ARB protects podocytes from HIV-1 nephropathy independently of podocyte AT1

BACKGROUND

Angiotensin I-converting enzyme inhibitors and angiotensin receptor blockers protect podocytes more effectively than other anti-hypertensive drugs. Transgenic rats overexpressing angiotensin II Type 1 (AT1) receptor selectively in podocytes have been shown to develop glomerulosclerosis. The prevailing hypothesis is that angiotensin II has a capacity of directly acting on the AT1 receptor of podocytes to induce injury. We therefore investigated the mechanism of reno-protective effect of AT1 receptor in a mouse model of HIV-1 nephropathy.

METHODS

We generated transgenic mice carrying the HIV-1 gene (control/HIV-1) or both HIV-1 gene and podocyte-selectively nullified AT1 gene (AT1KO/HIV-1). In these mice, we measured urinary protein or albumin excretion and performed histological analysis.

RESULTS

At 8 months of age, AT1KO/HIV-1 (n = 13) and control/HIV-1 (n = 15) mice were statistically indistinguishable with respect to urinary albumin/creatinine ratio (median 2.5 versus 9.1 mg/mg), glomerulosclerosis (median 0.63 versus 0.45 on 0-4 scale) and downregulation of nephrin (median 6.90 versus 7.02 on 0-8 scale). In contrast to the observed lack of effect of podocyte-specific AT1KO, systemic AT1 inhibition with AT1 blocker (ARB) significantly attenuated proteinuria and glomerulosclerosis in HIV-1 mice.

CONCLUSION

These results indicate that the protective effect of ARB is mediated through its receptors on cells other than podocytes, such as efferent arteriolar smooth muscle cells.

Low glomerular density with glomerulomegaly in obesity-related glomerulopathy

BACKGROUND AND OBJECTIVES

Obesity-related glomerulopathy is a secondary form of glomerular disease that may occur in obese individuals. It is histologically characterized by marked glomerulomegaly closely related to glomerular hyperfiltration. This study examined glomerular density (nonsclerotic glomerular number per renal cortical area of biopsy specimen) in patients with obesity-related glomerulopathy to determine whether any differences in this measure is associated with disease status.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Glomerular density and glomerular volume in renal biopsy samples from patients with obesity-related glomerulopathy were compared with those of kidney transplant donors and patients with IgA nephropathy. Kidneys obtained from persons without renal diseases during autopsy were also analyzed to investigate the effects of obesity on glomerular density and glomerular volume.

RESULTS

Glomerular density of kidneys from patients with obesity-related glomerulopathy (1.7±0.6/mm(2)) was significantly lower than that in biopsy samples from kidney transplant donors (3.1±1.0/mm(2)) and patients with IgA nephropathy (3.5±1.5/mm(2)). However, an analysis of autopsy cases without renal diseases showed that the glomerular density in overweight (2.9±0.7/mm(2)) or obese (3.1±1.1/mm(2)) persons was similar to that in nonobese (3.1±0.6/mm(2)) individuals. Biopsy specimens of patients with obesity-related glomerulopathy showed marked glomerulomegaly. However, glomerular volume was only modestly increased in the autopsy-examined kidneys from overweight or obese persons without renal diseases.

CONCLUSIONS

Low glomerular density associated with glomerulomegaly may be a characteristic histologic finding of patients with obesity-related glomerulopathy.

Submucosal endoscopic tumor resection for subepithelial tumors in the esophagus and cardia

BACKGROUND AND STUDY AIMS

Resection of submucosal tumors by means of endoscopy has been reported using a variety of techniques, but cannot be performed safely in tumors originating from the muscularis propria. Using the submucosal tunnel created by the technique of peroral endoscopic myotomy (POEM), we report the first series describing the new technique of submucosal endoscopic tumor resection (SET) for tumors of the esophagus and cardia.

PATIENTS AND METHODS

SET was attempted in nine consecutive patients with tumors (size >2cm) of either the esophagus or cardia with clinical indications for lesion removal. Following creation of a submucosal tunnel from 5 cm above the tumor, as described previously, the tumor was dissected from the overlying mucosa/submucosa and then carefully removed from the muscular layer using triangle-tip and insulated-tip knives. Following specimen retrieval through the tunnel, the orifice was closed by clips.

RESULTS

Of the nine patients, two had tumors that were too large (60 mm and 75 mm, respectively) to allow safe removal due to loss of endoscopic overview. All remaining tumors (maximal tumor extension 12-30 mm) could be resected safely using this method. No complications occurred and follow-up was unremarkable. On histology, all tumors were resected completely (one gastrointestinal stromal tumor, five leiomyomas). The technique had to be modified in one patient with an aberrant pancreas.

CONCLUSIONS

SET is a promising new technique for selected submucosal tumors in the esophagus and cardia up to a size of 4 cm and should be studied further.

A lower level of reduced albumin induces serious cardiovascular incidence among peritoneal dialysis patients

BACKGROUND

Human serum albumin is composed of human mercaptoalbumin (HMA) with cysteine residues having reducing powers and of oxidized human non-mercaptoalbumin. Previously, we reported that a lower HMA level is closely related to serious cardiovascular disease (CVD) incidence and mortality among hemodialysis patients. However, the relationship between HMA level and CVD incidence among peritoneal dialysis (PD) patients is unclear.

METHODS

We measured the redox state of human serum albumin using high-performance liquid chromatography in 30 continuous ambulatory PD patients. The association between HMA and incidental CVD events was evaluated.

RESULTS

Eight patients experienced symptomatic CVD events (5 patients died) at the 5-year follow-up. The concentration and fraction of HMA (cHMA and f(HMA), respectively) showed significantly lower values in patients with CVD than those without CVD (cHMA 1.58 ± 0.39 and 2.16 ± 0.43 g/dL, f(HMA) 48.9 ± 5.4 and 56.4 ± 8.6%, respectively). Multiple forward stepwise regression analysis using cHMA and f(HMA) as the criterion variables was performed, and C-reactive protein and hemoglobin were adopted as significant explanatory variables in the former equation, whereas urea nitrogen was adopted in the latter equation. Multiple logistic regression analysis revealed that cHMA is a statistically, and f(HMA) is a marginally significant explanatory variable of CVD incidence (p = 0.0369, R = -0.260 and p = 0.0580, R = -0.214, respectively).

CONCLUSIONS

Lower HMA level, which might be caused by chronic inflammation, anemia and accumulation of dialyzable uremic toxin(s), is closely related to serious CVD incidence among PD patients.

Effect of κ-opioid receptor agonist on the growth of non-small cell lung cancer (NSCLC) cells

BACKGROUND

It is becoming increasingly recognised that opioids are responsible for tumour growth. However, the effects of opioids on tumour growth have been controversial.

METHODS

The effects of κ-opioid receptor (KOR) agonist on the growth of non-small cell lung cancer (NSCLC) cells were assessed by a cell proliferation assay. Western blotting was performed to ascertain the mechanism by which treatment with KOR agonist suppresses tumour growth.

RESULTS

Addition of the selective KOR agonist U50,488H to gefitinib-sensitive (HCC827) and gefitinib-resistant (H1975) NSCLC cells produced a concentration-dependent decrease in their growth. These effects were abolished by co-treatment with the selective KOR antagonist nor-BNI. Furthermore, the growth-inhibitory effect of gefitinib in HCC827 cells was further enhanced by co-treatment with U50,488H. With regard to the inhibition of tumour growth, the addition of U50, 488H to H1975 cells produced a concentration-dependent decrease in phosphorylated-glycogen synthase kinase 3β (p-GSK3β).

CONCLUSION

The present results showed that stimulation of KOR reduces the growth of gefitinib-resistant NSCLC cells through the activation of GSK3β.

Characteristics of spontaneous calcium oscillations in renal tubular epithelial cells

BACKGROUND

The kidney is a major organ involved in calcium (Ca(2+)) metabolism. Ca(2+) is transported through renal tubular epithelial cells. The intracellular free calcium concentration ([Ca(2+)](i)) is tightly controlled at a low concentration, but transient increases and oscillations in [Ca(2+)](i) are induced by various conditions. In this study, we investigated the mechanisms underlying the spontaneous [Ca(2+)](i) oscillations observed in MDCK cells.

METHODS

[Ca(2+)](i) was monitored in fura-2-loaded Madin-Darby canine kidney (MDCK) cells using a calcium imaging system. We investigated the mechanism by which [Ca(2+)](i) changed by applying drugs or by changing the extracellular Ca(2+) concentration.

RESULTS

Spontaneous [Ca(2+)](i) oscillations occurred in MDCK cells. The oscillations occurred irregularly and were not transmitted to neighboring cells. Spontaneous [Ca(2+)](i) oscillations in MDCK cells were initiated by Ca(2+) release from ryanodine/IP(3)-sensitive intracellular calcium stores, and their frequency was largely unaffected by the extracellular Ca(2+) concentration. Moreover, the frequency of the oscillations was increased by extracellular nucleotide, but was decreased when the nucleotides were removed.

CONCLUSIONS

Our study suggested that [Ca(2+)](i) release from ryanodine/IP(3)-sensitive intracellular calcium stores mediates spontaneous [Ca(2+)](i) oscillations in MDCK cells. Calcium oscillations may be associated with the function of the renal tubular epithelial cells.

Diffuse tubulointerstitial nephritis accompanied by renal crystal formation in an HIV-infected patient undergoing highly active antiretroviral therapy

This report presents a human immunodeficiency virus (HIV) patient that developed a slowly progressive renal impairment over years under highly active antiretroviral therapy (HAART). The renal biopsy showed diffuse tubulointerstitial nephritis accompanied by crystal formations that were surrounded by multinuclear giant cells. Furthermore, rod-like crystals were detected in the urinary sediments. Tenofovir and Atazanavir were thought to be the causative drugs for the renal injury. Therefore, the possibility of HARRT-induced nephrotoxicity should be considered in HIV-infected patients, even though the activity of HIV is controlled by such therapies.

Effects of combined antihypertensive therapy with losartan/hydrochlorothiazide on uric acid metabolism

OBJECTIVE

The Jikei Optimal Antihypertensive Treatment (JOINT) study originally evaluated the effect of a fixed-dose formulation of losartan (LOS) (50 mg) plus 12.5 hydrochrolthiazide (HCTZ) for achieving better blood pressure (BP) control in patients with uncontrolled hypertension. This study is a sub-analysis of the JOINT study, focusing on the effect of LOS/HCTZ on the uric acid (UA) metabolism.

METHODS

Among 228 participants in the JOINT study, a total of 164 patients whose blood and urinary UA specimens were available were included in the present analyses.

RESULTS

Six months after switching from the prior antihypertensive agent(s) to a single tablet formulation of LOS/HCTZ, the overall serum UA concentration (sUA) increased from 6.0 ± 1.6 mg/dL to 6.2 ± 1.6 mg/dL (p=0.029). The urinary UA/creatinine (Cr) ratio increased from 0.45 +/- 0.21 to 0.50 +/- 0.25 (p=0.014), and the fractional excretion of UA (FEUA) also increased, from 7.1 +/- 3.6 to 7.0 +/- 4.3, p=0.04). Multivariate regression analyses of the basal parameters showed the change in sUA (ΔUA) to correlate with the basal sUA (β=-0.483, p<0.001), estimated glomerular filtration rate (eGFR) (β=-0.202, p=0.007) and systolic BP (β=0.147, p=0.038). In addition, the ΔUA also correlated with the changes in the estimated glomerular filtration rate (ΔeGFR) (β=-0.332, p<0.001). When the patients were classified into two groups depending on their basal sUA, those with a basal sUA ≥ 7 mg/dL exhibited a decrease in their sUA, whereas the rest of those with a sUA <7 mg/dL experienced an increase. Furthermore, patients who had previously been treated with LOS alone had a greater increase in the sUA than those treated with an angiotensin II blocker (ARB) other than LOS alone.

CONCLUSION

Antihypertensive therapy with a single tablet formulation of LOS/HCTZ is considered to be a useful option for controlling both BP and sUA, especially in uncontrolled hypertensive patients with hyperuricemia.

Metanephros transplantation inhibits the progression of vascular calcification in rats with adenine-induced renal failure

BACKGROUND/AIM

Recent research has shown that transplanted metanephroi form primitive vascularized kidneys with histologically recognizable renal features. The aim of the present study was to determine the metabolic function of transplanted metanephroi in rats with chronic renal failure (CRF), with particular reference to secondary hyperparathyroidism and vascular calcification.

METHODS

CRF was induced in 11-week-old male Wistar rats by maintaining them on a 0.75% adenine diet for 4 weeks, followed by normal diet for an additional 2 weeks. At the end of adenine loading, whole metanephroi from embryonic day 15 rats were transplanted into the omentum and epididymis of the transplantation group. Vascular calcification was evaluated 2 weeks after metanephroi transplantation.

RESULTS

Metanephros transplantation significantly reduced vascular calcium and phosphorus content and suppressed the progression of vascular calcification as indicated by von Kossa staining of the media of the thoracic aorta. However, no significant differences between the adenine-fed control and transplantation groups were found regarding the serum levels of 1,25(OH)2D3, calcium or phosphorus or the calcium × phosphorus product.

CONCLUSION

The present study has shown that transplantation of metanephroi suppresses the progression of vascular calcification via a mechanism that is independent of calcium-phosphorus dynamics.

Home systolic blood pressure on the morning of dialysis days has prognostic impact for hypertensive hemodialysis patients

Background

Hypertension is a leading cause of cardiovascular (CV) disease in the general population. Although hypertension is very common in maintenance hemodialysis (HD) patients, adequate blood pressure (BP) values and measurement timing have not been defined.

Methods

A total of 49 hypertensive HD patients were recruited. Average age was 63 ± 11 years, and duration of dialysis therapy was 6.2 ± 4.2 years. Dialysis unit BPs and various types of home BPs were separately measured, and which BPs were the most critical markers in evaluating the effect of hypertension on left ventricular hypertrophy and CV events was investigated.

Results

Predialysis systolic BPs were not correlated with any home BPs. Left ventricular mass index (LVMI) had a significant positive correlation with home BPs, especially morning systolic BPs on HD days (P < 0.01) and non-HD days (P < 0.05), on univariate and multivariate analysis. In contrast, predialysis BPs did not correlate with LVMI. During the follow-up period (47 ± 18 months), it was demonstrated that diabetes and home BPs, especially systolic BPs on the morning of HD days, were significant predictors of CV events on multivariate Cox regression analysis. A 10 mmHg increase in BP had a significantly elevated relative risk for CV events.

Conclusions

Home BP, especially systolic BPs in the morning on HD days, can provide pivotal information for management of HD patients.

A case of idiopathic membranoproliferative glomerulonephritis with a transient glomerular deposition of nephritis-associated plasmin receptor antigen

The differential diagnosis of acute poststreptococcal glomerulonephritis (APSGN) and idiopathic membranoproliferative glomerulonephritis (MPGN) is sometimes difficult, as they share several key features in their laboratory and histological findings, especially during the acute phase of the diseases. We herein report an idiopathic case of MPGN in which the glomerular deposition of nephritis-associated plasmin receptor (NAPlr), a recently identified nephritic antigen for APSGN, was demonstrated. A 24-year-old postpartum woman developed nephrotic syndrome and hypocomplementemia. Although she showed no apparent findings of a prior infection, her serum titer of antistreptolysin O antibody was elevated. Renal biopsies were performed twice at intervals of 6 months, both of which showed findings fully consistent with those of MPGN. Of note, fluorescent immunostaining for NAPlr was positive in the glomeruli of the first biopsy but not in the second. Despite the use of a corticosteroid, hypocomplementemia persisted for more than 1 year. It was therefore suggested that a streptococcal infection may have influenced the development of glomerular injury in this idiopathic case of MPGN.

Glomerular density-associated changes in clinicopathological features of minimal change nephrotic syndrome in adults

BACKGROUND

Differences in nephron number and/or glomerular size between individuals, in relation to intrauterine growth retardation or low birth weight, have been suggested to affect the clinical course of minimal change nephrotic syndrome (MCNS) in children. However, no previous study has investigated the potential influences of these histological variables on the clinical course of adult patients with MCNS.

METHODS

The glomerular density (GD; the number of non-sclerotic glomeruli per renal cortical area) and the glomerular volume (GV) were evaluated using renal biopsy specimens from adult patients with a histological diagnosis of MCNS (n = 50). Relationships between these variables and clinicopathological features, including the initial response to corticosteroid therapy, were analyzed.

RESULTS

Both the GD (1.5-6.5/mm(2)) and the GV (1.2-4.4 × 10(6) μm(3)) showed about 4-fold variations, and a close inverse correlation was observed between these two variables. Notably, the MCNS patients with a low GD showed a trend towards having similar clinicopathological characteristics as patients with a histological diagnosis of focal segmental glomerular sclerosis, as compared to the MCNS patients with a high GD. In addition, during the initial treatment with corticosteroids, the number of patients achieving complete remission was significantly lower in the MCNS patients with a low GD than that in the MCNS patients with a high GD.

CONCLUSION

These results suggest that the GD in renal biopsies may be an important determinant of the glomerular size variability, and can therefore influence the clinical phenotype, such as the response to corticosteroid therapy, in adult patients with MCNS.

Discordant clinicopathological features in monozygotic twins with IgA nephropathy

This report describes a pair of identical twins with IgA nephropathy (IgAN). One of them showed diffuse mesangial proliferation with crescent formations in the glomeruli, moderate proteinuria and required intensive therapies including corticosteroids for remission. In contrast, the other had only focal mesangial alterations and exhibited only a subtle level of urinary abnormalities throughout the follow-up without steroid therapy. Although our monozygotic twins have completely identical genotypes, the clinicopathological features of their IgAN were quite discordant. The present cases suggest that not only genetic factors but also epigenetic differences may be involved in the progression of IgAN.

Successful treatment of nephrotic syndrome caused by recurrent IgA nephropathy with chronic active antibody-mediated rejection three years after kidney transplantation

Here, we report the successful treatment of a 38-yr-old Japanese man diagnosed with recurrent immunoglobulin A nephropathy (IgAN) with chronic active antibody-mediated rejection (CAAMR), three yr after undergoing living-related donor kidney transplantation. Immediately after transplantation, the allograft function was well maintained with a serum creatinine (S-Cr) level of <1.8 mg/dL. About three yr after transplantation, urine protein excretion had reached 4.59 g/d, and the S-Cr level had increased to more than 2.0 mg/dL. Based on the allograft biopsy, we diagnosed nephrotic syndrome because of recurrence of IgAN with CAAMR. Subsequently, we performed a tonsillectomy, administered three sessions of steroid pulse therapy, and added losartan for the recurrence of IgAN. We also changed his immunosuppressant from mizoribine to mycophenolate mofetil to treat the CAAMR. The nephrotic syndrome improved with the multiple therapeutic approaches; however, the S-Cr level did not decrease below 2.0 mg/dL. We possibly could have performed additional treatments such as rituximab and intravenous immunoglobulin for the CAAMR, but therapeutic strategies for CAAMR have not yet been established.

Low glomerular density is a risk factor for progression in idiopathic membranous nephropathy

BACKGROUND

The adverse histological features predicting a progressive loss of renal function in idiopathic membranous nephropathy (IMN), before the establishment of impaired renal function with advanced glomerulosclerosis and/or interstitial fibrosis, are still poorly understood. The present study examined the relationship between the glomerular density (GD; non-sclerotic glomerular number/renal cortical area of biopsy) and the renal prognosis in IMN patients, especially in those without any apparent renal dysfunction at the time of diagnosis.

METHODS

The predictive value of the factors at biopsy, including the GD, on the renal outcome was retrospectively analyzed in the 65 IMN patients with an estimated glomerular filtration rate (eGFR) of ≥ 60 mL/min/1.73 m(2) (mean, 80 mL/min/1.73 m(2)) at biopsy.

RESULTS

The individual values for GD ranged from 1.6 to 6.5/mm(2) with 4-fold variation. A lower GD was associated with progression based on a ≥ 50% reduction in eGFR or reaching to end-stage renal disease. An association between a lower GD and progression was observed, especially in patients with persistent proteinuria of ≥ 1 g/day at follow-up. In contrast, any patients who achieved proteinuria of <1 g/day at follow-up did not show progression regardless of their GD levels. In addition, among the various clinicopathological factors observed, the GD was the only factor at biopsy that independently predicted the slope of the renal function during the observation periods.

CONCLUSION

These results suggest that low GD is a plausible risk factor for progression in IMN patients, especially in those that do not achieve a remission of proteinuria during the follow-up.

Molecular taxonomy of bambusicolous fungi: Tetraplosphaeriaceae, a new pleosporalean family with Tetraploa-like anamorphs

A new pleosporalean family Tetraplosphaeriaceae is established to accommodate five new genera; 1) Tetraplosphaeria with small ascomata and anamorphs belonging to Tetraploa s. str., 2) Triplosphaeria characterised by hemispherical ascomata with rim-like side walls and anamorphs similar to Tetraploa but with three conidial setose appendages, 3) Polyplosphaeria with large ascomata surrounded by brown hyphae and anamorphs producing globose conidia with several setose appendages, 4) Pseudotetraploa, an anamorphic genus, having obpyriform conidia with pseudosepta and four to eight setose appendages, and 5) Quadricrura, an anamorphic genus, having globose conidia with one or two long setose appendages at the apex and four to five short setose appendages at the base. Fifteen new taxa in these genera mostly collected from bamboo are described and illustrated. They are linked by their Tetraploa s. l. anamorphs. To infer phylogenetic placement in the Pleosporales, analyses based on a combined dataset of small- and large-subunit nuclear ribosomal DNA (SSU+LSU nrDNA) was carried out. Tetraplosphaeriaceae, however, is basal to the main pleosporalean clade and therefore its relationship with other existing families was not completely resolved. To evaluate the validity of each taxon and to clarify the phylogenetic relationships within this family, further analyses using sequences from ITS-5.8S nrDNA (ITS), transcription elongation factor 1-α (TEF), and β-tubulin (BT), were also conducted. Monophyly of the family and that of each genus were strongly supported by analyses based on a combined dataset of the three regions (ITS+TEF+BT). Our results also suggest that Tetraplosphaeria (anamorph: Tetraploa s. str.) is an ancestral lineage within this family. Taxonomic placement of the bambusicolous fungi in Astrosphaeriella, Kalmusia, Katumotoa, Massarina, Ophiosphaerella, Phaeosphaeria, Roussoella, Roussoellopsis, and Versicolorisporium, are also discussed based on the SSU+LSU phylogeny.

A class-wide phylogenetic assessment of Dothideomycetes

We present a comprehensive phylogeny derived from 5 genes, nucSSU, nucLSU rDNA, TEF1, RPB1 and RPB2, for 356 isolates and 41 families (six newly described in this volume) in Dothideomycetes. All currently accepted orders in the class are represented for the first time in addition to numerous previously unplaced lineages. Subclass Pleosporomycetidae is expanded to include the aquatic order Jahnulales. An ancestral reconstruction of basic nutritional modes supports numerous transitions from saprobic life histories to plant associated and lichenised modes and a transition from terrestrial to aquatic habitats are confirmed. Finally, a genomic comparison of 6 dothideomycete genomes with other fungi finds a high level of unique protein associated with the class, supporting its delineation as a separate taxon.

The long-term antiproteinuric effect of eplerenone, a selective aldosterone blocker, in patients with non-diabetic chronic kidney disease

Introduction: There is still insufficient data concerning the clinical effects of eplerenone, a selective aldosterone blocker, in patients with non-diabetic chronic kidney disease (CKD).

Methods: This study included non-diabetic CKD patients with urinary protein excretion (UPE) of 1.0 g/gCr or more in spite of long-term treatment with renin–angiotensin system (RAS) inhibitors. The clinical effects of eplerenone (25–50 mg/day) were investigated for 12 months.

Results: Eplerenone treatment was associated with a 38% reduction in UPE after 12 months. There was only a slight increase in the serum potassium level. The reduction of proteinuria was observed more prominently in patients with modestly impaired renal function than in those with preserved renal function at baseline.

Conclusion: The long-term administration of low-dose eplerenone was effective and safe for the treatment of non-diabetic CKD patients who showed persistent proteinuria in spite of therapy with RAS inhibitors.

Nonenzymatic cross-linking pentosidine increase in bone collagen and are associated with disorders of bone mineralization in dialysis patients

Disorders of bone and mineral metabolism are common complications in chronic kidney disease (CKD) patients and lead to significantly increased fracture risk, morbidity, and mortality of cardiovascular disease due to ectopic calcifications, contributing to a worsening prognosis. Bone strength is determined by not only bone mineral density but also bone quality, which is dependent on bone collagen cross-links. Collagen cross-links are classified into enzymatic immature and mature types and nonenzymatic advanced glycation end products (AGEs). Pentosidine is well established as one of the AGEs that accumulates markedly in CKD patients. The chemistry, function, and clinical relevance of cross-links have been revealed, whereas bone quality and the relationship with bone mineralization in CKD patients are not clear. We performed transiliac bone biopsies on 22 dialysis patients (mean age 56 ± 9 years) with severe secondary hyperparathyroidism and measured cross-links by evaluating bone histomorphometry. Cross-links data were compared with age-matched non-CKD subjects (mean age 58 ± 8 years, n = 17). Enzymatic collagen cross-links were formed to a similar extent compared with non-CKD subjects and showed a positive correlation with plasma intact parathyroid hormone. Pentosidine was remarkably increased in dialysis patients and inversely correlated with bone-formation rate/bone volume and mineral apposition rate. This study suggests that AGE collagen cross-links strongly associate with disorders of bone metabolism in dialysis patients.

Low-grade endotoxemia contributes to chronic inflammation in hemodialysis patients: examination with a novel lipopolysaccharide detection method

Chronic inflammation has recently been proposed to play a major role in the development of cardiovascular disease and mortality among advanced chronic kidney disease (CKD) patients; however, why advanced CKD promotes chronic inflammation is still unclear. We hypothesized that a very low level of plasma endotoxin (lipopolysaccharide [LPS]) contributes to chronic inflammation in advanced CKD patients. We measured the plasma LPS levels using a novel LPS detection method (ESP method, a method for endotoxin detection using laser scattering photometry) concurrently with serum C-reactive protein (CRP) levels and various blood tests in 17 stable hemodialysis (HD) patients. As a result, the median LPS levels measured by the ESP method was 0.23 pg/mL (range, 0.01-3.89) (inflow, start of HD), 0.22 pg/mL (<0.01-9.97) (outflow, start of HD), 0.37 pg/mL (<0.01-7.42) (inflow, end of HD), and 1.07 pg/mL (<0.01-10.66) (dialysate), respectively; statistically significant differences were not detected between them. The predialysis median CRP level was 0.19 mg/dL (0.04-3.02). The logarithm of plasma LPS independently correlated with serum CRP (R = 0.595, P = 0.0103). In multiple (forward stepwise) regression analysis, in which CRP was determined to be the criterion variable, LPS (log), albumin, and the white blood cell count were adopted as independent explanatory variables (R = 0.401, -0.397 and 0.387, respectively). In conclusion, the present study revealed a significant relationship between LPS and CRP using the novel ESP method, and suggested that very low-grade endotoxemia is contributing to systemic inflammation in HD patients.

The redox state of albumin and serious cardiovascular incidence in hemodialysis patients

Human serum albumin is composed of human mercaptoalbumin (HMA) with cysteine residues having reducing powers and oxidized human non-mercaptoalbumin. The aim of this study is to clarify whether such redox state of albumin (HSA-redox) influences the incidence of cardiovascular disease (CVD) in chronic kidney disease patients on regular hemodialysis (HD). We measured HSA-redox using high-performance liquid chromatography in 86 anuric HD patients. The association between HSA-redox and incidental CVD events was evaluated. Twenty patients experienced symptomatic CVD events (16 patients died) at the 2-year follow-up. The fraction of HMA (f(HMA)) showed a significantly lower value in patients with CVD than that without CVD, in both pre-HD (36.5 ± 5.8% and 44.6 ± 9.8%, respectively) and post-HD (57.2 ± 6.2% and 67.2 ± 7.4%, respectively). The adjusted odds ratio (OR) for the incidental CVD event in patients with pre-HD f(HMA) < 40% was 5.0 (95% CI; 1.2 to 21.3), and that in patients with post-HD f(HMA) < 60% was 20.6 (3.2 to 134.7). Likewise, the adjusted OR for the CVD death in patients with pre-HD f(HMA) < 40% was 2.5 (0.6 to 12.5), and that in patients with post-HD f(HMA) < 60% was 25.6 (2.5 to 262.8). In conclusion, HSA-redox is closely related to serious CVD incidence and mortality among HD patients.

A case of slowly progressive scleroderma kidney

A rapidly progressive renal deterioration accompanied by acute-onset/uncontrolled hypertension characterizes scleroderma renal crisis (SRC), a life-threatening complication that occurs in patients with systemic sclerosis (SSc). To date, however, SSc with advanced renal failure has only rarely been reported in the absence of SRC. We report here an atypical case of diffuse cutaneous SSc where renal insufficiency progressed slowly to end-stage renal failure over a 14-year follow-up period after the diagnosis of SSc. In the renal biopsy, which was obtained at a relatively early stage of renal impairment, we found histological findings consistent with those of scleroderma kidneys. Unlike typical SRC, however, the larger renal arteries seemed to be unaffected. These histological findings were probably responsible for the "slowly progressive" renal impairment over the years without causing typical SRC.

Difference in coronary artery intima and media calcification in autopsied patients with chronic kidney disease

BACKGROUND

In patients with chronic kidney disease (CKD), coronary artery calcification occurs at two distinct sites in the vessel wall: the intima and the media. Arterial media calcification (AMC), a nonocclusive condition, affects hemodynamics differently compared to arterial intima calcification (AIC), which occurs in atherosclerotic plaques. Arterial calcification is considered a cell-regulated process resembling intramembranous bone formation. The purpose of this retrospective observational study was to clarify the morphological differences between AIC and AMC and to evaluate the role of vascular smooth muscle cells (VSMCs) and macrophages in AIC and AMC formation.

METHODS

We histologically analyzed 14 tissue specimens from 14 autopsies of patients with CKD Stage 5D who underwent hemodialysis and 5 specimens from 5 patients with CKD Stage 2 - 3 (90 ml/min/1.73 m2 > estimated GFR >= 30 ml/min/1.73 m2). We performed immunohistochemical staining of osteopontin (OPN) as a marker for bone matrix protein, alpha-smooth muscle actin (alphaSMA) for VSMCs, Cbfa1/Runx2 as a marker for osteoblastic differentiation of VSMCs, and CD68 for macrophages.

RESULTS

In the CKD 2/3 group, we also found AIC and AMC. OPN and CD68 expression in the CKD 2/3 group was similar to that in the CKD 5D group. Although we did not find Cbfa1/Runx2 positive cell expression in the CKD 2/3 group, we did find it in the CKD 5D group. We found CD68-positive cells predominantly in AIC and absent in AMC in both groups.

CONCLUSIONS

These findings suggest that the influence of Cbfa1/Runx2 pathway in coronary artery calcification depends on the CKD Stage. Expression of CD68-positive cells depends on the location of the coronary artery calcification.

[Study on the predictors for superimposed preeclampsia in patients with IgA nephropathy]

OBJECTIVE

Pregnancy in chronic kidney disease (CKD) patients is often associated with hypertension and/or the worsening of renal function and neonatal death. The present study explored the clinical characteristics of predictive factors for hypertension in biopsy-proven IgA nephropathy patients with superimposed preeclampsia (SPE).

PATIENTS AND METHODS

The subjects were 34 Japanese women with IgA nephropathy whose renal specimen for histological tests was obtained before pregnancy. We retrospectively investigated the relevant clinical factors to explain a rise in blood pressure (BP). The histological findings were evaluated with respect to the quantitative measurements of both global glomerulosclerosis and interstitial damage.

RESULTS

Renal biopsies before pregnancies showed that the global glomerular sclerosing index and interstitial damage in the SPE group were significantly higher than in the normal group. The prevalence of SPE was 38.2 % (normal pregnancy 21, SPE 13 cases). The neonatal death rate was 3.0 % (1/34)overall. Just before conception, systolic blood pressure (SBP), serum creatinine (Cr)and blood urea nitrogen (BUN) concentration in the SPE were significantly higher than in normal pregnancies. In contrast, CCr and eGFR were lower in the SPE group than in the normal group. At delivery, serum Cr, BUN and uric acid (UA) concentration in the SPE group were significantly higher than in the normal group. In contrast, CCr and eGFR were lower in the SPE than in the normal group. At delivery, correlation analysis revealed a significant correlation between SBP or diastolic BP (DBP) and the histological severity, between SBP or DBP and daily protein excretion, and between SBP or DBP and serum Cr concentration. With respect to the birth weight of newborns, there was a significant negative correlation between the birth weight and the global glomerular sclerosing rate, and between the birth weight and serum Cr concentration or BUN. A stepwise multiple regression analysis showed that predictive factors for a rise in SBP during pregnancy were the degree of interstitial damage and daily urinary protein excretion. These results suggest that renal function, the magnitude of urinary protein excretion, serum Cr, BUN, UA concentrations, and the severity of histological abnormalities are all associated with SPE occurrence. The predictors of a rise in BP were interstitial damage and urinary protein excretion at pregnancy. In addition, Receiver Operating Characteristic (ROC) analysis showed that both glomerular sclerosis and interstitial damage could be potential predictors for SPE.

CONCLUSION

Histological severity in renal biopsy, urinary protein excretion and renal function are associated with SPE in patients with IgA nephropathy. Among these associations, the histological findings and urinary protein excretion may serve as useful predictors for a rise in BP.

Distribution of transient receptor potential vanilloid 1 channel-expressing nerve fibers in mouse rectal and colonic enteric nervous system: relationship to peptidergic and nitrergic neurons

In the gut, transient receptor potential vanilloid (TRPV) 1 activation leads to release of neurotransmitters such as neuropeptides and nitric oxide. However, the distribution of TRPV1 nerve fibers and neurotransmitters released form sensory nerve endings in the enteric nervous system are currently not well understood. The present study investigated the immunohistochemical distribution of TRPV1 channels, sensory neuropeptides, and nitric oxide and their co-localization in mouse large intestine. Numerous TRPV1 and calcitonin gene-related peptide (CGRP) immunoreactivities were detected, mainly in the mucosa, submucosal layer, and myenteric plexus. Abundant substance P (SP), neurokinin A (NKA), and neuronal nitric oxide synthase (nNOS)-immunoreactivity were revealed in muscle layers. Motor function studies of circular and longitudinal muscles found that contractile responses to capsaicin in the rectum were most sensitive among the rectum, and distal, transverse, and proximal colon. Double labeling studies were carried out in horizontal sections of mouse rectum. TRPV1/protein gene product (PGP)9.5 double labeled axons were observed, but PGP9.5 and neuronal nuclear protein immunopositive cell bodies did not express TRPV1 immunoreactivity in the myenteric plexus. In the mucosa, submucosal layer, deep muscular plexus, circular muscle, myenteric plexus and longitudinal muscle layer, TRPV1 nerve fibers were found to contain CGRP, SP and nNOS. SP and NKA were almost entirely colocalized at the axons and cell bodies in all layers. Double labeling with c-Kit revealed that TRPV1 nerve fibers localized adjacent to the interstitial cells of Cajal (ICC). These results suggest that the TRPV1-expressing nerve and its neurotransmitters regulate various functions of the large intestine.

Establishment and analysis of SLC22A12 (URAT1) knockout mouse

In order to elucidate the mechanisms of post-exercise acute renal failure, one of the complications of hereditary renal hypouricemia, we have targeted the mouse Slc22a12 gene by the exchange of exons 1-4 with pMC1neo-polyA. The knockout mice revealed no gross anomalies. The concentration ratio of urinary urate/creatinine of the knockout mice was significantly higher than that of wildtype mice, indicating an attenuated renal reabsorption of urate. The plasma levels of urate were around 11 muM and were similar among the genotypes. Although the fractional excretion of urate of knockout mice was tend to higher than that of wildtype mice, the urate reabsorption ability remained in the kidney of knockout mice, indicating a urate reabsorptive transporter other than Urat1.

Common defects of ABCG2, a high-capacity urate exporter, cause gout: a function-based genetic analysis in a Japanese population

Gout based on hyperuricemia is a common disease with a genetic predisposition, which causes acute arthritis. The ABCG2/BCRP gene, located in a gout-susceptibility locus on chromosome 4q, has been identified by recent genome-wide association studies of serum uric acid concentrations and gout. Urate transport assays demonstrated that ABCG2 is a high-capacity urate secretion transporter. Sequencing of the ABCG2 gene in 90 hyperuricemia patients revealed several nonfunctional ABCG2 mutations, including Q126X. Quantitative trait locus analysis of 739 individuals showed that a common dysfunctional variant of ABCG2, Q141K, increases serum uric acid. Q126X is assigned to the different disease haplotype from Q141K and increases gout risk, conferring an odds ratio of 5.97. Furthermore, 10% of gout patients (16 out of 159 cases) had genotype combinations resulting in more than 75% reduction of ABCG2 function (odds ratio, 25.8). Our findings indicate that nonfunctional variants of ABCG2 essentially block gut and renal urate excretion and cause gout.

Rapidly progressive cryoglobulinemic glomerulonephritis

The clinical course of cryoglobulinemic glomerulonephritis (CGGN) is usually slowly progressive, and only a minority of these patients progress to end-stage renal failure. This report describes an atypical case of a patient with CGGN who demonstrated a rapidly progressive and irreversible renal deterioration. After presenting with symptoms of an upper respiratory infection, the patient exhibited oliguric acute renal failure, which was followed by systemic efflorescence accompanied by a fever. The laboratory analyses of his serum revealed the patient to be cryoglobulin-positive with markedly decreased serum C4 levels and an increased anti-streptolysin O titer. A serological test for the hepatitis C virus was negative. A renal biopsy showed that the patient had diffuse endocapillary and extracapillary proliferation together with marked endoluminal thrombi and subendothelial deposits in glomeruli. An electron microscopic examination demonstrated the presence of electron-dense subendothelial, subepithelial and huge intraluminal deposits with a specific annular and cylindrical structure. These features were consistent with active and severe CGGN. Despite aggressive treatment with corticosteroid pulses and a plasma exchange, a second renal biopsy demonstrated further advanced renal injury and revealed no signs of recovery.