Association between urinary biomarkers MMP-7/TIMP-2 and reduced renal function in children with ureteropelvic junction obstruction.

IMPORTANCE: Extracellular matrix proteins and enzymes involved in degradation have been found to be associated with tissue fibrosis and ureteropelvic junction obstruction (UPJO). In this study we developed a promising urinary biomarker model which can identify reduced renal function in UPJ obstruction patients. This can potentially serve as a non-invasive way to enhance surgical decision making for patients and urologists. OBJECTIVE: We sought to develop a predictive model to identify UPJO patients at risk for reduced renal function. DESIGN: Prospective cohort study. SETTING: Pre-operative urine samples were collected in a prospectively enrolled UPJO biomarker registry at our institution. Urinary MMP-2, MMP-7, TIMP-2, and NGAL were measured as well as clinical characteristics including hydronephrosis grade, differential renal function, t1/2, and UPJO etiology. PARTICIPANTS: Children who underwent pyeloplasty for UPJO. MAIN OUTCOME MEASUREMENT: Primary outcome was reduced renal function defined as MAG3 function <40%. Multivariable logistic regression was applied to identify the independent predictive biomarkers in the original Training cohort. Model validation and generalizability were evaluated in a new UPJO Testing cohort. RESULTS: We included 71 patients with UPJO in the original training cohort and 39 in the validation cohort. Median age was 3.3 years (70% male). By univariate analysis, reduced renal function was associated with higher MMP-2 (p = 0.064), MMP-7 (p = 0.047), NGAL (p = 0.001), and lower TIMP-2 (p = 0.033). Combining MMP-7 with TIMP-2, the multivariable logistic regression model predicted reduced renal function with good performance (AUC = 0.830; 95% CI: 0.722-0.938). The independent testing dataset validated the results with good predictive performance (AUC = 0.738). CONCLUSIONS AND RELEVANCE: Combination of urinary MMP-7 and TIMP-2 can identify reduced renal function in UPJO patients. With the high sensitivity cutoffs, patients can be categorized into high risk (aggressive management) versus lower risk (observation).

Clinical outcome of pediatric and young adult subclinical varicoceles: a single-institution experience.

Subclinical varicocele represents an abnormality of veins of the pampiniform plexus on scrotal ultrasound (US) without a clinically palpable varicocele. Its significance remains unclear. While guidelines do not recommend surgical intervention, clinical management is variable. As there is limited information on long-term outcome of subclinical varicoceles due to challenges in diagnosis and management, we performed a single-institution, retrospective review of patients from October 1999 to October 2014 with subclinical varicocele and with available US studies reviewed by a single radiologist. Subclinical varicocele was defined as dilation of the pampiniform venous plexus on US involving ≥2 vessels with diameter >2.5 mm, without clinical varicocele on physical examination or prior inguinal surgery. Thirty-six of 98 patients identified were confirmed as having a subclinical varicocele and analyzed. The mean age at initial visit was 15.5 years, with a mean follow-up of 26.5 months. The majority were right-sided (69.4%, n = 25), usually with a contralateral clinical varicocele. Testicular asymmetry (>20% volume difference of the affected side by testicular atrophy index formula) was assessed in 9 patients with unilateral subclinical varicocele without contralateral clinical or subclinical varicocele and observed in 1 patient. Of 17 patients with follow-up, 3 (17.6%) progressed to clinical varicocele without asymmetric testicular volume, as most remained subclinical or resolved without surgery. In our experience, subclinical varicoceles appeared unlikely to progress to clinical varicoceles, to affect testicular volume, or to lead to surgery. Although our study is limited in numbers and follow-up, this information may aid clinical management strategies and guide future prospective studies.

Characterizing Patients with Recurrent Urinary Tract Infections in Vesicoureteral Reflux: A Pilot Study of the Urinary Proteome.

Recurrent urinary tract infections (UTIs) pose a significant burden on the health care system. Underlying mechanisms predisposing children to UTIs and associated changes in the urinary proteome are not well understood. We aimed to investigate the urinary proteome of a subset of children who have vesicoureteral reflux (VUR) and recurrent UTIs because of their risk of developing infection-related renal damage. Improving diagnostic modalities to identify UTI risk factors would significantly alter the clinical management of children with VUR. We profiled the urinary proteomes of 22 VUR patients with low grade VUR (1-3 out of 5), a history of recurrent UTIs, and renal scarring, comparing them to those obtained from 22 age-matched controls. Urinary proteins were analyzed by mass spectrometry followed by protein quantitation based on spectral counting. Of the 2,551 proteins identified across both cohorts, 964 were robustly quantified, as defined by meeting criteria with spectral count (SC) ≥2 in at least 7 patients in either VUR or control cohort. Eighty proteins had differential expression between the two cohorts, with 44 proteins significantly up-regulated and 36 downregulated (q <0.075, FC ≥1.2). Urinary proteins involved in inflammation, acute phase response (APR), modulation of extracellular matrix (ECM), and carbohydrate metabolism were altered among the study cohort.

Robot-assisted laparoscopic lower pole partial nephrectomy in the pediatric patient.

INTRODUCTION: In pediatric urology, partial nephrectomy is used primarily to remove a non-functioning renal moiety in a duplicated system. There are few data on infants undergoing this procedure. As such, we present a robot-assisted laparoscopic lower pole partial nephrectomy in an infant. METHODS: Our patient was an 11-month-old (10.7 kg) male with a history of prenatal hydronephrosis, who was diagnosed postnatally with a duplicated right collecting system and severe hydroureteronephrosis of the right lower collecting system. A DMSA scan demonstrated no radiotracer uptake in the right lower pole. A robot-assisted laparoscopic lower pole partial nephrectomy was performed. RESULTS: A lower pole partial nephrectomy was accomplished. At 1 month postoperatively, an ultrasound demonstrated no hydronephrosis or perinephric fluid collection. CONCLUSIONS: Robotic partial nephrectomy is safe and feasible in pediatrics including both older children and infants. It is successful for both upper and lower pole partial nephrectomies.

Urinary Proteomics Yield Pathological Insights for Ureteropelvic Junction Obstruction.

Prenatal hydronephrosis is a common condition that may spontaneously resolve after birth. However, this condition can result in renal damage and requires surgical correction in a number of cases. Preventing renal damage is paramount, but existing diagnostic technology is invasive, exposes infants to radiation, is costly, and is often indeterminate. A better understanding of the pathophysiology of renal obstruction as reflected in the urinary proteome may provide new insights into the disease that could potentially alter the clinical management of hydronephrosis. We performed a quantitative proteomics study of urine that was surgically obtained from eight clinically significant, unilaterally obstructed infants versus eight healthy controls, with the goal of identifying quantitatively varying proteins and the biological networks associated with them. Notably, urine was obtained from both the obstructed kidney and the bladder. Over 1100 proteins were identified, and a total of 76 quantitatively varying proteins were identified. Proteins involved in oxidative stress, inflammation, and renal disease pathways showed the most significant abundance differences. This study gives a deeper understanding of the critical proteomic changes associated with renal obstruction and represents the deepest proteomic profile of renal obstruction to date.

Pediatric Robot-Assisted Laparoscopic Pyeloplasty.

The laparoscopic approach to the pyeloplasty procedure has proven to be safe and effective in the pediatric population. Multiple studies have revealed outcomes comparable to the open approach. However, a major drawback to laparoscopy is the technical challenge of precise suturing in the small working space in children. The advantages of robotic surgery when compared to conventional laparoscopy have been well established and include motion scaling, enhanced magnification, 3-dimensional stereoscopic vision, and improved instrument dexterity. As a result, surgeons with limited laparoscopic experience are able to more readily acquire robotic surgical skills. Limitations of the robotic platform include its high costs for acquisition and maintenance, as well as the need for additional robotic surgical training. In this article, we review the current status of the robot-assisted laparoscopic pyeloplasty, including a brief history, comparative outcomes, cost considerations, and training.

Myelogenous leukemia in adult inbred MHC-defined miniature swine: a model for human myeloid leukemias.

This manuscript reports on five cases of spontaneous myelogenous leukemia, similar to human disease, occurring within highly inbred, histocompatible sublines of Massachusetts General Hospital (MGH) MHC-defined miniature swine. In cases where a neoplasm was suspected based on clinical observations, samples were obtained for complete blood count, peripheral blood smear, and flow cytometric analysis. Animals confirmed to have neoplasms were euthanized and underwent necropsy. Histological samples were obtained from abnormal tissues and suspect lesions. The phenotype of the malignancies was assessed by flow cytometric analysis of processed peripheral blood mononuclear cells and affected tissues. Five cases of spontaneous myeloid leukemia were identified in adult animals older than 30 months of age. All animals presented with symptoms of weight loss, lethargy, and marked leukocytosis. At autopsy, all animals had systemic disease involvement and presented with severe hepatosplenomegaly. Three of the five myelogenous leukemias have successfully been expanded in vitro. The clustered incidence of disease in this closed herd suggests that genetic factors may be contributing to disease development. Myelogenous leukemia cell lines established from inbred sublines of MGH MHC-defined miniature swine have the potential to be utilized as a model to evaluate therapies of human leukemia.

Approaches to avoid immune responses induced by repeated subcutaneous injections of allogeneic umbilical cord tissue-derived cells.

BACKGROUND: Cellular treatments for repairing diseased tissues represent a promising clinical strategy. Umbilical cord tissue-derived cells (UTC) are a unique source of cells with a low immunogenic profile and potential for tissue repair. By using UTC from miniature swine, we previously demonstrated that despite their low immunogenic phenotype, UTC could induce an immune response under certain inflammatory conditions and after multiple subcutaneous (SC) injections. Given that repeat dosing of cells may be necessary to achieve a lasting therapeutic benefit, in this study, we examined approaches to avoid an immune response to multiple SC injections of UTC. METHODS: By using in vitro and in vivo measures of sensitization to SC cellular injections, we assessed the effects of varying the location of administration site, prolongation of timing between injections, and use of immunosuppressive treatments on repeated cellular injections in Massachusetts General Hospital major histocompatibility complex-defined miniature swine. RESULTS: Although under normal conditions, a single SC injection of major histocompatibility complex-mismatched UTC did not induce a detectable immune response, multiple SC injections of UTC demonstrated rapid humoral and cell-mediated immune responses. Avoidance of an immune response to repeat SC injection was achieved by concurrent immunosuppression with each dose of UTC. CONCLUSIONS: UTC and other similar cell types believed to be nonimmunogenic have the potential to induce immune responses under certain conditions. These studies provide important considerations and guidelines for preclinical studies investigating allogeneic cellular therapies.

Immunogenicity of umbilical cord tissue derived cells.

Umbilical cord tissue provides a unique source of cells with potential for tissue repair. Umbilical cord tissue-derived cells (UTCs) are MHC class I (MHCI) dull and negative for MHC class II (MHCII), but can be activated to increase MHCI and to express MHCII with IFN-gamma stimulation. Mesenchymal stem cells with similar characteristics have been inferred to be nonimmunogenic; however, in most cases, immunogenicity was not directly assessed. Using UTC from Massachusetts General Hospital MHC-defined miniature swine, we assessed immunogenicity across a full MHC barrier. Immunogenicity was assessed by in vitro assays including mixed lymphocyte reaction (MLR) and flow cytometry to detect serum alloantibody. A single injection of MHC-mismatched unactivated UTCs did not induce a detectable immune response. When injected in an inflamed region, injected repeatedly in the same region or stimulated with IFN-gamma prior to injection, UTCs were immunogenic. As clinical cellular repair strategies may involve injection of allogeneic cells into inflamed regions of damaged tissue or repeated doses of cells to achieve the desired benefit, our results on the immunogenicity of these cells in these circumstances may have important implications for optimal success and functional improvement for this cellular treatment strategy for diseased tissues.

Establishment of transplantable porcine tumor cell lines derived from MHC-inbred miniature swine.

The lack of transplantable tumors has limited assessment of graft-versus-tumor effects following hematopoietic cell transplantation in clinically relevant large-animal models. We describe the derivation and characterization of porcine tumor cell lines with initial efforts of tumor transplantation using immunocompromised mice and highly inbred sublines of Massachusetts General Hospital major histocompatibility complex (MHC)-inbred miniature swine. Autopsies were performed routinely on swine that died unexpectedly or had suspicion of malignancy based on clinical symptoms or peripheral blood analysis. Tissue samples were obtained for pathology, phenotyped by flow cytometry, and placed in culture. Based on growth, lines were selected for passage into nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice and miniature swine. Porcine tumor recipients were preconditioned with total body irradiation from 0 to 500 cGy or with a 30-day course of oral cyclosporine. We identified 19 cases of hematologic tumors. Nine distinct tumor cell lines were established from 8 of these cases, including 3 derived from highly inbred sublines. In vivo tumor growth and serial transfer were observed in immunocompromised mice for one tumor cell line and in miniature swine for 1 of 2 tumor cell lines expanded for this purpose. These results suggest the possibility of developing a transplantable tumor model in this large-animal system.

Risk factors for the development of post-transplant lymphoproliferative disorder in a large animal model.

A high incidence of a post-transplant lymphoproliferative disorder (PTLD) is observed in miniature swine conditioned for allogeneic hematopoietic cell transplantation using a protocol involving T-cell depletion and cyclosporine therapy. This study was designed to assess contributing factors to disease development. Forty-six animals were studied including 12 (26%) that developed PTLD. A number of risk factors for PTLD were examined, including degree of immunosuppression, degree of MHC mismatch and infection by a porcine lymphotrophic herpesvirus (PLHV-1). Flow cytometry was used to measure host and donor T- and B-cell levels in the peripheral blood. Porcine lymphotrophic herpesvirus viral load was determined by quantitative PCR. Animals developing PTLD had significantly lower levels of T cells on the day of transplant. Cyclosporine levels did not differ significantly between animals with and without PTLD. Animals receiving transplants across a two-haplotype mismatch barrier showed an increased incidence of PTLD. All animals with PTLD had significant increases in PLHV-1 viral loads. Porcine lymphotrophic herpesvirus viral copy numbers remained at low levels in the absence of disease. The availability of a preclinical large-animal model with similarities to PTLD of humans may allow studies of the pathogenesis and treatment of that disorder.