KANK deficiency leads to podocyte dysfunction and nephrotic syndrome.

Steroid-resistant nephrotic syndrome (SRNS) is a frequent cause of progressive renal function decline and affects millions of people. In a recent study, 30% of SRNS cases evaluated were the result of monogenic mutations in 1 of 27 different genes. Here, using homozygosity mapping and whole-exome sequencing, we identified recessive mutations in kidney ankyrin repeat-containing protein 1 (KANK1), KANK2, and KANK4 in individuals with nephrotic syndrome. In an independent functional genetic screen of Drosophila cardiac nephrocytes, which are equivalents of mammalian podocytes, we determined that the Drosophila KANK homolog (dKank) is essential for nephrocyte function. RNAi-mediated knockdown of dKank in nephrocytes disrupted slit diaphragm filtration structures and lacuna channel structures. In rats, KANK1, KANK2, and KANK4 all localized to podocytes in glomeruli, and KANK1 partially colocalized with synaptopodin. Knockdown of kank2 in zebrafish recapitulated a nephrotic syndrome phenotype, resulting in proteinuria and podocyte foot process effacement. In rat glomeruli and cultured human podocytes, KANK2 interacted with ARHGDIA, a known regulator of RHO GTPases in podocytes that is dysfunctional in some types of nephrotic syndrome. Knockdown of KANK2 in cultured podocytes increased active GTP-bound RHOA and decreased migration. Together, these data suggest that KANK family genes play evolutionarily conserved roles in podocyte function, likely through regulating RHO GTPase signaling.

MDR1 polymorphisms and idiopathic nephrotic syndrome in Slovak children: preliminary results.

BACKGROUND: The role of the multidrug resistance-1 (MDR1 or ABCB1) gene polymorphisms 1236T>C, 2677T>G, and 3435T>C was studied in relation to susceptibility, demographics, and pathological characteristics, as well as their role in the therapeutic response (TR) to prednisone treatment in children with idiopathic nephrotic syndrome (INS). MATERIAL/METHODS: The polymorphisms were analyzed using the polymerase chain reaction-restriction fragment length polymorphism method in 46 children with INS and in 100 healthy controls. Different genetic models (codominant, dominant, recessive, and overdominant) were used for testing of associations between polymorphisms and phenotypes. RESULTS: Statistical analysis showed a significantly increased chance of TR in children carrying 3435TC genotype (OR=5.13, 95% CI=1.18-22.25; overdominant model). Moreover, INS patients under 6 years of age had significantly decreased frequencies of MDR1 1236CC (7.7% vs. 35%, p=0.029) or 2677GG (3.8% vs. 30.0%, p=0.033) genotypes. We also observed that patients with minimal change in disease and patients under 6 years of age at the onset of INS were initial responders more frequently when compared with children with focal segmental glomerulosclerosis and patients ≥6 years old at the onset (p=0.0001, p=0.027, respectively). CONCLUSIONS: These data suggest that prednisone TR may be influenced by histology, age at the onset of INS, and MDR1 3435T>C polymorphism. The MDR1 1236T>C and 2677T>G polymorphisms were significantly associated with age at onset. Larger multicenter studies and studies across other ethnic groups are needed to elucidate the contradictory implications of MDR1 polymorphisms with INS in children.

Correlation between antibodies and histology in celiac disease: incidence of celiac disease is higher than expected in the pediatric population.

The present study aims to report on the correlation between the degree of negativity of anti-endomysial antibodies and anti-tissue transglutaminase antibodies in the IgA and IgG classes with regard to histological grade, in 44 newly diagnosed children with celiac disease (CD). Samples with negative antibodies, but a positive histology from a 5-year program searching for CD in the pediatric population were collected. A total of 4247 biopsy samples were used in this study. We documented that certain pediatric patients are seronegative, while the disease is active and the incidence of CD is higher than expected in the pediatric population. This is an important finding, which demonstrates the lack of association between autoantibodies and lesions, and justifies the use of biopsies for an accurate CD diagnosis and the importance of revising the diagnostic criteria in a clinical, endoscopic and serological context. We recommend a more active search for incidences of the disease in the pediatric population. Serological markers are not the main method for the diagnosis of CD as they are considered to only have a supporting role clinically. Biopsies of the small intestine are always necessary for the diagnosis of CD in these patients.

Reduced inflammation accompanies diminished myelin damage and repair in the NG2 null mouse spinal cord.

BACKGROUND: Multiple sclerosis (MS) is a demyelinating disease in which blood-derived immune cells and activated microglia damage myelin in the central nervous system. While oligodendrocyte progenitor cells (OPCs) are essential for generating oligodendrocytes for myelin repair, other cell types also participate in the damage and repair processes. The NG2 proteoglycan is expressed by OPCs, pericytes, and macrophages/microglia. In this report we investigate the effects of NG2 on these cell types during spinal cord demyelination/remyelination. METHODS: Demyelinated lesions were created by microinjecting 1% lysolecithin into the lumbar spinal cord. Following demyelination, NG2 expression patterns in wild type mice were studied via immunostaining. Immunolabeling was also used in wild type and NG2 null mice to compare the extent of myelin damage, the kinetics of myelin repair, and the respective responses of OPCs, pericytes, and macrophages/microglia. Cell proliferation was quantified by studies of BrdU incorporation, and cytokine expression levels were evaluated using qRT-PCR. RESULTS: The initial volume of spinal cord demyelination in wild type mice is twice as large as in NG2 null mice. However, over the ensuing 5 weeks there is a 6-fold improvement in myelination in wild type mice, versus only a 2-fold improvement in NG2 null mice. NG2 ablation also results in reduced numbers of each of the three affected cell types. BrdU incorporation studies reveal that reduced cell proliferation is an important factor underlying NG2-dependent decreases in each of the three key cell populations. In addition, NG2 ablation reduces macrophage/microglial cell migration and shifts cytokine expression from a pro-inflammatory to anti-inflammatory phenotype. CONCLUSIONS: Loss of NG2 expression leads to decreased proliferation of OPCs, pericytes, and macrophages/microglia, reducing the abundance of all three cell types in demyelinated spinal cord lesions. As a result of these NG2-dependent changes, the course of demyelination and remyelination in NG2 null mice differs from that seen in wild type mice, with both myelin damage and repair being reduced in the NG2 null mouse. These studies identify NG2 as an important factor in regulating myelin processing, suggesting that therapeutic targeting of the proteoglycan might offer a means of manipulating cell behavior in demyelinating diseases.

Surgical management of bronchopulmonary carcinoid tumors: experience over 8 years and review of the literature.

AIMS AND BACKGROUND: An increased incidence of neuroendocrine tumors in the last decade has been noticed worldwide. Our purpose was to study the characteristics, surgical approaches and outcome in patients with primary bronchopulmonary carcinoid tumors. METHODS: Between 2001 and 2007, bronchopulmonary carcinoid tumors were removed in 11 of a total of 287 patients who underwent surgery for primary lung malignancies in our tertiary referral center. RESULTS: The patient group consisted of 3 men and 8 women (mean age 52.9 +/- 5.2 years, range 19-76 years). At presentation, 10 of 11 patients were symptomatic, with cough, pneumonia, breathlessness and hemoptysis being the most frequent symptoms. Histological findings revealed typical carcinoid in 10 patients and atypical carcinoid in one. The surgical approach included 8 lung resections (6 lobectomies, 1 bilobectomy, 1 segmentectomy), and 3 bronchoplastic tumor removals. In 2008, clinical examination and chest X-ray revealed no recurrence of the carcinoid and no long-term postoperative complications in any patient. CONCLUSIONS: In the light of our study and the review of the literature we conclude that early recognition of primary bronchopulmonary carcinoid tumors followed by adequate surgical removal of the malignancy are essential for complete remission of the disease.

An unusual coincidence of multiple synchronous kidney tumors with a metachronous rectal adenocarcinoma.

In synchronous surgery specimens (right-sided nephrectomy and left-sided partial nephrectomy), a unique combination of a papillary (chromophil) renal cell carcinoma (4 x 3.7 x 3.5 cm) and a renal oncocytoma (11 x 10 x 9 mm) in the right kidney and a renal carcinoid (2.5 x 2.3 x 1.1 cm) in the resected part of the left kidney has been found. This multiplicity and bilaterality, based on the findings of three distinct histogenetic types of kidney tumors, was accompanied by a metachronous rectal adenocarcinoma discovered 14 months later. After surgery, no radiation or other oncologic therapy was given. At present, our patient is well without any evidence of neoplastic disease three years after primary diagnosis. To the best of our knowledge, this is the first case of a combination of three distinct histogenetic types of synchronous renal tumors associated with a metachronous rectal adenocarcinoma treated with simple surgery. In the absence of cytogenetic studies, the possibility of a the presence of a hereditary renal cancer syndrome must be considered.

Novel MLH1 and MSH2 germline mutations in the first HNPCC families identified in Slovakia.

Hereditary nonpolyposis colorectal cancer (HNPCC) is a dominantly-inherited cancer predisposition syndrome, in which the susceptibility to cancer of the colon, endometrium and ovary is linked to germline mutations in DNA mismatch repair (MMR) genes. We have recently initiated a cancer prevention program in suspected HNPCC families in the Slovak Republic. The first ten families fulfilling Amsterdam criteria or Bethesda guidelines were screened for germline mutations in MLH1 and MSH2, two MMR genes most frequently mutated in HNPCC families. Six mutations were identified, five of which have not been reported previously. Two of the three new mutations in MLH1 (c.380+2T>A; c.307-2A>C) were absent from 100 chromosomes of healthy controls and probably cause a splicing defect, while the third was a 1 bp deletion (c.1261delA). In the MSH2 gene, one new nonsense (c.1030C>T [p.Q344X]) and one missense (c.524T>C [p.L175P]) mutation were identified. This latter variant was not found in 104 alleles of healthy control individuals. Moreover, a previously-reported pathogenic mutation (c.677G>T [p.R226L]) was found in one kindred. The clinical data and the genotypic and phenotypic evaluation of the tumors indicate that all the new alterations are pathogenic HNPCC mutations.