A missense mutation in mouse Nek8, which encodes a ciliary kinase, produces the juvenile cystic kidneys (jck) model of polycystic kidney disease, but the functions of Nek8 are incompletely understood. Here, we generated a Nek8-null allele and found that homozygous mutant mice die at birth and exhibit randomization of left-right asymmetry, cardiac anomalies, and glomerular kidney cysts. The requirement for Nek8 in left-right patterning is conserved, as knockdown of the zebrafish ortholog caused randomized heart looping. Ciliogenesis was intact in Nek8-deficient embryos and cells, but we observed misexpression of left-sided marker genes early in development, suggesting that nodal ciliary signaling was perturbed. We also generated jck/Nek8 compound heterozygotes; these mutants developed less severe cystic disease than jck homozygotes and provided genetic evidence that the jck allele may encode a gain-of-function protein. Notably, NEK8 and polycystin-2 (PC2) proteins interact, and we found that Nek8 2/2 and Pkd2 2/2 embryonic phenotypes are strikingly similar. Nek8-deficient embryos and cells did express PC2 normally, which localized properly to the cilia. However, similar to cells lacking PC2, NEK8-depleted inner medullary collecting duct cells exhibited a defective response to fluid shear, suggesting that NEK8 may play a role in mediating PC2-dependent signaling.

The authors compared pre-treatment and post-treatment characteristics of 206 prospectively enrolled patients with Kawasaki disease (KD) responsive to intravenous immunoglobulin (IVIG) with those of 23 (10% of total) IVIG non-responders. Demographic characteristics were similar in both groups. Compared to IVIG responders, non-responders had a longer total duration of fever and a higher incidence of coronary artery lesions. Prior to IVIG, non-responders had higher neutrophil differential and C-reactive protein, and lower cholesterol. 24 hours after the IVIG infusion, a total leucocyte count >13.1×10(9)/l, neutrophil differential >51% and total protein <72 g/l showed reasonable sensitivity (91%, 91% and 64%, respectively) and specificity (89%, 76% and 78%, respectively) as independent characteristics of non-response to IVIG. Laboratory parameters before and shortly after IVIG may reflect the severity of inflammation in KD patients and assist in informing further management.

Background and ObjectivesThis was a multicenter study to evaluate the usefulness of the tumor necrosis factor-alpha (TNF-α) blocker infliximab for treatment of Korean pediatric patients with refractory Kawasaki disease (KD).Subjects and MethodsData from 16 patients throughout Korea who were diagnosed with refractory KD and received infliximab were collected retrospectively.ResultsComplete response to therapy with cessation of fever occurred in 13 of 16 patients. C-reactive protein (CRP) concentrations decreased following infliximab infusion in all 14 patients in whom it was measured before and after treatment. There were no infusion reactions or complications associated with infliximab except in 1 case with acute hepatitis occurring during treatment followed by calculous cholecystitis 4 months later. Fifteen patients had coronary artery (CA) abnormalities before infliximab therapy. Three had transient mild dilatation and 9 had CA aneurysms, with subsequent normalization in 4 patients, persistent mild dilatation in 3, persistent aneurysm in 2, and there were 3 cases (2 with CA aneurysm, 1 with mild CA dilatation) without follow-up echocardiography.ConclusionThe results of this study suggest that infliximab may be useful in the treatment of refractory KD, and it appears that there is no significant further progression of CA lesions developing after infliximab treatment. Multicenter trials with larger numbers of patients and long-term follow-up are necessary to assess the clinical efficacy and safety of infliximab in refractory KD.

Background: Idiopathic cardiomyopathies (CMPs) are an important heterogeneous group of diseases. With the advance of therapeutic strategies, epidemiologic data on CMP have become very important, but only a few have been reported in Asian children. We conducted a retrospective epidemiologic study of primary CMP in Korean children. Methods and Results:Using a multicenter survey, we studied primary CMP among Korean children from January 1998 to December 2006 based on classification (2006) of CMP by the American Heart Association. A total of 277 primary CMP patients were reported from 17 cardiovascular centers. The average annual occurrence of new cases of primary CMP was 0.28 per 100,000 Korean children younger than 15 years of age (95% confidence interval (CI) 0.24-0.31). Dilated CMP (DCMP) was 66.43%, hypertrophic CMP (HCMP) 23.47%, restrictive CMP (RCMP) 6.50% and others 3.61%. The point prevalence of primary CMP at the end of the study was estimated as 2.11/100,000 (95%CI 1.83-2.43), DCMP 1.39/100,000, HCMP 0.51/100,000, RCMP 0.16/100,000 and others 0.04/100,000. Survival rates over 9 years were 69.8% in DCMP, 90.3% in HCMP, and 47.2% in RCMP.Conclusions: Recent point prevalence of childhood primary CMP in Korea was estimated as 2.11/100,000. Further epidemiologic study with a nationwide survey is necessary. (Circ J 2011; 75: 2228 - 2234

The lung is enveloped by a layer of specialized epithelium, the pulmonary mesothelium. In other organs, mesothelial cells undergo epithelialmesenchymal transition and contribute to organ stromal cells. The contribution of pulmonary mesothelial cells (PMCs) to the developing lung has been evaluated with differing conclusions. PMCs have also been indirectly implicated in lung fibrosis in the progressive, fatal lung disease idiopathic pulmonary fibrosis. We used fetal or postnatal genetic pulse labeling of PMCs to assess their fate in murine development, normal lung homeostasis, and models of pulmonary fibrosis. We found that most fetal PMC-derived mesenchymal cells (PMCDCs) expressed markers of pericytes and fibroblasts, only a small minority expressed smooth muscle markers, and none expressed endothelial cell markers. Postnatal PMCs did not contribute to lung mesenchyme during normal lung homeostasis or in models of lung fibrosis. However, fetal PMCDCs were abundant and actively proliferating within fibrotic regions in lung fibrosis models, suggesting that they actively participate in the fibrotic process. These data clarify the role of fetal and postnatal PMCDCs in lung development and disease.