouse with tonsillar cells from patients with IgA nephropathy.
IgA nephropathy (IgAN) is characterized by a predominant IgA deposition to the renal mesangium. Immunological abnormalities are closely related to the occurrence and progression of IgAN. Many reports have indicated that tonsillectomy favours the clinical course of IgAN. To understand the role of tonsil glands in the occurrence and progression of IgAN, we injected tonsillar lymphoid cells from patients with IgAN into severe combined immuno-deficient mice (SCID). Tonsillar glands were obtained surgically from 3 patients with IgAN (experimental group) and from 7 patients with chronic tonsillitis without any manifestation of renal diseases (control group). Tonsils were homogenized and resultant cells cryopreserved. On the day of injection, cells were thawed and passed through Ficoll-Paque gradients to obtain mononuclear cells. Fifty million cells were injected intraperitoneally into the SCID mice. After 8 weeks, transferred cells successfully reconstituted SCID, as shown by the fact that human immunoglobulins were detected in the sera of both groups. Renal histopathological examination revealed there was no IgA deposition to the mesangial area in either group. These results indicate that tonsillar mononuclear cells alone may not directly relate to the occurrence of IgAN.
Protein tyrosine kinases expressed in glomeruli and cultured glomerular cells: Flt-1 and VEGF expression in renal mesangial cells.
Protein tyrosine kinases play an important role in cellular proliferation and differentiation of various cell types. To identify potential tyrosine kinases involved in glomerular functions we have utilized the polymerase chain reaction (PCR) and degenerate oligonucleotides for isolation of such genes from isolated glomeruli, cultured mesangial cell, and glomerular endothelial cells. Sequence analysis of PCR-amplified cDNAs resulted in the isolation of 24 tyrosine kinases. Here we describe for the first time the constitutive expression of 15 tyrosine kinases, tyro-1, tyro-4, tyro-6, hyk, Ptk-3, Ryk, tie, yes, lyn, tec, Jak1, Jak2, Jak3, c-abl, and flk, in renal glomeruli. In addition, Flt-1, an endothelial cell-specific receptor for vascular endothelial growth factor (VEGF), is expressed in renal mesangial cells and its gene expression is up-regulated upon the stimulation of platelet-derived growth factor (PDGF) with the concomitant up-regulation of VEGF. These data suggest that possible involvement of VEGF/Flt-1 system in cytokine-induced mesangial cell proliferations.
Attenuation of immune complex nephritis in NZB/WF1 mice by a prostacyclin analogue.
Although prostaglandins have been shown to inhibit the evolution of the nephritis in NZB/W mice, the mechanisms of this effect are unknown. To characterize such inhibition, we injected the prostacyclin (PGI2) analogue, beraprost, into NZB/W mice, using 0.5 mg, 1.0 mg or 5.0 mg beraprost/kg body weight of test animals three times in 1 week when the mice were 2 months old. Evaluation included measurement of urine albumin excretion, serological parameters and splenic T cell subset, as well as examination of renal histology by light and fluorescence microscopy. Mice given beraprost showed a marked decrease in urine albumin excretion and in glomerular hypercellularity compared with untreated controls. Maximal beneficial effects occurred when the dose was 5.0 mg/kg of beraprost. These effects correlated with a reduction of immune complex deposition in glomeruli. In addition, beraprost reduced serum levels of immunoglobulins and anti-double-stranded DNA antibodies, and decreased the number of helper (L3T4+) T cells in splenocytes. These results indicate that beraprost attenuates the nephritis of NZB/W mice, and that the source of this effect is the reduced production of autoantibodies and deposition of immune complexes in glomeruli.
T-cell receptor beta-chain gene polymorphism and the prognosis of IgA nephropathy in Japanese patients.
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Role of the deletion of polymorphism of the angiotensin converting enzyme gene in the progression and therapeutic responsiveness of IgA nephropathy.
Studies conducted over the last decade demonstrated variable therapeutic efficacy of angiotensin converting enzyme (ACE) inhibitor on the progression of glomerular diseases, including IgA nephropathy. In this study, among patients with biopsy-proven IgA nephropathy, 53 patients in whom creatinine clearance had been monitored over 5 yr were recruited for study. These patients were classified into two groups according to whether or not renal function had declined as determined by the slope of creatinine clearance against time: group 1 had stable renal function; group 2 had declining renal function (average: -6.7 +/- 1.3 ml/min/yr). 21 of 53 patients were treated with ACE inhibitor and followed for 48 wk. Gene polymorphism consisting of insertion (I) or deletion (D) of a 287-bp DNA fragment (presumed to be a silencer element) of the ACE gene was determined by PCR. 46 age-matched individuals without history of proteinuria were analyzed as controls. The DD genotype was significantly more frequent in group 2 (43%) than in controls (7%) or group 1 patients with stable renal function (16%). 48 wk after ACE inhibitor administration, proteinuria significantly decreased in patients with DD genotype but not in those with ID or II genotypes. The results indicate that deletion polymorphism in the ACE gene, particularly the homozygote DD, is a risk factor for progression to chronic renal failure in IgA nephropathy. Moreover, this deletion polymorphism predicts the therapeutic efficacy of ACE inhibition on proteinuria and, potentially, on progressive deterioration of renal function.
Late-onset renal dysfunction in a patient with non-Hodgkin's lymphoma following an autologous bone marrow transplantation.
Various types of glomerulonephropathy have been reported in patients with malignant lymphoma. The present report describes a 21-year-old man with non-Hodgkin's lymphoma who developed renal insufficiency 4 months after undergoing autologous bone marrow transplantation without combined total body irradiation treatment. At the presentation of renal dysfunction, the malignant lymphoma had been in complete remission. A renal biopsy specimen revealed glomerular changes resembling those seen in patients with hemolytic uremic syndrome. However, hematologic examinations exhibited no evidence of thrombocytopenia or thrombotic microangiopathy, such as red cell fragmentations on the peripheral blood smear. Although the etiology of this nephropathy remains unclear, the chemotherapeutic agents administered in conditioning regimens for bone marrow transplantation were suspected of contributing to the renal insufficiency. Methylprednisolone pulse therapy appeared to be effective in arresting progression of the nephropathy. This case indicates that renal function should be monitored carefully in patients with malignant lymphoma after bone marrow transplantation, even if such patients lack the signs or symptoms of thrombotic microangiopathy.
Heparin selectively inhibits gene expression of matrix metalloproteinase transin in cultured mesangial cells.
The aim of this study is to examine the transcriptional regulation of matrix metalloproteinase transin in glomerular mesangial cells responding to inflammatory cytokines and heparin. Northern blot analysis revealed that IL-1 beta preferentially induced transin mRNA. The stimulatory effect was not specific to transin, and upregulation of procollagen alpha 1(IV), laminin B2 and tissue inhibitor of metalloproteinases-1 (TIMP-1) mRNAs was also observed. After IL-1 stimulation, expression of the transin transcript increased progressively for up to 48 hours, differing from the limited induction of procollagen alpha 1(IV) or TIMP-1. When mesangial cells were stimulated by IL-1 beta in the presence of heparin, transin expression was markedly suppressed in a dose-dependent manner. The inhibitory effect of heparin was specific to transin, and induction of procollagen alpha 1(IV), laminin B2 or TIMP-1 by IL-1 beta was not affected. These findings revealed the selective counter regulation by IL-1 beta and heparin of the transin expression in mesangial cells.