Seiichiro Higo

Focal segmental glomerulosclerosis after renal transplantation

Shimizu A, Higo S, Fujita E, Mii A, Kaneko T. Focal segmental glomerulosclerosis after renal transplantation.
Clin Transplant 2011: 25 (Suppl. 23): 6–14.
© 2011 John Wiley & Sons A/S.

Proliferative glomerulonephritis with monoclonal immunoglobulin G3κ deposits in association with parvovirus B19 infection

Proliferative glomerulonephritis with monoclonal immunoglobulin G deposits is a recently described disease entity, characterized by nonorganized electron-dense deposits in glomeruli and immunofluorescence findings indicating monoclonal immunoglobulin G deposits. The pathogenesis of many cases of proliferative glomerulonephritis with monoclonal immunoglobulin G deposits remains unknown. We herein report 2 patients with parvovirus B19 infection who developed acute nephritic syndrome with hypocomplementemia (patient 1) or persistent proteinuria and congestive heart failure (patient 2); however, neither patient had detectable levels of serum monoclonal immunoglobulin G. Renal biopsy in both patients showed diffuse endocapillary proliferative glomerulonephritis with monoclonal immunoglobulin G3κ deposits, and electron microscopy showed nonorganized electron-dense deposits mainly in the subendothelial and mesangial areas. Clinical symptoms, abnormal laboratory findings, and urinary abnormalities recovered spontaneously in both cases within 4 weeks. Our 2 cases may be the first reported patients with proliferative glomerulonephritis with monoclonal immunoglobulin G deposits possibly associated with parvovirus B19 infection. Virus infection-associated immune disorders could be implicated in the pathogenesis of proliferative glomerulonephritis with monoclonal immunoglobulin G deposits.

Development of lymphatic vasculature and morphological characterization in rat kidney.

BackgroundThe mechanisms and morphological characteristics of lymphatic vascular development in embryonic kidneys remain uncertain.MethodsWe examined the distribution and characteristics of lymphatic vessels in developing rat kidneys using immunostaining for podoplanin, prox-1, Ki-67, type IV collagen (basement membrane: BM), and α-smooth muscle actin (αSMA: pericytes or mural cells). We also examined the expression of VEGF-C.ResultsAt embryonic day 17 (E17), podoplanin-positive lymphatic vessels were observed mainly in the kidney hilus. At E20, lymphatic vessels extended further into the developing kidneys along the interlobar vasculature. In 1-day-old pups (P1) to P20, lymphatic vessels appeared around the arcuate arteries and veins of the kidneys, with some reaching the developing cortex via interlobular vessels. In 8-week-old adult rats, lymphatic vessels were extensively distributed around the blood vasculature from the renal hilus to cortex. Only lymphatic capillaries lacking continuous BM and αSMA-positive cells were present within adult kidneys, with none observed in renal medulla. VEGF-C was upregulated in the developing kidneys and expressed mainly in tubules. Importantly, the developing lymphatic vessels were characterized by endothelial cells immunopositive for podoplanin, prox-1, and Ki-67, with no surrounding BM or αSMA-positive cells.ConclusionDuring nephrogenesis, lymphatic vessels extend from the renal hilus into the renal cortex along the renal blood vasculature. Podoplanin, prox-1, Ki-67, type IV collagen, and αSMA immunostaining can detect lymphatic vessels during lymphangiogenesis.

Acute Graft-Versus-Host Disease of the Kidney in Allogeneic Rat Bone Marrow Transplantation

Allogeneic hematopoietic cell or bone marrow transplantation (BMT) causes graft-versus-host-disease (GVHD). However, the involvement of the kidney in acute GVHD is not well-understood. Acute GVHD was induced in Lewis rats (RT1l) by transplantation of Dark Agouti (DA) rat (RT1a) bone marrow cells (6.0×107 cells) without immunosuppression after lethal irradiation (10 Gy). We examined the impact of acute GVHD on the kidney in allogeneic BMT rats and compared them with those in Lewis-to-Lewis syngeneic BMT control and non-BMT control rats. In syngeneic BMT and non-BMT control rats, acute GVHD did not develop by day 28. In allogeneic BMT rats, severe acute GVHD developed at 21–28 days after BMT in the skin, intestine, and liver with decreased body weight (>20%), skin rush, diarrhea, and liver dysfunction. In the kidney, infiltration of donor-type leukocytes was by day 28. Mild inflammation characterized by infiltration of CD3+ T-cells, including CD8+ T-cells and CD4+ T-cells, and CD68+ macrophages to the interstitium around the small arteries was noted. During moderate to severe inflammation, these infiltrating cells expanded into the peritubular interstitium with peritubular capillaritis, tubulitis, acute glomerulitis, and endarteritis. Renal dysfunction also developed, and the serum blood urea nitrogen (33.9±4.7 mg/dL) and urinary N-acetyl-β-D-glucosaminidase (NAG: 31.5±15.5 U/L) levels increased. No immunoglobulin and complement deposition was detected in the kidney. In conclusion, the kidney was a primary target organ of acute GVHD after BMT. Acute GVHD of the kidney was characterized by increased levels of urinary NAG and cell-mediated injury to the renal microvasculature and renal tubules.

Hepatic artery reconstruction prevents ischemic graft injury, inhibits graft rejection, and mediates long-term graft acceptance in rat liver transplantation.

BACKGROUND Hepatic artery (HA) reconstruction is performed in the clinical liver transplantation. METHODS We assessed the importance of HA reconstruction in the success of liver transplantation. Orthotopic liver transplantation was performed without immunosspression from Lewis (RT1l) to Lewis rats (syngeneic transplantation) as well as Lewis to BN (RT1n) rats (allogeneic transplantation) with or without HA reconstruction. We examined graft function, pathology, and mRNA levels using DNA arrays in both arterialized and nonarterialized liver grafts. RESULTS In Lewis-to-Lewis syngeneic grafts, both the arterialized and nonarterialized grafts survived >120 days with normal graft function. lnfiltration of CD3(+) T cells and CD68(+) macrophages, marked bile duct proliferation with apoptotic epithelial cells, and expansion and increasing fibrosis of portal areas were evident in the nonarterialized grafts at day 120, although preservation of architecture was noted in the arterialized grafts. DNA array analysis of nonarterialized syngeneic grafts demonstrated the upregulation of mRNA of cell death-related proteins, cell cycle-related proteins, and inflammation-related proteins than those in arterialized grafts. Moreover, the arterialized Lewis-to-BN allogeneic grafts could survive for a long time with less severe graft dysfunction than those in non-arterialized allogeneic grafts. CONCLUSIONS HA reconstruction in liver transplantation inhibited hypoxic injury and subsequent inflammation and bile duct proliferation, prevented the augmentation of T-cell-and antibody-mediated rejection, and mediated long-term graft acceptance. HA reconstruction is essential factor in the success of liver transplantation.

Caspase-3-Independent Internucleosomal DNA Fragmentation in Ischemic Acute Kidney Injury

Background/Aims: Renal tubular cell death in ischemia-reperfusion does not follow the classical apoptosis or necrosis phenotype. We characterized the morphological and biochemical features of injured tubular epithelial cells in ischemic acute kidney injury (AKI). Methods: Ischemic AKI was induced in rats by 60 min of ischemia followed by 24 h of reperfusion. Light and electron microscopic TUNEL (LM-TUNEL and EM-TUNEL), gel electrophoresis of extracted DNA, and caspase-3 involvement were examined during the development of death. Results: Damaged tubular epithelial cells with condensed and LM-TUNEL-positive (+) nuclei were prominent at 12 and 18 h after reperfusion with DNA ‘ladder’ pattern on gel electrophoresis. EM-TUNEL+ cells were characterized by nuclei with condensed and clumping chromatin, whereas the cytoplasm showed irreversible necrosis. The protein levels and activity of caspase-3 did not increase in kidneys after reperfusion. In addition, caspase inhibitor (ZVAD-fmk) failed to inhibit DNA fragmentation and prevent tubular epithelial cell death in ischemic AKI. Conclusion: Caspase-3-independent internucleosomal DNA fragmentation occurs in injured tubular epithelial cells undergoing irreversible necrosis in ischemic AKI. The manner of this cell death may be identical to the cell death termed apoptotic necrosis, aponecrosis, or necrapoptosis. Ischemia-reperfusion injury activates caspase-3-independent endonuclease, which in turn induces irreversible damage of tubular epithelial cells, and may contribute to the initiation and development of AKI.

Impact of anti-glomerular basement membrane antibodies and glomerular neutrophil activation on glomerulonephritis in experimental myeloperoxidase-antineutrophil cytoplasmic antibody vasculitis

BACKGROUND Antineutrophil cytoplasmic antibody (ANCA) and neutrophil interactions play important roles in ANCA-associated vasculitis (AAV) pathogenesis. However, mechanisms underlying the pathogenesis of crescent formation in ANCA-associated vasculitis have not been completely elucidated. To ascertain the involvement of these interactions in necrotizing crescentic glomerulonephritis (NCGN), we used an AAV rat model and investigated the effects of the anti-myeloperoxidase (MPO) antibody (Ab) titer, tumor necrosis factor α (TNF-α), granulocyte colony-stimulating factor (G-CSF) and subnephritogenic anti-glomerular basement membrane (GBM) Abs, as proinflammatory stimuli. METHODS NCGN was induced in Wistar Kyoto rats by human MPO (hMPO) immunization. Renal function, pathology, and glomerular cytokine and chemokine expression were evaluated in hMPO-immunized rats with/without several co-treatments (TNF-α, G-CSF or subnephritogenic anti-GBM Abs). Rat neutrophils activation by IgG purified from rat serum in each group was examined in vitro. RESULTS The hMPO-immunized rats had significantly higher level of anti-hMPO Ab production. The induced anti-hMPO Abs cross-reacted with TNF-α- or G-CSF-primed rat neutrophils secreting TNF-α and interleukin-1β in vitro. The reactivity of anti-MPO Abs against rat MPO, crescent formation with neutrophil extracellular traps and glomerular-activated neutrophil infiltration in the rat model were significantly enhanced by subnephritogenic anti-GBM Ab but not by TNF-α or G-CSF administration. The model rats injected with the subnephritogenic anti-GBM Abs showed increased urinary albumin excretion and serum TNF-α, chemokine (C-X-C) ligand 1 (CXCL1) and CXCL2 levels. TNF-α, CXCL1, CXCL2 and CXCL8 increased in the glomeruli with significant amounts of crescent formation. In addition, in vitro activated neutrophils decreased CXC chemokine receptor 1 (CXCR1) and CXCR2 expressions. CONCLUSIONS The coexistence of subnephritogenic anti-GBM Abs leads to the inflammatory environment in glomeruli that is amplified by the interaction of ANCA and neutrophils. Development of NCGN in MPO-AAV may be necessary for not only the accumulation of neutrophils in glomeruli, but also the aberrant neutrophil activation on glomerulonephritis.

Glomerular capillary and endothelial cell injury is associated with the formation of necrotizing and crescentic lesions in crescentic glomerulonephritis.

BACKGROUND The associations of glomerular capillary and endothelial injury with the formation of necrotizing and crescentic lesions in cases of crescentic glomerulonephritis (GN) have not been evaluated in detail. METHODS Glomerular capillary and endothelial cell injury were assessed in renal biopsy specimens of crescentic GN, including those from patients with anti-neutrophil cytoplasmic autoantibodies (ANCA) -associated GN (n=45), anti-glomerular basement membrane (GBM) GN (n=7), lupus GN (n=21), and purpura GN (n=45) with light and electron microscopy and immunostaining for CD34. RESULTS In ANCA-associated GN, anti-GBM GN, lupus GN, and purpura GN, almost all active necrotizing glomerular lesions began as a loss of individual CD34-positive endothelial cells in glomerular capillaries, with or without leukocyte infiltration. Subsequently, necrotizing lesions developed and were characterized by an expansive loss of CD34-positive cells with fibrin exudation, GBM rupture, and cellular crescent formation. With electron microscopy, capillary destruction with fibrin exudation were evident in necrotizing and cellular crescentic lesions. During the progression to the chronic stage of crescentic GN, glomerular sclerosis developed with the disappearance of both CD34-positive glomerular capillaries and fibrocellular-to-fibrous crescents. In addition, the remaining glomerular lobes without crescents had marked collapsing tufts, a loss of endothelial cells, and the development of glomerular sclerosis. CONCLUSIONS The loss of glomerular capillaries with endothelial cell injury is commonly associated with the formation of necrotizing and cellular crescentic lesions, regardless of the pathogeneses associated with different types of crescentic GN, such as pauci-immune type ANCA-associated GN, anti-GBM GN, and immune-complex type GN. In addition, impaired capillary regeneration and a loss of endothelial cells contribute to the development of glomerular sclerosis with fibrous crescents and glomerular collapse.

Chronic antibody-mediated responses may mediate chronic rejection in rat orthotopic liver transplantation.

The category of chronic antibody-mediated rejection (AMR) is not included in Banff schema for liver allograft rejection. In the present study, we examined the pathology of chronic rejection using rat liver transplantation. Orthotopic liver transplantation from Lewis to BN rats was performed without immunosuppression, and with or without HA reconstruction. We studied grafts at day 120 for arterialized and day 39 for nonarterialized transplants focusing on the immunoglobulin G (IgG) deposition and the pathologic characteristics of rejection. About 20% of arterialized grafts survived more than 120 days. Between day 7 and day 120, T-cell infiltration to arterialized grafts was accompanied by IgG deposition in portal veins, hepatic arteries, and bile ducts in portal areas, sinusoids and hepatocytes. At day 120, arterialized grafts were morphologically characterized by late chronic rejection with IgG deposition, intraluminal portal veins fibrosis, intimal fibrous thickening of hepatic arteries, diffuse sinusoidal fibrosis, as well as injury and loss of bile ducts due to fibrosis. The severities of T cell-mediated rejection and AMR were higher in nonarterialized than arterialized grafts. Nonarterialized Lewis liver grafts in BN rats were rejected by day 39, as characterized by late chronic rejection with IgG deposition and cellular infiltration. In conclusion, chronic AMR may be involved in chronic rejection of liver transplantations. When chronic AMR was involved in chronic liver graft rejection, typical late morphological changes emerged within a short period.

Effects of olmesartan and imidapril on the plasma adiponectin, P-selectin, and MDA-LDL levels of diabetic nephropathy patients.

Diabetic nephropathy, one of the most important complications of diabetic mellitus, is a common cause of end stage renal failure [1]. Overactivity of the renin-angiotensin system (RAS) has been implicated in the deterioration of renal function in patients with diabetic nephropathy [2,3]. Angiotensin-converting-enzyme (ACE) and angiotensin-receptor blockers (ARB) slow the worsening of the glomerular filtration rate (GFR) and reduce the rate of albumin excretion [2-4]. Diabetic nephropathy is also associated with insulin resistance, a hypercoagulable state, and oxidative stress and can lead to endothelial dysfunction [5-7]. Many clinical studies have shown that reninangiotensin system blockade reduces insulin resistance, inflammation, and oxidative stress [8,9]. RAS blockade has also been revealed to have pleiotropic effects. Theoretically, combining anACEIwith anARB should result in more complete RAS inhibition while providing the beneficial effects of increased bradykinin levels and AT2 receptor activation [1012]. In clinical practice, many patients cannot tolerate high doses of ACEI or ARB as they can cause hypotension events and other adverse effects, such as hyperkalemia, a decreased hemoglobin level, or acute reductions in GFR [13-15]. Combination therapy involving submaximal doses of ACEI and ARB was demonstrated to have favorable effects in such patients [16,17]. Twenty patients (twelve men and eight women, age: 60.8± 13.4 years, mean±SD) with diabetic nephropathy participated in this study. Diabetic nephropathy was defined as the presence of microand macro albuminuria. The mean serum creatinine was 1.11±0.51 mg/dl (0.51~2.27 mg/dl). The concentrations of LDLcholesterol and HDL-cholesterol were 98.6±18.3 mg/dl and 54.8± 15.2 mg/day, respectively. The concentration of HDL-cholesterol was 54.8±15.2 mg/day, The triglyceride concentration was 153.4± 15.2 mg/dl. The hemoglobin A1C concentration was 6.8±1.0%. The patients who were administrated with blockade of the reninangiotensin system within 8 weeks were excluded. This study was approved by the local ethical committee. Informed consent for additional blood sampling was obtained from all patients. We administered a submaximal dose of olmesartan medoxomil (olmesartan; 10 mg/day) for 12 weeks. After 12 weeks, we added imidapril hydrochloride (imidapril) for 12 weeks. The dosage of imidapril was 5 mg/day, unless the patients systolic BP decreased to b100 mmHg or they suffered postural dizziness, in which case the dose of imidapril was reduced. The final dosage of imidapril ranged from 2.5 to 5 mg/day. Blood and urine samples were obtained at the baseline, 13th week, and 25th week. Blood was centrifuged at 4 °C, and plasma samples were frozen until they were analyzed. The plasma concentrations of adiponectin and P-selectin were determined using ELISAs (Otsuka Pharmaceuticals Co. Ltd., Takara). The ELISA used for the measurement of MDA-LDL was based on a previously described method