A Study of Morphological Changes in Renal Afferent Arterioles Induced by Angiotensin II Type 1 Receptor Blockers in Hypertensive Patients.

BACKGROUND: Renin-angiotensin-aldosterone system blockers are known to reduce hypertrophy of vascular smooth muscle cells (SMCs) in hypertensive cases. However, we have reported marked proliferative changes of renal afferent arteriolar SMCs in rats induced by a long-term administration of angiotensin II type 1 receptor blockers (ARBs) and an angiotensin-converting enzyme inhibitor (ACEI). In this study, we examined the morphological changes of afferent arteriolar walls in human kidneys with or without ARBs/ACEIs. METHODS: Forty-four wedge resections were taken from patients aged 45-74 years from 92 nephrectomized kidneys due to malignancy at Toho University Omori Medical Center between 2013 and 2016. They were divided into the following three groups: 18 hypertensive patients treated with antihypertensive agents including ARBs or ACEIs (the HTARB group), 6 hypertensive patients treated with calcium channel blockers without ARBs/ACEIs (the HTCCB group), and 20 normotensive patients (the normotensive group) as a control. Cases expecting vascular changes such as diabetes were excluded. In each case renal arterioles were measured as the ratio of inner/outer arteriolar diameter, and pathologists estimated morphological abnormal changes, scoring each specimen independently. RESULTS: The ratio in the HTARB group was 0.39 ± 0.05 (mean ± SD), and was significantly the lowest among the three groups (0.46 ± 0.02 in the HTCCB, 0.53 ± 0.02 in the normotensive group; p = 0.0107 vs. HTCCB, p = 0.00001 vs. normotensive). The ratio in the three groups significantly correlated with the estimated glomerular filtration rate (r = 0.4915, p < 0.0007). The afferent arteriolar SMCs in the HTARB group frequently showed marked proliferative and irregular changes. The score of SMC abnormalities estimated regarding the proliferation, irregularity of the arrangement, and size in hilar afferent arteriolar SMCs was highest in the HTARB group and showed statistical significance (p = 0.0088, p = 0.00001, and p = 0.025 versus other two groups). CONCLUSIONS: We consider that these morphological changes in arterioles are induced by ARBs/ACEIs. These changes could induce an important suppression of glomerular hyperfiltration and could lead to glomerular ischemia. However, the clinical consequences of these morphological changes in correlation with ARBs/ACEIs were not sufficiently clear and require further analysis. We should consider renal arteriolar morphological changes when using ARBs/ACEIs.

Changes in renal vessels associated with long-term administration of angiotensin converting enzyme inhibitor in Zucker fatty rats.

Background Recently, we showed that long-term angiotensin receptor blocker (ARB) administration induced unusual proliferative changes in smooth muscle cells (SMCs) of afferent arterioles of the kidneys of Zucker fatty rats (ZFRs). In this study, we investigated renal afferent arteriolar changes induced by the long-term administration of an angiotensin converting enzyme inhibitor (ACEI) in ZFRs. Materials and Methods Fourteen 6-week-old male ZFRs were divided into two groups (n=14): the ZFR+ACEI group (n=6) was fed a standard diet containing ACEI (Enalapril, 2 mg/kg/day), and the ZFR control group (n=8) for 12 weeks. Blood pressure and proteinuria were examined and morphological studies on kidneys were performed. Results Remarkable proliferative changes in the afferent arteriolar SMCs were frequently observed in the group given ACEI; (66.1 ± 12.9%) compared with the control group (1.77 ± 1.56%, P<0.001). Conclusions It was indicated that long-term ACEI administration induced unusual proliferative changes in SMCs in afferent arterioles of ZFRs. These changes could reduce intraglomerular pressure by narrowing the lumens of afferent arterioles, but they could cause irreversible damage to the arterioles.

Direct Renin Inhibitor is Better than Angiotensin II Receptor Blocker for Intrarenal Arterioles.

BACKGROUND/AIMS: We have reported that the long-term administration of angiotensin II receptor blockers (ARBs) induced unusual proliferative changes of renal afferent arteriolar smooth muscle cells (SMCs) in rats, associated with the overproduction of renin. In this study, we examined that a direct renin inhibitor (DRI: Aliskilen; Novartis Pharma Co, USA) might induce different changes on afferent arteriolar walls compared to ARBs. METHOD: Twenty one 6-weeks-old male spontaneous hypertensive rats (SHRs) were divided into the following three groups: high-dose DRI group (n=7), low-dose DRI group (n=5) and control group (n=9). The rats were fed a standard diet (0.4%NaCl) containing high-dose (150mg/kg/day), low-dose (30mg/kg/day) DRI and without DRI for 12 weeks. The kidneys were examined by histological and immunohistochemical studies. Systolic blood pressure, 24-h urine samples and blood samples were also examined. RESULTS: The afferent arteriolar SMC walls in the two DRI groups showed no proliferative changes. The positive renin expression area was the largest in the high-dose DRI group among the three groups (14.3±4.0µm2, 6.7±2.0µm2, 2.6±0.9µm2/glomerlus, p=0.020, p=0.008, p=0.017, respectively). CONCLUSION: The long-term DRI administration increases tissue and circulatory renin; however, afferent arteriolar proliferative changes as shown in ARBs were not induced.

Glomerular damage in experimental proliferative glomerulonephritis under glomerular capillary hypertension.

BACKGROUND/AIMS: Immunologically and hemodynamically mediated the destruction of glomerular architecture is thought to be the major causes of end-stage renal failure. The purpose of this study is to evaluate the effect of glomerular hypertension on glomerular injury and the progression of glomerular sclerosis after Thy-1 nephritis was induced. METHOD: Thy-1 nephritis was induced in the stroke-prone spontaneously hypertensive rat strain (SHR-SP) (group SP) and in age-matched Wistar-Kyoto (WKY) (group WKY) rats, following unilateral nephrectomy (UNX), and a vehicle was injected alone in UNX SHR-SP as control (group SC). RESULT: The degree of glomerular damage in response to a single dose of anti-thy-1 antibody, and its functional consequences (eg. proteinuria, diminished GFR) are more pronounced in group SP than normotensive group WKY and hypertensive group SC without mesangial cell injury. While normotensive group WKY rats recovered completely from mesangial cell injury on day 28-42, glomeruli in group SP kept on persistent macrophage infiltration, α-SMA expression on day 42-56. In addition, glomerular capillary repair with the GECs was rarely seen in pronouncedly proliferative and sclerostic areas. The incidence of glomerular sclerosis and the level of proteinuria were markedly increased by day 56 in the group SP. CONCLUSIONS: Our results demonstrate that glomerular hypertension aggravate glomerular damage and glomerulosclerosis in this model of Thy 1 nephritis.

Glomerular basement membrane injuries in IgA nephropathy evaluated by double immunostaining for α5(IV) and α2(IV) chains of type IV collagen and low-vacuum scanning electron microscopy.

BACKGROUND: The glomerulus contains well-developed capillaries, which are at risk of injury due to high hydrostatic pressure, hyperfiltration, hypertension and inflammation. However, the pathological alterations of the injured glomerular basement membrane (GBM), the main component of the glomerular filtration barrier, are still uncertain in cases of glomerulonephritis. METHODS: We examined the alterations of the GBM in 50 renal biopsy cases with IgA nephropathy (31.8 ± 17.6 years old) using double immunostaining for the α2(IV) and α5(IV) chains of type IV collagen, and examining the ultrastructural alterations by transmission electron microscopy (TEM) and low-vacuum scanning electron microscopy (LV-SEM). RESULTS: The GBM of IgA nephropathy cases showed various morphological and qualitative alterations. In the TEM findings, thinning, gaps, rupture, thickening with a lamellar and reticular structure and double contours were detected in the GBM. Double immunostaining for α5(IV) and α2(IV) showed thickening of the GBM with reduced α5(IV) and increased α2(IV), or mosaic images of α5(IV) and α2(IV), and holes, fractures, spiny projections and rupture of α5(IV) in the GBM. In addition, LV-SEM showed an etched image and multiple holes in a widening and wavy GBM. These findings might be associated with the development of a brittle GBM in IgA nephropathy. CONCLUSION: Glomerular basement membrane alterations were frequently noted in IgA nephropathy, and were easily evaluated by double immunostaining for α2(IV) and α5(IV) of type IV collagen and LV-SEM. The application of these analyses to human renal biopsy specimens may enhance our understanding of the alterations of the GBM that occur in human glomerular diseases.

Proliferative changes of renal arteriolar walls induced by administration of angiotensin II receptor blocker are frequent in juvenile rats.

INTRODUCTION: Our previous study of angiotensin II receptor blocker (ARB) administration in rats induced unusual proliferative changes of smooth muscle cells in renal arteriolar walls. The present study examined if the incidence of the changes depended on the rats' age, and how long it would take to find changes. MATERIALS AND METHODS: Six-week-old (juvenile spontaneous hypertensive rats (SHRs)+ARB group, n=15) and 20-week-old (adult SHRs+ARB group, n=10) male SHRs were fed a standard diet (0.4% NaCl) containing valsartan (10 mg/kg/day; Novartis Co.). Fifteen age-matched SHRs were studied as controls. After 4, 8, and 12 weeks, the rat kidneys were examined under light and electron microscopes and through immunohistochemical studies. RESULTS: Extremely concentric proliferative changes in afferent arteriolar walls were frequently observed in the juvenile SHR+ARB group compared to the adult SHR+ARB group (48.7±6.8% vs 19.3±6.9%; p=0.0307) at the 12(th) week. Increased renin expression and arteriolar changes were found from the 4(th) week in the juvenile SHR+ARB group. CONCLUSION: This study indicates that ARB administration induces unusual proliferative changes and a marked renin-producing cell increase in afferent arterioles more frequently in juveniles than adult rats. It is suggested that the treatment of ARB in juveniles might have a higher risk of changes in renal afferent arterioles.

Immunohistochemical Characteristics of IgG4-Related Tubulointerstitial Nephritis: Detailed Analysis of 20 Japanese Cases.

Although tubulointerstitial nephritis with IgG4+ plasma cell (PC) infiltration is a hallmark of IgG4-related kidney disease (IgG4-RKD), only a few studies are available about the minimum number of IgG4+ PC needed for diagnosis along with IgG4+/IgG+ PC ratio in the kidney. In addition, the significance of the deposition of IgG or complement as a reflection of humoral immunity involvement is still uncertain. In this study, we analyzed 20 Japanese patients with IgG4-RKD to evaluate the number of IgG4+ PCs along with IgG4+/IgG+ PC ratio and involvement of humoral immunity. The average number of IgG4+ PCs was 43.8/hpf and the average IgG4+/IgG+ or IgG4+/CD138+ ratio was 53%. IgG and C3 granular deposits on the tubular basement membrane (TBM) were detected by immunofluorescence microscopy in 13% and 47% of patients, respectively. Nine patients had a variety of glomerular lesions, and 7 of them had immunoglobulin or complement deposition in the glomerulus. In conclusion, we confirmed that infiltrating IgG4+ PCs > 10/hpf and/or IgG4/IgG (CD138)+ PCs > 40% was appropriate as an item of the diagnostic criteria for IgG4-RKD. A relatively high frequency of diverse glomerular lesions with immunoglobulin or complement deposits and deposits in TBM may be evidence of immune complex involvement in IgG4-related disease.

Characteristic tubulointerstitial nephritis in IgG4-related disease.

Nephropathy associated with IgG4-related disease is characterized by tubulointerstitial nephritis. To better identify its pathology, the present study analyzed clinicopathologic features of IgG4-related tubulointerstitial nephritis cases from across Japan. Sixteen cases were identified as IgG4-related nephropathy using the criterion of high serum IgG4 levels (>135 mg/dL) with abnormal kidney computed tomography or elevated serum creatinine levels. Male predominance (75%) and advanced age (average, 62.0 years) were noted. Eight cases displayed no autoimmune pancreatitis. Renal computed tomography abnormalities were found in 12 of 13 cases examined. Renal dysfunction was found in 15 of 16 cases at biopsy. Distinctive features of tubulointerstitial lesions included (1) well-demarcated borders between involved and uninvolved areas; (2) involvement of the cortex and medulla, often extending beyond the renal capsule and with occasional extension to retroperitoneal fibrosis; (3) interstitial inflammatory cells comprising predominantly plasma cells and lymphocytes, with a high prevalence of IgG4-positive cells often admixed with fibrosis; (4) peculiar features of interstitial fibrosis resembling a "bird's-eye" pattern comprising fibrosis among inter-plasma cell spaces; and (5) deposits visible by light and immunofluorescent microscopy in the tubular basement membrane, Bowman capsule, and interstitium that are restricted to the involved portion, sparing normal parts. Ultrastructural analysis revealed the presence of myofibroblasts with intracellular/pericellular collagen accompanied by plasma cell accumulation from an early stage. Histology could not discriminate between IgG4-related tubulointerstitial nephritis with and without autoimmune pancreatitis. In conclusion, the distinctive histologic features of IgG4-related tubulointerstitial nephritis can facilitate the differential diagnosis of tubulointerstitial nephritis, even without autoimmune pancreatitis or an abnormal computed tomography suggesting a renal tumor.

Proposal for diagnostic criteria for IgG4-related kidney disease.

BACKGROUND: IgG4-related disease has attracted wide attention recently. It is characterized by a high level of serum IgG4 and dense infiltration of IgG4-positive plasma cells into multiple organs, with the kidney being one representative target. Although several sets of diagnostic criteria for autoimmune pancreatitis (AIP) are available and renal lesion is recognized as an extra-pancreatic manifestation of AIP, it is difficult to differentiate IgG4-related tubulointerstitial nephritis (TIN) without AIP from other types of TIN. To clarify the entity of IgG4-related kidney disease (IgG4-RKD) and support in-depth studies, the Japanese Society of Nephrology has established a working group to prepare diagnostic criteria for IgG4-RKD. METHOD: The working group analyzed 41 patients with IgG4-RKD, and collected the following data to devise a diagnostic algorithm and diagnostic criteria for IgG4-RKD: clinical features including extra-renal organ involvement, urinalysis and serological features including serum IgG4 levels, imaging findings demonstrated by computed tomography (CT), renal histology with IgG4 immunostaining, and response to steroid therapy. RESULTS: The conditions for criteria are as follows. (1) Presence of some kidney damage, as manifested by abnormal urinalysis or urine marker(s) and/or decreased kidney function with either elevated serum IgG level, hypocomplementemia, or elevated serum IgE level. (2) Kidney imaging studies showing abnormal renal imaging findings, i.e., multiple low density lesions on enhanced CT, diffuse kidney enlargement, hypovascular solitary mass in the kidney, and hypertrophic lesion of the renal pelvic wall without irregularity of the renal pelvic surface. (3) Serum IgG4 level exceeding 135 mg/dl. (4) Renal histology showing two abnormal findings: (a) dense lymphoplasmacytic infiltration with infiltrating IgG4-positive plasma cells >10/high power field (HPF) and/or ratio of IgG4-positive plasma cells/IgG positive plasma cells >40%. (b) Characteristic 'storiform' fibrosis surrounding nests of lymphocytes and/or plasma cells. (5) Extra-renal histology showing dense lymphoplasmacytic infiltration with infiltrating IgG4-positive plasma cells >10/HPF and/or ratio of IgG4-positive plasma cells/IgG-positive plasma cells >40%. The diagnosis is classified into 3 stages of definite, probable and possible according to the combinations of the above conditions. Thirty-nine cases (95.1%) were diagnosed with IgG4-RKD according to the criteria. CONCLUSION: The provisional criteria and algorithm appear to be useful for clarifying the entity of IgG4-RKD and seeking underlying IgG4-RKD cases; however, further experience is needed to confirm the validity of these criteria.

Changes in renal vessels following the long-term administration of an angiotensin II receptor blocker in Zucker fatty rats.

INTRODUCTION: The nephro-protective effects of angiotensin II receptor blockers (ARBs) are widely known; however, there are few reports of long-term effects focusing on the renal vessels. We studied afferent arteriolar changes induced by the long-term administration of an ARB. MATERIALS AND METHODS: Thirty-two 6-week-old male Zucker fatty rats (ZFRs) were divided into following four groups (n = 8 in each): ZFR Group and ZFR+High Group fed a standard or high-salt diet, respectively; ZFR+ARB Group and ZFR+High+ARB Group fed a standard or high-salt diet with ARB (Olmesartan, 5 mg/kg/day), respectively. Blood pressure, proteinuria, morphological examinations and glomerular haemodynamics in vivo were studied. RESULTS: Marked proliferative changes in the afferent arteriolar smooth muscle cells (SMCs) were frequently observed in the two groups given ARBs; in the ZFR+ARB group (77.3±10.3%) compared with the two groups without ARB (1.7%, p < 0.005; 1.2%, p < 0.0005) and 37.4±15.6% in the ZFR+High+ARB group. Proteinuria markedly decreased in the groups treated with ARBs, but the glomerular erythrocyte velocities showed no differences. CONCLUSIONS: Our findings indicate that long-term ARB administration induced unusual proliferative changes in SMCs of afferent arterioles of ZFRs. These changes could narrow arteriolar lumens and reduce intraglomerular pressure, but they could cause also irreversible damage to the arterioles.

A differential diagnostic model of diabetic nephropathy and non-diabetic renal diseases.

BACKGROUND: Renal diseases in diabetes include diabetic nephropathies (DN) and non-diabetic renal diseases (NDRD). The clinical differentiation between these two categories is usually not so clear and effective. This study aims to develop a quantified differential diagnostic model. METHODS: We consecutively screened the diabetic patients with overt proteinuria but no severe renal failure for kidney biopsy from 1993 to 2003. The finally enrolled 110 patients were divided into two groups according to pathological features (60 in DN group and 50 in NDRD group). Clinical and laboratory data were compared between two groups. Then a diagnostic model was developed based on the logistic regression analysis. RESULTS: Forty-six percent of patients were NDRD including a variety of pathological types. Many differences between DN and NDRD were found by comparison of the clinical indices. In the final logistic regression analysis, only diabetes duration (Dm), systolic blood pressure (Bp), HbA1c (Gh), haematuria (Hu) and diabetic retinopathy (Dr) showed statistical significance. Based on the logistic regression model: pi = e(z)/(1 + e(z)), a diagnostic model was constructed as follows: P(DN) = exp(-13.5922 + 0.0371Dm + 0.0395Bp + 0.3224Gh - 4.4552Hu + 2.9613Dr)/ [1 + exp(-13.5922 + 0.0371Dm + 0.0395Bp + 0.3224Gh - 4.4552Hu + 2.9613Dr)]. P(DN) was the probability of DN diagnosis (P(DN) >or= 0.5 as DN, P(DN) < 0.5 as NDRD). Validation tests showed that this model had good sensitivity (90%) and specificity (92%). CONCLUSIONS: This diagnostic model may be helpful to clinical differentiation of DN and NDRD in type 2 diabetic patients with overt proteinuria.

Expression and activation of STAT3 in chronic proliferative immune complex glomerulonephritis and the effect of fosinopril.

BACKGROUND: Signal transducers and activators of transcription (STATs) are cytoplasmic proteins that are activated in response to stimulation from various cytokines. Among these, STAT3 is an important member that has been implicated in the inflammatory proliferation of cells. We hypothesized that STAT3 may be activated in kidneys of rats having modified chronic immune complex glomerulonephritis, and that angiotensin-converting enzyme (ACE) inhibition with fosinopril may prevent the activation of STAT3 and subsequent upregulation of tissue inhibitor of metalloproteinase-1 (TIMP-1), which are effects that may explain the therapeutic effects of fosinopril on nephritis. METHODS: Fifty-one Wistar rats were randomly divided into three groups that included a control group, a model group and a fosinopril group. Bovine serum albumin (BSA) nephritis was induced by subcutaneous immunization and daily intraperitoneal (i.p.) administration of BSA. To accentuate the nephritis, we performed uni-nephrectomy and gave 100 microg of lipopolysaccharide (LPS) as an i.p. injection. Macrophage infiltration (ED-1) was assessed with immunohistochemistry. The expression and activation of STAT3 and the expression of TIMP-1, one of the STAT3 downstream genes, were observed in renal tissues of rats by means of immunohistochemistry, electrophoretic mobility shift assay (EMSA), western blot and northern blot. The relationships between STAT3 phosphorylation, 24 h urinary protein excretion and TIMP-1 expression were also analysed. RESULTS: Northern blot showed that the mRNA expression of both STAT3 and TIMP-1 was significantly increased in kidneys from the model group, but significantly decreased in the fosinopril group (P<0.05). Western blot analysis revealed similar increases in the expression of STAT3, phospho-STAT3 (p-STAT3) and TIMP-1 in the model group. Analysis of immunohistochemistry showed that STAT3 and p-STAT3 were expressed in very few cells of normal rats, that expression was strong in model rats and that this increased expression was attenuated in the fosinopril group (P<0.05). The expression of p-STAT3 in glomeruli was positively correlated with 24 h proteinuria as well as with glomerular TIMP-1 expression. Double staining showed that some ED-1-positive cells also contained p-STAT3-positive staining. CONCLUSIONS: The present study showed that STAT3 is expressed and activated in kidneys of rats with modified immune complex glomerulonephritis. These rats also had increased ED-1-positive cells, with some cells showing simultaneous expression of p-STAT3 and ED-1, which may contribute to glomerular inflammatory proliferation and extracellular matrix accumulation. Finally, fosinopril downregulated STAT3 activation and ED-1 influx, which are effects that may attenuate renal damage in this model.

Characteristics and risk factors of intrarenal arterial lesions in patients with IgA nephropathy.

BACKGROUND: Although the clinical importance of immunoglobulin-A nephropathy (IgAN) is widely recognized, the characteristics of intrarenal arterial lesions in this disease and the main factors associated with them have not been studied extensively, and a large-scale analysis of intrarenal arterial lesions in IgAN has not been performed. METHODS: To clarify these issues, we investigated the prevalence, underlying factors and significance of intrarenal arterial lesions in 1005 patients with IgAN. We distinguished different degrees of severity of small artery and arteriolar lesions (mild, moderate and severe), using a semi-quantitative scoring system. We compared the arterial lesions of IgAN patients with those of 627 non-IgAN patients, who had mesangial proliferating glomerulonephritis without IgA deposits, and of 221 patients with membranous nephropathy (MN). RESULTS: The IgAN patients with arterial lesions were significantly younger than the non-IgAN and MN patients (mean ages 34.6 vs 40.4 and 47.7 years, respectively). The prevalence of intrarenal small artery and arteriolar lesions was 54.6% in IgAN patients, compared with 26.6 and 47.1% in non-IgAN and MN patients, respectively; the percentages of moderate/severe arterial lesions were 37.0 vs 21.6 and 23.1%, respectively; and the percentages of hyaline changes were 43.7 vs 16.8 and 21.2%, respectively. The differences in the prevalence of lesions between IgAN patients and the two other groups were statistically significant for all three parameters. Our search for possible relationships between arterial-arteriolar lesions and various indirect outcome markers disclosed significant associations with hypertension, higher serum creatinine and uric acid, high urinary protein excretion, glomerulosclerosis, tubular atrophy and interstitial fibrosis. Furthermore, these parameters were changed more markedly in IgAN patients with moderate/severe arterial lesions and hyaline changes than in IgAN patients who had mild arterial lesions and wall thickening alone. CONCLUSIONS: The prevalence of small intrarenal arterial-arteriolar lesions was higher in IgAN patients than in non-IgAN and MN patients; moreover, the lesions in IgAN patients were associated with younger age, were more severe and exhibited a higher degree of hyaline changes. Finally, the severity of small arterial- arteriolar lesions was linked to several markers of adverse outcome.

Hepatocyte growth factor-stimulating endothelial cell growth and accelerating glomerular capillary repair in experimental progressive glomerulonephritis.

Hepatocyte growth factor (HGF) is one of the major growth factors that stimulate the growth and the migration of vascular endothelial cells. In this study, we examined the beneficial effects of HGF for glomerular repair in an experimental progressive glomerulonephritis (GN) model prepared by injecting both anti-Thy-1.1 antibody (day 0) and habu-snake venom (day 1) in rats. The rats received continuous intraperitoneal administration of recombinant human HGF (80 microg/100 g/day) or vehicle control at an early stage (day 2 to day 9), after severe glomerular injury. The vehicle-infused control rats initially showed severe mesangiolysis with large ballooning (day 2), followed by the prominent proliferation of mesangial cells with minimal capillary regeneration (day 5 to week 2), and global sclerosis with chronic renal failure (week 4 to week 8). Although mesangiolysis with large ballooning and mesangial cell proliferation were also observed in the HGF-infused rats, glomerular capillary regeneration with marked endothelial cell proliferation occurred during HGF administration from day 2 to day 9. Subsequently, the glomerulus was repaired with the development of the capillary network and the reduction of mesangial hypercellularity from week 2 to week 4, and almost all of the glomeruli showed a normal structure by week 8. The HGF-treated rats showed significantly better renal functions (Cr: 0.3 +/- 0.1 vs. 3.5 +/- 1.1 mg/dl in control, p < 0.001), less proteinuria (21.2 +/- 8.0 mg/day vs. 421.4 +/- 45.1 mg/day in control, p < 0.001) and less glomerular sclerosis at week 8 than the vehicle-infused rats. We conclude that HGF accelerated glomerular repair through the growth of capillary endothelial cells and capillary regeneration in experimental progressive GN. Administering HGF is a logical and efficient strategy for treating progressive GN with severe capillary destruction.

Wound healing involves induction of cyclooxygenase-2 expression in rat skin.

Cyclooxygenase (COX), an enzyme essential for prostaglandin biosynthesis, has two isoforms, COX-1 and -2. We investigated temporal and spatial changes in localization of these two COX proteins and mRNAs after excisional injury in rat skin. We also quantified the expression of these proteins and studied the effects of a specific COX-2 inhibitor on healing. Immunohistochemistry and in situ hybridization respectively indicated that the COX-2 protein and mRNA were expressed mainly within the basal layer of the epidermis, peripheral cells in the outer root sheath of hair follicles, and fibroblast-like cells and capillaries near epidermal wound edges. Much less intense expression was observed in normal skin than in injured skin. Western analysis demonstrated marked induction of COX-2 protein beginning within 12 hours and peaking 3 days after injury. In contrast, localization of COX-1 protein and mRNA, as well as the amount of protein expression, showed no significant change during wound healing. Administration of the COX-2 inhibitor delayed re-epithelialization in the early phase of wound healing and also inhibited angiogenesis. Thus, COX-2 induction may be important in cutaneous wound healing.

Unusual petal-like fibromuscular dysplasia as a cause of acute abdomen and circulatory shock.

Fibromuscular dysplasia (FMD) is a nonatherosclerotic, noninflammatory segmental arterial occlusive disorder that involves primarily the renal and carotid arteries, and less often the coronary, iliac, and visceral arteries. We report the case of 78-year-old Japanese woman who presented with acute abdomen complicated by shock. Autopsy revealed hemorrhagic necrosis of the small intestine due to severe narrowing of the mesenteric arteries. Histologically, smooth muscles showed in-bundle hyperplasia surrounding the adventitia together with medial and perimedial fibrodysplasia of these arteries, forming the characteristic petal-like appearance of FMD. No occlusive thrombus was observed. Further, another medial fibrodysplasia type of FMD was also seen in the renal and left circumflex coronary arteries. Unusual proliferation of smooth muscles resulted in the petal-like atypical FMD at the superior mesenteric artery.

Peritubular capillary regression during the progression of experimental obstructive nephropathy.

Injury to the renal microvasculature may be a major factor contributing to the progression of renal disease. Although severe disruption of peritubular capillaries (PTC) could lead to marked tubulointerstitial scarring, elucidation of that process remains incomplete. This study investigated the morphologic changes in PTC and their likely regulation by vascular endothelial growth factor (VEGF) during the progression of tubulointerstitial injuries. Unilateral ureteral obstruction was induced in Wistar rats by ligation of the left ureter, and the kidneys were then collected at selected times. PTC lumina and the expression of VEGF and its receptor Flk-1 were immunohistochemically detected. Morphologic changes in PTC endothelial cells were examined by using Ki67 staining, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling, and electron-microscopic studies. In the first week of the disease period, immunohistochemical labeling of tubular VEGF intensified, with accompanying deformation and dilation of adjacent thrombomodulin (TM)-positive PTC lumina; an angiogenic response of endothelial cells was demonstrated with Ki67 and TM double-staining. During the subsequent 2 wk, tubular VEGF labeling decreased until it was virtually absent, an effect confirmed by Western blotting. Concomitantly, labeling of the VEGF receptor Flk-1 in PTC endothelial cells decreased and PTC lumina began to regress, demonstrating endothelial cell apoptosis (as detected in terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling and electron-microscopic studies). By the end of week 4, the numbers of TM-positive PTC lumina were significantly decreased in areas of marked tubulointerstitial scarring. These results suggest that PTC regression, involving an early, unsustained, angiogenic response followed by progressive endothelial cell apoptosis, could be a potential factor contributing to tubulointerstitial scarring in this unilateral ureteral obstruction model.

Peritubular capillary injury during the progression of experimental glomerulonephritis in rats.

The functional and morphologic changes occurring in the peritubular capillaries (PTC) of the kidney during the progression of renal disease are not yet completely understood. In this study, the features of PTC disruption observed in a rat anti-glomerular basement membrane-induced glomerulonephritis (GN) model were characterized. Contributions to the progression of the disease made by other interstitial components, including ED-1-positive macrophages and CD3-positive T cells, were also investigated. Within 7 d of inducing GN, severe necrotizing glomerular injuries were observed. Thrombomodulin staining revealed that within 3 to 8 wk, there was a significant (P < 0.001) decline in the number of PTC, accompanied by a marked accumulation of macrophages, T cells, and fibrotic material. By the end of this period, most PTC were severely damaged or lost, and tubulointerstitial scarring was noted in the affected areas. Furthermore, PTC endothelial cell apoptosis occurred concomitantly, as shown by application of terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling methods and electron microscopy. It was presumed that the PTC injury was mediated possibly by the infiltrating macrophages and T cells, which, together with destruction of the PTC structure, correlated significantly with the impairment of renal function. These findings suggest that PTC disruption and the subsequent regression of the capillary network may contribute to the development of the tubulointerstitial injury largely responsible for the renal dysfunction in progressive GN.