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Introduction: Membranous nephropathy (MN) is a common cause of nephrotic syndrome in adults and can be primary or secondary. The antigenic target of antibodies in 70% of primary cases is phospholipase A2 receptor (PLA2R). The presence or absence of mesangial electron-dense deposits has been used to distinguish between primary and secondary MN. Mesangial deposits suggest MN due to lupus, infection, or other causes, though they are reported to occur in approximately 10% of primary MN. Staining for PLA2R is now frequently used for confirming a diagnosis of primary MN. If mesangial deposits predict a secondary cause, they should be more frequent in PLA2R-negative biopsies. Methods: A review of institutional kidney biopsies between March 2017 and June 2020 identified all cases of MN. Cases with a diagnosis of lupus or near “full-house” staining by immunofluorescence microscopy (IF) were excluded. Light microscopy, IF, and electron microscopy (EM) were performed. PLA2R staining was performed by IF. EM for all cases was reviewed and electron-dense deposit location, distribution, and size were determined. Results: Ninety-three cases of MN were identified, of which 86 had both PLA2R staining and EM performed. Of these, 51 cases (59%) were positive for PLA2R and 35 (41%) were negative. Mesangial electron-dense deposits were present in 22 (25.6%) of the 86 cases, including 27.5% (14/51) of PLA2R-positive cases and 22.8% (8/35) of PLA2R-negative cases. No difference was seen in size or distribution of deposits, or other features considered suggestive of secondary MN. Conclusion: PLA2R-negative cases were not more likely to have mesangial deposits than PLA2R-positive cases. Mesangial deposits should not be used as an indicator of secondary MN.

It has been recognized that T cells have a pathogenic role in anti-neutrophil cytoplasmic antibody- (ANCA) associated vasculitis, in addition to being dominant cells in the interstitium in ANCA glomerulonephritis (GN). Given there are differences in renal outcomes based on ANCA type, we sought to characterize the interstitial infiltrate in ANCA GN to determine differences in relation to ANCA type and renal function. Immunohistochemistry stains for CD3, CD4, CD20, C4d and FOXP3 were done in renal biopsies of patients with ANCA GN. Light microscopy was used to determine the percentage of cortical interstitium containing positive cells. Demographics, ANCA type and entry eGFR were recorded. The level of staining was compared between ANCA type and entry eGFR using Wilcoxon rank-sum test. Renal biopsies of 16 patients with MPO and 14 with PR3 ANCA GN were studied. CD3 cells were the predominant cells, with all biopsies staining positive for CD4 and FOXP3. C4d staining was negative in all biopsies, with no significant difference in staining between MPO and PR3 groups for any of the identified cell types. However, regardless of ANCA type, FOXP3 staining was significantly higher in patients with baseline GFR 10 mL/min/1.73 m2(mean 7.54, SD 6.6 versus mean 2.67, SD 3.6; p = 0.04). These data confirm the role of T cells in ANCA GN and demonstrate no differences in interstitial T and B cell infiltrates between PR3 and MPO ANCA GN. Higher FOXP3 signal associates with lower renal function, suggesting a role for regulatory T cells. Further characterization of this T cell subset should be explored in future studies.

Objectives Indocyanine green (ICG) is a fluorescent dye which was initially used for liver functional assessment. Moreover, it is of value for intraoperative visualization of liver segments and bile ducts or primary and secondary liver tumors. Especially in minimally invasive liver surgery, this is essential to enhance the precision of anatomical guided surgery and oncological quality. As early adopters of ICG implementation into laparoscopic and robotic-assisted liver surgery in Germany, we summarize the current recommendations and share our experiences. Methods Actual strategies for ICG application in minimally invasive liver surgery were evaluated and summarized during a review of the literature. Experiences in patients who underwent laparoscopic or robotic-assisted liver surgery with intraoperative ICG staining between 2018 and 2020 from the Magdeburg registry for minimally invasive liver surgery (MD-MILS) were evaluated and the data were analyzed retrospectively. Results ICG can be used to identify anatomical liver segments by fluorescence angiography via direct or indirect tissue staining. Fluorescence cholangiography visualizes the intra- and extrahepatic bile ducts. Primary and secondary liver tumors can be identified with a sensitivity of 69–100%. For this 0.5 mg/kg body weight ICG must be applicated intravenously 2–14 days prior to surgery. Within the MD-MILS we identified 18 patients which received ICG for intraoperative tumor staining of hepatocellular carcinoma (HCC), cholangiocarcinoma, peritoneal HCC metastases, adenoma, or colorectal liver metastases. The sensitivity for tumor staining was 100%. In 27.8% additional liver tumors were identified by ICG fluorescence. In 39% a false positive signal could be detected. This occurred mainly in cirrhotic livers. Conclusions ICG staining is a simple and useful tool to assess individual hepatic anatomy or to detect tumors during minimally invasive liver surgery. It may enhance surgical precision and improve oncological quality. False-positive detection rates of liver tumors can be reduced by respecting the tumor entity and liver functional impairments.

Kidney involvement is common in patients with systemic lupus erythematosus (SLE). This study investigates the clinical and prognostic characteristics of thrombotic microangiopathy (TMA) compared to class IV lupus nephritis in SLE patients. A retrospective review of patients who underwent kidney biopsy, with a primary diagnosis of SLE and TMA between June 2006 and September 2018 was conducted. Those patients were subsequently compared to patients with class IV lupus nephritis between January 2018 and December 2018. Demographics, laboratory, and serological data at the time of biopsy were abstracted. Among 214 SLE patients records screened, 27 were included in the final analysis. Eight patients had lupus-related TMA without evidence of active lupus nephritis, while 19 patients had class IV lupus nephritis without evidence of TMA. TMA patients had significantly higher lactate dehydrogenase levels (718 ± 499 vs. 264 ± 107.7 U/L, p = 0.009), serum C3 (100.6 ± 39.3 vs. 65.8 ± 27 mg/dL, p = 0.049), white blood cell count (14743.8 ± 7933.3 vs. 5807.9 ± 2053.2 × 10E3/uL, p

Introduction In patients with systemic lupus erythematosus (SLE) without concurrent active urinary sediment or unexplained acute kidney injury (AKI), current guidelines recommend performing a kidney biopsy in those with at least 500 mg/24-hour (European League Against Rheumatism/European Renal Association-European Dialysis and Transplant Association [EULAR/ERA-EDTA]) or 1000 mg/24-hour (American College of Rheumatology [ACR]) proteinuria. To evaluate the relevance of these indications, we studied histopathologic findings in patients with SLE with proteinuria below these cutoffs. Methods We retrospectively reviewed the clinical, laboratory and histological characteristics of patients with SLE with, Graphical abstract

Acute kidney injury (AKI) due to cisplatin is a significant problem that limits its use as an effective chemotherapeutic agent. T cell receptor+CD4−CD8− double negative (DN) T cells constitute the major T cell population in the human and mouse kidney, express programmed cell death protein (PD)-1, and protect from ischemic AKI. However, the pathophysiological roles of DN T cells in cisplatin-induced AKI is unknown. In this study, wild-type mice were treated with cisplatin (30 mg/kg) or vehicle, and the effects on kidney DN T cell numbers and function were measured. In vitro experiments evaluated effects of kidney DN T cells on cisplatin-induced apoptosis and PD ligand 1 (PD-L1) in renal epithelial cells. Adoptive transfer experiments assessed the therapeutic potential of DN T cells during cisplatin-induced AKI. Our results show that kidney DN T cell population increased at 24 h and declined by 72 h after cisplatin treatment. Cisplatin treatment increased kidney DN T cell proliferation, apoptosis, CD69, and IL-10 expression, whereas CD62L, CD44, IL-17A, interferon-γ, and TNF-α were downregulated. Cisplatin treatment decreased both PD-1 and natural killer 1.1 subsets of kidney DN T cells with a pronounced effect on the PD-1 subset. In vitro kidney DN T cell coculture decreased cisplatin-induced apoptosis in kidney proximal tubular epithelial cells, increased Bcl-2, and decreased cleaved caspase 3 expression. Cisplatin-induced expression of PD ligand 1 was reduced in proximal tubular epithelial cells cocultured with DN T cells. Adoptive transfer of DN T cells attenuated kidney dysfunction and structural damage from cisplatin-induced AKI. These results demonstrate that kidney DN T cells respond rapidly and play a protective role during cisplatin-induced AKI.

Hypertensive patients are frequently treated with inhibitors of the renin-angiotensin system (RASi). In renin knockout mice, cells programmed for the renin phenotype ( Renin null cells) stimulate the concentric hypertrophy of intrarenal arteries and arterioles. The Renin null cells invade the arteriolar walls and stimulate the concentric growth of smooth muscle cells (SMCs). EM exam showed disorganized glomerular arterioles, marked layering of SMCs and increased basement membrane, compared to a single organized SMC layer in WT mice. The hypertrophy leads to flow obstruction, ischemia, and renal failure.We hypothesize that Renin null cells or renin-expressing cells from animals treated with RASi possess a unique transcriptome that drives their own abnormal fate and the concentric accumulation of SMCs.To test this, we performed single-cell RNA-seq in WT and Renin null cells. We also tested genetically hypertensive mice and their normotensive controls treated with captopril for 6 months. Further, we examined renal biopsies from patients treated with RAS inhibitors for more than 5 years, age-matched controls without RAS inhibitors, and healthy control kidneys.The transcriptional profile of Renin null cells was markedly different from the profile of WT cells. Gene ontology indicated that Renin null cells possess a contractile rather than the endocrine phenotype of WT cells ( p P P P 2 , without RAS; 677.8 ± 313.4 μm 2 , vs. long-term RAS; 1347 ± 529.9 μm 2 , P =0.003).In conclusion, renin cells stimulated by inhibition of RAS have specific molecular programs that contribute to arterial disease.

Inhibitors of the renin-angiotensin system (RAS) are widely used to treat hypertension. Using mice harboring fluorescent cell lineage tracers, single-cell RNA-Seq, and long-term inhibition of RAS in both mice and humans, we found that deletion of renin or inhibition of the RAS leads to concentric thickening of the intrarenal arteries and arterioles. This severe disease was caused by the multiclonal expansion and transformation of renin cells from a classical endocrine phenotype to a matrix-secretory phenotype: the cells surrounded the vessel walls and induced the accumulation of adjacent smooth muscle cells and extracellular matrix, resulting in blood flow obstruction, focal ischemia, and fibrosis. Ablation of the renin cells via conditional deletion of β1 integrin prevented arteriolar hypertrophy, indicating that renin cells are responsible for vascular disease. Given these findings, prospective morphological studies in humans are necessary to determine the extent of renal vascular damage caused by the widespread use of inhibitors of the RAS.

Background Microscopic polyangiitis (MPA) is a subtype of anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV), involving small and medium sized vessels, often affecting the kidneys and lungs. Anti-neutrophil cytoplasmic antibody (ANCA) is detected in up to 90% of cases of MPA and its detection helps guide diagnosis, however cases of ANCA-negative MPA have been reported, hence definitive diagnosis relies on tissue biopsy. Case report A 23-year-old man was evaluated for dyspnea and pleuritic chest pain, and found to have bilateral intra-alveolar opacities and hilar adenopathy. Diagnostic work up revealed positive anti-nuclear antibodies (ANA) and negative ANCA, which in the setting of a non-classical presentation, delayed diagnosis and appropriate treatment. Due to persistent symptoms and a high suspicion for autoimmune disease with pulmonary-renal syndrome, he underwent lung biopsy which revealed intra-alveolar hemorrhage and capillaritis indicative of microscopic polyangiitis (MPA). Surprisingly, kidney biopsy was not typical of classic MPA, but revealed less common features. Due to therapeutic noncompliance he was readmitted multiple times thereafter with rare complications of MPA such as acute pancreatitis and hemorrhagic pericardial effusion with tamponade. Conclusion This case serves as an important clinical reminder to consider AAV even in those with negative ANCA serologies and a high suspicion for pulmonary-renal syndrome. It also demonstrates the high morbidity in cases of diagnostic delay and inadequate treatment.

Background Crystalglobulin-associated nephropathy (CAN), a rare subtype of monoclonal gammopathy, usually associated with multiple myeloma and occasionally monoclonal gammopathy of uncertain significance (MGUS), is characterized by occluding monoclonal pseudothrombi within renal glomerular capillaries and/or interstitial arterioles. Ultrastructurally, these pseudothrombi are unique for having a crystalline substructure. We describe a case of an adult patient with monoclonal B-cell lymphocytosis (MBL) and acute renal failure whose kidney biopsy revealed a rare diagnosis of CAN. Case presentation A 63-year old male presented with a 2-month history of edema, arthralgia and malaise. He had acute kidney injury with hematoproteinuria on urine analysis. Serum and urine protein electrophoresis were both negative. A renal biopsy however revealed features of CAN. Organomegaly, bone pain and lymphadenopathy were absent. A repeat serum electrophoresis was positive for IgA kappa and a free light chain assay showed elevated free kappa light chains. Flow cytometry done subsequently revealed a diagnosis of MBL, chronic lymphocytic leukemia (CLL) type. Conclusion CAN in association with MBL/CLL has not been previously described in literature, and our case highlights yet another instance of monoclonal gammopathy of renal significance (MGRS) where a small B-cell clone resulted in extensive renal pathology without systemic manifestations.

BK polyomavirus–associated nephropathy (BKpyVAN) remains a cause of graft loss in kidney transplant recipients on immunosuppressive therapy. Its diagnosis relies on the identification of BK virus (BKV) in the renal allograft biopsy by positive immunohistochemical (IHC) stain for the viral SV40 large T antigen, although in situ hybridization (ISH) for viral DNA is used in some centers. We examined tissue detection of BKV RNA by RNAscope, a novel, automated ISH test, in 61 allograft biopsies from 56 patients with BKpyVAN. We found good correlation between the estimate of BKV tissue load by RNAscope ISH and SV40 IHC ( R2= 0.65, p

Crystal-storing histiocytosis (CSH) is a rare manifestation of monoclonal gammopathy in which histiocytes containing monoclonal proteins in their cytoplasm are found in various organs of the body including the kidney. Within the kidney, these monoclonal crystal-laden histiocytes have been described to occur in the interstitium (most commonly) or in the glomerular mesangium. CSH within glomerular capillary loops has rarely been reported. We describe three cases of CSH primarily affecting the glomerular capillaries and review the literature of CSH in general. Twenty cases of CSH involving the kidney are present in the literature; three describe CSH in glomeruli, only one of which showed histiocytes predominantly in glomerular capillary loops, while 15 had predominantly or solely interstitial CSH. Most cases involve IgG kappa crystals with only one case involving lambda light chain. Patients with CSH predominantly involving the glomerular capillaries showed a trend toward lower serum creatinine and proteinuria at presentation, and several patients with CSH lacked a definitive diagnosis of a monoclonal gammopathy at the time of diagnosis, emphasizing the role that kidney biopsy and particularly electron microscopy play in diagnosis of this entity.

We reported a unique case with the coexistence of classic and cutaneous polyarteritis nodosa (PAN), and microscopic polyangiitis (MPA) in hepatitis virus-associated vasculitis. A 77-year-old Asian man presented with extremity weakness and weight loss found to have bilateral foot drop and rash on his hands and legs. Labs reveal positive for hepatitis B core antibody and perinuclear-antineutrophil cytoplasmic antibody (p-ANCA), decreased C3 and C4 levels. Skin biopsy of rash shows medium vessel vasculitis suggesting PAN. Interestingly, renal biopsy showed features of necrotising medium-sized arteritis consistent with PAN and focal crescentic glomerulonephritis consistent with MPA. The patient was treated with 1 g of solumedrol daily for 3 days, followed by oral steroids and cyclophosphamide treatment for vasculitis, and entecavir for chronic hepatitis B infection, resulting in resolution of symptoms. The patient has not had a relapse at 6 months.

The surgical treatment of hepatopancreatobiliary (HPB) diseases requires complex operative procedures. Within the last decades the morbidity (36-50 %) and mortality (

Autosomal dominant polycystic kidney disease (ADPKD), caused by PKD1 and PKD2 gene mutations, is one of the most common genetic diseases, affecting up to 1 in 500 people. Mutations of PKD1 account for over 85% of ADPKD cases. However, mechanisms of disease progression and explanations for the wide range in disease phenotype remain to be elucidated. Moreover, functional roles of PKD1 in the renal stromal compartment are poorly understood. In this work, we tested if Pkd1 is essential for development and maintenance of the renal stromal compartment and if this role contributes to pathogenesis of polycystic kidney disease using a novel tissue-specific knockout mouse model. We demonstrate that deletion of Pkd1 from renal stromal cells using Foxd1-driven Cre causes a spectrum of defects in the stromal compartment, including excessive apoptosis/proliferation and extracellular matrix deficiency. Renal vasculature was also defective. Further, mutant mice showed epithelial changes and progressive cystogenesis in adulthood modeling human ADPKD. Altogether, we provide robust evidence to support indispensable roles for Pkd1 in development and maintenance of stromal cell derivatives by using a novel ADPKD model. Moreover, stromal compartment defects caused by Pkd1 deletion might serve as an important mechanism for pathogenesis of ADPKD.

IgG2 heavy chain deposition disease (HCDD) is extremely rare. To date, only 4 cases have been reported in medical literature. To our knowledge, we report the first case of IgG2 HCDD accompanied by kappa plasma cell dyscrasia.

Recipients of incompatible allografts are at increased risk of graft loss. We hypothesized that analysis of sequential biopsies from these grafts could define progression of graft lesions and identify features predictive of progression.We studied the time course of histologic injury in 745 kidney graft biopsies from 129 patients transplanted with a positive crossmatch human leukocyte antigen-incompatible kidney between 2000 and 2010 (follow-up of 1-9 years).Graft survival was 98% at 1 year and 80% at 5 years after transplantation. Throughout follow-up, 70% of patients experienced rejection, with 52% showing subclinical rejection in the first year. Cell-mediated rejection was more frequent than antibody-mediated rejection throughout follow-up. Transplant glomerulopathy (TxGN; cg≥1) developed in 47% of patients over the period of the study, as early as 3 months in a few patients. TxGN was preceded by glomerulitis in more than 90% of cases, with a median time interval of 12 months. Glomerulitis and detectable posttransplantation donor-specific antibodies were risk factors for TxGN (P0.0001 and P0.05). C4d-negative antibody-mediated rejection manifesting as capillaritis (g≥1 and ptc≥1) with detectable donor-specific antibodies was observed in some recipients (20%). There was progressively higher average tubulointerstitial scarring (ci+ct) from 3 to 6 to 12 months (P0.001).Despite good graft survival, a significant incidence of biopsy-proven rejection occurred in this subset of closely monitored human leukocyte antigen-incompatible recipients throughout follow-up. Microcirculation inflammation, particularly glomerulitis, irrespective of C4d, is associated with a high risk of development of TxGN at 1 year.

Reproductive tract abnormalities and male infertility have higher incidence in autosomal dominant polycystic kidney disease (ADPKD) patients than in general population. In this work, we revealed that Pkd1, whose mutations account for 85% of ADPKD cases, is essential for male reproductive tract development. Disruption of Pkd1 caused a spectrum of defects in the murine male reproductive tract. The earliest visible defect in Pkd1-/- reproductive tract was cystic dilation of the efferent ducts, which are derivatives of the mesonephric tubules. Epididymis development was delayed or arrested in the Pkd1-/- mice. No sign of epididymal coiling was seen in the Pkd1 null mice. Disruption of Pkd1 in epithelia alone using the Pax2-cre mice was sufficient to cause efferent duct dilation and coiling defect in the epididymis, suggesting that Pkd1 is critical for epithelial development and maintenance in male reproductive tract. In-depth analysis showed that Pkd1 is required to maintain tubulin cytoskeleton and important for Tgf-β/Bmp signal transduction in the epithelia of male reproductive tract. Altogether, our results provide the first direct evidence for developmental roles of Pkd1 in male reproductive tract and provide new insights in reproductive tract abnormalities and infertility in ADPKD patients.

BACKGROUND Focal segmental glomerulosclerosis (FSGS) recurs after kidney transplantation in more than 30% of cases and can lead to allograft loss. Serum soluble urokinase-type plasminogen activator receptor (suPAR) is implicated in the pathogenesis of native and recurrent FSGS. METHODS We conducted a retrospective study of 25 adults with posttransplantation FSGS. We investigated the relationship between suPAR levels and podocyte changes and the impact of therapy on podocyte structure. We assessed response to therapy by improvement in proteinuria, allograft function, and resolution of histologic changes. RESULTS A median (interquartile range) of 15 (10-23) plasmapheresis sessions was administered; 13 of the subjects also received rituximab. Median pretreatment suPAR levels were higher among those with severe (≥75%) versus those with mild (≤25%) podocyte foot process effacement (13,030 vs. 4806 pg/mL; P=0.02). Overall, mean±SD of proteinuria improved from 5.1±3.8 to 2.1±2.8 mg/dL (P=0.003), mean podocyte effacement decreased from 57%±33% to 22%±22% (P=0.0001), estimated glomerular filtration rates increased from median (interquartile range) of 32.9 (20.6-44.2) to 39.3 (28.8-63.4; P

Disseminated intravascular coagulation (DIC)-positive kidneys have historically been turned down for fear of poor outcomes. Higher severity injuries, which are prone to DIC, are typically seen in younger, otherwise healthy potential donors. The continued kidney allograft shortage has generated interest in the use of these DIC-positive grafts. There have been some reports of acceptable outcomes of renal transplantation using kidneys from donors with DIC. There are multiple clinical series demonstrating good outcomes from DIC-positive kidneys when the extent of glomeruli containing fibrin thrombi is less than 50% and donor renal function is preserved. These grafts are frequently associated with a period of delayed graft function.We report 2 transplants with kidneys from brain dead donors with known DIC.Both donors had renal failure and pretransplant renal biopsies showing 100% of the glomeruli containing fibrin thrombi. The recipients experienced delayed graft function requiring hemodialysis which was discontinued on postoperative days 18 and 39 for cases 1 and 2, respectively. Both patients are now over 14 months posttransplant with stable allograft function.Until clearer organ selection criteria are established, caution should be exercised when considering the use of kidneys with a similar phenotype and allocation decisions made by a multidisciplinary transplant team on a case-by-case basis.

Background. Venous neointimal hyperplasia is the most common cause of arteriovenous (AV) fistula and graft dysfunction following dialysis access surgery. However, the pathogenetic impact of pre-existing venous neointimal hyperplasia at the time of AV access creation on final clinical success is currently unknown in the setting of advanced chronic kidney disease (CKD) and end-stage renal disease (ESRD) patients. The aim of this study was to perform a detailed histological, morphometric, and immunohistochemical analysis of vein specimens in advanced CKD and ESRD patients collected at the time of new vascular access placement. Methods. Vein samples from 12 patients were collected at the time of AV access creation near the site of AV anastomosis. Histological, immunohistochemistry and morphometric studies were performed on these vein samples. Results. Examination of the tissue specimens obtained at the time of surgery showed neointimal hyperplasia in 10 of 12 specimens, ranging from minimal to very severe. The majority of cells within the neointima were myofibroblasts with a minority of contractile smooth muscle cells present. Conclusion. Our work represents a detailed description of the morphometric and cellular phenotypic lesions present in the veins of CKD and ESRD patients, prior to dialysis access placement. These studies (i) suggest the future possibility of a new predictive marker (pre-existing venous neointimal hyperplasia) for AV dialysis access dysfunction and (ii) open the door for the future development of novel local therapies for optimization of the venous substrate on which the dialysis access is created.

Proton receptors are G protein-coupled receptors that accept protons as ligands and function as pH sensors. One of the proton receptors, GPR4, is relatively abundant in the kidney, but its potential role in acid-base homeostasis is unknown. In this study, we examined the distribution of GPR4 in the kidney, its function in kidney epithelial cells, and the effects of its deletion on acid-base homeostasis. We observed GPR4 expression in the kidney cortex, in the outer and inner medulla, in isolated kidney collecting ducts, and in cultured outer and inner medullary collecting duct cells (mOMCD1 and mIMCD3). Cultured mOMCD1 cells exhibited pH-dependent accumulation of intracellular cAMP, characteristic of GPR4 activation; GPR4 knockdown attenuated this accumulation. In vivo, deletion of GPR4 decreased net acid secretion by the kidney and resulted in a nongap metabolic acidosis, indicating that GPR4 is required to maintain acid-base homeostasis. Collectively, these findings suggest that GPR4 is a pH sensor with an important role in regulating acid secretion in the kidney collecting duct.

BACKGROUND: Obesity is increasing worldwide at an alarming rate. Particularly in Western countries, obesity and related problems have become a serious medical problem and an enormous socio-economic burden. DISCUSSION: Currently, surgery is the only avail-able treatment for patients with severe obesity which leads to sustained weight loss and cure of co-morbidities in the majority of the patients. The increase in the number of bariatric opera-tions and the occasional failure and complications of these surgical procedures have resulted in an increased need for revision surgery. Overall, 10-25 % of patients are expected to need a revision for failure of the primary bariatric procedure. The main indications for revision procedures are inadequate weight loss, surgery-related complications as well as surgical emergencies and long-term complications caused by malnutrition or -vitamin deficiencies. Unfortunately, there are currently no randomised trials to answer the ques-tion as to which operation should be performed in which patient and after which procedure. Deci-sions are often influenced by the expertise and preference of the operating surgeon as well as by patient’s preference. Thus, a systematic review of published data to this complex issue appears to be helpful and important for daily surgical prac-tise. CONCLUSIONS: Revision bariatric procedures are technically more complex and associated with increased postoperative complications. These operations should basically be performed in cen-tres with profound expertise in this field of surgery, and - whenever possible - laparoscopically. However, every abdominal surgeon should be able to diagnose and treat some acute complica-tions. After failed restrictive procedures, revision is recommended only in cases of complications but with adequate weight loss at the time of -fail-ure. Otherwise, conversion to combined procedures should be considered. After the failure of combined procedures, further weight loss or successful treatment of complications can be achieved by adding more restriction and / or malabsorption components. The latter is associated with an increased risk of nutri-tional sequelae.

Background. Current antihumoral therapies in transplantation and autoimmune disease do not target the mature antibody-producing plasma cell. Bortezomib is a first in class proteosomal inhibitor, that is Food and Drug Administration approved, for the treatment of plasma cell-derived tumors that is multiple myeloma. We report the first clinical experience with plasma cell-targeted therapy (bortezomib) as an antirejection strategy. Methods. Eight episodes of mixed antibody-mediated rejection (AMR) and acute cellular rejection (ACR) in six transplant recipients were treated with bortezomib at labeled dosing. Monitoring included serial donor-specific antihuman leukocyte antigen antibody (DSA) levels and repeated allograft biopsies. Results. Six kidney transplant patients received bortezomib for AMR and concomitant ACR. In each case, bortezomib therapy provided (1) prompt rejection reversal, (2) marked and prolonged reductions in DSA levels, (3) improved renal allograft function, and (4) suppression of recurrent rejection for at least 5 months. Moreover, immunodominant DSA (iDSA) (i.e., the antidonor human leukocyte antigen antibody with the highest levels) levels were decreased by more than 50% within 14 days and remained substantially suppressed for up to 5 months. One or more additional DSA were present at lower concentrations (non-iDSA) in each patient and were also reduced to nondetectable levels. Bortezomib-related toxicities (gastrointestinal toxicity, thrombocytopenia, and paresthesias) were all transient. Conclusions. Bortezomib therapy: (1) provides effective treatment of AMR and ACR with minimal toxicity and (2) provides sustained reduction in iDSA and non-iDSA levels. Bortezomib represents the first effective antihumoral therapy with activity in humans that targets plasma cells.

OBJECTIVE—Recent studies indicate an important role for nuclear receptors in regulating lipid and carbohydrate metabolism, fibrosis, and inflammation. Farnesoid X receptor (FXR) is a member of the nuclear hormone receptor superfamily. FXR is highly expressed in the liver, intestine, adrenal gland, and kidney. The primary bile acids are the highest affinity endogenous ligands for FXR. The effects of FXR agonists in diabetic kidney disease, the main cause of end-stage renal disease, however, have not been determined. RESEARCH DESIGN AND METHODS—To identify the effect of FXR activation in modulation of diabetic nephropathy, we treated 1) C57BL/6J mice on low-fat diet or high-fat diet with FXR agonists (GW4064 or cholic acid) for 1 week; 2) C57BLKS/J-db/db mice and their lean mates with GW4064 for 1 week; and 3) C57BL/6J-db/db mice and their lean mates with cholic acid for 12 weeks. RESULTS—We found that FXR agonists modulate renal sterol regulatory element–binding protein-1 (SREBP-1) expression and lipid metabolism and renal expression of profibrotic growth factors, proinflammatory cytokines, and oxidative stress enzymes and decrease glomerulosclerosis, tubulointerstitial fibrosis, and proteinuria. In renal mesangial cells, overexpression of FXR or treatment with GW4064 also inhibited SREBP-1c and other lipogenic genes, transforming growth factor-β, and interleukin-6, suggesting a direct role of FXR in modulating renal lipid metabolism and modulation of fibrosis and inflammation. CONCLUSIONS—These results therefore indicate a new and important role for FXR in the kidney and provide new therapeutic avenues for the treatment of diabetic nephropathy.

Transcription factor Nrf2 protects from experimental acute kidney injury (AKI) and is promising to limit progression in human chronic kidney disease (CKD) by upregulating multiple antioxidant genes. We recently demonstrated that deletion of Keap1, the endogenous inhibitor of Nrf2, in T lymphocytes significantly protects from AKI. In this study, we investigated the effect of Keap1 deletion on Nrf2 mediated antioxidant response in the renal tubular epithelial cells. We deleted Keap1 exon 2 and 3 in the renal tubular epithelial cells by crossing Ksp-Cre mice with Keap1 floxed (Keap1 f/f) mice. Deletion of Keap1 gene in the kidney epithelial cells of Ksp-Keap1 -/- mice and its effect on Nrf2 target gene expression was performed using PCR and real-time PCR respectively. Histological evaluation was performed on H&E stained sections. Complete blood count, serum and urine analysis were performed to assess systemic effects of defective kidney development. Student’s T test was used to determine statistical difference between the groups. Ksp-Cre resulted in the deletion of Keap1 exon 2 and 3 and subsequent upregulation of Nrf2 target genes, Nqo1, Gclm and Gclc in the kidney epithelial cells of Ksp-Keap1 -/- mice at baseline. Renal epithelial cell specific deletion of Keap1 in Ksp-Keap1 -/- mice caused marked renal pelvic expansion and significant compression of medullary parenchyma consistent with hydronephrosis in both (3 month-old) males and females. Kidneys from 6 month-old Ksp-Keap1 -/- mice showed progressive hydronephrosis. Hematological, biochemical and urinary analysis showed significantly higher red blood cell count (p = 0.04), hemoglobin (p = 0.01), hematocrit (p = 0.02), mean cell volume (p = 0.02) and mean cell hemoglobin concentration (p = 0.003) in Ksp-Keap1 -/- mice in comparison to Keap1 f/f mice. These unexpected findings demonstrate that Keap1 deletion in renal tubular epithelial cells results in an abnormal kidney development consistent with hydronephrosis and reveals a novel Keap1 mediated signaling pathway in renal development.

Arteriovenous fistula (AVF) stenosis remains an important cause of AVF maturation failure for which there are currently no effective therapies. To understand the mechanisms involved, we have examined the pattern of cellular proliferation at different time points in a pig model of AVF stenosis. Immunohistochemical analysis of cellular proliferation was performed at 2, 7, 28, and 42 days. The distribution of cellular proliferation within the different layers of the vessel wall was also studied. An ANOVA analysis was used to identify differences between the magnitude of cellular proliferation at different time points and within different layers of the vessel wall. Adventitial proliferation occurred at 2 days and declined over time. Intimal and medial proliferation peaked at 7 days and then decreased over time. There was minimal proliferation in all three layers at the 28- and 42-day time points. An important finding was the presence of active myofibroblast proliferation within "neointimal buds" at the 7-day time point. Results suggest that there could be early adventitial activation, followed by a passage of these cells into the medial and intimal layers. These suggest that the application of perivascular antiproliferative (adventitial) therapies at the time of surgery could potentially reduce AVF maturation failure.

BACKGROUND The correlation between histopathologic phenotypes and allograft outcomes among patients desensitized for donor-specific antibody (HLA-incompatible) is unknown. METHODS We analyzed 1-year biopsies from desensitized recipients transplanted between 1999 and 2010 and estimated graft survival for each histologic phenotype identified. Median time posttransplant for the 1-year biopsy was 367 days (interquartile range 357-388 days) and median follow-up of all patients post-1-year biopsy was 42 months (interquartile range 19.5-65 months). RESULTS Transplant glomerulopathy was present in 25.0% of biopsies and resulted in worse graft survival (66.7% vs. 96.7%, P

Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common inherited genetic diseases, caused by mutations in PKD1 and/ or PKD2. Infertility and reproductive tract abnormalities in male ADPKD patients are very common and have higher incidence than in the general population. In this work, we reveal novel roles of Pkd2 for male reproductive system development. Disruption of Pkd2 caused dilation of mesonephric tubules/efferent ducts, failure of epididymal coiling, and defective testicular development. Deletion of Pkd2 in the epithelia alone was sufficient to cause reproductive tract defects seen in Pkd2 � /� mice, suggesting that epithelial Pkd2 plays a pivotal role for development and maintenance of the male reproductive tract. In the testis, Pkd2 also plays a role in interstitial tissue and testicular cord development. In-depth analysis of epithelial-specific knockout mice revealed that Pkd2 is critical to maintain cellular phenotype and developmental signaling in the male reproductive system. Taken together, our data for the first time reveal novel roles for Pkd2 in male reproductive system development and provide new insights in male reproductive system abnormality and infertility in ADPKD patients.

Renal involvement by sarcoidosis in native and transplanted kidneys classically presents as non caseating granulomatous interstitial nephritis. However, the incidence of sarcoidosis in native and transplant kidney biopsies, its frequency as a cause of end stage renal disease and its recurrence in renal allograft are not well defined, which prompted this study. The electronic medical records and the pathology findings in native and transplant kidney biopsies reviewed at the Johns Hopkins Hospital from 1/1/2000 to 6/30/2011 were searched. A total of 51 patients with a diagnosis of sarcoidosis and renal abnormalities requiring a native kidney biopsy were identified. Granulomatous interstitial nephritis, consistent with renal sarcoidosis was identified in kidney biopsies from 19 of these subjects (37%). This is equivalent to a frequency of 0.18% of this diagnosis in a total of 10,023 biopsies from native kidney reviewed at our institution. Follow-up information was available in 10 patients with biopsy-proven renal sarcoidosis: 6 responded to treatment with prednisone, one progressed to end stage renal disease. Renal sarcoidosis was the primary cause of end stage renal disease in only 2 out of 2,331 transplants performed. Only one biopsy-proven recurrence of sarcoidosis granulomatous interstitial nephritis was identified. Conclusions Renal involvement by sarcoidosis in the form of granulomatous interstitial nephritis was a rare finding in biopsies from native kidneys reviewed at our center, and was found to be a rare cause of end stage renal disease. However, our observations indicate that recurrence of sarcoid granulomatous inflammation may occur in the transplanted kidney of patients with sarcoidosis as the original kidney disease.

Venous stenosis, secondary to venous neointimal hyperplasia (VNH), at the arteriovenous anastomosis (AV) is a major etiology of vascular access failure in AV fistulas (AVF) and AV grafts (AVG). Recently, our group has reported that severe VNH also occurs prior to vascular access placement. The objective of this study was to perform a comparison of the cellular phenotypes within the neointima from veins collected from subjects at the time of new vascular access creation and stenotic veins from subjects with failed AVGs and AVFs. Vein samples, collected at the time of new access surgery, and stenotic vein segments, collected at access revision, were evaluated for expression of α-smooth muscle actin (SMA), vimentin, and desmin within the neointima, and quantified using semiquantitative scoring. Within the neointima, the majority of cells from vein samples collected at the time of new access surgery were contractile smooth muscle cells, and veins from stenotic AVF and AVG were predominately myofibroblasts. Our results suggest the possibility of different mechanistic pathways in response to vascular injury that occurs prior to vascular access creation vs. after access creation, and that divergent therapeutic approaches may be needed for treating vascular injury in these two settings.

Purpose Venous stenosis secondary to neointimal hyperplasia is a major etiology of early arteriovenous fistula (AVF) failure. The natural history of AVF failure is likely influenced by progressive vascular insults to the vein prior to and after AVF creation. The main objectives of this study were to ( 1 ) provide a histologic and morphometric description of non-chronic kidney disease (CKD), upper extremity vein specimens and ( 2 ) perform a morphometric analysis to study venous histology from non-CKD upper extremity veins, veins collected at the time of new vascular access surgery and veins collected from failed stenotic AVFs. Methods Vein samples from 11 non-CKD deceased donors, 29 subjects receiving new vascular access creation and 20 subjects with stenotic failed AVFs were collected for histologic and morphometric analysis. Results The mean values of average intima/media thickness ± S.E. from veins collected from non-CKD subjects, subjects receiving new vascular access and subjects with stenotic AVFs were 0.16±0.02, 0.43±0.07 and 3.84±0.55, respectively (pConclusions Our results demonstrate a progressively increasing venous neointimal hyperplasia development from the non-CKD period through the period of AVF creation and failure. Vascular injuries from complications of progressive CKD prior to access placement and vascular injuries after vascular access placement may play important roles in these progressive vascular changes, and need to be further elucidated.

Purpose Arteriovenous fistula non-maturation because of a peri-anastomotic venous stenosis is currently a huge clinical problem for which there are no effective therapies. Methods In an attempt to further define the cellular pathways involved in this process we have assessed the pattern and intensity of macrophage infiltration at different time points in a pig model of AVF stenosis. Results Our results demonstrate an early and eccentric pattern of macrophage infiltration at 2d with a rapid disappearance of this infiltrate by 7d. Conclusion We suggest that this early and eccentric macrophage infiltration could play an important role in the pathogenesis of AVF non-maturation.

ABO-incompatible kidney transplant recipients may have a higher incidence of BK virus allograft nephropathy (BKVAN) compared with ABO-compatible recipients. It is unclear whether HLA-incompatible recipients share this risk or whether this phenomenon is unique to ABO-incompatible recipients. DESIGN, SETTING, PARTICIPATION, MEASUREMENTS: This study analyzed adult incompatible kidney transplant recipients from 1998 to 2010 (62 ABO-incompatible and 221 HLA-incompatible) and identified patients in whom BKVAN was diagnosed by biopsy (per protocol or for cause). This was a retrospective analysis of a prospectively maintained database that compared BKVAN incidence and outcomes between ABO- and HLA-incompatible recipients, respectively. BKVAN link to rejection and graft accommodation phenotype were also explored. The Johns Hopkins Institutional Review Board approved this study.Risk for BKVAN was greater among ABO-incompatible than HLA-incompatible patients (17.7% versus 5.9%; P=0.008). Of BKVAN cases, 42% were subclinical, diagnosed by protocol biopsy. ABO-incompatibility and age were independent predictors for BKVAN on logistic regression. C4d deposition without histologic features of glomerulitis and capillaritis (graft accommodation-like phenotype) on 1-year biopsies of ABO-incompatible patients with and without BKVAN was 40% and 75.8%, respectively (P=0.04). Death-censored graft survival (91%) and serum creatinine level among surviving kidneys (1.8 mg/dl) were identical in ABO- and HLA-incompatible patients with BKVAN (median, 1399 and 1017 days after transplantation, respectively).ABO-incompatible kidney recipients are at greater risk for BKVAN than HLA-incompatible kidney recipients. ABO-incompatible recipients not showing the typical graft accommodation-like phenotype may be at heightened risk for BKVAN, but this observation requires replication among other groups.

SLC26A7 (human)/Slc26a7 (mouse) is a recently identified chloride-base exchanger and/or chloride transporter that is expressed on the basolateral membrane of acid-secreting cells in the renal outer medullary collecting duct (OMCD) and in gastric parietal cells. Here, we show that mice with genetic deletion of Slc26a7 expression develop distal renal tubular acidosis, as manifested by metabolic acidosis and alkaline urine pH. In the kidney, basolateral Cl(-)/HCO3(-) exchange activity in acid-secreting intercalated cells in the OMCD was significantly decreased in hypertonic medium (a normal milieu for the medulla) but was reduced only mildly in isotonic medium. Changing from a hypertonic to isotonic medium (relative hypotonicity) decreased the membrane abundance of Slc26a7 in kidney cells in vivo and in vitro. In the stomach, stimulated acid secretion was significantly impaired in isolated gastric mucosa and in the intact organ. We propose that SLC26A7 dysfunction should be investigated as a potential cause of unexplained distal renal tubular acidosis or decreased gastric acid secretion in humans.

Background. Haemodialysis vascular access dysfunction (due to venous stenosis and thrombosis) is a leading cause of hospitalization and morbidity. The aim of the current study was to identify the specific cell types present within stenotic tissue samples from patients with AV fistula and graft failure. Methods. Discarded tissue segments were collected from the stenotic portions (usually near the graft-vein anastomosis or the AV anastomosis) of 23 dialysis grafts and 20 AV fistulae, and examined for expression of smooth muscle alpha actin, desmin, vimentin and a macrophage marker. Results. The majority of cells within the venous neointima (both grafts and fistulae) were myofibroblasts, with a smaller number of desmin positive smooth muscle cells. The graft neointima had a similar cellular phenotype, albeit without any desmin positive contractile smooth muscle cells. The majority of cells within the PTFE graft material were macrophages. Analysis of sequential sections revealed the presence of fibroblasts within the venous neointima and intragraft region. Conclusions. Our results demonstrate that contractile smooth muscle cells, myofibroblasts, fibroblasts and macrophages all play a role in the pathogenesis of dialysis access dysfunction (grafts and fistulae). Targeting these specific cell types might result in the development of novel therapeutic paradigms for haemodialysis vascular access dysfunction.

Expression of spermine/spermidine- N1-acetyltransferase (SSAT), the rate-limiting enzyme of polyamine backconversion cascade, increases after ischemia-reperfusion injuries (IRI). We hypothesized that SSAT plays an important role in the mediation of IRI. To test our hypothesis, wild-type (SSAT-wt) and SSAT-deficient (SSAT-ko) mice were subjected to liver or kidney IRI by ligation of hepatic or renal arteries. The liver and kidney content of putrescine (Put), a downstream by-product of SSAT activity, increased in SSAT-wt animals but not in SSAT-ko animals after IRI, indicating that polyamine backconversion is not functional in SSAT-deficient mice. When subjected to hepatic IRI, SSAT-ko mice were significantly protected against liver damage compared with SSAT-wt mice. Similarly, SSAT-ko animals subjected to renal IRI showed significantly greater protection against damage to kidney tubules than SSAT-wt mice. These studies indicate that SSAT-deficient animals are protected against IRI and suggest that SSAT is an important mediator of the tissue damage in IRI.

Venous stenosis is a significant problem in arteriovenous fistulae, likely due to anatomical configuration and wall shear stress profiles. To identify linkages between wall shear stress and the magnitude and pattern of vascular stenosis, we produced curved and straight fistulae in a pig model. A complete wall stress profile was calculated for the curved configuration and correlated with luminal stenosis. Computer modeling techniques were then used to derive a wall shear stress profile for the straight arteriovenous fistula. Differences in the wall shear stress profile of the curved and straight fistula were then related to histological findings. There was a marked inverse correlation between the magnitude of wall shear stress within different regions of the curved arteriovenous fistula and luminal stenosis in these same regions. There were also significantly greater differences in wall shear stress between the outer and inner walls of the straight as compared to curved arteriovenous fistula, which translated into a more eccentric histological pattern of intima-media thickening. Our results suggest a clear linkage between anatomical configuration, wall shear stress profiles, and the pattern of luminal stenosis and intima-media thickening in a pig model of arteriovenous fistula stenosis. These results suggest that fistula failure could be reduced by using computer modeling prior to surgical placement to alter the anatomical and, consequently, the wall shear stress profiles in an arteriovenous fistula.

Background Current antibody-mediated rejection (AMR) therapies (intravenous immunoglobulin, apheresis, rituximab, polyclonal antibodies) do not target the primary antibody producing B cells, that is, the plasma cell. We report the preliminary results from the first clinical experience with plasma cell targeted therapy with bortezomib. Bortezomib is approved by the US Food and Drug Administration for the treatment of plasma cell tumors (multiple myeloma). Methods Kidney transplant patients with mixed acute cellular rejection (ACR) and AMR episodes (by Banff ‘97 criteria, update 2005) were treated with bortezomib (1.3 mg/m 2 per dose × 4) at standard labeled doses. Patients were monitored by serial donor specific anti-HLA antibody (DSA) determinations [Luminex/Labscreen beads] and quantified by conversion to fluorescence intensity to molecules of equivalent soluble fluorescence (MESF). Results Five patients were treated with bortezomib. Each patient also had coexisting ACR. In each case, bortezomib treatment led to prompt ACR and AMR rejection reversal. DSA levels decreased significantly in all patients (except 1 patient who had short follow-up). Observed toxicities from bortezomib included a transient grade III thrombocytopenia (1 patient) and mild-to-moderate nausea, vomiting, and/or diarrhea (3/5 patients). Opportunistic infections were not observed. Conclusions Bortezomib therapy provides effective reduction in DSA levels with long-term suppression. These preliminary results indicate that proteasome inhibition provides an effective means for reducing HLA antibody levels in transplant recipients.

Focal segmental glomerulosclerosis (FSGS) is a major cause of end-stage renal disease. In this report we used laser capture microdissection to purify diseased glomeruli, and microarrays to provide universal gene expression profiles. The results provide a deeper understanding of the molecular mechanisms of the disease process and suggest novel therapeutic strategies. Consistent with earlier studies, molecular markers of the differentiated podocyte, including WT1, nephrin, and VEGF, were dramatically downregulated in the diseased glomerulus. We also observed multiple changes consistent with increased TGF-β signaling, including elevated expression of TGF-β2, TGF-β3, SMAD2, TGF-β1 receptor, and thrombospondin. In addition, there was relatively low level expression of Csf1r, a marker of macrophages, but elevated expression of the chemokines CXCL1, CXCL2, CCL3, and CXCL14. We also observed strongly upregulated expression of Sox9, a transcription factor that can drive a genetic program of chondrogenesis and fibrosis. Further, the gene with the greatest fold increase in expression in the diseased glomerulus was osteopontin, which has been previously strongly implicated in kidney fibrosis in the unilateral ureteral obstruction mouse model. These results confirm old findings, and indicate the involvement of new genetic pathways in the cause and progression of FSGS.

Objective Safer and more effective therapies are needed for the treatment of systemic lupus erythematosus (SLE). B lymphocytes have been shown to play fundamental pathogenic roles in SLE, and therefore, elimination of B cells with the use of rituximab may represent a new therapy for SLE. Methods A phase I/II dose-escalation trial of rituximab added to ongoing therapy in SLE was conducted. Rituximab was administered as a single infusion of 100 mg/m2 (low dose), a single infusion of 375 mg/m2 (intermediate dose), or as 4 infusions (1 week apart) of 375 mg/m2 (high dose). CD19+ lymphocytes were measured to determine the effectiveness of B cell depletion. The Systemic Lupus Activity Measure (SLAM) score was used as the primary outcome for clinical efficacy. Results Rituximab was well tolerated in this patient population, with most experiencing no significant adverse effects. Only 3 serious adverse events, which were thought to be unrelated to rituximab administration, were noted. A majority of patients (11 of 17) had profound B cell depletion (to

We report a new case of biopsy-confirmed mesalazine-induced interstitial nephritis in an 18-year-old male with ulcerative colitis. His renal function improved with drug discontinuation and corticosteroid treatment. An English literature review revealed an additional 22 cases of this complication that, taken together, showed (1) a male predominance, (2) an absence of specific symptoms or findings on urinalysis, (3) a 61% frequency of residual chronic renal insufficiency with 13% of patients developing end-stage renal disease, and (4) an apparent favorable response to steroid therapy. We conclude that patients receiving 5-aminosalicylates should be routinely monitored with serum creatinine measurements to prevent this uncommon but potentially serious adverse drug reaction.

A64-year-old white woman was admitted to University of Rochester Medical Center in August 2000 with a 1-month history of intermittent fever, malaise, and upper and lower extremity joint pain. Medical workup revealed a hematocrit of 32%, proteinuria, and a serum creatinine of 4.4 mg/dL. Serum immunoelectrophoresis showed an IgA spike, and serum immunofixation confirmed the presence of an IgA monoclonal gammopathy with a total quantitated serum IgA level of 316 mg/dL (normal range, 90 to 325 mg/dL) and a level of 1,280 mg/dL (normal range, 200 to 440 mg/dL). Urine protein electrophoresis revealed a monoclonal spike composed of free light chains.

Developing mammalian embryonic kidney becomes progressively more elaborate as the ureteric bud branches into undifferentiated mesenchyme. Morphological perturbations of nephrogenesis, such as those seen in inherited renal diseases or induced in transgenic animals, require careful and often tedious documentation by multiple methodologies. We have applied a relatively quick and simple approach combining two-photon microscopy and advanced three-dimensional (3-D) imaging techniques to visualize and evaluate these complex events. As compared with laser confocal microscopy, two-photon microscopy offers superior optical sectioning deep into biological tissues, permitting analysis of large, heterogeneous, 3-D structures such as developing mouse kidney. Embryonic and newborn mouse kidneys were fluorescently labeled with lectins, phalloidin, or antibody. Three-dimensional image volumes were then collected. The resulting volume data sets were processed using a novel 3-D visualization technique. Reconstructed image volumes demonstrate the dichotomous branching of ureteric bud as it progresses from a simple, symmetrical structure into an elaborate, asymmetrical collecting system of multiple branches. Detailed morphology of in situ cysts was elucidated in a transgene-induced mouse model of polycystic kidney disease. We expect this integration of two-photon microscopy with advanced 3-D image analysis will provide a powerful tool for illuminating a variety of complex developmental processes in multiple dimensions.

Glycosphingolipid depletion in fabry disease lymphoblasts with potent inhibitors of glucosylceramide synthase. Background Fabry disease is an inherited X-linked disorder resulting in the loss of activity of the lysosomal hydrolase α-galactosidase A and causing the clinical manifestations of renal failure, cerebral vascular disease, and myocardial infarction. The phenotypic expression of this disorder is manifest by the accumulation of glycosphingolipids containing α-galactosyl linkages, most prominently globotriaosylceramide. Methods Based on quantitative structure activity studies, we recently reported two newly designed glucosylceramide synthase inhibitors based on 1-phenyl-2-palmitoylamino-3-pyrrolidino-1-propanol (P4). These inhibitors, 4′-hydroxy-P4 and ethylenedioxy-P4, were evaluated for their ability to deplete globotriaosylceramide and other glucosylceramide-based lipids in Fabry lymphocytes and were compared with N -butyldeoxynojirimycin, another reported glucosylceramide synthase inhibitor. Results Concentrations as low as 10 nmol/L of 4′-hydroxy-P4 and ethylenedioxy-P4 resulted in 70 and 80% depletion, respectively, of globotriaosylceramide, with maximal depletion occurring at three days of treatment. There was no impairment of cell growth. In contrast, N -butyldeoxynojirimycin only minimally lowered globotriaosylceramide levels, even at concentrations as high as 10 μmol/L. Globotriaosylceramide depletion was confirmed by the loss of binding of FITC-conjugated verotoxin B subunit to the lymphoblasts. Conclusions These findings suggest that selective glucosylceramide synthase inhibitors are highly effective in the depletion of globotriaosylceramide from Fabry cell lines. We suggest that these compounds have potential therapeutic utility in the treatment of Fabry disease.