Expression of sodium-dependent dicarboxylate transporter 1 (NaDC1/SLC13A2) in normal and neoplastic human kidney.

Regulated dicarboxylate transport is critical for acid-base homeostasis, prevention of calcium nephrolithiasis, regulation of collecting duct sodium chloride transport, and the regulation of blood pressure. Although luminal dicarboxylate reabsorption via NaDC1 (SLC13A2) is believed to be the primary mechanism regulating renal dicarboxylate transport, the specific localization of NaDC1 in the human kidney is currently unknown. This study's purpose was to determine NaDC1's expression in normal and neoplastic human kidneys. Immunoblot analysis demonstrated NaDC1 expression with an apparent molecular weight of ~61 kDa. Immunohistochemistry showed apical NaDC1 immunolabel in the proximal tubule of normal human kidney tissue; well-preserved proximal tubule brush border was clearly labeled. Apical NaDC1 expression was evident throughout the entire proximal tubule, including the initial proximal convoluted tubule, as identified by origination from the glomerular tuft, and extending through the terminal of the proximal tubule, the proximal straight tubule in the outer medulla. We confirmed proximal tubule localization by colocalization with the proximal tubule specific protein, NBCe1. NaDC1 immunolabel was not detected other than in the proximal tubule. In addition, NaDC1 immunolabel was not detected in tumors of presumed proximal tubule origin, clear cell and papillary renal cell carcinoma, or in tumors of nonproximal tubule origin, oncocytoma and chromophobe carcinoma. In summary, 1) in the human kidney, apical NaDC1 immunolabel is present throughout the entire proximal tubule, and is not detectable in other renal cells; and 2) NaDC1 immunolabel is not present in renal tumors. These studies provide important information regarding NaDC1's role in human dicarboxylate metabolism.

Virus-Derived Chemokine Modulating Protein Pre-Treatment Blocks Chemokine-Glycosaminoglycan Interactions and Significantly Reduces Transplant Immune Damage.

Immune cell invasion after the transplantation of solid organs is directed by chemokines binding to glycosaminoglycans (GAGs), creating gradients that guide immune cell infiltration. Renal transplant is the preferred treatment for end stage renal failure, but organ supply is limited and allografts are often injured during transport, surgery or by cytokine storm in deceased donors. While treatment for adaptive immune responses during rejection is excellent, treatment for early inflammatory damage is less effective. Viruses have developed highly active chemokine inhibitors as a means to evade host responses. The myxoma virus-derived M-T7 protein blocks chemokine: GAG binding. We have investigated M-T7 and also antisense (ASO) as pre-treatments to modify chemokine: GAG interactions to reduce donor organ damage. Immediate pre-treatment of donor kidneys with M-T7 to block chemokine: GAG binding significantly reduced the inflammation and scarring in subcapsular and subcutaneous allografts. Antisense to N-deacetylase N-sulfotransferase1 (ASONdst1) that modifies heparan sulfate, was less effective with immediate pre-treatment, but reduced scarring and C4d staining with donor pre-treatment for 7 days before transplantation. Grafts with conditional Ndst1 deficiency had reduced inflammation. Local inhibition of chemokine: GAG binding in donor organs immediately prior to transplant provides a new approach to reduce transplant damage and graft loss.

Incidental Finding of a Large Right Atrial Thrombus in a Patient With Cerebral Lymphoma.

Right atrial (RA) masses are rare, challenging to diagnose, and potentially life-threatening with high mortality if untreated. We present a patient presenting with diffuse large B-cell lymphoma in the brain that was incidentally found to have a large RA mass. For a better definition of the RA mass, extensive workup using multimodality imaging including chest computed tomography, transthoracic echocardiography, transesophageal echocardiography, cardiac magnetic resonance imaging, and left heart catheterization was warranted. The imaging demonstrated a large RA mass extending through the tricuspid valve into the right ventricle and superior and inferior vena cava without a mobile component. The mass was then successfully resected, and further histology examination was performed to rule out lymphoma and rare subtypes of diffuse large B-cell lymphoma. The comprehensive workup proved the RA mass to be a calcified thrombus rather than a direct metastatic spread of lymphoma.

p16 expression in conventional and desmoplastic trichilemmomas.

The expression of p16 in cutaneous neoplasms is upregulated in melanocytic neoplasms, ultraviolet radiation-induced neoplasms, such as actinic keratoses and squamous cell carcinomas, and in lesions related to human papillomavirus, such as Bowen's disease and bowenoid papulosis. In cervical dysplasia and tonsillar carcinoma, there is such a close relationship between p16 and human papillomavirus (HPV) to the extent that p16 immunostaining is used as a surrogate marker for the presence of HPV proteins. In this study we were interested in the expression pattern of p16 in trichilemmomas. Twenty-six conventional and 19 desmoplastic trichilemmomas were immunohistochemically stained for p16. p16 immunostaining was noted in the majority of conventional (80.8%) and desmoplastic trichilemmomas (73.7%). The staining pattern was both nuclear and cytoplasmic. The staining intensity was more pronounced in the desmoplastic variant. We describe for the first time p16 expression in trichilemmomas and discuss our findings in conjunction with p16 expression found in other cutaneous neoplasms. Additionally, the relationship of p16 to HPV infection is critically evaluated.

Modifying the Organ Matrix Pre-engraftment: A New Transplant Paradigm?

The availability of solid organs for transplantation remains low and there is a substantial need for methods to preserve the viability of grafted tissues. Suppression of solid-organ transplant rejection has traditionally focused on highly effective T cell inhibitors that block host immune lymphocyte responses. However, persistent and destructive innate and acquired immune reactions remain difficult to treat, causing late graft loss. Pretreatment of grafts to reduce organ rejection provides an alternate strategy. Approaches using antithrombotics, stem cells, genetic modifications, modulation of infrastructural components (connective tissue, CT; glycocalyx) of donor organs, and engineering of new organs are under investigation. We discuss here new approaches to modify transplanted organs prior to engraftment as a method to reduce rejection, focusing on the CT matrix.

Serp-2, a virus-derived apoptosis and inflammasome inhibitor, attenuates liver ischemia-reperfusion injury in mice.

BACKGROUND: Ischemia-reperfusion injury (IRI) is an antigen-independent, innate immune response to arterial occlusion and ischemia with subsequent paradoxical exacerbation after reperfusion. IRI remains a critical problem after vessel occlusion and infarction or during harvest and surgery in transplants. After transplant, liver IRI (LIRI) contributes to increased acute and chronic rejection and graft loss. Tissue loss during LIRI has been attributed to local macrophage activation and invasion with excessive inflammation together with hepatocyte apoptosis and necrosis. Inflammatory and apoptotic signaling are key targets for reducing post-ischemic liver injury.Myxomavirus is a rabbit-specific leporipoxvirus that encodes a suite of immune suppressing proteins, often with extensive function in other mammalian species. Serp-2 is a cross-class serine protease inhibitor (serpin) which inhibits the inflammasome effector protease caspase-1 as well as the apoptotic proteases granzyme B and caspases 8 and 10. In prior work, Serp-2 reduced inflammatory cell invasion after angioplasty injury and after aortic transplantation in rodents. In this report, we explore the potential for therapeutic treatment with Serp-2 in a mouse model of LIRI. METHODS: Wildtype (C57BL/6 J) mice were subjected to warm, partial (70%) hepatic ischemia for 90 min followed by treatment with saline or Serp-2 or M-T7, 100 ng/g/day given by intraperitoneal injection on alternate days for 5 days. M-T7 is a Myxomavirus-derived inhibitor of chemokine-GAG interactions and was used in this study for comparative analysis of an unrelated viral protein with an alternative immunomodulating mechanism of action. Survival, serum ALT levels and histopathology were assessed 24 h and 10 days post-LIRI. RESULTS: Serp-2 treatment significantly improved survival to 85.7% percent versus saline-treated wildtype mice (p = 0.0135), while M-T7 treatment did not significantly improve survival (p = 0.2584). Liver viability was preserved by Serp-2 treatment with a significant reduction in serum ALT levels (p = 0.0343) and infarct scar thickness (p = 0.0016), but with no significant improvement with M-T7 treatment. Suzuki scoring by pathologists blinded with respect to treatment group indicated that Serp-2 significantly reduced hepatocyte necrosis (p = 0.0057) and improved overall pathology score (p = 0.0046) compared to saline. Immunohistochemistry revealed that Serp-2 treatment reduced macrophage infiltration into the infarcted liver tissue (p = 0.0197). CONCLUSIONS: Treatment with Serp-2, a virus-derived inflammasome and apoptotic pathway inhibitor, improves survival after liver ischemia-reperfusion injury in mouse models. Treatment with a cross-class immune modulator provides a promising new approach designed to reduce ischemia-reperfusion injury, improving survival and reducing chronic transplant damage.

Selective Deletion of Heparan Sulfotransferase Enzyme, Ndst1, in Donor Endothelial and Myeloid Precursor Cells Significantly Decreases Acute Allograft Rejection.

Early damage to transplanted organs initiates excess inflammation that can cause ongoing injury, a leading cause for late graft loss. The endothelial glycocalyx modulates immune reactions and chemokine-mediated haptotaxis, potentially driving graft loss. In prior work, conditional deficiency of the glycocalyx-modifying enzyme N-deacetylase-N-sulfotransferase-1 (Ndst1f/f TekCre+) reduced aortic allograft inflammation. Here we investigated modification of heparan sulfate (HS) and chemokine interactions in whole-organ renal allografts. Conditional donor allograft Ndst1 deficiency (Ndst1-/-; C57Bl/6 background) was compared to systemic treatment with M-T7, a broad-spectrum chemokine-glycosaminoglycan (GAG) inhibitor. Early rejection was significantly reduced in Ndst1-/- kidneys engrafted into wildtype BALB/c mice (Ndst1+/+) and comparable to M-T7 treatment in C57Bl/6 allografts (P < 0.0081). M-T7 lost activity in Ndst1-/- allografts, while M-T7 point mutants with modified GAG-chemokine binding displayed a range of anti-rejection activity. CD3+ T cells (P < 0.0001), HS (P < 0.005) and CXC chemokine staining (P < 0.012), gene expression in NFκB and JAK/STAT pathways, and HS and CS disaccharide content were significantly altered with reduced rejection. Transplant of donor allografts with conditional Ndst1 deficiency exhibit significantly reduced acute rejection, comparable to systemic chemokine-GAG inhibition. Modified disaccharides in engrafted organs correlate with reduced rejection. Altered disaccharides in engrafted organs provide markers for rejection with potential to guide new therapeutic approaches in allograft rejection.

MPO-C-ANCA-associated necrotising and crescentic glomerulonephritis.

The patterns of ANCA staining usually relate closely to antibodies against myeloperoxidase and proteinase-3. C-ANCA is mainly antibodies to proteinase-3 and P-ANCA is antibodies to myeloperoxidase. C-ANCA with antibodies to MPO with clinical sequelae is unusual.

A 61-year-old male with generalised lymphadenopathy presenting with shortness of breath and infiltrates on chest radiography.

Can you diagnose this 61-year-old male with generalised lymphadenopathy, dyspnoea and radiographic infiltrates? http://ow.ly/AXDg306hfqo.

Stop Being So Sensitive: An Exceptionally Rare Report of Ustekinumab-Induced Sub-acute Hypersensitivity Pneumonitis.

Hypersensitivity pneumonitis (HSP) is a rare syndrome characterised by granulomatous inflammatory lung disease due to repeated sensitisation from a specific antigen. We present the case of a 61-year old male veteran with a history of nodular eczema who presented with 2 weeks of progressive dyspnoea on exertion and pleuritic chest pain. The patient was started on ustekinumab 5 weeks prior to presentation. Initial workup revealed ground-glass opacities on computed tomography (CT) scan of the chest. Cardiac workup was unrevealing with a normal myocardial perfusion stress test. The patient was started on inhaled corticosteroids and albuterol for reactive airway disease. Due to the persistence of symptoms despite treatment, the patient underwent bronchoscopy with bronchoalveolar lavage (BAL), transbronchial biopsy and endobronchial ultrasound-guided biopsy (EBUS). Bronchoscopy showed normal appearing airways of both right and left lungs. The BAL was remarkable for chronic inflammation and pulmonary macrophages. The BAL cell count differential was 1% granulocytes, 50% lymphocytes, 17% eosinophils and 32 mononuclear cells. The pathology from the mediastinal lymph nodes showed reactive inflammatory cells and no malignancy. The pathology from the transbronchial biopsy of the anterior basilar segment of the right lower lobe showed organising pneumonia with occasional ill-defined granulomas that stained negative for Acid Fast Bacilli (AFB) and Grocott's methenamine (GMS) appeared to be consistent with hypersensitivity pneumonitis. Based on the pathological diagnosis of HSP, the patient was managed with discontinuation of ustekinumab, with subsequent improvement of his symptoms. To our knowledge, this is the first report suggesting ustekinumab, like other biological therapies, has the potential to cause HSP.

Use of C4d as a diagnostic tool to classify membranoproliferative glomerulonephritis.

BACKGROUND: Membranoproliferative glomerulonephritis (MPGN type I, II and III) was reclassified in 2013 as MPGN and C3 glomerulopathy (C3G) based on the complement system activation mechanism. OBJECTIVES: To evaluate whether C4d, a component of the classical pathway, could be a diagnostic tool in differentiating between MPGN and C3G. METHODS: We conducted a retrospective study of 15 MPGN type I, II and III and 13 minimal change disease (MCD) patients diagnosed between 2000 and 2012. C4d staining using the peroxidase method was employed. RESULTS: Using the 2013 C3G consensus classification, the 15 MPGN types I, II and III biopsies were re-classified as MPGN (8) and C3G (7). Following C4d staining, of the 8 biopsies diagnosed as MPGN, 4 had classical pathway involvement [C1q (+), C3 (+), C4d (+)]; two had lectin pathway involvement [C1q (-), C3 (+), C4d (+)]; and, two were reclassified as C3G because the absence of C4d and C1q suggested the presence of the alternative pathway [C1q (-), C3 (+), C4d (-)]. Three of the seven C3G biopsies presented classical pathway involvement and were reclassified as MPGN. The alternative pathway was present in one of the other 4 biopsies considered to be C3G. Two C3G biopsies involved the lectin pathway and the one case of dense deposit disease had lectin pathway involvement. CONCLUSIONS: C4d staining may help to differentiate between MPGN and C3G. In addition, the lectin pathway could play a role in the pathogenesis of these glomerulopathies.

An 84-Year-Old Man With Progressive Dyspnea and an Abnormal Chest CT Scan.

CASE PRESENTATION: An 84-year-old man without a history of smoking presented with progressive dyspnea of 6 months' duration accompanied by fatigue and unintentional weight loss. He denied fever, chills, chest pain, hemoptysis, rash, joint pains, or muscle aches. He had multiple hospitalizations for similar presentations that were diagnosed as pneumonia. History was significant for diastolic heart failure, hypertension, and type 2 diabetes mellitus.

Quantitation of HER2/neu expression in primary gastroesophageal adenocarcinomas using conventional light microscopy and quantitative image analysis.

CONTEXT: Human epidermal growth factor receptor 2 (HER2/neu) is overexpressed in a proportion of gastroesophageal (GE) adenocarcinomas, and trastuzumab treatment results in significant improvement in overall survival in patients with HER2/neu-overexpressing GE tumors. Grading of HER2/neu expression in GE tumors and its clinical application is different from that of breast cancer. HER2/neu immunohistochemistry (IHC) image analysis (IA), widely used in breast cancer, has not been studied in GE tumors. OBJECTIVE: To evaluate the correlation between manual HER2/neu IHC scoring and HER2/neu IHC image analysis in GE adenocarcinomas with characterization of associated clinicopathologic features. DESIGN: Tumor grade, growth pattern, and stage were evaluated in 116 cases of primary GE adenocarcinoma biopsy and resection specimens. Using anti-HER2/neu antibody and the proposed HER2/neu scoring system for gastric cancer, HER2/neu IHC expression was recorded after manual scoring and automated IA interpretation. RESULTS: HER2/neu overexpression (IHC 3+) was detected in 19% (10 of 54) of gastric tumors, and overall correlation between manual HER2/neu IHC interpretation and IA interpretation was 78% (42 of 54). HER2/neu overexpression (IHC 3+) was detected in 26% (16 of 62) of GE junction tumors, and the overall correlation between manual HER2/neu IHC interpretation and IA interpretation was 84% (52 of 62). CONCLUSIONS: The HER2/neu IHC scoring system for GE adenocarcinomas differs from that of breast carcinoma. Automated IA, validated for scoring of HER2/neu IHC in breast cancer, has a low correlation between HER2/neu IHC 2+ and IHC 3+ cases scored by conventional light microscopy and cannot be reliably used in the interpretation of HER2/neu IHC expression in GE adenocarcinomas.