Mutations involving elastic tissue proteins result in a broad spectrum of phenotypes affecting skin, skeleton, ocular and vascular structures, including tortuous blood vessels and cutis laxa. Here we report on a female newborn with apparently long fingers, aortic aneurysm, tortuous pulmonary arteries and mild generalized lax skin. She died at 27 days of age due to severe respiratory distress and inoperable systemic vascular abnormalities. Skin biopsy showed marked paucity and fragmentation of elastic fibers and autopsy revealed occlusion of the pulmonary artery. DNA analysis identified compound heterozygous mutations ((c.835C > T (p.R279C)/c.1070_1073dupCCGC) in fibulin-4, a recently recognized elastic fiber associated protein. Analyses of dermal fibroblasts from the patient indicated that fibulin-4 mRNAs with the 4-bp duplication transcribed from one allele are probably subject to nonsense-mediated decay, whereas synthesis and secretion of the missense R279C fibulin-4 protein from the other allele is severely impaired. Immunostaining demonstrated a total absence of fibulin-4 fibers in the extracellular matrix deposited by the patient's fibroblasts. Our studies provide evidence that deficiency in fibulin-4 leads to a perinatal lethal condition associated with elastic tissue abnormalities.
Hyperfiltration subjects podocytes to increased tensile stress and fluid flow shear stress (FFSS). We showed a 1.5- to 2.0-fold increase in FFSS in uninephrectomized animals and altered podocyte actin cytoskeleton and increased synthesis of prostaglandin E2 (PGE2) following in vitro application of FFSS. We hypothesized that increased FFSS mediates cellular changes through specific receptors of PGE2. Presently, we studied the effect of FFSS on cultured podocytes and decapsulated isolated glomeruli in vitro, and on solitary kidney in uninephrectomized sv129 mice. In cultured podocytes, FFSS resulted in increased gene and protein expression of cyclooxygenase (COX)-2 but not COX-1, prostanoid receptor EP2 but not EP4, and increased synthesis and secretion of PGE2, which were effectively blocked by indomethacin. Next, we developed a special flow chamber for applying FFSS to isolated glomeruli to determine its effect on an intact glomerular filtration barrier by measuring change in albumin permeability (Palb) in vitro. FFSS caused an increase in Palb that was blocked by indomethacin (P < 0.001). Finally, we show that unilateral nephrectomy in sv129 mice resulted in glomerular hypertrophy (P = 0.006), increased glomerular expression of COX-2 (P < 0.001) and EP2 (P = 0.039), and increased urinary albumin excretion (P = 0.001). Activation of the COX-2-PGE2-EP2 axis appears to be a specific response to FFSS in podocytes and provides a mechanistic basis for alteration in podocyte structure and the glomerular filtration barrier, leading to albuminuria in hyperfiltration-mediated kidney injury. The COX-2-PGE2-EP2 axis is a potential target for developing specific interventions to ameliorate the effects of hyperfiltration-mediated kidney injury in the progression of chronic kidney disease.
We conclude that measurement of synaptopodin has the potential to be used as a marker to study the alteration in podocyte cell and response to therapy in INS.
Background: Juvenile polyps (JPs) are the most common gastrointestinal polyps diagnosed in children. There is paucity of evidence differentiating polyp burden groups and the presence and significance of neoplastic changes. Methods: A retrospective chart review of patients, ages birth through 18 years with nonsyndromic JPs was performed from 2003 to 2017. Abstracted data included basic demographics, age, clinical presentation, colonoscopy findings, and pathology report. Slides of polyps with neoplasia were reviewed by a pathologist. Results: A total of 213 subjects underwent 326 procedures and 435 polypectomies. Subjects with positive family history, positive gene mutations, or numerous (>10) polyps were excluded. Groups were defined by polyp number (1, 2–4, 5–10). Polyp recurrence on repeat colonoscopy was significantly related to polyp burden (1 polyp: 1.5%/2–4 polyps 19.2%/5–10 polyps 82.6%: P < 0.001). Polyp distribution was significantly different amongst different groups with isolated polyps favoring a distal distribution. JPs harboring adenomatous foci were reported in 26 (12%) patients. JPs harboring adenomatous foci were significantly more likely to be proximally distributed but the presence of adenomatous transformation within the polyps did not correlate with polyp number or the likelihood of polyp recurrence on repeat colonoscopy. Conclusions: JP recurrence is positively and significantly related to polyp burden. JP harbored adenomatous changes independent of polyp number, underscoring a possible malignant potential in JPs. In the absence of a consistent genotype or pedigree, the presence of adenomatous transformation within JPs cannot be construed as a biomarker for syndromic juvenile polyposis.
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