Publications by authors named "Chatziantoniou C"

Blood flow velocity in the cerebral perforating arteries can be quantified in a two-dimensional plane with phase contrast magnetic imaging (2D PC-MRI). The velocity pulsatility index (PI) can inform on the stiffness of these perforating arteries, which is related to several cerebrovascular diseases. Currently, there is no open-source analysis tool for 2D PC-MRI data from these small vessels, impeding the usage of these measurements.

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Background: We have previously reported that the gap junction protein connexin 43 (Cx43) was upregulated in chronic renal disease in humans and rodents and plays a crucial role in the progression of experimental nephropathy. In this study, we investigated its role after renal ischemia/reperfusion (rIR), which is a major mechanism of injury in acute renal injury (AKI) and renal transplant graft dysfunction.

Methods: Wild-type mice (WT) and mice in which Cx43 expression was genetically reduced by half (Cx43 ±) were unilaterally nephrectomized.

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The tricellular tight junctions are crucial for the regulation of paracellular flux at tricellular junctions, where tricellulin (MARVELD2) and angulins (ILDR1, ILDR2, or LSR) are localized. The role of ILDR2 in podocytes, specialized epithelial cells in the kidney, is still unknown. We investigated the role of ILDR2 in glomeruli and its influence on blood filtration.

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Deep insights into the complex cellular and molecular changes occurring during (patho-)physiological conditions are essential for understanding the interactions and regulation of proteins. This understanding is crucial for research and diagnostics. However, the effectiveness of conventional immunofluorescence and light microscope, tools for visualizing the spatial distribution of cells or proteins, are limited both in resolution and multiplexity in complex tissues.

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Unlike classical protein kinase A, with separate catalytic and regulatory subunits, EPACs are single chain multi-domain proteins containing both catalytic and regulatory elements. The importance of cAMP-Epac-signaling as an energy provider has emerged over the last years. However, little is known about Epac1 signaling in chronic kidney disease.

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Raine syndrome (RNS) is a rare autosomal recessive osteosclerotic dysplasia. RNS is caused by loss-of-function disease-causative variants of the FAM20C gene that encodes a kinase that phosphorylates most of the secreted proteins found in the body fluids and extracellular matrix. The most common RNS clinical features are generalized osteosclerosis, facial dysmorphism, intracerebral calcifications and respiratory defects.

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Renin is the key enzyme of the systemic renin-angiotensin-aldosterone system, which plays an essential role in regulating blood pressure and maintaining electrolyte and extracellular volume homeostasis. Renin is mainly produced and secreted by specialized juxtaglomerular (JG) cells in the kidney. In the present study, we report for the first time that the conserved transmembrane receptor neuropilin-1 (NRP1) participates in the development of JG cells and plays a key role in renin production.

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Background: High circulating DPP3 (dipeptidyl peptidase 3) has been associated with poor prognosis in critically ill patients with circulatory failure. In such situation, DPP3 could play a pathological role, putatively via an excessive angiotensin peptides cleavage. Our objective was to investigate the hemodynamics changes induced by DPP3 in mice and the relation between the observed effects and renin-angiotensin system modulation.

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The glomerular filtration barrier (GFB), composed of endothelial cells, glomerular basement membrane, and podocytes, is a unique structure for filtering blood while detaining plasma proteins according to size and charge selectivity. Structurally, the fenestrated endothelial cells, which align the capillary loops, are in close proximity to mesangial cells. Podocytes are connected by specialized intercellular junctions known as slit diaphragms and are separated from the endothelial compartment by the glomerular basement membrane.

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Objective: To investigate the feasibility of diffusion-weighted magnetic resonance imaging (DW-MRI) as a predictive imaging marker after neoadjuvant chemotherapy in patients with rhabdomyosarcoma.

Material And Methods: We performed a multicenter retrospective study including pediatric, adolescent and young adult patients with rhabdomyosarcoma, Intergroup Rhabdomyosarcoma Study group III/IV, treated according to the European paediatric Soft tissue sarcoma Study Group (EpSSG) RMS2005 or MTS2008 studies. DW-MRI was performed according to institutional protocols.

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Chronic kidney diseases affect a substantial percentage of the adult population worldwide. This observation emphasizes the need for novel insights into the molecular mechanisms that control the onset and progression of renal diseases. Recent advances in genomics have uncovered a previously unanticipated link between the non-coding genome and human kidney diseases.

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Focal segmental glomerulosclerosis (FSGS) is a major cause of end-stage renal disease and remains without specific treatment. To identify new events during FSGS progression, we used an experimental model of FSGS associated with nephroangiosclerosis in rats injected with L-NAME (N-nitro-L-arginine methyl ester). After transcriptomic analysis we focused our study on the role of Isthmin-1 (ISM1, an anti-angiogenic protein involved in endothelial cell apoptosis.

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Article Synopsis
  • The study explores how various tumor segmentation strategies in diffusion-weighted MRI affect the apparent diffusion coefficient (ADC) in pediatric rhabdomyosarcoma patients.
  • A review of 76 articles identified common segmentation strategies, with findings showing significant variation in methods used to define regions of interest, volume, and areas excluded during the process.
  • Results indicated that excluding certain tumor areas led to lower ADC measurements, emphasizing the need for standardized segmentation methods in future MRI studies to improve treatment response monitoring.
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Background: Alterations of renal hemodynamics play an essential role in renal homeostasis and kidney diseases. Recent data indicated that semaphorin 3C (SEMA3C), a secreted glycoprotein involved in vessel development, can modulate renal vascular permeability in acute kidney injury, but whether and how it might impact systemic and renal hemodynamics is unknown.

Objectives: The objective of the study was to explore the effect of SEMA3C on systemic and renal hemodynamics.

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Notch3 plays an important role in the differentiation and development of vascular smooth muscle cells. Mice lacking Notch3 show deficient renal autoregulation. The aim of the study was to investigate the mechanisms involved in the Notch3-mediated control of renal vascular response.

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Diabetic nephropathy (DN) remains the most common reason for end-stage renal disease and a leading cause of kidney replacement therapy. Multifactorial pathophysiological mechanisms underlie the development of DN. Among the signalling pathways involved, nuclear factor-κB (NF-κB) plays a key role in pathogenesis triggering inflammation, oxidative stress and fibrosis.

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Microvasculature consisting of endothelial cells and pericytes is the main site of injury during antibody-mediated rejection (ABMR) of renal grafts. Little is known about the mechanisms of activation of pericytes in this pathology. We have found recently that activation of Notch3, a mediator of vascular smooth muscle cell proliferation and dedifferentiation, promotes renal inflammation and fibrosis and aggravates progression of renal disease.

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To guide the development of therapeutic interventions for acute kidney injury, elucidating the deleterious pathways of this global health problem is highly warranted. Emerging evidence has indicated a pivotal role of endothelial dysfunction in the etiology of this disease. We found that the class III semaphorin SEMA3C was ectopically upregulated with full length protein excreted into the blood and truncated protein secreted into the urine upon kidney injury and hypothesized a role for SEAM3C in acute kidney injury.

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Background: Polycystic kidney disease (PKD) is a genetic disorder affecting millions of people worldwide that is characterized by fluid-filled cysts and leads to end-stage renal disease (ESRD). The hallmarks of PKD are proliferation and dedifferentiation of tubular epithelial cells, cellular processes known to be regulated by Notch signaling.

Methods: We found increased Notch3 expression in human PKD and renal cell carcinoma biopsies.

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The enamel renal syndrome (ERS) is a rare disorder featured by amelogenesis , gingival fibromatosis and nephrocalcinosis. ERS is caused by bi-allelic mutations in the secretory pathway pseudokinase FAM20A. How mutations in may modify the gingival connective tissue homeostasis and cause fibromatosis is currently unknown.

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Under healthy conditions, foot processes of neighbouring podocytes are interdigitating and connected by an electron-dense slit diaphragm. Besides slit diaphragm proteins, typical adherens junction proteins are also found to be expressed at this cell-cell junction. It is therefore considered as a highly specialized type of adherens junction.

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Background: Vascular permeability (VP) is a fundamental aspect of vascular biology. A growing number of studies have revealed that many signalling pathways govern VP in both physiological and pathophysiological conditions. Furthermore, emerging evidence identifies VP alteration as a pivotal pathogenic factor in acute kidney injury, chronic kidney disease, diabetic kidney disease, and other proteinuric diseases.

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Enamel renal syndrome (ERS) is a rare recessive disorder caused by loss-of-function mutations in (family with sequence similarity 20 member A, OMIM #611062). Enamel renal syndrome is characterized by amelogenesis imperfecta, delayed or failed tooth eruption, intrapulpal calcifications, gingival overgrowth and nephrocalcinosis. Although gingival overgrowth has consistently been associated with heterotopic calcifications the pathogenesis, structure and interactions of the mineral deposits with the surrounding connective tissue are largely unknown.

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Article Synopsis
  • Periostin, a matricellular protein, is linked to the progression of chronic kidney disease (CKD) but its role in acute kidney injury (AKI) was previously unknown.
  • In experiments with mice, researchers found that periostin production increased during the kidney repair phase after ischemia-reperfusion injury, and overexpression of periostin protected against renal damage while knockout mice experienced worsened injury.
  • The study concluded that periostin plays a protective role in AKI by inhibiting cell damage and promoting pro-regenerative responses from macrophages, suggesting that it could be a key player in kidney repair mechanisms.
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Article Synopsis
  • Chronic allograft dysfunction (CAD) is the leading cause of kidney transplant failure, characterized by the replacement of healthy kidney tissue with fibrosis.
  • The study investigated the role of cannabinoid receptor 1 (CB1) in CAD by analyzing its expression in kidney biopsies from 26 transplant patients, finding that CB1 was low in healthy grafts but increased significantly during CAD, particularly in tubular cells.
  • The research also demonstrated that blocking CB1 with rimonabant reduced collagen production in kidney cells, suggesting that targeting the cannabinoid system could be a potential therapeutic strategy for managing fibrosis in CAD.
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