Cold Storage Followed by Transplantation Induces Immunoproteasome in Rat Kidney Allografts: Inhibition of Immunoproteasome Does Not Improve Function

BACKGROUND

It is a major clinical challenge to ensure the long-term function of transplanted kidneys. Specifically, the injury associated with cold storage of kidneys compromises the long-term function of the grafts after transplantation. Therefore, the molecular mechanisms underlying cold-storage-related kidney injury are attractive therapeutic targets to prevent injury and improve long-term graft function. Previously, we found that constitutive proteasome function was compromised in rat kidneys after cold storage followed by transplantation. Here, we evaluated the role of the immunoproteasome (iproteasome), a proteasome variant, during cold storage (CS) followed by transplantation.

METHODS

Established in vivo rat kidney transplant model with or without CS containing vehicle or iproteasome inhibitor (ONX 0914) was used in this study. The iproteasome function was performed using rat kidney homogenates and fluorescent-based peptide substrate specific to β5i subunit. Western blotting and quantitative RT-PCR were used to assess the subunit expression/level of the iproteasome (β5i) subunit.

RESULTS

We demonstrated a decrease in the abundance of the β5i subunit of the iproteasome in kidneys during CS, but β5i levels increased in kidneys after CS and transplant. Despite the increase in β5i levels and its peptidase activity within kidneys, inhibiting β5i during CS did not improve graft function after transplantation.

SUMMARY

These results suggest that the pharmacological inhibition of immunoproteasome function during CS does not improve graft function or outcome. In light of these findings, future studies targeting immunoproteasomes during both CS and transplantation may define the role of immunoproteasomes on short- and long-term kidney transplant outcomes.

Stem Cell Theory of Cancer: Clinical Implications for Cellular Metabolism and Anti-Cancer Metabolomics

Although Otto Warburg may be right about the role of glycolysis versus OXPHOS in cancer metabolism, it remains unclear whether an altered metabolism is causative or correlative and is the main driver or a mere passenger in the pathogenesis of cancer. Currently, most of our successful treatments are designed to eliminate non-cancer stem cells (non-CSCs) such as differentiated cancer cells. When the treatments also happen to control CSCs or the stem-ness niche, it is often unintended, unexpected, or undetected for lack of a pertinent theory about the origin of cancer that clarifies whether cancer is a metabolic, genetic, or stem cell disease. Perhaps cellular context matters. After all, metabolic activity may be different in different cell types and their respective microenvironments-whether it is in a normal progenitor stem cell vs. progeny differentiated cell and whether it is in a malignant CSC vs. non-CSC. In this perspective, we re-examine different types of cellular metabolism, e.g., glycolytic vs. mitochondrial, of glucose, glutamine, arginine, and fatty acids in CSCs and non-CSCs. We revisit the Warburg effect, an obesity epidemic, the aspartame story, and a ketogenic diet. We propose that a pertinent scientific theory about the origin of cancer and of cancer metabolism influences the direction of cancer research as well as the design of drug versus therapy development in cancer care.

Giant left pheochromocytoma with vascular anomalies and pelvic horseshoe kidney: a case report

BACKGROUND

Pheochromocytoma is a neuroendocrine tumor, and its treatment is dependent on surgical resection. Due to the wide availability of cross-sectional imaging, pheochromocytomas are commonly seen as small tumors less than 10 cm in size and are mostly treated with minimally invasive surgery. Their concomitant presence with horseshoe kidney or other anatomical and vascular anomalies is rare. Herein, we present a surgically complex giant pheochromocytoma case who underwent an open left radical adrenalectomy.

CASE PRESENTATION

A 41-year-old Hispanic female presented with a 12 × 8 cm left hypervascular adrenal mass, pelvic horseshoe kidney, and severely dilated large left retro-aortic renal vein which branched into a left adrenal vein, congested left ovarian vein, and left uterine plexus. She was managed with insulin and metformin for uncontrolled diabetes with an A1c level of 9% and doxazosin for persistent hypertension. Clinical diagnosis of pheochromocytoma was confirmed with elevated urine and serum metanephrine and normetanephrine. The pre-operative ACTH was within normal range with a normal dexamethasone suppression test and 24-hour urine free cortisol. The adrenalectomy of the highly aggressive adrenal mass was performed via open approach to obtain adequate surgical exposure. Due to the large size of the tumor and its significant involvement with multiple adjacent structures, coordination with multiple surgical teams and close hemodynamic monitoring by anesthesiology was required for successful patient outcomes including preservation of blood supply to the pelvic horseshoe kidney. The histopathological diagnosis was pheochromocytoma with negative surgical margins. The patient was followed at 1, 4, 12, and 24 weeks postoperatively. She had a normal postoperative eGFR and was able to discontinue antihypertensive and antidiabetic medications at four weeks. She had transient adrenal insufficiency, which resolved at five months. The horseshoe kidney was intact except for a minimal area of hypo-enhancement in the left superior renal moiety due to infarction, which was significantly improved at six months.

CONCLUSION

Our patient had a giant pheochromocytoma with anatomical variations complicating an already surgically challenging procedure. Nonetheless, with multiple provider collaboration, detailed pre-operative surgical planning, and meticulous perioperative monitoring, radical resection of the giant pheochromocytoma was safe and feasible with successful postoperative outcomes.

Stem Cell Origin of Cancer: Clinical Implications for Cancer Immunity and Immunotherapy

A simple way to understand the immune system is to separate the self from non-self. If it is self, the immune system tolerates and spares. If it is non-self, the immune system attacks and destroys. Consequently, if cancer has a stem cell origin and is a stem cell disease, we have a serious problem and a major dilemma with immunotherapy. Because many refractory cancers are more self than non-self, immunotherapy may become an uphill battle and pyrrhic victory in cancer care. In this article, we elucidate cancer immunity. We demonstrate for whom, with what, as well as when and how to apply immunotherapy in cancer care. We illustrate that a stem cell theory of cancer affects our perspectives and narratives of cancer. Without a pertinent theory about cancer's origin and nature, we may unwittingly perform misdirected cancer research and prescribe misguided cancer treatments. In the ongoing saga of immunotherapy, we are at a critical juncture. Because of the allure and promises of immunotherapy, we will be treating more patients not immediately threatened by their cancer. They may have more to lose than to gain, if we have a misconception and if we are on a wrong mission with immunotherapy. According to the stem cell theory of cancer, we should be careful with immunotherapy. When we do not know or realize that cancer originates from a stem cell and has stem-ness capabilities, we may cause more harm than good in some patients and fail to separate the truth from the myth about immunotherapy in cancer care.

Stem Cell Origin of Cancer: Implications of Oncogenesis Recapitulating Embryogenesis in Cancer Care

From this perspective, we wonder about the clinical implications of oncology recapturing ontogeny in the contexts of neoantigens, tumor biomarkers, and cancer targets. We ponder about the biological ramifications of finding remnants of mini-organs and residuals of tiny embryos in some tumors. We reminisce about classical experiments showing that the embryonic microenvironment possesses antitumorigenic properties. Ironically, a stem-ness niche-in the wrong place at the wrong time-is also an onco-niche. We marvel at the paradox of TGF-beta both as a tumor suppressor and a tumor promoter. We query about the dualism of EMT as a stem-ness trait engaged in both normal development and abnormal disease states, including various cancers. It is uncanny that during fetal development, proto-oncogenes wax, while tumor-suppressor genes wane. Similarly, during cancer development, proto-oncogenes awaken, while tumor-suppressor genes slumber. Importantly, targeting stem-like pathways has therapeutic implications because stem-ness may be the true driver, if not engine, of the malignant process. Furthermore, anti-stem-like activity elicits anti-cancer effects for a variety of cancers because stem-ness features may be a universal property of cancer. When a fetus survives and thrives despite immune surveillance and all the restraints of nature and the constraints of its niche, it is a perfect baby. Similarly, when a neoplasm survives and thrives in an otherwise healthy and immune-competent host, is it a perfect tumor? Therefore, a pertinent narrative of cancer depends on a proper perspective of cancer. If malignant cells are derived from stem cells, and both cells are intrinsically RB1 negative and TP53 null, do the absence of RB1 and loss of TP53 really matter in this whole narrative and an entirely different perspective of cancer?

Incidental, Solitary, and Unilateral Adrenal Metastasis as the Initial Manifestation of Lung Adenocarcinoma

An adrenal incidentaloma is an adrenal mass ≥ 1 cm in size discovered on imaging performed for indications other than suspected adrenal disease. It has variable etiologies, which can be benign or malignant, including primary or metastatic disease. We present a rare case of metastatic lung adenocarcinoma with isolated unilateral adrenal metastases, presenting as an adrenal incidentaloma in an asymptomatic patient with no known history of malignancy. A 76-year-old man with a past medical history of chronic obstructive pulmonary disease (COPD) and heavy tobacco use was admitted for the evaluation and treatment of pneumonia. He was found to have an incidental 4.6 cm unilateral adrenal mass on his CT chest. He underwent a workup for the mass, including further imaging studies that were indeterminate and a hormonal workup that concluded that the mass was nonfunctional. Due to the patient's comorbidities, it was determined that he was not a surgical candidate. A multidisciplinary team recommended a biopsy, which revealed metastatic lung adenocarcinoma. The primary lung cancer was located using positron emission tomography with 2-deoxy-2-(fluorine-18) fluoro-D-glucose combined with computed tomography (F-FDG-PET/CT). The patient was evaluated by an oncology service and started on chemotherapy. In this case report, we discuss the approach for evaluating adrenal incidentalomas as well as the role the biopsy has in this process based on a literature review. In addition, we draw a comparison between our case and similar cases in the literature while highlighting the differences that make this case unique.

Malignant rhabdoid tumor arising in a mixed epithelial, stromal tumor of kidney: report of a male case, review of the literature

Mixed epithelial and stromal tumor (MEST) of the kidney is a rare biphasic tumor composed of both stromal and epithelial components, the latter showing a variable proportion of solid to cystic areas. These tumors show a marked female predominance, commonly occur in perimenopausal age groups, and often have an ovarian-type stroma with ER and PR positivity, suggesting steroids may play a role in pathogenesis. Although typically benign, rare cases showing malignant transformation have been reported. We present a case of a 42-year-old man with a 10 cm right kidney mass located in the renal pelvis. Histologically, the majority of the tumor was composed of a diffuse, sheet-like growth of malignant cells demonstrating a rhabdoid morphology with large nuclei, prominent nucleoli, and eosinophilic eccentric cytoplasm. Brisk mitotic activity and coagulative type necrosis was also noted. Intimately associated with this malignant rhabdoid component was a much smaller portion of tumor featuring variably sized bland epithelial tubules embedded within a stroma composed of bland spindle cells and areas of hyalinization, diagnostic of MEST. By immunohistochemistry, the malignant rhabdoid tumor portion of the neoplasm showed complete loss of nuclear INI-1, while the MEST component retained nuclear expression of this antigen. With these features taken together, our case represents a malignant rhabdoid tumor arising in a background of MEST. To our knowledge, this case represents the first case of a MEST showing malignant transformation in the form of malignant rhabdoid tumor in a male patient in the English language literature.

Reduction in SNAP-23 Alters Microfilament Organization in Myofibrobastic Hepatic Stellate Cells

Hepatic stellate cells (HSC) are critical effector cells of liver fibrosis. In the injured liver, HSC differentiate into a myofibrobastic phenotype. A critical feature distinguishing myofibroblastic from quiescent HSC is cytoskeletal reorganization. Soluble NSF attachment receptor (SNARE) proteins are important in trafficking of newly synthesized proteins to the plasma membrane for release into the extracellular environment. The goals of this project were to determine the expression of specific SNARE proteins in myofibroblastic HSC and to test whether their alteration changed the HSC phenotype in vitro and progression of liver fibrosis in vivo. We found that HSC lack the t-SNARE protein, SNAP-25, but express a homologous protein, SNAP-23. Downregulation of SNAP-23 in HSC induced reduction in polymerization and disorganization of the actin cytoskeleton associated with loss of cell movement. In contrast, reduction in SNAP-23 in mice by monogenic deletion delayed but did not prevent progression of liver fibrosis to cirrhosis. Taken together, these findings suggest that SNAP-23 is an important regular of actin dynamics in myofibroblastic HSC, but that the role of SNAP-23 in the progression of liver fibrosis in vivo is unclear.

Metastatic melanoma with dedifferentiation and extensive rhabdomyosarcomatous heterologous component

Melanoma may undergo dedifferentiation and sarcomatous transformation with loss of melanocytic markers. Dedifferentiated melanoma rarely forms true rhabdomyoblasts with skeletal muscle immunophenotype (rhabdomyosarcomatous heterologous component). A 52-year-old woman was diagnosed with invasive melanoma (Breslow thickness 0.83 mm) of the upper back in 2012, treated by wide local excision only. In 2013, an axillary mass was excised to show metastatic melanoma with 2 morphologies: an epithelioid morphology expressing S100 and MART-1 and a spindled morphology with loss of melanocytic markers but strong expression of desmin. This metastasis was found to have BRAF V600E mutation. In 2015, a thoracic epidural mass biopsy showed atypical spindle cells with focal HMB-45 but essentially no S100 expression. Numerous rhabdomyoblasts, some with striations that were strongly positive for desmin and myogenin, were present. In 2016, a right nephrectomy was performed for metastasis to the kidney, and showed sheets of spindle cells and rhabdomyoblasts expressing desmin and myogenin but not S100. Only focal areas demonstrated expression of HMB-45 and SOX-10, supporting the melanocytic origin of the tumor. The numerous rhabdomyoblasts and the loss of S100 expression in the metastatic lesions in this case could have easily led to misdiagnosis if the clinical history was not known.

Clinical characteristics and prognostic factors in multiple myeloma patients with light chain deposition disease

Light chain deposition disease (LCDD) is characterized by monotypic immunoglobulin depositions which will eventually lead to loss of organ function if left untreated. While the kidney is almost always affected, the presence and degree of LCDD in other organs vary. Ten to thirty percent of LCDD patients have underlying Multiple Myeloma (MM), yet outcome and prognostic markers in this particular patient group are still lacking. Here, we analyzed 69 patients with MM and biopsy proven LCDD and report on renal and extra-renal involvement and its impact on prognosis as well as renal response depending on hematologic response. Coexisting light chain diseases such as AL amyloid and cast nephropathy were found in 30% of patients; those with LCDD and concurrent amyloid tended to have shorter survival. Cardiac involvement by LCDD was seen in one-third of our patients and was associated with shorter overall survival; such patients also had a significantly higher risk of treatment-related mortality (TRM) after stem cell transplant (SCT) compared to LCDD patients without cardiac involvement. This study highlights that MM patients with LCDD present with different clinical features compared to previously reported LCDD cohorts. Rapid initiation of treatment is necessary to prevent progressive renal disease and worse outcome. Coexisting light chain diseases and cardiac involvement are more common than previously reported and confer worse clinical outcome, emphasizing the need for careful patient careful patient evaluation and treatment selection.

Rolipram Improves Outcome in a Rat Model of Infant Sepsis-Induced Cardiorenal Syndrome

While the mortality rate associated with sepsis in children has fallen over the years, it still remains unacceptably high. The development of both acute cardiac dysfunction and acute kidney injury during severe sepsis is categorized as type 5 cardiorenal syndrome (CRS) and is poorly understood in infants. To address this lack of understanding and the need for an appropriate animal model in which to conduct relevant preclinical studies, we developed a model of infant sepsis-induced CRS in rat pups then evaluated the therapeutic potential of the phosphodiesterase (PDE) 4 inhibitor, rolipram. Rat pups at 17-18-days old were subjected to cecal ligation and puncture (CLP) to induce fecal polymicrobial sepsis. Uptake of Evans Blue dye was used to assess renal microvascular leakage. Intravital videomicroscopy was used to assess renal microvascular perfusion and oxidant generation. Glomerular filtration rate (GFR) was used to assess renal function. Left ventricular (LV) catheterization and echocardiography were used to assess cardiac function. Impairment of both cardiac and renal function developed rapidly following CLP, indicating type 5 CRS. Most notable were the rapid decline in LV diastolic function, the decline in cardiac output, renal microvascular failure, and the decline in GFR. A dose-response study with rolipram determined 0.1 mg/kg, ip as the lowest most efficacious dose to protect the renal microcirculation. Rolipram was then evaluated using a clinically relevant delayed dosing paradigm (a single dose at 6 h post-CLP). With delayed dosing, rolipram restored the renal microcirculation and reduced microvascular leakage but did not reduce oxidant generation in the kidney nor restore GFR. In contrast, delayed dosing with rolipram restored cardiac function. Rolipram also improved 4-days survival. In summary, CLP in the rat pup produces a clinically relevant pediatric model of sepsis-induced CRS. The PDE4 inhibitor rolipram was effective in improving renal microvascular function and cardiac function, which improved mortality. These findings suggest that rolipram should be evaluated further as adjunctive therapy for the septic infant with CRS.

Could knee inflammatory synovitis be induced by pembrolizumab?

Pembrolizumab, a selective anti-PD-1 humanized monoclonal antibody, reactivates T cells to fight cancer. Immune-related adverse events such as autoimmune colitis, pneumonitis, hepatitis, nephritis, hypophysitis, and thyroiditis may occur during, or weeks to months after therapy. Pemprolizumab-induced synovitis is rarely reported. With the wide use of immunotherapy to treat cancers, physicians need to be aware of this rare immune-related adverse event and provide immediate treatment to avoid permanent joint damage.

Tuberous sclerosis complex: Hamartin and tuberin expression in renal cysts and its discordant expression in renal neoplasms

Tuberous sclerosis complex (TSC) results from mutation of TSC1 or TSC2 that encode for hamartin and tuberin. It affects the kidneys often in advance of extra-renal stigmata. We studied 14 TSC cases, and 4 possible TSC cases with multiple angiomyolipomas (AMLs) for hamartin and tuberin protein expression to determine if the staining profile could predict mutation status or likelihood of TSC with renal-limited disease. The 18 cases included 15 nephrectomies and 1 section of 6 TSC-associated renal cell carcinomas (RCC). Controls included the non-neoplastic kidney in 5 tumor nephrectomies, 4 sporadic cases of AML and 6 clear cell RCCs. In the 14 TSC cases, 9 had AMLs, 9 had RCCs, 5 had polycystic kidney disease and 8 had eosinophilic cysts (EC) lined by large eosinophilic cells. The controls and study cases showed luminal staining of proximal tubules (PT) and peripheral membrane staining in distal tubules/collecting ducts for hamartin and cytoplasmic staining for tuberin. Eosinophilic cysts had a luminal PT-like stain with hamartin and a cytoplasmic reaction for tuberin. Hamartin stained myoid cells in all AMLs. Tuberin was negative in all but 1AML, an epithelioid AML. All but 1 RCC were positive for tuberin; 13 RCCs (7 TSC/6 non-TSC) were negative for hamartin and 4 showed a weak reaction. We conclude that the ECs of TSC are proximal tubule-derived. The hamartin and tuberin staining profiles of AMLs and most RCCs are reciprocal precluding prediction of the mutation in TSC, and fail to predict if a patient with multifocal AML has TSC.

A Case of Cardiac Light Chain Deposition Disease in a Patient with Solitary Plasmacytoma

Patient: Male, 31

Final Diagnosis: Light chain depsotion disease

Symptoms: —

Medication: —

Clinical Procedure: None

Specialty: Hematology

Peritoneal seeding following incomplete resection of mixed epithelial stromal tumor of the kidney: First case report

Mixed epithelial stromal tumor (MEST) is rare and typically benign renal cystic neoplasm that cannot be clinically distinguished from cystic renal cell carcinoma. Its mainstay course of diagnosis and treatment remains surgical excision. Recurrence and malignant transformation is rare but has previously been described. To our best knowledge, we present the first case of peritoneal seeding resulting in a paracolonic MEST following incomplete resection in a patient with benign MEST. This signifies a new pathological behavior for MEST, predominantly, a benign kidney tumor. In addition, documentation with more cases of MEST is needed to further understand its pathogenesis, clinical behavior, malignant potential, and optimal management.

Pharmacologic targeting of sphingosine-1-phosphate receptor 1 improves the renal microcirculation during sepsis in the mouse

Microvascular failure is hallmark of sepsis in humans and is recognized as a strong predictor of mortality. In the mouse subjected to cecal ligation and puncture (CLP) to induce a clinically relevant sepsis, renal microvascular permeability increases and peritubular capillary perfusion declines rapidly in the kidney leading to acute kidney injury (AKI). Sphingosine-1-phosphate (S1P) is a key regulator of microvascular endothelial function. To investigate the role of S1P in the development of microvascular permeability and peritubular capillary hypoperfusion in the kidney during CLP-induced AKI, we used a pharmacologic approach and a clinically relevant delayed dosing paradigm. Evans blue dye was used to measure renal microvascular permeability and intravital video microscopy was used to quantitate renal cortical capillary perfusion. The S1P receptor 1 (S1P1) agonist SEW2871 [5-[4-phenyl-5-(trifluoromethyl)-2-thienyl]-3-[3-(trifluoromethyl)phenyl]-1,2,4-oxadiazole] and S1P2 antagonist JTE-013 [N-(2,6-dichloro-4-pyridinyl)-2-[1,3-dimethyl-4-(1-methylethyl)-1H-pyrazolo[3,4-b]pyridin-6-yl]-hydrazinecarboxamide] were administered at the time of CLP and produced a dose-dependent but partial reduction in renal microvascular permeability at 6 hours after CLP. However, neither agent improved capillary perfusion at 6 hours. With delayed administration at 6 hours after CLP, only SEW2871 reversed microvascular permeability when measured at 18 hours. Importantly, SEW2871 also restored capillary perfusion and improved renal function. These data suggest that S1P1 and S1P2 do not regulate the early decline in renal capillary perfusion. However, later in the course of sepsis, pharmacologic stimulation of S1P1, even when delaying therapy until after injury has occurred, improves capillary and renal function, suggesting this approach should be evaluated as an adjunct therapy during sepsis.

Rolipram improves renal perfusion and function during sepsis in the mouse

Microcirculatory dysfunction is correlated with increased mortality among septic patients and is believed to be a major contributor to the development of acute kidney injury (AKI). Rolipram, a selective phosphodiesterase 4 (PDE4) inhibitor, has been shown to reduce microvascular permeability and in the kidney, increase renal blood flow (RBF). This led us to investigate its potential to improve the renal microcirculation and preserve renal function during sepsis using a murine cecal ligation and puncture (CLP) model to induce sepsis. Rolipram, tested at doses of 0.3-10 mg/kg i.p., acutely restored capillary perfusion in a bell-shaped dose-response effect with 1 mg/kg being the lowest most efficacious dose. This dose also acutely increased RBF despite transiently decreasing mean arterial pressure. Rolipram also reduced renal microvascular permeability. It is noteworthy that delayed treatment with rolipram at 6 hours after CLP restored the renal microcirculation, reduced blood urea nitrogen and serum creatinine, and increased glomerular filtration rate at 18 hours. However, delayed treatment with rolipram did not reduce serum nitrate/nitrite levels, a marker of nitric oxide production, nor reactive nitrogen species generation in renal tubules. These data show that restoring the microcirculation with rolipram, even with delayed treatment, is enough to improve renal function during sepsis despite the generation of oxidants and suggest that PDE4 inhibitors should be evaluated further for their ability to treat septic-induced AKI.

Progressive kidney failure as the sole manifestation of extrapulmonary sarcoidosis

Sarcoidosis is a chronic multisystem disorder characterized by an accumulation of T lymphocytes and mononuclear phagocytes, non-caseating epitheliod granulomas and derangement of normal tissue architecture in affected organs. Sarcoidosis can affect any organ system, however approximately 90% of patients with sarcoidosis have pulmonary, lymph node, cutaneous or ocular manifestations. Renal involvement in sarcoidosis is rare and clinically significant renal dysfunction even less common. We present a case of isolated renal sarcoidosis which manifested with progressively worsening renal function and hypercalcemia. A systematic diagnostic approach with pertinent laboratory studies, imaging and renal biopsy elucidated the diagnosis of renal sarcoidosis without any evidence of systemic involvement.

Light Chain Proximal Tubulopathy: Expanding the Pathologic Spectrum with and without Deposition of Crystalline Inclusions

Light chain proximal tubulopathy (LCPT) is an uncommon form of renal disease associated with dysproteinemias. It is characterized by intracytoplasmic deposition of crystallized mostly kappa monoclonal light chains in proximal tubules (PTs). Crystals are located within lysosomes by electron microscopy (EM). Rare lambda LCPT cases without crystals by EM were described. Retrospectively, we reviewed clinical, light microscopic (LM), immunofluorescence (IF), and EM findings in 9 cases) (8 males, 1 female; mean age 57 years (38–81)) with multiple myeloma. LM showed abundant cytoplasmic droplets in PT cells in all cases. Droplets were also present in the podocytes, endothelial and parietal cells in one case. IF revealed staining of crystals with kappa in 3 and lambda in 6. EM showed electron dense rectangular, rhomboid, or needle shaped crystals in PT cells in 3 cases (33%), one of which had crystals in podocytes and interstitial cells. Six lambda LCPT cases showed no crystals by EM (67%). This may reflect differences in the physicochemical properties of light chains. The mechanisms of crystal accumulation in these cells and the significance of this finding are unknown.

Reduced kidney lipoprotein lipase and renal tubule triglyceride accumulation in cisplatin-mediated acute kidney injury

Peroxisome proliferator-activated receptor-α (PPARα) activation attenuates cisplatin (CP)-mediated acute kidney injury by increasing fatty acid oxidation, but mechanisms leading to reduced renal triglyceride (TG) accumulation could also contribute. Here, we investigated the effects of PPARα and CP on expression and enzyme activity of kidney lipoprotein lipase (LPL) as well as on expression of angiopoietin protein-like 4 (Angptl4), glycosylphosphatidylinositol-anchored-HDL-binding protein (GPIHBP1), and lipase maturation factor 1 (Lmf1), which are recognized as important proteins that modulate LPL activity. CP caused a 40% reduction in epididymal white adipose tissue (WAT) mass, with a reduction of LPL expression and activity. CP also reduced kidney LPL expression and activity. Angptl4 mRNA levels were increased by ninefold in liver and kidney tissue and by twofold in adipose tissue of CP-treated mice. Western blots of two-dimensional gel electrophoresis identified increased expression of a neutral pI Angptl4 protein in kidney tissue of CP-treated mice. Immunolocalization studies showed reduced staining of LPL and increased staining of Angptl4 primarily in proximal tubules of CP-treated mice. CP also increased TG accumulation in kidney tissue, which was ameliorated by PPARα ligand. In summary, a PPARα ligand ameliorates CP-mediated nephrotoxicity by increasing LPL activity via increased expression of GPHBP1 and Lmf1 and by reducing expression of Angptl4 protein in the proximal tubule.

Hemodynamic changes in the kidney in a pediatric rat model of sepsis-induced acute kidney injury

Sepsis is a leading cause of acute kidney injury (AKI) and mortality in children. Understanding the development of pediatric sepsis and its effects on the kidney are critical in uncovering new therapies. The goal of this study was to characterize the development of sepsis-induced AKI in the clinically relevant cecal ligation and puncture (CLP) model of peritonitis in rat pups 17-18 days old. CLP produced severe sepsis demonstrated by time-dependent increase in serum cytokines, NO, markers of multiorgan injury, and renal microcirculatory hypoperfusion. Although blood pressure and heart rate remained unchanged after CLP, renal blood flow (RBF) was decreased 61% by 6 h. Renal microcirculatory analysis showed the number of continuously flowing cortical capillaries decreased significantly from 69 to 48% by 6 h with a 66% decrease in red blood cell velocity and a 57% decline in volumetric flow. The progression of renal microcirculatory hypoperfusion was associated with peritubular capillary leakage and reactive nitrogen species generation. Sham adults had higher mean arterial pressure (118 vs. 69 mmHg), RBF (4.2 vs. 1.1 ml·min(-1)·g(-1)), and peritubular capillary velocity (78% continuous flowing capillaries vs. 69%) compared with pups. CLP produced a greater decrease in renal microcirculation in pups, supporting the notion that adult models may not be the most appropriate for studying pediatric sepsis-induced AKI. Lower RBF and reduced peritubular capillary perfusion in the pup suggest the pediatric kidney may be more susceptible to AKI than would be predicted using adults models.

Renal oncocytoma revisited: a clinicopathological study of 109 cases with emphasis on problematic diagnostic features

AIM

To evaluate problematic diagnostic features in renal oncocytoma.

METHODS AND RESULTS

One hundred and nine cases of oncocytoma were reviewed and the problematic gross and microscopic features recorded. Multifocal and bilateral neoplasms were found in 12 (11%) and five (4.6%) cases, respectively. Haemorrhage was seen grossly in 30 (27.5%) neoplasms and a central scar was identified in 35 (32.1%). On microscopy, perinephric fat extension was present in 17 (15.6%) neoplasms and vascular extension was identified in four (3.7%) oncocytomas. Rare mitoses and focal coagulative necrosis were identified in two (1.8%) cases each. Focal clear cell changes were found in 16 (14.7%) oncocytomas, typically within hyalinized areas. Limited foci with chromophobe-like histology (not exceeding 5% of the neoplasm) were found in 13 (11.9%) oncocytomas. In 12 (11%) oncocytomas, rare papillary formations were noted in the lumina of microcysts. Significant nuclear atypia, oncoblasts and entrapped tubules were identified in 27 (24.8%), 41 (37.6%) and 40 (36.7%) neoplasms, respectively. After a median follow-up of 52 months (range 1-113 months), there was no disease recurrence, progression or death attributed to oncocytoma.

CONCLUSIONS

The recognition of the spectrum of morphological changes observed in renal oncocytoma should help pathologists establish a diagnosis of oncocytoma in problematic cases.

The significance of foot process effacement in immunoglobulin a nephropathy: clinicopathologic study of 161 cases with light, immunofluorescence and electron microscopic studies

IGA nephropathy (IGAN) is the most common glomerular disease worldwide. Patients may present with hematuria and non-nephrotic (NNRP) or uncommonly nephrotic range proteinuria (NRP). To the authors' knowledge, correlation of podocyte foot process effacement (FPE) with subclasses of IGAN and proteinuria (PT) has not been studied. Retrospectively, 161 cases of IGAN with light, immunofluorescence, and electron microscopy (EM) were reviewed and classified according to Haas classification. EM was available in 110 out of 161 (67%) cases. FPE was evaluated as mild, <30%; moderate, 30–70%; and severe, >70% and was correlated with class and the level of PT. Out of 161 cases, 101 were males and 60 were females with M:F ratio of 1.71:1. In 72 cases, race was known as follows: white, 63 (88%); black, 6 (8%); Hispanic, 2 (3%); Asian, 1 (1%). Clinical history was available in 94 cases: PT 39 cases (42%), PT+hematuria 33 cases (35%), hematuria 15 cases (16%), and renal failure in 7 cases (7%). In 88 cases with FPE, PT was nephrotic in 21 and non-nephrotic in 29 cases. FPE is common in IGAN. No correlation between FPE and IGAN subclass (p=.42) or proteinuria group and IGAN subclass (p=.10) is present. Whether FPE is simply a reflection of other pathologic mechanisms and its significance in the pathophysiology of IGAN requires further investigation.

Morphologic Manifestations of Combined Light-chain Deposition Disease and Light-chain Cast Nephropathy

There are few data on morphology of light-chain deposition disease (LCDD) of kidney with coexistent light-chain cast nephropathy (LCCN). Here, the authors report the morphology in 23 cases of LCDD and LCCN. They retrospectively evaluated 23 renal biopsies with light (LM), immunofluorescence (IF), and electron microscopy (EM). Twenty-one patients had myeloma, 1 had a monoclonal gammopathy, and in 1 no illness was found. Nodular glomerulosclerosis, the LM lesion suggestive of LCDD, was noted in only 3 of 23 cases. Glomeruli were unremarkable in 16 (69%) cases. The diagnostic casts of LCCN were seen in all biopsies. Linear light chain (LC) immunoreactivity was observed in 23 (100%) cases (18 kappa, 5 lambda); GBM + TBM in 13, TBM only in 7, GBM only in 1, TBM and interstitium in 1, GBM, TBM and mesangium in 1. Casts were positive with same LC in all cases (100%). Fifteen cases (65%) showed granular electron-dense deposits; GBM only in 5, TBM only in 5, GBM and TBM in 4, mesangium in 1. In 8 patients without EM deposits, the diagnosis of LCDD was rendered by IF. Fifteen (65%) had deposits detectable by IF and EM, 8 (37%) had deposits with IF only. LCCN dominated the LM findings in all patients. There were minimal or no glomerular changes by LM. This study shows the lack of characteristic LM findings of LCDD in combined cases of LCDD and LCCN and emphasizes the difficulty for-definitive diagnosis-without IF and EM.

Granular cell tumour of the ureter: first case reported

A 33-year-old woman presented with nonspecific, colicky pain of the left lower abdomen. Computed tomography (CT) revealed a 2-cm mass engulfing the mid-left ureter. Ureteroscopy and biopsy revealed normal mucosa, and CT-guided biopsy of the mass was nondiagnostic. The patient underwent laparoscopic exploration. A frozen section taken from the mass revealed a granular cell tumour. We excised the whole involved portion of the ureter and performed end-to-end ureteroureteral anastamosis. The postoperative course was uneventful. Examination of a segment of resected ureter revealed a granular cell tumour diffusely infiltrating the wall of the ureter. There were no features suggesting a malignant phenotype. On follow-up, the patient was found to have developed a stricture at the anastomotic area, which was successfully treated with balloon dilatation. To our knowledge, this is the first reported case of a granular cell tumour involving the ureter.

The utility of Pax-2 as an immunohistochemical marker for renal cell carcinoma in cytopathology

Pax-2 is a homeogene expressed during kidney development. Its expression in renal cell carcinoma (RCC) has been previously evaluated in histologic samples with a high sensitivity and specificity. Here, we investigated the utility of Pax-2 immunohistochemistry (IHC) for RCC in cytologic material, in comparison with a variety of other neoplasms. Pax-2 IHC was performed on cell block sections of 33 RCCs (14 primary, 19 metastatic) and 35 non-RCC malignancies, including 26 carcinomas, five mesenchymal tumors, one neuroblastoma, two melanomas, and one lymphoma, from fine-needle aspirations and body fluids. The presence or absence of nuclear staining and its intensity and distribution in positive cases were evaluated. Of 33 RCCs, Pax-2 was positive in 20 (61%) and negative in 13 (39%). All staining was nuclear, with an admixture of weakly or strongly staining nuclei. Only an endometrial adenocarcinoma was positive in the non-RCC group. The sensitivity and specificity of Pax-2 IHC for RCC were 61 and 97%, respectively. Pax-2 is a moderately sensitive and highly specific marker for RCC in cytologic material, with a lower sensitivity compared with tissue sections, likely due to a patchy expression pattern, and should be included in the immunohistochemical work-up of malignancies.

Evidence for the role of reactive nitrogen species in polymicrobial sepsis-induced renal peritubular capillary dysfunction and tubular injury

Acute kidney injury (AKI) remains a frequent and serious complication of human sepsis that contributes significantly to mortality. For better understanding of the development of AKI during sepsis, the cecal ligation and puncture (CLP) murine model of sepsis was studied using intravital video microscopy (IVVM) of the kidney. IVVM with FITC-dextran was used to determine the percentage of capillaries with continuous, intermittent or no flow at 0 (sham), 10, 16, and 22 h after CLP. There was a dramatic fall in capillary perfusion as early as 10 h after CLP that persisted through 22 h. The percentage of vessels with continuous flow at 16 h decreased from 73 +/- 2% in shams to 16 +/- 2% (P < 0.05), whereas the percentage of vessels with no flow increased from 4 +/- 1% in shams to 42 +/- 2% (P < 0.05). The capillary perfusion defect preceded the rise in serum creatinine. IVVM with dihydrorhodamine-123 was used to quantify in real time reactive nitrogen species (RNS) generation by renal tubules, and the inducible nitric oxide synthase inhibitor L-iminoethyl-lysine (mg/kg) was used to examine the role of inducible nitric oxide synthase inhibitor on capillary dysfunction and RNS generation. Tubular generation of RNS was significantly elevated at 10 h after CLP and was associated with tubules that were bordered by capillaries with reduced perfusion. L-iminoethyl-lysine significantly reversed the capillary perfusion defect, blocked RNS generation, and reduced AKI. These data show that capillary dysfunction and RNS generation contribute to tubular injury and suggest that RNS should be considered a potential therapeutic target in the treatment of sepsis-induced AKI.

Human Papillomavirus DNA and P16INK4A are not detected in renal tumors with immunohistochemistry and signal-amplified in situ hybridization in paraffin-embedded tissue

The association between human papillomavirus (HPV) infection and carcinogenesis has long been established in literature, with the strongest evidence for its role in cervical carcinoma. The role of HPV in urological tumors has been investigated and sporadic reports have linked HPV infection to bladder, prostate, renal, penile, and testicular cancer. Although less rigorously studied, there are a few conflicting results about the role of HPV in the development of malignant renal tumors. Moreover, no data are available for association of HPV DNA and expression of P16 in benign renal tumors. Formalin-fixed, paraffin-embedded tissues from 62 renal tumors (40 clear cell, 9 papillary, and 3 chromophobe renal cell carcinomas, 1 collecting duct carcinoma, 2 urothelial carcinoma of renal pelvis and 7 oncocytomas) were immunostained with low-risk and high-risk HPV DNA (6, 11, 16, 18, 31, 33, 42, 51, 52, 56, 58). Tissue microarray sections of 62 tumors were stained with P16 by immunohistochemistry. Signal amplified colorimetric in situ hybridization was performed on microarray sections using biotinylated probes for HPV subtypes 6, 11, 16, 18. A nuclear dot-like signal was considered positive for low-risk and high-risk HPV by immunohistochemistry and in situ hybridization and nuclear or cytoplasmic staining is considered positive for P16. No staining for HPV DNA and P16 was found in any type of renal tumors. Our results support that HPV does not seem to play a role in the development of benign and malignant renal tumors.

Peritubular capillary dysfunction and renal tubular epithelial cell stress following lipopolysaccharide administration in mice

The mortality rate for septic patients with acute renal failure is extremely high. Since sepsis is often caused by lipopolysaccharide (LPS), a model of LPS challenge was used to study the development of kidney injury. Intravital video microscopy was utilized to investigate renal peritubular capillary blood flow in anesthetized male C57BL/6 mice at 0, 2, 6, 10, 18, 24, 36, and 48 h after LPS administration (10 mg/kg ip). As early as 2 h, capillary perfusion was dramatically compromised. Vessels with continuous flow were decreased from 89 +/- 4% in saline controls to 57 +/- 5% in LPS-treated mice (P < 0.01), and vessels with intermittent flow were increased from 6 +/- 2% to 31 +/- 5% (P < 0.01). At 2 h, mRNA for intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 were elevated 50- and 27-fold, respectively, suggesting that vascular inflammation is an early event that may contribute to capillary dysfunction. By 10 h, vessels with no flow increased from 5 +/- 2% in saline controls to 19 +/- 3% in LPS-treated mice (P < 0.05). By 48 h, capillary function was returning toward control levels. The decline in functional capillaries preceded the development of renal failure and was paralleled by induction of inducible nitric oxide synthase in the kidney. Using NAD(P)H autofluorescence as an indicator of cellular redox stress, we found that tubular cell stress was highly correlated with the percentage of dysfunctional capillaries (r(2) = 0.8951, P < 0.0001). These data show that peritubular capillary dysfunction is an early event that contributes to tubular stress and renal injury.

High-grade prostatic intraepithelial neoplasia in needle biopsy as risk factor for detection of adenocarcinoma: current level of risk in screening population

OBJECTIVES

To assess the current incidence of prostate carcinoma detection in serial biopsies in a prostate-specific antigen-based screening population after a diagnosis of isolated high-grade prostatic intraepithelial neoplasia (HG-PIN) in needle biopsy tissue.

METHODS

We retrospectively identified 190 men with a diagnosis of isolated HG-PIN in needle biopsy tissue. Most men (86%) were diagnosed from 1996 to 2000. Logistic regression analysis was used to predict the presence of carcinoma in these 190 men and in a control group of 1677 men with only benign prostatic tissue in needle biopsy tissue.

RESULTS

The cumulative risk of detection of carcinoma on serial sextant follow-up biopsies was 30.5% for those with isolated HG-PIN compared with 26.2% for the control group (P = 0.2). Patient age (P = 0.03) and serum prostate-specific antigen level (P = 0.02) were significantly linked to the risk of cancer detection, but suspicious digital rectal examination findings (P = 0.1), the presence of HG-PIN (P = 0.2), and the histologic attributes of PIN were not (all with nonsignificant P values). HG-PIN found on the first repeat biopsy was associated with a 41% risk of subsequent detection of carcinoma compared with an 18% risk if benign prostatic tissue was found on the first repeat biopsy (P = 0.01).

CONCLUSIONS

The results of our study have shown that the current level of risk for the detection of prostate carcinoma in a screened population is 30.5% after a diagnosis of isolated HG-PIN in a needle biopsy. This risk level is lower than the previously reported risk of 33% to 50%. HG-PIN is a risk factor for carcinoma detection only when found on consecutive sextant biopsies. The data presented here should prompt reconsideration of repeat biopsy strategies for HG-PIN, and re-evaluation of the absolute necessity of repeat biopsy for all patients with HG-PIN.

Anti-inflammatory effect of fibrate protects from cisplatin-induced ARF

Recently, we demonstrated that peroxisome proliferator-activated receptor-α (PPARα) ligand ameliorates cisplatin-induced acute renal failure (ARF) by preventing inhibition of substrate oxidation, and also by preventing apoptosis and necrosis of the proximal tubule (Li S, Bhatt R, Megyesi J, Gokden N, Shah SV, and Portilla D. Am J Physiol Renal Physiol 287: F990–F998, 2004). In the following studies, we examined the protective effect of PPARα ligand on cisplatin-induced inflammatory responses during ARF. Mice subjected to a single intraperitoneal injection of cisplatin developed ARF at day 3. Cisplatin increased mRNA and protein expression of TNF-α, RANTES, and also upregulated endothelial adhesion molecules ICAM-1/VCAM-1 and chemokine receptors CCR1/CCR5. Cisplatin also led to neutrophil infiltration in the corticomedullary region. Pretreatment of wild-type mice with WY-14,643, a fibrate class of PPARα ligands, before cisplatin significantly suppressed cisplatin-induced upregulation of cytokine/chemokine expression, prevented neutrophil accumulation, and ameliorated renal dysfunction. In contrast, treatment with PPARα ligand before cisplatin did not prevent cytokine/chemokine production, neutrophil accumulation, and did not protect kidney function in PPARα null mice. In addition, we observed that cisplatin-induced NF-κB binding activity in nuclear extracts from wild-type mice was markedly reduced by treatment with PPARα ligand. These results demonstrate that PPARα exerts an anti-inflammatory effect in kidney tissue by a mechanism that includes inhibition of NF-κB DNA binding activity, and this effect results in inhibition of neutrophil infiltration, cytokine/chemokine release, and amelioration of cisplatin-induced ARF.

Metastatic renal cell carcinoma to prostate

Clinically apparent renal cell carcinoma that has metastasized to the prostate is a rare finding. When identified, it has been associated with widespread metastatic disease and short-term survival. We present a case of metachronous renal cell carcinoma found only in the prostate with the longest reported interval of 9 years between radical nephrectomy and clinically apparent disease.

A clonal reciprocal t(2;7)(p13;p13) in plantar fibromatosis

Cytogenetic reports of plantar fibromatosis are rare, and to our knowledge no clonal reciprocal translocations have been reported in these lesions. Reciprocal chromosome translocations have been identified in a number of solid tumors and in some cases have helped identify genes involved in their pathogenesis. We report a case of plantar fibromatosis with the novel finding of a t(2;7)(p13;p13) balanced reciprocal translocation as the sole cytogenetic abnormality.

A reciprocal t(4;9)(q31;p22) in a solitary neurofibroma

Cytogenetic reports of solitary neurofibromas are rare and, to our knowledge, no clonal reciprocal translocations have been reported in these tumors. Reciprocal chromosome translocations have been identified in a number of solid tumors and can have both diagnostic and prognostic significance. We report the first case of a solitary circumscribed neurofibroma with a (4;9)(q31;p22) balanced reciprocal translocation as the sole cytogenetic abnormality.

PPAR-alpha ligand ameliorates acute renal failure by reducing cisplatin-induced increased expression of renal endonuclease G

Cisplatin injury to the kidney is characterized, in part, by inhibition of substrate oxidation, inflammation, and tubular cell death in the form of apoptosis and necrosis. Recently, we demonstrated that cisplatin-induced inhibition of substrate oxidation can be reversed by the administration of peroxisome proliferator-activated receptor-alpha (PPAR-alpha) ligands, resulting in amelioration of renal function. We therefore hypothesize that by improving fatty acid oxidation in vivo might protect renal function by reducing both apoptosis and necrosis in cisplatin-treated mice. Mice subjected to a single intraperitoneal injection of cisplatin developed acute renal failure (ARF) at days 3 and 4. At day 4 after cisplatin injection mRNA, protein levels and enzyme activity of proapoptotic renal endonuclease G (Endo G) were increased compared with saline-treated mice. In situ hybridization and immunohistochemical studies localized the increased expression of Endo G mRNA to the cytosolic compartment and Endo G protein to the nuclear compartment of proximal tubules in cisplatin-treated mice. Pretreatment of PPAR-alpha wild-type mice with PPAR-alpha ligand WY-14643 reduced significantly cisplatin-induced increased protein expression and enzyme activity of Endo G and prevented the nuclear translocation of mitochondrial Endo G. Morphological examination of tubular injury in the PPAR-alpha wild-type mice that received PPAR-alpha ligand and cisplatin did show significant amelioration of acute tubular necrosis, as well as a significant reduction in the number of apoptotic cells in the proximal tubule when compared with the cisplatin-treated group. In contrast, in PPAR-alpha-null mice treated with the ligand and cisplatin, Endo G protein expression was not reduced and this was accompanied by lack of protection of kidney function. We conclude that PPAR-alpha ligand protects against cisplatin-induced renal injury via a PPAR-alpha-dependent mechanism by reducing the expression and enzyme activity of proximal tubule Endo G, which results in amelioration of both proximal tubule cell apoptosis and necrosis.

Simultaneous generation of multiple mitochondrial DNA mutations in human prostate tumors suggests mitochondrial hyper-mutagenesis

Multiple somatic mitochondrial DNA mutations are frequently reported in human tumors, but the process leading to homoplasmic transformation and accumulation of multiple mutations in the same tumor cell lineage remains a mystery. We address possible mechanisms responsible for the generation of multiple mitochondrial (mt)DNA mutations observed in a high frequency of prostate tumors using sensitive mutant-specific PCR coupled with laser capture microdissection. Analysis of prostate tumors with multiple mtDNA mutations in the control region indicates that the mutations are locally confined, that the multiple mutations exist on the same molecules and that more than one mtDNA mutant species co-exists in the same neoplastic lesion. These results suggest an unusually rapid process in mtDNA mutagenesis during tumor progression. On the basis of prostate tumor cell kinetics, we propose a unique process of mitochondrial hyper-mutagenesis, probably mediated by cellular oxidative stress, to account for a burst of multiple mtDNA mutations in human prostate tumors.

Diagnostic utility of renal cell carcinoma marker in cytopathology

Renal cell carcinoma (RCC) not uncommonly presents with metastases and causes diagnostic difficulty to the cytopathologist who is involved in the initial diagnostic workup of tumors with an unknown primary site. RCC marker (RCC Ma) recognizes a human proximal tubule antigen and was shown to have high specificity and relatively low sensitivity in preliminary studies on routinely processed tissue sections. We investigated the diagnostic usefulness of RCC Ma immunohistochemically in fine-needle aspiration (FNA) samples. A total of 34 FNA samples obtained from the following carcinomas were used: 7 RCCs, 5 metastatic RCCs, 4 hepatocellular carcinomas, 2 non-small cell carcinomas of the lung, 3 metastatic non-small cell carcinomas of the lung, 4 invasive ductal carcinomas of the breast, 2 pancreatic ductal adenocarcinomas, 4 metastatic transitional cell carcinomas of the urinary bladder, and 3 metastatic colon carcinomas. Routinely processed cell block sections of FNA specimens were stained with RCC Ma by using routine immunohistochemistry. Presence and distribution of staining were evaluated. Two of 7 (29%) primary and 2 of 5 (40%) metastatic RCCs showed immunoreactivity in less than 50% of carcinoma cells. Staining was focal, cytoplasmic, and granular. Scattered positive cells were present in two of the four hepatocellular carcinomas. All breast, lung, pancreas, colon, and transitional cell carcinomas were negative. RCC antibody has a low sensitivity (33%), most likely because of its focal staining pattern, and a high specificity (91%) in FNA specimens. Immunoreactivity in metastatic carcinoma of an unknown primary site, especially as part of a panel of antibodies, is useful in diagnostic cytopathology. RCC antibody has not been studied in hepatocellular carcinoma, and the significance of positivity observed in some of our cases is unclear.