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Circulating apoptotic proteins are increased in long-term disease-free breast cancer survivors.

Circulating apoptotic proteins are increased in patients with heart failure. We evaluated whether circulating soluble (s) apoptosis-related proteins and inflammation markers are increased in long-term disease free breast cancer survivors and associated with cardiotoxicity, and if subgroups could be identified based on the applied treatments. Circulating tumour necrosis factor (TNF) alpha, sTNF-receptor (sTNF-R) 1 and 2, sFas, sFas ligand, sTNF-related apoptosis inducing ligand (sTRAIL) and serum HER2 were measured with immunoassay. High-sensitivity C-reactive protein (HS-CRP), fibrinogen, plasma B-type and N-terminal atrial natriuretic peptide (NT-ANP and BNP) were also determined. Thirty-four patients with median 6.0 years follow-up and 12 healthy age-matched women were enrolled. Chemotherapy, consisting of five cycles fluorouracil, epirubicin (90 mg/m(2)), cyclophosphamide (FEC) (n=14) or four cycles FEC followed by myeloablation with high-dose carboplatin, cyclophosphamide, thiotepa (n=20), preceded irradiation and tamoxifen. Circulating apoptosis markers were higher in patients than in controls. No associations with cardiac dysfunction were observed. sFas ligand and sTRAIL were higher in the high-dose than in the standard-dose group. In conclusion, we observed increased circulating apoptotic protein levels in long-term disease-free breast cancer survivors, treated with adjuvant chemoradiotherapy, particularly after myeloablative chemotherapy. The potential relation with late cardiotoxicity of antineoplastic therapy deserves further study.

Adult↗

Circulating interleukin (IL)-1 beta, IL-6 and tumor necrosis factor-alpha in children with febrile infection--a comparison with C-reactive protein.

Circulating interleukin (IL)-1 beta, IL-6, and tumor necrosis factor (TNF)-alpha were examined in 42 febrile children with fever lasting more than 4 days. Their diagnosis were probable viral syndrome in 22, urinary tract infection (UTI) in 10, and probable bacterial pneumonia in 10. None of our study patients had detectable serum IL-1 beta. TNF-alpha levels were significantly higher in children with pneumonia than in those with viral syndrome (p < 0.01). Children with UTI and pneumonia had significantly higher IL-6 and CRP, compared to those with probable viral syndrome (p < 0.01 for both IL-6 and CRP). When appropriate cutoff values are chosen, IL-6 had greatly improved specificity (86.4%, > 20 pg/ml) to demonstrate UTI and pneumonia, as compared to that using CRP (48%, > 40 mg/l). After three days' antibiotic treatment, IL-6 fell to control levels in children with UTI and pneumonia, while CRP remained elevated. There was no difference in TNF-alpha values before and after treatment. Thus, IL-6, rather than IL-1 beta and TNF-alpha, may be a helpful diagnostic tool for evaluation of pediatric febrile infection. Sequential studies involving more patients are needed to determine whether IL-6 is better than CRP in this clinical setting.

Adolescent↗

Quantification of circulating activated protein C in human plasma by immunoassays--enzyme levels are proportional to total protein C levels.

We have developed a simple assay that measures the circulating activated protein C (APC) in plasma. The assay requires collection of duplicate blood samples, one in citrate plus heparin and the other in citrate plus inhibitors of the enzyme. In the heparin tube, APC reacts completely and irreversibly with its major plasma inhibitors, protein C inhibitor (PCI) and alpha 1-antitrypsin (alpha 1AT), and the complexes formed are measured by ELISAs. The amount of circulating APC is calculated from the difference between the total amount of complexed APC (sample in citrate plus heparin) and the amount of APC complexed in vivo (sample in citrate plus inhibitor). Over 95% of the APC added to blood collected with heparin was recovered in the assay. The assay can easily be performed in four hours, and had a detection limit of 0.1 ng/ml APC. The mean APC level in 18 protein C heterozygous members from seven kindreds was significantly lower (0.6 +/- 0.3 ng/ml) than in 20 healthy controls (1.1 +/- 0.3 ng/ml) (p < 0.001), whereas the mean level in 10 non-affected members from the kindreds studied was 1.5 +/- 0.3 ng/ml. In the group of 12 nonanticoagulated heterozygous protein C-deficient individuals, the three patients with a history of venous thrombosis had a mean APC level significantly lower than the nine asymptomatic members (p < 0.01), both subgroups showing similar protein C levels. There was a significant correlation in all groups between the levels of APC and the levels of protein C antigen (r = 0.758, p < 0.0001) and activity (r = 0.745, p < 0.0001), which means that APC circulating levels are proportional to protein C levels and suggests that the protein C level is the limiting factor in the rate of protein C activation in vivo.

Adolescent↗

Causal association between 91 circulating inflammatory proteins and primary open-angle glaucoma: a bidirectional Mendelian randomization study.

BACKGROUND: Glaucoma, especially primary open-angle glaucoma (POAG), is a leading cause of irreversible vision loss. While elevated intraocular pressure is a major risk factor, the pathogenesis of POAG also involves genetics, oxidative stress, abnormal hemodynamics, and inflammatory factors. The role of systemic inflammation in POAG remains a subject of debate. This study aimed to investigate the causal relationships between circulating inflammatory proteins and POAG using a bidirectional Mendelian randomization (MR) approach. METHODS: A bidirectional two-sample MR analysis was conducted using genome-wide association study summary statistics. The primary stage involved 91 circulating inflammatory proteins and POAG, followed by a replication stage to verify significant findings using independent data and meta-analysis. The random-effects inverse-variance weighted model was employed as the primary method, complemented by multiple sensitivity analyses employed to ensure robustness, including multivariable MR to adjust for potential confounders. RESULTS: In the primary stage, 9 circulating inflammatory proteins were found to have significant causal effects on POAG. Specifically, the higher levels of Delta and Notch-like epidermal growth factor-related receptor (DNER) (OR: 1.12, 95&#xa0;% CI: 1.04-1.21, P&#xa0;=&#xa0;0.004), leukemia inhibitory factor (LIF) (OR: 1.20, 95&#xa0;% CI: 1.06-1.36, P&#xa0;=&#xa0;0.003), matrix metalloproteinase-10 (MMP-10) (OR: 1.08, 95&#xa0;% CI: 1.02-1.16, P&#xa0;=&#xa0;0.013), and stem cell factor (SCF) (OR: 1.09, 95&#xa0;% CI: 1.03-1.15, P&#xa0;=&#xa0;0.005) were positively associated with the risk of POAG. Conversely, the levels of fibroblast growth factor 19 (FGF-19) (OR: 0.88, 95&#xa0;% CI: 0.82-0.95, P&#xa0;=&#xa0;0.002), interleukin-18 (IL-18) (OR: 0.92, 95&#xa0;% CI: 0.86-0.99, P&#xa0;=&#xa0;0.019), IL-18 receptor 1 (IL-18R1) (OR: 0.96, 95&#xa0;% CI: 0.92-1.00, P&#xa0;=&#xa0;0.037), tumor necrosis factor ligand superfamily member 14 (TNFSF14) (OR: 0.91, 95&#xa0;% CI: 0.86-0.97, P&#xa0;=&#xa0;0.004), and tumor necrosis factor-related activation-induced cytokine (TRANCE) (OR: 0.94, 95&#xa0;% CI: 0.88-1.00, P&#xa0;=&#xa0;0.041) exhibited inverse associations with the risk of POAG. Multivariable MR analysis adjusting for confounders supported the roles of DNER, FGF-19, IL-18, IL18R1, LIF, and SCF. The replication stage confirmed the significant associations for FGF-19 (OR: 0.89, 95&#xa0;% CI: 0.84-0.95, P&#xa0;=&#xa0;4.63&#xa0;&#xd7;&#xa0;10-4), IL-18 (OR: 0.93, 95&#xa0;% CI: 0.89-0.97, P&#xa0;=&#xa0;0.002), IL-18R1 (OR: 0.96, 95&#xa0;% CI: 0.93-0.99, P&#xa0;=&#xa0;0.023), and LIF (OR: 1.18, 95&#xa0;% CI: 1.04-1.34, P&#xa0;=&#xa0;0.013). Sensitivity analyses further supported the robustness of these findings. CONCLUSION: This study elucidated the causal relationships between circulating inflammatory proteins and POAG, highlighting FGF-19, IL-18, IL-18R1, and LIF as potential therapeutic targets. These findings provide new insights for the prevention and management of POAG, although further studies are needed to understand the precise biological mechanisms.

Humans↗

Circulating inflammatory proteins and osteomyelitis: A bidirectional Mendelian randomization and colocalization analysis.

Circulating inflammatory proteins (CIPs) have been implicated in the progression of osteomyelitis (OM); however, whether these proteins play a causal role or are merely a consequence remains unclear. This study aimed to assess the causal relationships between CIPs and OM using a bidirectional 2-sample Mendelian randomization (MR) approach. MR analyses were performed using genome-wide association study summary statistics for 91 inflammation-related proteins (n&#x2005;=&#x2005;14,824) and OM (1881 cases and 3,91,037 controls). The inverse variance weighted method was used as the primary analytical approach, supplemented by MR-Egger, weighted median, simple mode, and weighted mode methods. Sensitivity analyses were conducted to evaluate heterogeneity, horizontal pleiotropy, and robustness. Colocalization analysis was applied to identify shared causal variants, and pathway enrichment analysis was used to explore underlying biological mechanisms. Forward MR analysis revealed that elevated levels of tumor necrosis factor-beta (TNF-&#x3b2;) were significantly associated with increased OM risk (odds ratio [OR]&#x2005;=&#x2005;1.132; 95% confidence interval [CI]: 1.052-1.217; false discovery rate [FDR]&#x2005;=&#x2005;0.027). Conversely, decreased levels of osteoprotegerin (OR&#x2005;=&#x2005;0.772; 95% CI: 0.671-0.889; FDR&#x2005;=&#x2005;0.015) and adenosine deaminase (OR&#x2005;=&#x2005;0.811; 95% CI: 0.736-0.894; FDR&#x2005;<&#x2005;0.001) were associated with increased OM risk. Reverse MR analysis identified increased levels of interleukin-15 receptor alpha, C-X-C motif chemokine ligand 1, fms-related tyrosine kinase 3 ligand, interleukin-20, interleukin-10 (IL10), C-C motif chemokine ligand 19, and CXCL6 as being significantly associated with OM susceptibility (all FDR&#x2005;<&#x2005;0.05). Colocalization analysis provided strong evidence for a shared causal variant between TNF-&#x3b2; and OM (posterior probability for hypothesis 4&#x2005;=&#x2005;0.999). Enrichment analyses indicated involvement of implicated proteins in Toll-like receptor signaling and T-helper 17 cell differentiation pathways. This study identified several CIPs - including TNF-&#x3b2;, osteoprotegerin, and adenosine deaminase - as potentially causal in OM development. These findings highlight promising targets for future immunomodulatory therapies aimed at preventing or mitigating osteomyelitis.

Humans↗

Circulating placental protein 14: in the first trimester of spontaneous and IVF pregnancies.

Circulating placental protein 14 (PP14) levels were measured during the first trimester in three groups of pregnant women: (i) natural conception (n = 15); (ii) pituitary desensitization with buserelin and ovarian stimulation with human menopausal gonadotrophin (HMG) followed by in-vitro fertilization and embryo transfer (IVF-ET) (n = 15); and (iii) ovarian stimulation with clomiphene citrate and HMG, followed by IVF-ET (n = 16). A 7- to 8-fold increase in serum PP14 levels was observed in normal pregnancies between weeks 4 and 10. This increase was earlier and less marked in group (ii) and absent in group (iii). These findings support the concept that endometrial function is altered in pregnancies achieved following ovarian stimulation. Alternatively, if the ovary is an important source of PP14, then these data suggest that in contrast to ovarian synthesis of steroids and the peptide relaxin, ovarian stimulation results in an impairment of PP14 synthesis, and that this is most marked when clomiphene citrate has been used.

Adult↗

A circulating shock protein that depolarizes cells in vitro depresses myocardial contractility and rate in isolated rat hearts.

Previously, we identified the presence of a circulating shock protein (CSP) in the plasma of hemorrhaged rats that depolarizes a variety of cells in vitro. In isolated perfused rat hearts, partially purified CSP produced dose-dependent decreases in contractility and heart rate associated with an increase in coronary perfusion pressure (CPP). Electrical pacing failed to prevent the negative inotropic effects. Preventing the coronary vasoconstriction with nitroglycerin or attenuating it with a cyclooxygenase inhibitor also failed to prevent the inotropic or chronotropic effects of CSP. Carbocyclic thromboxane A2 (50ng/min) caused a similar increase in CPP to CSP but had no effect on contractility or rate during the first minute of infusion. These data indicate that the protein that appears in rat plasma after hemorrhage produces negative inotropic and chronotropic effects on the isolated heart that are independent of changes in CPP. Vasoactive arachidonic acid metabolites elicited by CSP are partially responsible for the increase in coronary vascular resistance.

Animals↗

Low level of circulating activated protein C is a risk factor for venous thromboembolism.

The levels of circulating activated protein C (APC) reflect in vivo protein C activation. The aim of this study was to determine whether a low APC level is an independent risk factor for venous thromboembolism (VTE). We measured APC in 160 patients with a history of VTE and without recognized thrombophilic defects, and in 199 healthy individuals. The mean (+/- SD) APC level was lower in patients (0.99 +/- 0.44 ng/ml) than in controls (1.19 +/- 0.41 ng/ml) (p < 0.0001), and showed a different distribution in the two groups. Thirty-eight patients (23.7%) had APC levels below the 5th percentile of the control group (<0.69 ng/ml) and 57 patients (35.6%) had APC levels below the 10th percentile (<0.77 ng/ml). APC levels <0.69 ng/ml increased the risk of a single or recurrent episode of VTE 4.2-fold (95% confidence interval, 2.0-9.0) or 6.9-fold (2.6-17.9). respectively, and APC levels <0.77 ng/ml increased these risks 3.4-fold (1.9-6.2) or 5.1-fold (2.3-11.2), respectively, compared with controls. Familial studies revealed that in some cases the low APC phenotype seems to be hereditary. We conclude that a low level of circulating APC in individuals without any of the most recognized thrombophilic defects is a prevalent, independent risk factor for VTE, and that it predisposes to recurrent VTE.

Adult↗

Antiplasmin-cleaving enzyme is a soluble form of fibroblast activation protein.

Circulating antiplasmin-cleaving enzyme (APCE) has a role in fibrinolysis and appears structurally similar to fibroblast activation protein (FAP), a cell-surface proteinase that promotes invasiveness of certain epithelial cancers. To explore this potential relationship, we performed comparative structure/function analyses of the 2 enzymes. APCE from human plasma and recombinant FAP (rFAP) exhibited identical pH optima of 7.5, extinction coefficients (in(280 nm)(1%)) of 20.2 and 20.5, common sequences of tryptic peptides, and cross-reactivity with FAP antibody. APCE and rFAP are homodimers with monomeric subunits of 97 and 93 kDa. Only homodimers appear to have enzymatic activity, with essentially identical kinetics toward Met-alpha2-antiplasmin (Met-alpha2AP) and peptide substrates. APCE and rFAP cleave both Pro3-Leu4 and Pro12-Asn13 bonds of Met-alpha2AP, but relative kcat/Km values for Pro12-Asn13 are about 16-fold higher than for Pro3-Leu4. APCE and rFAP demonstrate higher kcat/Km values toward a peptide modeled on P4-P4' sequence surrounding the Pro12-Asn13 primary cleavage site than for Z-Gly-Pro-AMC and Ala-Pro-AFC substrates. These data support APCE as a soluble derivative of FAP and Met-alpha2AP as its physiologic substrate. Conversion of Met-alpha2AP by membrane or soluble FAP to the more easily fibrin-incorporable form, Asn-alpha2AP, may increase plasmin inhibition within fibrin surrounding certain neoplasms and have an impact on growth and therapeutic susceptibility.

Amino Acid Sequence↗

The bloodless rat: a new model for macromolecular transport studies across lung endothelium.

To examine the effect of circulating proteins on the passage of intravenously injected native ferritin across pulmonary capillary endothelium, rats were exchange transfused with FC-43 fluorocarbon emulsion (FCE) under ether anesthesia. Protein concentration was reduced to less than 1.1 mg/ml by exchange transfusion, followed by FCE containing 15, 30, or 60 mg/ml of lyophilized rat serum protein (LRSP). Two minutes after ferritin injection lungs were prepared for ultrastructural morphometry. The diameter and numerical density of vesicles remained unchanged under all experimental conditions; however, at 0.6 mg/ml of circulating protein there was a 5- and 10-fold increase, respectively in percent vesicle (%VL) and basement membrane labeling (BML) by ferritin. This was reversible; at 60 mg/ml of circulating protein %VL and BML was indistinguishable from controls. Following a reduction of circulating protein to less than 1.1 mg/ml, the addition of 15 mg/ml LRSP reduced %VL but had no effect on BML. This suggests that in addition to shuttling vesicles there may be a second mechanism for the transport of ferritin, possibly involving transendothelial chains of vesicles.

Animals↗

Molecular basis for protein S hereditary deficiency: genetic defects observed in 118 patients with type I and type IIa deficiencies. The French Network on Molecular Abnormalities Responsible for Protein C and Protein S Deficiencies.

Circulating protein S (PS) is partly bound to C4b-binding protein, and only free PS can act as a cofactor for protein C (PC), a natural anticoagulant. Two types of PS deficiencies are commonly observed in patients with unexplained thrombosis, and they are characterized by having both a low total PS level and a low free PS level (type I) or by having only a low free PS level (type IIa). To elucidate the genetic mechanisms responsible for these two plasma phenotypes, we screened 118 symptomatic patients with type I or type IIa PS deficiency for a PS gene coding sequence variation. A total of 34 mutations, 17 of which were novel, were identified in 65 propositi (70% in type I and 44% in type IIa). In type I deficiency, 29 different mutations were distributed throughout the coding sequence. In type IIa deficiency, five different missense mutations were clustered in exons XII and XIII, with a Ser 460 to Pro mutation accounting for most cases (82%). This points to a role of the domain encoded by exons XII and XIII in the distribution between bound and free PS. The Ser 460 to Pro mutation was associated with the factor V Arg 506 to Gin mutation or a PC gene mutation in about half the patients, suggesting a cooperative effect on clinical expression.

DNA Mutational Analysis↗

Proteomic patterns according to ejection fraction: an EMPEROR-programme analysis.

AIMS: Left ventricular ejection fraction (LVEF) has been incorporated as an inclusion criterion in HF trials. Patient's characteristics, event risk, and treatment response vary according to LVEF. A better understanding of the biological processes across LVEF is warranted. To study proteomic biomarker expression across LVEF using data from the EMPEROR-Programme. METHODS: Two thousand two hundred and fifty-four patients who had proteomic measurements available using 1134 proteins overlapping between the Explore 1536 and 3072 Olink&#xae; platforms were included. Main analyses were performed within the EMPEROR-Preserved dataset due to differences in entry criteria between EMPEROR-Preserved and EMPEROR-Reduced with higher entry N-terminal pro B-type natriuretic peptide (NT-proBNP) levels that varied by LVEF cut-offs in the latter. Protein concentrations were compared using ordinal logistic regression across LVEF categories: 41%-49%, 50%-59%, and &#x2265;60%. The resulting &#x3b2;-coefficient indicates the change in the log-odds for the outcome of being in a lower LVEF category for every NPX unit in log2 scale. Analyses were adjusted for covariates and a false-discovery-rate (FDR) correction was applied. RESULTS: A total of 297 proteins exhibited a trend of expression across LVEF categories in EMPEROR-Preserved after adjustment for potential confounders and correction for test multiplicity. Of these, the top 10 proteins were: NT-pro BNP (&#x3b2; = 0.18, 95% CI 0.09-0.27), Wnt inhibitory factor-1 (&#x3b2; = 0.40, 95% CI 0.19-0.61), sialomucin core protein 24 (&#x3b2; = 0.48, 95% CI 0.22-0.74), phospholipid transfer protein (&#x3b2; = 0.38, 95% CI 0.17-0.59), natriuretic peptides B (&#x3b2; = 0.13, 95% CI 0.06-0.20), intercellular adhesion molecule 5 (&#x3b2; = 0.31, 95% CI 0.14-0.49), neural cell adhesion molecule 2 (&#x3b2; = 0.45, 95% CI 0.19-0.70), neural cell adhesion molecule L1-like protein (&#x3b2; = 0.45, 95% CI 0.19-0.71), interactor protein for cytohesin exchange factors 1 (&#x3b2; = 0.12, 95% CI 0.05-0.19), and 3-ketoacyl-CoA thiolase, peroxisomal (&#x3b2; = 0.17, 95% CI 0.07-0.26). The correlation between these proteins and LVEF was generally weak (Rho &#x2264;0.2). CONCLUSIONS: Within EMPEROR-Preserved, the top differentially expressed circulating proteins suggest that pathways related to natriuretic peptides, cell-adhesion, and clonal haematopoiesis are overexpressed at mildly-reduced ejection fraction, but none of the proteins passed the 5%FDR cut-off, and the correlation between circulating proteins and LVEF was weak. These findings suggest that circulating proteins may not be a good discriminant of ejection fraction.

Humans↗

Circulating angiogenic proteins in trisomy 13.

OBJECTIVE: Women who are carrying a trisomy 13 fetus are more prone to develop preeclampsia. Excess circulating soluble fms-like tyrosine kinase-1 has been implicated recently in the pathogenesis of preeclampsia. Since the fms-like tyrosine kinase-1/soluble fms-like tyrosine kinase-1 gene is located on chromosome 13q12, we hypothesized that the extra copy of this gene in trisomy 13 may lead to excess circulating soluble fms-like tyrosine kinase-1, reduced free placental growth factor level, and increased soluble fms-like tyrosine kinase-1/placental growth factor ratio. This may then contribute to the increased risk of preeclampsia that has been observed in these patients. Our objective was to characterize the maternal circulating angiogenic proteins in trisomy 13 pregnancies. STUDY DESIGN: Maternal serum samples of trisomy 13, 18, 21 and normal karyotype pregnancies were obtained from first and second trimester screening programs. We chose 17 cases of trisomy 13 that were matched for maternal age, freezer storage time, and parity with 85 normal karyotype control samples. Additionally, 20 cases of trisomy 18 and 17 cases of trisomy 21 were included. Cases and control samples were assayed for levels of soluble fms-like tyrosine kinase-1 and placental growth factor by enzyme-linked immunosorbent assay in a blinded fashion. Because of the skewed distributions of soluble fms-like tyrosine kinase-1 and placental growth factor, nonparametric analytic techniques were used, and the results are reported as median and ranges. RESULTS: In early pregnancy trisomy 13 cases and control samples, the median circulating soluble fms-like tyrosine kinase-1/placental growth factor ratios were 17.0 (range, 1.2-61.3) and 6.7 (range, 0.8-62.9), respectively (P = .003). The median soluble fms-like tyrosine kinase-1/placental growth factor ratios in trisomy 18 and 21 were 4.8 (range, 0.9-53.9) and 5.1 (range, 1.0-18.1), which were not significantly different than the control samples. Furthermore, the differences between trisomy 13 and control samples were more pronounced in the second trimester specimens than in the specimens from the first trimester. CONCLUSION: These data suggest that alterations in circulating angiogenic factors may be involved intimately in the pathogenesis of preeclampsia in trisomy 13. A larger clinical study that measures these factors longitudinally and correlates them with pregnancy outcomes is needed to further establish the link between trisomy 13, altered angiogenic factors, and preeclampsia.

Angiogenic Proteins↗

The epitopes for some antiphospholipid antibodies are adducts of oxidized phospholipid and beta2 glycoprotein 1 (and other proteins).

Circulating autoantibodies to phospholipids (aPLs), such as cardiolipin (CL), are found in patients with antiphospholipid antibody syndrome (APS). We recently demonstrated that many aPLs bound to CL only after it had been oxidized (OxCL), but not to a reduced CL analogue that could not undergo oxidation. We now show that the neoepitopes recognized by some aPLs consist of adducts formed between breakdown products of oxidized phospholipid and associated proteins, such as beta2 glycoprotein 1 (beta2GP1). Addition of human beta2GP1, polylysine, native low-density lipoprotein, or apolipoprotein AI to OxCL-coated wells increased the anticardiolipin antibody (aCL) binding from APS sera that first had been diluted so that no aCL binding to OxCL could be detected. No increase in aCL binding was observed when these proteins were added to wells coated with reduced CL. The ability of beta2GP1, polylysine, or low-density lipoprotein to be a "cofactor" for aCL binding to OxCL was greatly reduced when the proteins were methylated. Incubation of beta2GP1 with oxidized 1-palmitoyl-2-linoleyl-[1-14C]-phosphatidylcholine (PC), but not with dipalmitoyl-[1-14C]-PC, led to formation of covalent adducts with beta2GP1 recognized by APS sera. These data suggest that the reactive groups of OxCL, such as aldehydes generated during the decomposition of oxidized polyunsaturated fatty acids, form covalent adducts with beta2GP1 (and other proteins) and that these are epitopes for aCLs. Knowledge that the epitopes recognized by many aPLs are adducts of oxidized phospholipid and associated proteins, including beta2GP1, may give new insights into the pathogenic events underlying the clinical manifestations of APS.

Antibodies, Antiphospholipid↗

Localization of hyaluronan in human liver sinusoids: a histochemical study using hyaluronan-binding protein.

Circulating hyaluronan is mostly derived from lymph, fibroblast and Ito cells in the liver, and more than 90% of hyaluronan is degraded in hepatic sinusoidal endothelial cells. Thus, elevated serum hyaluronan is regarded as an indication of hepatic fibrosis with activated Ito cells and dysfunctional sinusoidal endothelial cells. We studied the distribution of hyaluronan in human liver sinusoids to determine the influences on elevated hyaluronan levels in sera. Histochemical examination was made using hyaluronan-binding protein (HABP) and serial sections of liver tissue for staining of alpha-smooth muscle actin (ASMA) (an indicator of activated Ito cells) and of ulex europaeus agglutinin I lectin (UEA-1) (closely related to hepatic sinusoidal capillarization). Positive staining, indicating the presence of hyaluronan, was noted in fibrous regions around the portal tracts, areas of focal necrosis in the liver parenchyma, and walls of the sinusoids in chronic hepatitis. In this group, hyaluronan-positive areas corresponded to positive ASMA staining and faint staining of UEA-1. On the contrary, in liver cirrhosis, UEA-1-positive areas were essentially identical to hyaluronan-positive areas and to ASMA-negative areas in sinusoidal walls. Hyaluronan and ASMA could be detected in the same areas of sinusoidal walls in chronic hepatitis, but not in liver cirrhosis. Hyaluronan appears to be mainly related to the staining of activated Ito cells in chronic hepatitis. Therefore, we concluded that in chronic hepatitis, the production of hyaluronan was accelerated in Ito cells; however, degradation of hyaluronan by sinusoidal endothelial cells continued. On the contrary, in liver cirrhosis, hyaluronan production decreased in Ito cells, and a marked transformation of sinusoidal endothelial cells with hepatic sinusoidal capillarization indicated loss of the ability to degrade hyaluronan. These different mechanisms in chronic hepatitis and liver cirrhosis may operate in the sinusoidal walls and may cause the elevation of hyaluronan in sera.

Biomarkers↗

Protein mediators of chronic kidney disease in Type 2 diabetes: A mendelian randomization study.

BACKGROUND: Chronic kidney disease (CKD) occurs in 20-50% of the people living with Type 2 diabetes (T2D) and is the leading cause of kidney failure worldwide. The cause of CKD is not fully understood, and few interventions prevent CKD in individuals living with diabetes. Here, we use large-scale proteomics data to identify circulating proteins that mediate the relationship between T2D and kidney disorders. METHODS AND FINDINGS: First, we used two-sample mendelian randomization (MR) and identified 71 circulating proteins whose levels were altered by genetic predisposition to T2D based on circulating proteomic GWAS from deCODE with 35,559 individuals and T2D GWAS with 80,154 cases. Then, we used cis-genetic variants to proxy the causal effect of some of these T2D-influenced circulating proteins and found that, collectively, five proteins (INHBC, GNPTG, LPO, AGRN, and CTSD) affected three kidney traits (blood urea nitrogen [BUN], estimated glomerular filtration rate [eGFR] and CKD risk) based on GWAS with up to 1,004,040 participants. Notably, we found that higher levels of circulating INHBC protein were estimated to lead to a lower eGFR and higher BUN based on MR analyses. We then replicated this MR analysis with proteomic GWAS from four additional cohorts, namely, UKB-PPP, Fenland, ARIC, and EPIC-Norfolk. We observed a consistent direction of effect across all four proteomic GWAS datasets, supporting the robustness of our results against platform and cohort variation. In observational analyses, increased circulating INHBC levels were associated with increased hazard for kidney disease diagnosis in 37,854 UK Biobank participants. We estimated that circulating INHBC levels mediate 1.3% (95% confidence interval [0.85%, 1.9%]) of the association between T2D and kidney disease diagnosis. There are important limitations in this study. Firstly, although we observed limited evidence for violations to the MR assumptions, some are untestable. Secondly, our study was not based on individuals with diabetic kidney diseases, but rather independent population-based studies assessing diabetes and kidney function separately. Therefore, additional functional analyses in disease specific cohort are needed. CONCLUSIONS: Collectively, these findings suggest that T2D influences the risk of CKD, in part, through increased circulating INHBC levels.

Humans↗

Exploring Causal Links Between 91 Circulating Inflammatory Proteins and Hashimoto's Thyroiditis: A Bidirectional Mendelian Randomization Study.

BACKGROUND: Increasing evidence has linked inflammation to Hashimoto's thyroiditis (HT) etiology. However, the causal role of circulating inflammatory proteins in HT remains uncertain. To investigate this, we conducted a bidirectional Mendelian randomization (MR) study. METHODS: Genetic data for 91 inflammatory proteins and HT were sourced from publicly available GWAS databases. The PhenoScanner database was then searched for pleiotropic SNPs associated with potential confounders. Inverse variance weighted (IVW) analysis was used as the primary analysis, simultaneously supplemented by five sensitivity analyses to strengthen the results. RESULTS: The results revealed that, after false discovery rate (FDR) correction, interleukin (IL)-12p40 was causally associated with increased risk of HT (OR [95% CI]&#x2009;=&#x2009;1.295 [1.172, 1.431], p = 3.66 &#xd7; 10-7, PFDR&#x2009;=&#x2009;3.33&#xd7;10-5). Conversely, none of the inflammatory proteins was a consequence of HT. CONCLUSION: This study suggests that IL-12p40 is probably one of the factors correlated with HT etiology, contributing to a better understanding of the pathogenesis of HT and underscoring the potential for therapeutic interventions targeting inflammatory proteins.

Humans↗