Human peritoneal tight junction, transporter and channel expression in health and kidney failure, and associated solute transport

Next to the skin, the peritoneum is the largest human organ, essentially involved in abdominal health and disease states, but information on peritoneal paracellular tight junctions and transcellular channels and transporters relative to peritoneal transmembrane transport is scant. We studied their peritoneal localization and quantity by immunohistochemistry and confocal microscopy in health, in chronic kidney disease (CKD) and on peritoneal dialysis (PD), with the latter allowing for functional characterizations, in a total of 93 individuals (0-75 years). Claudin-1 to -5, and -15, zonula occludens-1, occludin and tricellulin, SGLT1, PiT1/SLC20A1 and ENaC were consistently detected in mesothelial and arteriolar endothelial cells, with age dependent differences for mesothelial claudin-1 and arteriolar claudin-2/3. In CKD mesothelial claudin-1 and arteriolar claudin-2 and -3 were more abundant. Peritonea from PD patients exhibited increased mesothelial and arteriolar claudin-1 and mesothelial claudin-2 abundance and reduced mesothelial and arteriolar claudin-3 and arteriolar ENaC. Transperitoneal creatinine and glucose transport correlated with pore forming arteriolar claudin-2 and mesothelial claudin-4/-15, and creatinine transport with mesothelial sodium/phosphate cotransporter PiT1/SLC20A1. In multivariable analysis, claudin-2 independently predicted the peritoneal transport rates. In conclusion, tight junction, transcellular transporter and channel proteins are consistently expressed in peritoneal mesothelial and endothelial cells with minor variations across age groups, specific modifications by CKD and PD and distinct associations with transperitoneal creatinine and glucose transport rates. The latter deserve experimental studies to demonstrate mechanistic links.Clinical Trial registration: The study was performed according to the Declaration of Helsinki and is registered at www.clinicaltrials.gov (NCT01893710).

Therapeutic targeting of chronic kidney disease-associated DAMPs differentially contributing to vascular pathology

Chronic Kidney Disease (CKD) is associated with markedly increased cardiovascular (CV) morbidity and mortality. Chronic inflammation, a hallmark of both CKD and CV diseases (CVD), is believed to drive this association. Pro-inflammatory endogenous TLR agonists, Damage-Associated Molecular Patterns (DAMPs), have been found elevated in CKD patients' plasma and suggested to promote CVD, however, confirmation of their involvement, the underlying mechanism(s), the extent to which individual DAMPs contribute to vascular pathology in CKD and the evaluation of potential therapeutic strategies, have remained largely undescribed. A multi-TLR inhibitor, soluble TLR2, abrogated chronic vascular inflammatory responses and the increased aortic atherosclerosis-associated gene expression observed in nephropathic mice, without compromising infection clearance. Mechanistically, we confirmed elevation of 4 TLR DAMPs in CKD patients' plasma, namely Hsp70, Hyaluronic acid, HMGB-1 and Calprotectin, which displayed different abilities to promote key cellular responses associated with vascular inflammation and progression of atherosclerosis in a TLR-dependent manner. These included loss of trans-endothelial resistance, enhanced monocyte migration, increased cytokine production, and foam cell formation by macrophages, the latter via cholesterol efflux inhibition. Calprotectin and Hsp70 most consistently affected these functions. Calprotectin was further elevated in CVD-diagnosed CKD patients and strongly correlated with the predictor of CV events CRP. In nephropathic mice, Calprotectin blockade robustly reduced vascular chronic inflammatory responses and pro-atherosclerotic gene expression in the blood and aorta. Taken together, these findings demonstrated the critical extent to which the DAMP-TLR pathway contributes to vascular inflammatory and atherogenic responses in CKD, revealed the mechanistic contribution of specific DAMPs and described two alternatives therapeutic approaches to reduce chronic vascular inflammation and lower CV pathology in CKD.

Peritoneal transformation shortly after kidney transplantation in pediatric patients with preceding chronic peritoneal dialysis

BACKGROUND

The unphysiological composition of peritoneal dialysis (PD) fluids induces progressive peritoneal fibrosis, hypervascularization and vasculopathy. Information on these alterations after kidney transplantation (KTx) is scant.

METHODS

Parietal peritoneal tissues were obtained from 81 pediatric patients with chronic kidney disease stage 5 (CKD5), 72 children on PD with low glucose degradation product (GDP) PD fluids, and from 20 children 4-8 weeks after KTx and preceding low-GDP PD. Tissues were analyzed by digital histomorphometry and quantitative immunohistochemistry.

RESULTS

While chronic PD was associated with peritoneal hypervascularization, after KTx vascularization was comparable to CKD5 level. Submesothelial CD45 counts were 40% lower compared with PD, and in multivariable analyses independently associated with microvessel density. In contrast, peritoneal mesothelial denudation, submesothelial thickness and fibrin abundance, number of activated, submesothelial fibroblasts and of mesothelial-mesenchymal transitioned cells were similar after KTx. Diffuse peritoneal podoplanin positivity was present in 40% of the transplanted patients. In subgroups matched for age, PD vintage, dialytic glucose exposure and peritonitis incidence, submesothelial hypoxia-inducible factor 1-alpha abundance and angiopoietin 1/2 ratio were lower after KTx, reflecting vessel maturation, while arteriolar and microvessel p16 and cleaved Casp3 were higher. Submesothelial mast cell count and interleukin-6 were lower, whereas transforming growth factor-beta induced pSMAD2/3 was similar as compared with children on PD.

CONCLUSIONS

Peritoneal membrane damage induced with chronic administration of low-GDP PD fluids was less severe after KTx. While peritoneal microvessel density, primarily defining PD transport and ultrafiltration capacity, was normal after KTx and peritoneal inflammation less pronounced, diffuse podoplanin positivity and profibrotic activity were prevalent.

MO714: PARK7—A Novel Therapeutic Target for Peritoneal Dialysis Induced Peritoneal Membrane and Vascular Transformation

BACKGROUND AND AIMS

Patients with chronic kidney disease (CKD) suffer from increased oxidative stress, which is further aggravated in patients on peritoneal dialysis (PD). Parkinson disease protein 7 (PARK7) has antioxidant and antiapoptotic activity; its role in PD is unknown.

METHOD

Transcriptome and proteome data sets from microdissected omental arterioles obtained from age-matched non-CKD children, children with CKD5 and children on PD with fluids containing low or high concentrations of glucose degradation products (GDP; n = 6/group) underwent PARK7 related gene set analysis (FDR < 0.05). Respective parietal peritoneal tissues (n = 60) underwent digital histomorphometry analyses. PARK7 western blotting was performed in effluents of eight children on high-GDP PD. Human umbilical endothelial cells (HUVEC) viability (MTT assay) and transepithelial electrical resistance (TER, Transwells) and 4-, 10- and 70-kDa dextran transport were measured (n = 6–12/group). As an extreme phenotype approach of PD toxicity, C57/BL6J mice were treated with chlorhexidine digluconate (CG) and PARK7 activator for 7 days and parietal peritoneal damage was quantitated (n = 6–8/group).

RESULTS

Arteriolar transcriptome analyses in children on low-GDP PD demonstrated the enrichment of PARK7 related GO terms of oxidant detoxification as compared to CKD5 and in children on high-GDP PD that of reactive oxygen species-, mitochondria- and apoptosis-related processes. On the proteome level the DNA repair/organization, catabolic and mitochondria associated processes were enriched in children on low-GDP PD, and mitochondrial processes in children on high-GDP PD.

PARK7 was detected in the parietal peritoneal tissues in mesothelial, endothelial and inflammatory cells, in myocytes and fibroblasts and was present in the PD effluents. Total peritoneal and submesothelial PARK7 abundance was similar in controls, patients with CKD5 and in patients on low-GDP PD, but 2-fold increased in patients on high GDP PD compared to controls and CKD5. Mesothelial PARK7 was 2-fold increased in children on low-GDP PD versus CKD5, endothelial PARK7 abundance was similar in all four groups.

In low-GDP PD patients endothelial PARK7 abundance correlated with vessel lumen/vessel diameter ratio (r = 0.53, P = 0.06), i.e. inversely with lumen obliteration. Submesothelial PARK7 correlated with microvessel density (r = 0.55, P = 0.05), with submesothelial hypoxia inducible factor-1 and angiopoietin-1 and -2 (ρ = 0.63, P = 0.023; r = 0.91, P < 0.0001; r = 0.60, P = 0.03) but not with VEGF. Submesothelial and endothelial PARK7 correlated with respective caspase 3 abundances (r = 0.74/0.68, P = 0.009/0.015).

In HUVEC methylglyoxal (MG) dose- and time-dependently reduced viability, coincubation with PARK7 activator partially preserved endothelial cell viability. In Transwells, MG treatment decreased TER and increased dextran transport, but none of them was improved by PARK7 activation.

In mice treated with CG submesothelial thickness was 2-fold increased, microvessel density was unchanged; PARK7 protein abundance was 5-fold reduced. Co-treatment of CG with PARK7 activator prevented the submesothelial thickening.

CONCLUSION

PD modifies arteriolar PARK7 related biological processes of oxidant detoxification, mitochondria- and apoptosis-related processes. PARK7 is ubiquitously expressed in the parietal peritoneum and regulated by the GDP content of PD fluids. In patients on low-GDP PD, PARK7 abundance correlated with the degree of arteriolar lumen narrowing, and VEGF-independent angiogenesis. Activation of PARK7 preserves endothelial cell viability in vitro and prevents CG induced peritoneal membrane damage in mice and thus represents a potential novel therapeutic approach.

MO465: Molecular Mechanisms of Vascular Ageing in Children With Chronic Kidney Disease

BACKGROUND AND AIMS

Paediatric patients with chronic kidney disease (CKD) develop significant atherosclerosis and vascular calcifications until early adulthood. Largely devoid of confounding lifestyle related factors and underlying disease mostly limited to congenital abnormalities of the kidneys and urinary tract, these patients provide highly sensitive and specific information on early CKD-induced molecular mechanisms of vascular disease and on putative therapeutic targets.

METHOD

Standardized omental and parietal peritoneal tissue samples from 95 non-CKD individuals [median age 9.2 (interquartile range, IQR 15), 110 children with CKD5 (median age 8.6 (IQR 12)] underwent digital histomorphometry. Omental arterioles microdissected from surrounding fat tissue underwent whole-exome and proteome analyses, followed by gene set enrichment and Ingenuity pathway analysis. Vascular calcification pathway analysis was performed for 370 biological processes and molecular functions associated with vascular calcification extracted from Gene Ontology database. Key regulated pathways were validated by quantitative immunostaining. The effects of uraemic toxins on endothelial integrity were studied in vitro in human umbilical arterial and vein endothelial cells in Transwells.

RESULTS

Lumen to vessel diameter (L/V) ratio was reduced in patients with CKD5. Parietal peritoneal arteriole L/V ratio was 0.54 (0.2) versus 0.63 (0.1) in non-CKD controls, omental arteriole L/V ratio 0.58 (0.1) versus 0.76 (0.1) in controls (both P < 0.001), indicating significant CKD5 related vascular disease. These findings were independent of underlying disease entities and gender. The parietal peritoneal submesothelial space exhibited infiltration of single CD45 positive lymphocytes, mesothelial cells which had undergone epithelial-to-mesenchymal-transition, and isolated peritoneal fibrin deposits. Submesothelial TGF-ß induced pSMAD was 4-fold increased and IL-17A 2-fold, while VEGF was not different compared to non-CKD controls.

Gene set enrichment analysis of omental arteriolar multi-omics identified enrichment of pathways including telomere extension by telomerase, chromatin histone methylation, actin cytoskeleton, integrin- and tight junction signaling, and focal adhesion in children with CKD5 children compared to controls (P < 0.05). Vascular calcification pathway analysis identified 16/370 pathways significantly enriched on arteriolar transcriptome (P < 0.01), related to Wnt signalling, extracellular matrix organization, complement activation, autophagy and ossification. Applying the same threshold on proteome level, 10 calcification-related arteriolar pathways were identified and included DNA damage, fatty acid metabolism, calcium ion binding, extracellular matrix organization and complement activation.

In independent age-matched cohorts, CKD5 children had shorter endothelial telomere and less endothelial methylated histone 3. The endothelial complement system was activated and arteriolar actin cytoskeleton interacting proteins gamma actin and profilin-1 were reduced in CKD5, cofilin-1 remained unchanged. In vitro, methylglyoxal and 3.4-di-deoxyglucosone-3-ene reduced transendothelial resistance, increased endothelial monolayer permeability and induced cytoskeleton disassembly (zonula occludens-1 and F-actin). These effects were prevented by co-incubation with anserine, 3-methylhistidine and alanyl-glutamine, but not by carnosine, L-histidine, 1-methylhistidine and methyl-alanyl.

CONCLUSION

CKD5 results in major vascular ageing already in early childhood. Multi-omics analysis of omental arterioles identified specific mechanisms of CKD-induced vascular ageing and of vascular calcification. Endothelial cell barrier integrity is impaired, and in vitro reversed by specific dipeptides.

FC088: Molecular and Functional Characterization of the Mesothelial and Endothelial Cell Barrier in Health, Ckd and Peritoneal Dialysis

BACKGROUND AND AIMS

Tight junctions (TJ) and transcellular ion channels and transporters define solute transport characteristics across cellular barriers, which is of particular interest in patients on peritoneal dialysis (PD). Little is known about their cell specific expression, and regulation in PD. We studied their expression in human endothelial and mesothelial cell lines and in paediatric peritoneal tissues.

METHOD

In vitro, polarized primary human peritoneal mesothelial cells (HPMC), immortalized mesothelial cells (MeT-5A), human umbilical vein endothelial cells (HUVEC) and human capillary microvascular endothelial cells (HCMEC) underwent RNA sequencing, and gene enrichment analysis (GSEA, ClueGO/Cluepedia) for functional annotation. Key findings were reconfirmed by western blotting and confocal laser scanning immunofluorescence microscopy. Transepithelial electrical resistance (TER) and permeability fluxes of fluorescent 4-, 10- and 70-kDa dextran were measured in Transwells. Ex vivo, whole transcriptome and proteome data from microdissected omental arterioles were used for targeted pathway analysis in non-CKD children, chronic kidney disease (CKD5) and on PD with low and high glucose degradation product (GDP) content (n = 6/group). Mesothelial and endothelial peritoneal solute transporting proteins were quantified in parietal peritoneum of independent paediatric non-CKD, CKD5 and PD cohorts by digital immunohistochemistry.

RESULTS

A total of 9853 of 12 760 transcripts were common between all four cell lines. A total of 631 transcripts were MeT-5A, 366 HPMC, 99 HUVEC and 87 HCMEC specific. Next to the tissue origin and transformation status, the transcripts reflected major differences in extracellular matrix, glycocalyx and adhesion organization between HCMEC and HUVEC, and extracellular matrix, migration, growth factor and immune response between HPMC and MeT-5A cells. While total counts of cell junction, transmembrane and endocytosis related transcripts were similar among cell lines, the specific TJ, transmembrane and endocytosis related transcript patterns, differed substantially between endothelial and mesothelial cells. Of the functionally well described sealing TJs, claudin (CLDN)1 was expressed in mesothelial cells, and CLDN5 in endothelial cells. Findings were reconfirmed by western blotting and immunofluorescence staining. Functionally, transepithelial resistance (TER) was 50% lower for HCMEC compared to HPMC, MeT-5A and HUVEC; 4-, 10- and 70-kDa dextran permeability was increased in HCMEC.

Ex vivo, human arteriolar pathway analysis demonstrated upregulation of paracellular transport-related pathways in CKD5 versus non-CKD patients on protein level. Compared to CKD5, low GDP PD upregulated and high GDP PD downregulated these pathways on the transcriptome and protein levels. Transcellular transporter pathway regulation was variable.

In the parietal peritoneum the endothelial surface area for transport was age dependently 1.5–2-fold higher than the mesothelial surface area and the ratio markedly increased with low GDP PD. Validation in parietal peritoneal tissues, reconfirmed arteriolar sealing TJ regulation. Arteriolar CLDN2, a paracellular pore forming cation and water transporter, correlated with D/PCreatinine (r = 0.58) and D/D0Glucose (r = –0.62), mesothelial pore forming cation transporter CLDN15 with D/PCreatinine (r = 0.57) and D/D0Glucose (–0.66). Transcellular transporters for sodium, glucose and phosphate were hardly affected by PD; phosphate transporter PIT1 abundance correlated with serum phosphate (r = –0.48).

CONCLUSION

We provide the first comprehensive analysis of the peritoneal paracellular and transcellular determinants of solute transporters and its regulation by CKD and PD. Mesothelial and endothelial cell barrier sealing and transporter abundance differed substantially, and associated with PD membrane function, with functional data suggesting a key role of both the mesothelial and endothelial cell barrier.

Angiogenic Role of Mesothelium-Derived Chemokine CXCL1 During Unfavorable Peritoneal Tissue Remodeling in Patients Receiving Peritoneal Dialysis as Renal Replacement Therapy

Peritoneal dialysis (PD) is a valuable ‘home treatment’ option, even more so during the ongoing Coronavirus pandemic. However, the long-term use of PD is limited by unfavourable tissue remodelling in the peritoneal membrane, which is associated with inflammation-induced angiogenesis. This appears to be driven primarily through vascular endothelial growth factor (VEGF), while the involvement of other angiogenic signaling pathways is still poorly understood. Here, we have identified the crucial contribution of mesothelial cell-derived angiogenic CXC chemokine ligand 1 (CXCL1) to peritoneal angiogenesis in PD. CXCL1 expression and peritoneal microvessel density were analysed in biopsies obtained by the International Peritoneal Biobank (NCT01893710 at www.clinicaltrials.gov), comparing 13 children with end-stage kidney disease before initiating PD to 43 children on chronic PD. The angiogenic potential of mesothelial cell-derived CXCL1 was assessed in vitro by measuring endothelial tube formation of human microvascular endothelial cells (HMECs) treated with conditioned medium from human peritoneal mesothelial cells (HPMCs) stimulated to release CXCL1 by treatment with either recombinant IL-17 or PD effluent. We found that the capillary density in the human peritoneum correlated with local CXCL1 expression. Both CXCL1 expression and microvessel density were higher in PD patients than in the age-matched patients prior to initiation of PD. Exposure of HMECs to recombinant CXCL1 or conditioned medium from IL-17-stimulated HPMCs resulted in increased endothelial tube formation, while selective inhibition of mesothelial CXCL1 production by specific antibodies or through silencing of relevant transcription factors abolished the proangiogenic effect of HPMC-conditioned medium. In conclusion, peritoneal mesothelium-derived CXCL1 promotes endothelial tube formation in vitro and associates with peritoneal microvessel density in uremic patients undergoing PD, thus providing novel targets for therapeutic intervention to prolong PD therapy.

Glucose Derivative Induced Vasculopathy in Children on Chronic Peritoneal Dialysis

[Figure: see text].

MO683EXPRESSION OF PARACELLULAR JUNCTION COMPONENTS AND TRANSCELLULAR TRANSPORTERS IN HEALTH, CKD5 AND PERITONEAL DIALYSIS

Background and Aims

Tight junction (TJ) proteins have been suggested as molecular correlates for peritoneal semi-permeability and dialytic transport function in patients on peritoneal dialysis. Junction abundance in healthy individuals, in those with CKD5 and in patients on PD has not been described yet, the relation with peritoneal solute transport is unknown.

Method

Junction and transporter expression was analysed in multi-omics data sets from microdissected omental arterioles in children with normal renal function, CKD5 and on PD with low and high glucose degradation product (GDP) content (n=6/group). Parietal peritoneal tight junction proteins CLDN-1,-2,-3,-4,-5,-15, the adapter protein of claudins to actin cytoskeleton protein, zonula occludens-1 (ZO-1), the tricellular junction protein tricellulin (TriC), and transcellular transporters for sodium (ENaC), glucose (SGLT-1) and phosphate (PIT-1) were quantified in 40 non-CKD individuals, 20 children with CKD5 and 20 and 15 children on low- and high-GDP PD by quantitative, digital immunohistochemistry. Findings were correlated to 2-hour peritoneal equilibration test data obtained within 6 months of biopsy sampling (n=23). Primary human umbilical vein endothelial cells (HUVEC) were used to study the effects of single PD compounds on transepithelial electrical resistance (TER) and molecular size-dependent paracellular transport capacity. Co-stained monolayers were visualized by confocal microscopy. Single junction molecule localization and clustering were analysed by super resolution microscopy.

Results

Transcriptome and proteome pathway enrichment analysis of arteriolar junction and membrane protein demonstrated regulation in CKD5 versus health, and differential regulation by low- and high-GDP PD versus CKD5. In the parietal peritoneum all junctions and cellular transporters were expressed in endothelial and mesothelial cells. Pore forming CLDN-2, -4 and -15 were localized also in submesothelial immune cells. Parietal peritoneal junction abundance was age-dependent and also modified by CKD5 and PD. Mesothelial and endothelial abundance of the selective cation/water channel CLDN-2 increased in patients on low- and high-GDP PD fluids. Adaptor protein ZO-1 was upregulated in low GDP-PD versus CKD5, while sealing proteins CLDN -3 and -5 were downregulated. D/P creatinine, D/P phosphate, D/D0 glucose were similar in CKD5 and PD groups. D/P creatinine correlated with mesothelial CLDN-15, with arteriolar CLDN-2 and TriC and with endothelial ENaC. D/P phosphate correlated with endothelial CLDN-15, D/D0 glucose with mesothelial CLDN-4 and arteriolar CLDN-2. Capillary ZO-1 correlated with 24-h ultrafiltration standardized to body surface area and dialytic glucose exposure. In vitro, TER was decreased by low pH, glucose and 0.5µM methylglyoxal after 5h. Alanyl-glutamine (AlaGln) dose-dependently increased TER, and reduced 10kDa and 70kDa solute at 24mM, increased the abundance of ZO-1 and CLDN5 at cell-cell contacts, and on nanoscale clustering of the pore-forming CLDN2 and CLDN5.

Conclusion

Abundance of parietal peritoneal sealing and pore forming junctions and transcellular solute transporters varies with cell type and age and is differentially regulated by PD and associated with dialytic transport function. Our preliminary analyses illustrate the role of junctions and cellular transporters for solute transport across the peritoneal mesothelial and endothelial cell barrier. In-depth understanding of specific molecular functions should provide targets for modulation to improve efficacy of PD.

FC 109GLUCOSE DERIVATIVE INDUCED VASCULOPATHY IN CHILDREN ON PERITONEAL DIALYSIS

Background and Aims

Patients with chronic kidney disease patients (CKD) have an exceedingly high cardiovascular risk. While vasculopathy is further accelerated during peritoneal dialysis (PD), the pathophysiological role of reactive metabolites such as glucose degradation products (GDP) is uncertain.

Method

Omental and parietal peritoneal tissues from 100 non-CKD individuals, 107 children with CKD5, 60 children treated with neutral pH, low GDP, and 30 children treated with acidic pH, high GDP PD fluids underwent standardized digital histomorphometry. Omental arterioles localized within the fat tissue, protected from direct PD fluid exposure were microdissected for multi-omics analysis. Key regulated pathways were validated by quantitative immunostaining, with localization microscopy in peritoneal tissues of matched cohorts and in vitro in human umbilical vein endothelial cells.

Results

Arterioles from children with CKD5 exhibited reduced lumen to vessel ratio (L/V) and reduced endothelial telomere length compared to non-CKD individuals; gene ontology analysis identified enrichment of arteriolar genes associated with nuclear telomere cap complex and focal adhesion. Pathway analysis of arteriolar cross-omics identified top canonical pathways including telomere extension by telomerase, actin cytoskeleton, integrin and tight junction signalling.

Peritoneal vasculopathy progressed with PD vintage and was more pronounced with high versus low GDP exposure (p<0.001). Compared to CKD5, low GDP-PD upregulated 145/110 and downregulated 38/34 arteriolar genes/proteins, high GDP-PD upregulated 684/137 and supressed 1560/55 genes/proteins (p<0.01). High GDP milieu induced upregulation of arteriolar genes involved in cell death/apoptosis and suppressed genes related to cell viability/survival, cytoskeleton organization and immune response biofunctions. Vasculopathy associated canonical pathways concordantly regulated on arteriolar gene and protein level with high GDP exposure included cell death/proliferation, apoptosis, cytoskeleton organization, metabolism and detoxification, cell junction signalling, and immune response.

Quantitative validation in PD cohorts with similar PD vintage, dialytic glucose exposure and age (n=15 / group) verified increased proapoptotic activity and cytoskeleton disintegration with high-GDP exposure; single-molecule-localization microscopy demonstrated arteriolar endothelial zonula occludens-1 (ZO-1) disruption. Absolute and relative to endoluminal surface length, arteriolar endothelial cell counts were inversely correlated with GDP exposure, with apoptosis marker caspase-3, TGF-ß induced pSMAD2/3, interleukin-6, ZO-1 protein abundance and the degree of vasculopathy. In vitro, exposure to GDP 3,4-dideoxyglucosone-3-ene dose-dependently reduced nuclear endothelial lamin-A/C and membrane ZO-1 assembly. Transendothelial electrical resistance was decreased. ZO-1 and sealing tight junction claudin-5 protein abundance were decreased in cells after incubation with high GDP compared to low GDP PD fluid and culture media. On nanoscale level GDP reduced junction cluster formation in the membrane area.

Conclusion

Multi-omics analysis of omental arterioles from children without pre-existing vasculopathy and life-style related confounders identified key mechanisms of vascular aging in CKD5 and the major contribution of GDP to accelerated vasculopathy during PD, i.e. disruption of endothelial cell junctions and cytoskeleton and induction of apoptosis.

[Cholecystectomy in young women from the south-oriental area of Santiago: comparison between 2 periods]

The aim of this study was to know if cholecystectomy rates have decreased in young women, considering that these rates have decreased in the last years in the general chilean population. The frequency of previous cholecystectomy was compared in 1582 women aged 23.9 +/- 5.8 years admitted to a maternity for delivery between 1985 and 1986 and 4943 women aged 24.6 +/- 5.9 years admitted between 1989 and 1990 for the same reason. There was a reduction in cholecystectomy frequency from 4.7 to 2.5% specially among women 21 to 35 years old. Cholecystectomy was performed at a mean age of 23 years in both groups and 42.6% of the procedures were done before the first pregnancy. An unexpected finding was a lower body weight among women studied in the second period (62.5 +/- 9.1 vs 67.7 +/- 8.4 k).

[Blood pool in the study of hepatic hemangioma]

Blood pool scintigraphy is a useful tool in the diagnosis of hepatic hemangioma. We reviewed retrospectively the clinical histories of 24 patients with abnormal blood pool scintigraphies and a presumptive diagnosis of hepatic hemangioma, based on clinical or ultrasonographic findings. In 20 of these patients, blood pool scintigraphy was diagnostic for hepatic hemangioma. The diagnosis was confirmed by an asymptomatic clinical evolution of 12 to 78 months in all the patients, CT scan in 8, angiography in 5 and liver biopsy in one. In the remaining 4 patients scintigraphy ruled out the presence of a hepatic hemangioma. Our results are similar to previous reports in the literature and blood pool scintigraphy has a high specificity for the diagnosis of hepatic hemangioma.

[Symptomatic lithiasic biliary disease. Comparison between men and women undergoing cholecystectomy]

A prospective survey was carried out in 205 males and 667 females who had their gallbladder removed for gallstone disease during 1989 at a general hospital in Chile. Females had a greater prevalence of disease with an earlier appearance of symptoms leading to surgery at a younger age. In contrast, males developed a more aggressive form of the disease, with a shorter interval from appearance of symptoms and surgery.