Oligohydramnios associated with sonographically normal kidneys

We report a male newborn presenting with sonographically normal kidneys, oligohydramnios during late pregnancy, and persisting anuric renal failure. Despite intensive treatment, the patient suffered from severe hypotension and died at the age of 4 weeks. At autopsy, kidneys were found to be normal; on histology, deranged renal structures, in particular proximal tubuli and vessels, were noted, leading to the diagnosis of renal tubular dysgenesis (RTD). The diagnosis was confirmed by 2 heterozygous nonsense mutations of the ACE gene. Because the recurrence rate of RTD is 25% for the autosomal recessive trait, knowledge and genetic diagnosis of the disease is important for the parents.

Beneficial effects of integrin αvβ3-blocking RGD peptides in early but not late phase of experimental glomerulonephritis

BACKGROUND

Integrin αvβ3 plays an important role in the regulation of cell proliferation and neoangiogenesis. We found mesangial de novo expression of integrin αvβ3 in mesangioproliferative glomerulonephritis (MesGN). The aim of the study was to clarify if blockade of αvβ3 integrin with the specific αvβ3-blocking cyclic peptide RGDdFV (cRGD) has beneficial effects on the course of this disease.

METHODS

Habu snake venom (Habu) GN was induced in male C57BL/6 mice 1 week after uninephrectomy (6 mg Habu toxin/kg body weight intravenously). After 24 h, nephritic animals received αvβ3-inhibitory cRGD or cRAD control peptides for 3 or 7 days, respectively. The kidneys were investigated using morphometry, immunohistochemistry and TaqMan polymerase chain reaction.

RESULTS

At Day 3, serum creatinine and albuminuria were lower after cRGD compared to cRAD treatment. At Day 3, glomerulosclerosis index, percentage of glomerular injury, mesangial cell (MC) number and volume density of mesangial matrix were significantly lower (P < 0.05) in cRGD-treated mice than in cRAD-treated controls. At Day 7, only a mild effect of cRGD on mesangial matrix expansion and fibronectin messenger RNA was still detectable (P < 0.05). Complementary in vitro studies in MCs revealed that inhibition of αvβ3 by cRGD-blocked adhesion, reduced proliferation and increased apoptosis of MCs.

CONCLUSION

Habu GN inhibition of integrin αvβ3 by cRGD partly ameliorates early injury but has no or only mild effects on late glomerular lesions.

Kidney pathology precedes and predicts the pathological cascade of cerebrovascular lesions in stroke prone rats

Introduction

Human cerebral small vessel disease (CSVD) has been hypothesized to be an age-dependent disease accompanied by similar vascular changes in other organs. SHRSP feature numerous vascular risk factors and may be a valid model of some aspects of human CSVD. Here we compare renal histopathological changes with the brain pathology of spontaneously hypertensive stroke-prone rats (SHRSP).

Material and Methods

We histologically investigated the brains and kidneys of 61 SHRSP at different stages of age (12 to 44 weeks). The brain pathology (aggregated erythrocytes in capillaries and arterioles, microbleeds, microthromboses) and the kidney pathology (aggregated erythrocytes within peritubular capillaries, tubular protein cylinders, glomerulosclerosis) were quantified separately. The prediction of the brain pathology by the kidney pathology was assessed by creating ROC-curves integrating the degree of kidney pathology and age of SHRSP.

Results

Both, brain and kidney pathology, show an age-dependency and proceed in definite stages whereas an aggregation of erythrocytes in capillaries and arterioles, we parsimoniously interpreted as stases, represent the initial finding in both organs. Thus, early renal tubulointerstitial damage characterized by rather few intravasal erythrocyte aggregations and tubular protein cylinders predicts the initial step of SHRSPs' cerebral vascular pathology marked by accumulated erythrocytes. The combined increase of intravasal erythrocyte aggregations and protein cylinders accompanied by glomerulosclerosis and thrombotic renal microangiopathy in kidneys of older SHRSP predicts the final stages of SHRSPs' cerebrovascular lesions marked by microbleeds and thrombotic infarcts.

Conclusion

Our results illustrate a close association between structural brain and kidney pathology and support the concept of small vessel disease to be an age-dependent systemic pathology. Further, an improved joined nephrologic and neurologic diagnostic may help to identify patients with CSVD at an early stage.

Eplerenone prevents salt-induced vascular stiffness in Zucker diabetic fatty rats: a preliminary report

Background

Aldosterone levels are elevated in a rat model of type 2 diabetes mellitus, the Zucker Diabetic fatty rat (ZDF). Moreover blood pressure in ZDF rats is salt-sensitive. The aim of this study was to examine the effect of the aldosterone antagonist eplerenone on structural and mechanical properties of resistance arteries of ZDF-rats on normal and high-salt diet.

Methods

After the development of diabetes, ZDF animals were fed either a normal salt diet (0.28%) or a high-salt diet (5.5%) starting at an age of 15 weeks. ZDF rats on high-salt diet were randomly assigned to eplerenone (100 mg/kg per day, in food) (ZDF+S+E), hydralazine (25 mg/kg per day) (ZDF+S+H), or no treatment (ZDF+S). Rats on normal salt-diet were assigned to eplerenone (ZDF+E) or no treatment (ZDF). Normoglycemic Zucker lean rats were also divided into two groups receiving normal (ZL) or high-salt diet (ZL+S) serving as controls. Systolic blood pressure was measured by tail cuff method. The experiment was terminated at an age of 25 weeks. Mesenteric resistance arteries were studied on a pressurized myograph. Specifically, vascular hypertrophy (media-to-lumen ratio) and vascular stiffness (strain and stress) were analyzed. After pressurized fixation histological analysis of collagen and elastin content was performed.

Results

Blood pressure was significantly higher in salt-loaded ZDF compared to ZDF. Eplerenone and hydralazine prevented this rise similarily, however, significance niveau was missed. Media-to-lumen ratio of mesenteric resistance arteries was significantly increased in ZDF+S when compared to ZDF and ZL. Both, eplerenone and hydralazine prevented salt-induced vascular hypertrophy. The strain curve of arteries of salt-loaded ZDF rats was significantly lower when compared to ZL and when compared to ZDF+S+E, but was not different compared to ZDF+S+H. Eplerenone, but not hydralazine shifted the strain-stress curve to the right indicating a vascular wall composition with less resistant components. This indicates increased vascular stiffness in salt-loaded ZDF rats, which could be prevented by eplerenone but not by hydralazine. Collagen content was increased in ZL and ZDF rats on high-salt diet. Eplerenone and hydralazine prevented the increase of collagen content. There was no difference in elastin content.

Conclusion

Eplerenone and hydralazine prevented increased media-to-lumen ratio in salt-loaded ZDF-rats, indicating a regression of vascular hypertrophy, which is likely mediated by the blood pressure lowering-effect. Eplerenone has additionally the potential to prevent increased vascular stiffness in salt-loaded ZDF-rats. This suggests an effect of the specific aldosterone antagonist on adverse vascular wall remodelling.

Long-Term Relapse-Free Survival by Interdisciplinary Collaboration in a Patient with Metastatic Pancreatic Cancer (UICC IV)

INTRODUCTION

The prognostic outlook for patients suffering from pancreatic cancer is generally poor. Particularly in cases of advanced and metastatic disease, long-term relapse-free survival may be achieved only in a few cases.

CASE REPORT

A 45-year-old patient presented with metastatic pancreatic cancer. Liver metastases had been intra-operatively confirmed by histology. Prior to initiating treatment, a portacath was surgically implanted. Subsequently, the patient received a weekly dose of 1,000 mg/m(2) gemcitabine combined with 2,000 mg/m(2) high-dose 5-fluorouracil as a 24-hour infusion for palliative treatment. As the patient was suffering from a stenosis of the ductus hepaticus communis, an endoprosthesis was primarily implanted. After 18 applications of chemotherapy during which only low toxic side effects such as nausea, vomiting and alopecia (NCI-CTC grade 1) presented, a partial remission of the primary tumor was observed. In the course of chemotherapy treatment, the carbohydrate antigen 19-9 tumor marker value normalized. Thus, the interdisciplinary tumor board of the University of Erlangen decided to perform a laparoscopy to evaluate the status of liver metastases after palliative chemotherapy treatment. Subsequently, the primary tumor could be completely resected (pT2, pN0, pM0, L0, V0, G2, R0); liver metastases were not observed. Eight years after the initial diagnosis, the patient is relapse-free, professionally fully integrated and presents with an excellent performance status.

CONCLUSION

Patients suffering from metastatic pancreatic cancer may benefit from treatment combinations with palliative intent. In singular cases, patients may even have a curative treatment option, provided a close interdisciplinary collaboration exists.

[Hemolytic uremic syndrome following EHEC infection]

HISTORY AND ADMISSION FINDINGS

We report on four patients treated for typical hemolytic uremic syndrome (HUS) at our hospital during the outbreak in Germany in May 2011. Three out of four patients had previously travelled to northern Germany, one patient was exposed within the family.

INVESTIGATIONS

All patients were tested positive for enterohemorrhagic E.coli of the type O104:H4 in stool cultures and presented with signs of thrombotic microangiopathy and fragmented erythrocytes.

DIAGNOSIS, TREATMENT AND COURSE

Due to strong hemolytic activity (LDH >600 U/l), thrombocytopenia (< 60,000/µl) und acute kidney injury (creatinine >1.2 mg/dl) plasma separation with fresh frozen plasma was commenced in three out of four patients with the fourth patient exhibiting a self-limiting course. Altogether, it took 7 to 13 treatments until disease activity was stopped. During treatment, kidney injury recovered and all patients had negative stool cultures.

CONCLUSIONS

The HUS-outbreak 2011 in Germany was associated with a severe course in many patients, particularly in women. Treatment with plasma separation was successful to stop hemolysis and end disease activity.

Hypoxia-inducible transcription factors stabilization in the thick ascending limb protects against ischemic acute kidney injury

Hypoxia-inducible transcription factors (HIF) protect cells against oxygen deprivation, and HIF stabilization before ischemia mitigates tissue injury. Because ischemic acute kidney injury (AKI) often involves the thick ascending limb (TAL), modulation of HIF in this segment may be protective. Here, we generated mice with targeted TAL deletion of the von Hippel-Lindau protein (Vhl), which mediates HIF degradation under normoxia, using Tamm-Horsfall protein (Thp)-driven Cre expression. These mice showed strong expression of HIF-1α in TALs but no changes in kidney morphology or function under control conditions. Deficiency of Vhl in the TAL markedly attenuated proximal tubular injury and preserved TAL function following ischemia-reperfusion, which may be partially a result of enhanced expression of glycolytic enzymes and lactate metabolism. These results highlight the importance of the thick ascending limb in the pathogenesis of AKI and suggest that pharmacologically targeting the HIF system may have potential to prevent and mitigate AKI.

Caspase-8 regulates TNF-α-induced epithelial necroptosis and terminal ileitis

Dysfunction of the intestinal epithelium is believed to result in excessive translocation of commensal bacteria into the bowel wall that drives chronic mucosal inflammation in Crohn's disease; an incurable inflammatory bowel disease in humans characterized by inflammation of the terminal ileum¹. Beside the physical barrier established by the tight contact of cells, specialized epithelial cells such as Paneth cells and goblet cells provide innate immune defence functions by secreting mucus and antimicrobial peptides which hamper access and survival of bacteria adjacent to the epithelium². Epithelial cell death is a hallmark of intestinal inflammation and has been discussed as a pathogenic mechanism driving Crohn's disease (CD) in humans³. However, the regulation of epithelial cell death and its role in intestinal homeostasis remains poorly understood.

Here we demonstrate a critical role for caspase-8 in regulating necroptosis of intestinal epithelial cells (IEC) and terminal ileitis. Mice with a conditional deletion of caspase-8 in the intestinal epithelium (Casp8^ΔIEC) spontaneously developed inflammatory lesions in the terminal ileum and were highly susceptible to colitis. Casp8^ΔIEC mice lacked Paneth cells and showed reduced numbers of goblet cells suggesting dysregulated anti-microbial immune cell functions of the intestinal epithelium. Casp8^ΔIEC mice showed increased cell death in the Paneth cell area of small intestinal crypts. Epithelial cell death was induced by tumor necrosis factor (TNF) -α, was associated with increased expression of receptor-interacting protein 3 (RIP3) and could be inhibited upon blockade of necroptosis. Finally, we identified high levels of RIP3 in human Paneth cells and increased necroptosis in the terminal ileum of patients with Crohn's disease, suggesting a potential role of necroptosis in the pathogenesis of this disease. Taken together, our data demonstrate a critical function of caspase-8 in regulating intestinal homeostasis and in protecting IEC from TNF-α induced necroptotic cell death.

Endothelin in diabetic renal disease

Today diabetic nephropathy is the leading course of end-stage renal disease; the incidence and prevalence of diabetic renal disease is still continuing to increase, particularly in the Western world. Despite improvements in diagnosis and treatment of diabetic nephropathy, only partial renal protection is reached with the current standard therapy regiments, including angiotensin-converting enzyme inhibitors and/or angiotensin receptor blockers. Against this background, it is of particular importance to learn more about the pathogenesis of diabetic nephropathy and to find new therapeutic approaches which alone or in combination with standard therapy have the potential to prevent or delay the progression of diabetic nephropathy, thus improving kidney and patient survival. Among others, endothelin (ET) receptor blockers have emerged as a potential therapeutic option that operates on the basis of physiological and pathophysiological effects of endothelin. Of note, the ET system was shown to be involved in hypertension and kidney disease, particularly proteinuric nephropathies, and there is good experimental data indicating a specific role of ET in the pathogenesis and progression of diabetic nephropathy. ET receptor blockers have been shown to be nephroprotective in animal models of type 1 and type 2 diabetes mellitus with the effects partly independent of blood pressure lowering. In patients with hypertension and diabetic nephropathies, the data is controversial and depends on the stage of the disease and the drug used. It was only recently that a large international clinical study (ASCEND) provided evidence for beneficial effects of ET antagonist treatment, i.e. reduction in proteinuria. Due to the premature termination of the study, however, hard endpoints like death could no longer be assessed. Another very recent randomized, double-blind, placebo-controlled trial of subjects with diabetic nephropathy also provided evidence for a specific antiproteinuric effect of the ET receptor antagonist atrasentan on top of an already existing blockade of the renin-angiotensin system. Thus, it appears currently of great scientific and clinical interest to shed some light on the role of the ET system and its blockade in diabetic nephropathy.

[Evaluation of a renal biopsy: what information is important for nephrologists?]

A kidney biopsy is an important and frequently used diagnostic tool in routine nephrology. In order to obtain relevant clinical information from a renal biopsy close cooperation between clinicians and pathologists is mandatory. The better the information obtained from nephrologists and the better the understanding by nephrologists and the quality of the kidney biopsy, the more rewarding is the information from pathologists. The following paper will discuss some practical aspects regarding the interaction between nephrology and pathology which may not be known or poorly handled and may thus cause misunderstanding. In order to facilitate interaction between clinicians and pathologists some guidelines concerning the procedure and work-up of routine kidney biopsies have been established and will be discussed in detail.

The Fcγ receptor IIA R131H gene polymorphism is associated with endothelial function in patients with hypercholesterolaemia

OBJECTIVE

A gene polymorphism substituting arginine (R) for histidine (H) at position 131 has been described within the Fcγ receptor IIa (FcγRIIa). The R allele is associated with increased binding of CRP and enhanced activation of monocytes. FcγRIIa is also expressed on endothelial cells, and we hypothesized this polymorphism would be associated with alterations of endothelial function.

METHODS

Genomic DNA was extracted and allele-specific PCR reactions were used to determine the FcγRIIa H131R polymorphism in 78 hypercholesterolaemic subjects. Using strain gauge plethysmography, forearm blood flow (FBF) responses were determined to intra-arterial infusion of acetylcholine (ACH), for endothelium-dependent vasodilatation (EDV), to nitroprusside (NP), for endothelium-independent vasodilatation (EIV), to NG-monomethyl-l-arginine (l-NMMA), for basal NO activity, and to ACH in the presence of l-NMMA, to assess the contribution of NO release to EDV.

RESULTS

Homozygous carriers of the H allele (n=30) had significantly better EDV than homozygous carriers of the R allele (n=15), while heterozygotes showed an intermediate phenotype (n=33) (e.g. % increase of FBF to ACH 48μg/min: 527±359% in H/H versus 452±262% in H/R versus 332±413% in R/R, p=0.0012 by 2-way ANOVA). EIV and basal NO activity were not affected by genotype, and co-infusion of l-NMMA abolished the differences in EDV.

CONCLUSIONS

The R allele of the FcγRIIa polymorphism is associated with impaired EDV and reduced NO activity during endothelial cell stimulation. These data suggest that the functional effects of the FcγRIIa H131R gene polymorphism previously observed in vitro translate into clinically relevant alterations of endothelial function in vivo.

Bisphosphonate-associated osteonecrosis of the jaw is linked to suppressed TGFβ1-signaling and increased Galectin-3 expression: a histological study on biopsies

Background

Bisphosphonate associated osteonecrosis of the jaw (BRONJ) implies an impairment in oral hard- and soft tissue repair. An understanding of the signal transduction alterations involved can inform therapeutic strategies. Transforming growth factor β1 (TGFβ1) is a critical regulator of tissue repair; galectin-3 mediates tissue differentiation and specifically modulates periodontopathic bacterial infection. The aim of this study was to compare the expression of TGFβ1-related signaling molecules and Galectin-3 in BRONJ-affected and healthy mucosal tissues. To discriminate between BRONJ-specific impairments in TGFβ1 signaling and secondary inflammatory changes, the results were compared to the expression of TGFβ1 and Galectin-3 in mucosal tissues with osteoradionecrosis.

Methods

Oral mucosal tissue samples with histologically-confirmed BRONJ (n = 20), osteoradionecrosis (n = 20), and no lesions (normal, n = 20) were processed for immunohistochemistry. Automated staining with an alkaline phosphatase-anti-alkaline phosphatase kit was used to detect TGFβ1, Smad-2/3, Smad-7, and Galectin-3. We semiquantitatively assessed the ratio of stained cells/total number of cells (labeling index, Bonferroni-adjustment).

Results

TGFβ1 and Smad-2/3 were significantly decreased (p < 0.032 and p(0.028, respectively) in the BRONJ samples and significantly increased (p < 0.04 and p <0.043, respectively) in the osteoradionecrosis samples compared to normal tissue. Smad-7 was significantly increased (p < 0.031) in the BRONJ group and significantly decreased (p < 0.026) in the osteoradionecrosis group. Galectin-3 staining was significantly (p < 0.025) increased in both the BRONJ and the osteoradionecrosis (p < 0.038) groups compared to the normal tissue group. However, Galectin-3 expression was significantly higher in the BRONJ samples than in the osteoradionecrosis samples (p < 0.044).

Conclusion

Our results showed that disrupted TGFβ1 signaling was associated with delayed periodontal repair in BRONJ samples. The findings also indicated that impairments in TGFβ1-signaling were different in BRONJ compared to osteoradionecrosis. BRONJ appeared to be associated with increased terminal osseous differentiation and decreased soft tissue proliferation. The increase in Galectin-3 reflected the increase in osseous differentiation of mucoperiosteal progenitors, and this might explain the inflammatory anergy observed in BRONJ-affected soft tissues. The results substantiated the clinical success of treating BRONJ with sequestrectomy, followed by strict mucosa closure. BRONJ can be further elucidated by investigating the specific intraoral osteoimmunologic status.

High frequency of autoantibody-secreting cells and long-lived plasma cells within inflamed kidneys of NZB/W F1 lupus mice

Autoantibodies to double-stranded (ds) DNA represent a serological hallmark of systemic lupus erythematosus (SLE) and may critically contribute to the pathogenesis of lupus nephritis. Self-reactive antibodies might be partially produced by long-lived plasma cells (PCs), which mainly reside within the bone marrow and spleen. In contrast to short-lived PCs, long-lived PCs are extremely resistant to therapy and may sustain refractory disease courses. Recently, antibody-secreting cells were found within the inflamed kidneys of New Zealand black/white (NZB/W) F1 lupus mice as well as of patients with SLE. To analyze the longevity of the IgG-producing cells present in nephritic kidneys of NZB/W F1 mice we performed in vivo BrdU-labeling. We identified a higher frequency of long-lived than short-lived renal PCs, indicating that survival niches for long-lived PCs also exist within inflamed kidneys. Using ELISPOT assays, we found that on average 31% of renal IgG-producing cells reacted with dsDNA and 24% with nucleolin. Moreover, the frequencies of IgG-secreting cells specific for the autoantigens dsDNA and nucleolin were higher in the kidneys compared with those in the spleen and bone marrow.

WT1-dependent sulfatase expression maintains the normal glomerular filtration barrier

Paracrine signaling between podocytes and glomerular endothelial cells through vascular endothelial growth factor A (VEGFA) maintains a functional glomerular filtration barrier. Heparan sulfate proteoglycans (HSPGs), located on the cell surface or in the extracellular matrix, bind signaling molecules such as VEGFA and affect their local concentrations, but whether modulation of these moieties promotes normal crosstalk between podocytes and endothelial cells is unknown. Here, we found that the transcription factor Wilms' Tumor 1 (WT1) modulates VEGFA and FGF2 signaling by increasing the expression of the 6-O-endosulfatases Sulf1 and Sulf2, which remodel the heparan sulfate 6-O-sulfation pattern in the extracellular matrix. Mice deficient in both Sulf1 and Sulf2 developed age-dependent proteinuria as a result of ultrastructural abnormalities in podocytes and endothelial cells, a phenotype similar to that observed in children with WT1 mutations and in Wt1(+/-) mice. These kidney defects associated with a decreased distribution of VEGFA in the glomerular basement membrane and on endothelial cells. Collectively, these data suggest that WT1-dependent sulfatase expression plays a critical role in maintaining the glomerular filtration barrier by modulating the bioavailability of growth factors, thereby promoting normal crosstalk between podocytes and endothelial cells.

Early and late postnatal myocardial and vascular changes in a protein restriction rat model of intrauterine growth restriction

Intrauterine growth restriction (IUGR) is a risk factor for cardiovascular disease in later life. Early structural and functional changes in the cardiovascular system after IUGR may contribute to its pathogenesis. We tested the hypothesis that IUGR leads to primary myocardial and vascular alterations before the onset of hypertension. A rat IUGR model of maternal protein restriction during gestation was used. Dams were fed low protein (LP; casein 8.4%) or isocaloric normal protein diet (NP; casein 17.2%). The offspring was reduced to six males per litter. Immunohistochemical and real-time PCR analyses were performed in myocardial and vascular tissue of neonates and animals at day 70 of life. In the aortas of newborn IUGR rats expression of connective tissue growth factor (CTGF) was induced 3.2-fold. At day 70 of life, the expression of collagen I was increased 5.6-fold in aortas of IUGR rats. In the hearts of neonate IUGR rats, cell proliferation was more prominent compared to controls. At day 70 the expression of osteopontin was induced 7.2-fold. A 3- to 7-fold increase in the expression of the profibrotic cytokines TGF-β and CTGF as well as of microfibrillar matrix molecules was observed. The myocardial expression and deposition of collagens was more prominent in IUGR animals compared to controls at day 70. In the low-protein diet model, IUGR leads to changes in the expression patterns of profibrotic genes and discrete structural abnormalities of vessels and hearts in adolescence, but, with the exception of CTGF, not as early as at the time of birth. Invasive and non-invasive blood pressure measurements confirmed that IUGR rats were normotensive at the time point investigated and that the changes observed occurred independently of an increased blood pressure. Hence, altered matrix composition of the vascular wall and the myocardium may predispose IUGR animals to cardiovascular disease later in life.

ARFI-based tissue elasticity quantification in comparison to histology for the diagnosis of renal transplant fibrosis

BACKGROUND AND PURPOSE

Until recently clinical diagnosis of chronic renal allograft dysfunction could only be established invasively by renal biopsy. Given the risks of that procedure, a non-invasive, diagnostic test would be very advantageous. Novel ultrasound-based elasticity tools, using "Acoustic Radiation Force Impulse (ARFI)" technology are now available. Previously this technique has been utilised to quantify liver fibrosis. First results of these studies are promising. The purpose of our study was to investigate correlation between stiffness values obtained by ARFI-quantification and histological fibrosis score in renal transplants.

METHODS

We employed "Virtual Touch™ tissue quantification" (Siemens Acuson, S2000) to quantitatively measure tissue stiffness in the cortex of transplant kidneys. Eighteen patients were included in this prospective study, recording close temporal ARFI-quantification and fibrosis measurements. All patients undergoing renal transplant biopsy were examined with ARFI-quantification (15 measurements per transplant kidney). Resistive indices were also calculated from pulsed-wave Doppler ultrasound. Transplant biopsies were histologically evaluated by a reference nephropathologist and graded according to the percentage of fibrosis and to the BANFF-score. Due to the non-normal distribution of the data the Spearman-correlation-coefficient (rho) was used to assess the bivariate relationship of ARFI and fibrosis in the transplant kidney.

RESULTS

There was a significant positive moderate correlation between mean ARFI-values and the grade of fibrosis (rho = +0.465; p = 0.026). This correlation was also valid for the mean ARFI-values and the BANFF-category (rho = +0.468; p = 0.025). There was no significant correlation between the mean ARFI-values and the resistive indices in the transplant kidney (rho = +0.034; p = 0.904). Nevertheless, a positive correlation between the mean RI-values of the kidney and the grade of fibrosis was established (rho = +0.563; p = 0.015).

CONCLUSION

The mean values of ARFI measurements and the resistive indices are potentially independent explanation variables for evaluating the grade of fibrosis in transplant kidneys.

ADAMTS13--more than just TMA and TTP

ADAMTS13 (a disintegrin-like and metalloprotease with thrombospondin type-1 motifs 13) has been shown to be of major pathophysiological importance for thrombotic microangiopathy (TMA) in the setting of thrombocytic thrombocytopenic purpura (TTP) when either lacking (inherited TTP) or if antibodies against ADAMTS13 are present (acquired TTP). A potential pathophysiological role of ADAMTS13 has also been postulated in other diseases i.e. myocardial infarction, atrial fibrillation and diabetic angiopathy. Recent data provides evidence, however, for a completely different role of ADAMTS13 in vascular physiology and pathophysiology. In the present issue of Nephrology Dialysis and Transplantation, Bockmeyer et al. documented a physiological expression of ADAMTS13 in arteriolar vascular smooth muscle cells (VSMCs) which is maintained in the early, so-called benign nephrosclerosis, i.e. under conditions of early hypertensive vascular damage, and is completely lost if the damage proceeds to late, fibrotic stages of vascular injury. Thus, the recent report identifies ADAMTS13 as a new marker for the contractile phenotype of VSMC which is maintained in the early, hyalinotic phase of vascular damage, but is lost in later, more fibrotic stages of benign nephrosclerosis. This finding adds a novel and potentially important aspect to the unsolved and underestimated problem of benign or hypertensive nephrosclerosis.

Long-term evaluation of a selective retrograde coronary venous perfusion model in pigs (Sus scrofa domestica)

The lack of suitable target vessels remains a challenge for aortocoronary bypass grafting in end-stage coronary heart disease. This study aimed to investigate the arterialization of cardiac veins as an alternative myocardial revascularization strategy in an experimental long-term model in pigs. Selective retrograde perfusion of a coronary vein (aorta to coronary vein bypass, retrobypass) before ligation of the ramus interventricularis paraconalis (equivalent to the left anterior descending artery in humans) was performed in 20 German Landrace pigs (Sus scrofa domestica). Retroperfusion of the left anterior descending vein was performed in 10 pigs (RP+) but not in the other 10 (RP-), and the vena cordis magna was ligated (L+) in 5 pigs in each of these groups but left open (L-) in the remaining animals. Hemodynamic performance (for example, cardiac output) was significantly better in the group that underwent selective retroperfusion with proximal ligation of vena cordis magna (RP+L+; 4.1 L/min) compared with the other groups (RP+L-, 2.5 L/min; RP-L+, 2.2 L/min; RP-L-, 1.9 L/min). Long-term survival was significantly better in RP+L+ pigs (112±16 d) than in all other groups. Histologic follow-up studies showed significantly less necrosis in the RP+L+ group compared with all other groups. Venous retroperfusion is an effective technique to achieve long-term survival after acute occlusion of the left anterior descending artery in a pig model. In this model, proximal ligation of vena cordis magna is essential.

Recurrent gross hematuria with positive family history of IgA nephropathy and an unexpected diagnosis

A 12-year-old girl presented with recurrent gross hematuria over 3 months and regular findings in sonography of the urogenital tract. The first suspected diagnosis of familial IgA glomerulonephritis was excluded by kidney biopsy. After a further episode of gross hematuria leading to vesical tamponade, the patient received magnetic resonance imaging with angiography and urography, which was suspicious for a renal tumor. Consecutively, unilateral nephrectomy was performed and a nephroblastoma was diagnosed. This case demonstrates that even in grossly normal renal ultrasound, relapsing episodes of gross hematuria can be caused by renal tumor, and therefore in unclear situations, further diagnostic is necessary.

Msx-1 is suppressed in bisphosphonate-exposed jaw bone analysis of bone turnover-related cell signalling after bisphosphonate treatment

OBJECTIVES

Bone-destructive disease treatments include bisphosphonates and antibodies against receptor activator for nuclear factor κB ligand (aRANKL). Osteonecrosis of the jaw (ONJ) is a side-effect. Aetiopathology models failed to explain their restriction to the jaw. The osteoproliferative transcription factor Msx-1 is expressed constitutively only in mature jaw bone. Msx-1 expression might be impaired in bisphosphonate-related ONJ. This study compared the expression of Msx-1, Bone Morphogenetic Protein (BMP)-2 and RANKL, in ONJ-affected and healthy jaw bone.

MATERIAL AND METHODS

An automated immunohistochemistry-based alkaline phosphatase-anti-alkaline phosphatase method was used on ONJ-affected and healthy jaw bone samples (n = 20 each): cell-number ratio (labelling index, Bonferroni adjustment). Real-time RT-PCR was performed to quantitatively compare Msx-1, BMP-2, RANKL and GAPDH mRNA levels.

RESULTS

Labelling indices were significantly lower for Msx-1 (P < 0.03) and RANKL (P < 0.003) and significantly higher (P < 0.02) for BMP-2 in ONJ compared with healthy bone. Expression was sevenfold lower (P < 0.03) for Msx-1, 22-fold lower (P < 0.001) for RANKL and eightfold higher (P < 0.02) for BMP-2 in ONJ bone.

CONCLUSIONS

Msx-1, RANKL suppression and BMP-2 induction were consistent with the bisphosphonate-associated osteopetrosis and impaired bone remodelling in BP- and aRANKL-induced ONJ. Msx-1 suppression suggested a possible explanation of the exclusivity of ONJ in jaw bone. Functional analyses of Msx-1- RANKL interaction during bone remodelling should be performed in the future.