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- Gutbier, Birgitt, et al.
(author)
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Moraxella catarrhalis induces an immune response in the murine lung which is independent of human CEACAM5 expression and long-term smoke exposure.
- 2015
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In: American Journal of Physiology: Lung Cellular and Molecular Physiology. - : American Physiological Society. - 1522-1504 .- 1040-0605. ; 309:3, s. 250-261
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Journal article (peer-reviewed)abstract
- In patients with chronic obstructive pulmonary disease (COPD), Moraxella catarrhalis infection of the lower airways is associated with chronic colonization and inflammation during stable disease and acute exacerbations. Chronic smoke exposure induces chronic inflammation and impairs mucociliary clearance, thus contributing to bacterial colonization of the lower airways in COPD patients. The human-specific carcinoembryonic antigen-related cell adhesion molecule (CEACAM) 5, expressed in human airways, has been shown to contribute to epithelial colonization of CEACAM-binding pathogens. To investigate the impact of CEACAM5 expression on pulmonary M. catarrhalis colonization, we infected mice transgenic for human CEACAM5 (hCEACAM5) and wild type mice intratracheally with M. catarrhalis with or without preceding smoke exposure and analyzed bacterial colonization and local and systemic inflammation. Our results show that airway infection with M. catarrhalis accelerated acute local but not systemic inflammation, albeit independent of hCEACAM5 expression. Long-term smoke exposure alone or prior to M. catarrhalis infection did not contribute to increased local or systemic inflammation. No difference was found in pulmonary clearance of M. catarrhalis in hCEACAM5-transgenic mice compared to wild type mice. Smoke exposure neither altered time nor extent of persistence of M. catarrhalis in the lungs of both genotypes. In conclusion, M. catarrhalis induced a local acute immune response in murine airways. Neither hCEACAM5- expression nor chronic smoke exposure nor a combination of both was sufficient as prerequisites for the establishment of chronic M. catarrhalis colonization. Our results demonstrate the difficulties in mirroring conditions of chronic airways colonization of M. catarrhalis in a murine model.
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- Hoermann, Henrike, et al.
(author)
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Comparative meta-analysis of Kabuki syndrome with and without hyperinsulinemic hypoglycemia
- 2020
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In: Clinical Endocrinology. - : John Wiley & Sons. - 0300-0664 .- 1365-2265. ; 93:3, s. 346-354
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Journal article (peer-reviewed)abstract
- BACKGROUND AND OBJECTIVE: Kabuki syndrome (KS), caused by pathogenic variants in KMT2D or KDM6A, is associated with hyperinsulinemic hypoglycemia (HH) in 0.3-4% of patients. We characterized the clinical, biochemical and molecular data of children with KS and HH compared to children with KS without HH in a multicenter meta-analysis.METHODS: Data of seven new and 17 already published children with KS and HH were compared to 373 recently published KS patients without HH regarding molecular and clinical characteristics.RESULTS: Seven new patients were identified with seven different pathogenic variants in KDM6A (n=4) or KMT2D (n=3). All presented with HH on the first day of life and were responsive to diazoxide. KS was diagnosed between 9 months and 14 years of age. In the meta-analysis 24 KS patients with HH had a significantly higher frequency of variants in KDM6A compared to 373 KS patients without HH (50% vs. 11.5%, p<0.001), and KDM6A-KS was more likely to be associated with HH than KMT2D-KS (21.8% vs. 3.5%, p<0.001). Sex distribution and other phenotypic features did not differ between KS with and without HH.CONCLUSION: The higher incidence of HH in KDM6A-KS compared to KMT2D-KS indicates that KDM6A loss of function variants predispose more specifically to beta cell dysfunction compared to KMT2D variants. As difficulties to assign syndromic characteristics to KS in early infancy often lead to delayed diagnosis, genetic testing for KS should be considered in children with HH, especially in the presence of other extrapancreatic/syndromic features.
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- Hultström, Michael, et al.
(author)
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Collagen-binding proteins in age-dependent changes in renal collagen turnover : microarray analysis of mRNA expression
- 2012
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In: Physiological Genomics. - : American Physiological Society. - 1094-8341 .- 1531-2267. ; 44:10, s. 576-586
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Journal article (peer-reviewed)abstract
- Aging is associated with progressive structural and functional deterioration of the kidney. Among the morphological changes associated with renal aging is an accumulation of extracellular matrix (ECM) in the glomeruli and tubuloinsterstitium, which may ultimately lead to the development of renal fibrosis. The mechanisms governing the regulation of ECM metabolism during renal aging are only incompletely defined. We present data from a genome-wide mRNA expression study on renal tissue from 90 wk old male Wistar rats and 10 wk old controls using Illumina BeadArray cDNA microarray. Regulation of candidate gene products was verified by real-time PCR. Morphological changes were evaluated by routine histological methods. Activated fibroblasts were identified by their expression of alpha-smooth muscle actin and collagen I. Morphological analysis demonstrated an expansion of the tubulointerstitial compartment with increased amounts of fibrous collagen but no overt glomerular or tubular damage in the aged rats. Activated fibroblasts were readily detectable in the adventitial layer of large renal vessels in controls and were not found in the old animals. In agreement with this finding, gene expression analysis revealed significant downregulation of collagen I mRNA along with numerous other ECM components. Concomitantly, collagen-stabilizing proteins were induced, whereas matrix metalloproteinase 9, an enzyme involved in collagen breakdown, was reduced. In conclusion, our results suggest that ECM expansion during renal aging results from an augmented stabilization in conjunction with a reduced breakdown of collagen fibers. Collagen stabilizing proteins may be essential for the control of renal ECM turnover and the pathogenesis of kidney fibrosis.
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- Kuppe, Christoph, et al.
(author)
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Inverse correlation between vascular endothelial growth factor back-filtration and capillary filtration pressures
- 2018
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In: Nephrology, Dialysis and Transplantation. - : OXFORD UNIV PRESS. - 0931-0509 .- 1460-2385. ; 33:9, s. 1514-1525
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Journal article (peer-reviewed)abstract
- Background: Vascular endothelial growth factor A (VEGF) is an essential growth factor during glomerular development and postnatal homeostasis. VEGF is secreted in high amounts by podocytes into the primary urine, back-filtered across the glomerular capillary wall to act on endothelial cells. So far it has been assumed that VEGF back-filtration is driven at a constant rate exclusively by diffusion.Methods: In the present work, glomerular VEGF back-filtration was investigated in vivo using a novel extended model based on endothelial fenestrations as surrogate marker for local VEGF concentrations. Single nephron glomerular filtration rate (SNGFR) and/or local filtration flux were manipulated by partial renal mass ablation, tubular ablation, and in transgenic mouse models of systemic or podocytic VEGF overexpression or reduction.Results: Our study shows positive correlations between VEGF back-filtration and SNGFR as well as effective filtration rate under physiological conditions along individual glomerular capillaries in rodents and humans.Conclusion: Our results suggest that an additional force drives VEGF back-filtration, potentially regulated by SNGFR.
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- Schildroth, Janice, et al.
(author)
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Endothelin type A and B receptors in the control of afferent and efferent arterioles in mice
- 2011
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In: Nephrology, Dialysis and Transplantation. - : Oxford University Press (OUP). - 0931-0509 .- 1460-2385. ; 26:3, s. 779-789
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Journal article (peer-reviewed)abstract
- Background. Endothelin 1 contributes to renal blood flow control and pathogenesis of kidney diseases. The differential effects, however, of endothelin 1 (ET-1) on afferent (AA) and efferent arterioles (EA) remain to be established. Methods. We investigated endothelin type A and B receptor (ETA-R, ETB-R) functions in the control of AA and EA. Arterioles of ETB-R deficient, rescued mice [ETB (-/-)] and wild types [ETB(+/+)] were microperfused. Results. ET-1 constricted AA stronger than EA in ETB (-/-) and ETB(+/+) mice. Results in AA: ET-1 induced similar constrictions in ETB(-/-) and ETB(+/+) mice. BQ-123 (ETA-R antagonist) inhibited this response in both groups. ALA-ET-1 and IRL1620 (ETB-R agonists) had no effect on arteriolar diameter. L-NAME did neither affect basal diameters nor ET-1 responses. Results in EA: ET-1 constricted EA stronger in ETB(+/+) compared to ETB(-/-). BQ-123 inhibited the constriction completely only in ETB(-/-). ALA-ET-1 and IRL1620 constricted only arterioles of ETB(+/+) mice. L-NAME decreased basal diameter in ETB(+/+), but not in ETB(-/-) mice and increased the ET-1 response similarly in both groups. The L-NAME actions indicate a contribution of ETB-R in basal nitric oxide (NO) release in EA and suggest dilatory action of ETA-R in EA. Conclusions. ETA-R mediates vasoconstriction in AA and contributes to vasoconstriction in EA in this mouse model. ETB-R has no effect in AA but mediates basal NO release and constriction in EA. The stronger effect of ET-1 on AA supports observations of decreased glomerular filtration rate to ET-1 and indicates a potential contribution of ET-1 to the pathogenesis of kidney diseases.
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- Skogstrand, Trude, et al.
(author)
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Arterial damage precedes the development of interstitial damage in the nonclipped kidney of two-kidney, one-clip hypertensive rats
- 2013
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In: Journal of Hypertension. - 0263-6352 .- 1473-5598. ; 31:1, s. 152-159
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Journal article (peer-reviewed)abstract
- Background: The progression of damage in the renal cortex has not been investigated in the nonclipped kidney of the two-kidney, one-clip model of renal hypertension. In other hypertensive models, damage has been found to progress from the juxtamedullary cortex (JMC) and outward, which has been attributed to early vascular effects. Method: The present study investigated the relation between perivascular deposition of collagen and structural damage after 16 and 24 weeks of hypertension in the nonclipped kidney in rats. Results: Periarterial collagen density in the kidney was significantly increased already 16 weeks after clipping, at that time tubulointerstitial damage was not evident. After 24 weeks of clipping, periarterial collagen was further increased, and tubulointerstitial damage had developed in the JMC, whereas the outer cortex was protected. Interstitial collagen was not significantly increased in any cortex part during the course of the experiment. Collagen type I a1 mRNA was increased in the JMC after 24 weeks, and alpha smooth muscle actin histochemistry and collagen type I a2 in-situ hybridization identified myofibroblasts around the arteries after 16 and 24 weeks as the major source of this increase. Conclusion: Fibrosis in the nonclipped kidney of renal hypertensive rats starts around the juxtamedullary resistance vessels and then progresses in the JMC, whereas the outer cortex is protected. This suggests that pressure-induced injury to the vasculature attracts or activates fibroblasts in the perivascular area, which may allow damage to progress by impairing vessel function.
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