Association of major candidate protein biomarkers and long-term diabetic kidney disease progression among Asians with young-onset type 2 diabetes mellitus.

AIMS: We aim to determine the association of seven major candidate protein biomarkers and diabetic kidney disease (DKD) progression among Asians with young-onset type 2 diabetes mellitus (T2DM). METHODS: 824 T2DM patients (onset ≤ 40 years old) were classified as DKD progressors based on yearly estimated glomerular filtration rate (eGFR) decline of >3 ml/min/1.73 m2 or >40 % from baseline. Plasma leucine-rich α-2-glycoprotein 1 (pLRG1), tumor necrosis factor-receptor 1 (pTNF-R1), pigment epithelium-derived factor (pPEDF), urinary α-1-microglobulin (uA1M), kidney injury molecular 1 (uKIM-1), haptoglobin (uHP) and uromodulin (uUMOD) were measured using enzyme-linked immunoassays. RESULTS: Over 5.7 years of follow-up, 25.2 % of patients were DKD progressors. Elevated levels of pLRG1, pTNF-R1, pPEDF, uA1M, uKIM-1 and uHP were associated with DKD progression. The association between pTNF-R1 levels and DKD progression persisted after adjusting for clinical covariates (OR 1.84, 95 %CI 1.44-2.34, p < 0.001). The effects of pTNF-R1 were partially mediated through hyperglycemia (8 %) and albuminuria (10 %). Inclusion of pTNF-R1 in a clinical variable-based model improved the area under the receiver operating characteristics curve for predicting DKD progression by 0.02, from 0.72 (95 %CI 0.68-0.76) to 0.74 (95 %CI 0.70-0.78), p = 0.099. CONCLUSIONS: Among seven major candidate proteins, pTNF-R1, partially mediated through hyperglycemia and albuminuria, robustly predicted DKD progression among Asians with young-onset T2DM.

Unique hyaluronan structure of expanded oocyte-cumulus extracellular matrix in ovarian follicles.

In preovulatory follicles, after the endogenous gonadotropin surge, the oocyte-cumulus complexes (OCCs) produce hyaluronan (HA) in a process called "cumulus expansion". During this process, the heavy chains (HCs) of the serum-derived inter-alpha-trypsin inhibitor (IαI) family bind covalently to synthesized HA and form a unique structure of the expanded cumulus HA-rich extracellular matrix. Understanding the biochemical mechanism of the covalent linkage between HA and the HCs of the IαI family is one of the most significant discoveries in reproductive biology, since it explains basis of the cumulus expansion process running in parallel with the oocyte maturation, both essential for ovulation. Two recent studies have supported the above-mentioned findings: in the first, seven components of the extracellular matrix were detected by proteomic, evolutionary, and experimental analyses, and in the second, the essential role of serum in the process of cumulus expansion in vitro was confirmed. We have previously demonstrated the formation of unique structure of the covalent linkage of HA to HCs of IαI in the expanded gonadotropin-stimulated OCC, as well as interactions with several proteins produced by the cumulus cells: tumor necrosis factor-alpha-induced protein 6, pentraxin 3, and versican. Importantly, deletion of these genes in the mice produces female infertility due to defects in the oocyte-cumulus structure.

Urine biomarkers in type 2 diabetes mellitus with or without microvascular complications.

OBJECTIVE: To investigate the distribution of nine (9) urine biomarkers in people living with type 2 diabetes mellitus (T2DM), with or without microvascular complications. METHODS: In total, 407 people with T2DM were enrolled from 2021 to 2022. According to diabetic retinopathy (DR) and urinary albumin-creatinine ratio (UACR), the 407 people were divided into four (4) groups, DR(-)UACR(-), DR(+)UACR(-), DR(-)UACR(+), and DR( + )UACR(+). In addition, 112 healthy volunteers were enrolled during the same period. The nine (9) urine markers included α1-microglobulin (u-α1MG), immunoglobulin G (u-IgG), neutrophil gelatinase-associated lipid carrier protein (u-NGAL), cystatin C (u-CysC), retinol-binding protein (u-RBP), ß2-microglobulin (u-ß2MG), N-acetyl-ß-D-glucosaminidase (u-NAG), transferrin (u-Trf), and collagen type IV (u-Col). For each marker, the respective level of 97.5 percentile in healthy volunteers was taken as an upper reference limit. RESULTS: Among the 407 people, 248 individuals (61%) were DR(-)UACR(-), 100 (25%) were DR(-)UACR(+), 37 (9%) were DR(+)UACR(-), and 22 (5%) were DR(+)UACR(+). The u-NAG/Cr biomarker level showed a significant difference between healthy participants and people with T2DM. In the DR(-)UACR(-)group, u-Trf/Cr showed the highest positive rate (21.37%), followed by u-IgG/Cr (14.52%); u-NAG/Cr (10.48%); u-ß2MG/Cr (4.44%); u-CysC/Cr (4.03%); u-NGAL/Cr (4.03%); u-RBP/Cr (2.82%); u-α1MG/Cr (2.42%); 17.34% of people with T2DM showed multiple biomarkers positive (≥2 biomarkers). The positive rates of one biomarker (21.33%) and two biomarkers (18.67%) in people who have less than five (5) years of T2DM were almost close to those of the DR(-)UACR(-) group (21.37%, and 12.10%, respectively). CONCLUSION: Renal tubule biomarkers may be used as an indicator in the early detection and monitoring of renal injury in diabetes mellitus. The u-NAG biomarker should be measured for the people with T2DM of the first-time diagnosis.

Effects of Recombinant α1-Microglobulin on Early Proteomic Response in Risk Organs after Exposure to 177Lu-Octreotate.

Recombinant α1-microglobulin (A1M) is proposed as a protector during 177Lu-octreotate treatment of neuroendocrine tumors, which is currently limited by bone marrow and renal toxicity. Co-administration of 177Lu-octreotate and A1M could result in a more effective treatment by protecting healthy tissue, but the radioprotective action of A1M is not fully understood. The aim of this study was to examine the proteomic response of kidneys and bone marrow early after 177Lu-octreotate and/or A1M administration. Mice were injected with 177Lu-octreotate and/or A1M, while control mice received saline or A1M vehicle solution. Bone marrow, kidney medulla, and kidney cortex were sampled after 24 h or 7 d. The differential protein expression was analyzed with tandem mass spectrometry. The dosimetric estimation was based on 177Lu activity in the kidney. PHLDA3 was the most prominent radiation-responsive protein in kidney tissue. In general, no statistically significant difference in the expression of radiation-related proteins was observed between the irradiated groups. Most canonical pathways were identified in bone marrow from the 177Lu-octreotate+A1M group. Altogether, a tissue-dependent proteomic response followed exposure to 177Lu-octreotate alone or together with A1M. Combining 177Lu-octreotate with A1M did not inhibit the radiation-induced protein expression early after exposure, and late effects should be further studied.

Urinary α 1-microglobulin and ß 2-microglobulin as markers of early kidney injury in HIV-positive male patients on tenofovir-based antiretroviral therapy.

BACKGROUND: A retrospective study was conducted to explore the urinary expression of α 1-microglobulin (α1MG) and ß2-microglobulin (ß2MG) in patients with human immunodeficiency virus (HIV) infection, aiming to evaluate their predictive capability for renal injury. METHOD: One hundred and five male HIV-infected patients treated with Tenofovir (TDF) regimen (TDF+3TC or the third drug TDF/FTC+) were selected between March 1, 2021, and March 1, 2022, in Wuhan Jinyintan Hospital. Three months after TDF treatment, the renal function injury was evaluated with the standard creatinine clearance rate. The urinary levels of α1MG and ß2MG were compared between the initiation of TDF treatment and three months thereafter. Spearman correlation was utilized to analyze the correlation between the urinary expression of α1MG and ß2MG and renal injury in HIV patients. The logistic regression was used to analyze the predictive value of urinary α1MG and ß 2-microglobulin expression in renal injury. RESULTS: Up to the first follow-up, 29 (27.6%) cases of the 105 male HIV patients had varying degrees of renal function injury, including 14 (13.3%) mild injury, 9 (8.6%) moderate injury, and 6 (5.7%) severe injury cases. Patients with severe renal injury had the highest levels of urinary α1MG and ß2MG expression while those with mild injury demonstrated higher levels compared to the non-injury group (P < 0.05). Spearman correlation analysis indicated that urinary α1MG and ß2MG were positively correlated with renal impairment in HIV patients (Rho = -0.568, and -0.732; P < 0.001). The ROC curve analysis demonstrated that the area under the curve (AUC) for urine α1MG and ß2MG in predicting kidney damage among HIV patients were 0.928, 0.916, and 0.889, respectively. The sensitivity values were 96.55%, 82.76%, and 89.66% while the specificity values were 84.07%, 94.51%, and 89.29% for urine α1MG and ß2MG, respectively. CONCLUSION: The expression level of urinary α1MG and ß2MG in HIV patients was significantly higher compared to normal people. Detection of these two indexes can enable early determination of renal injury and its severity in HIV patients.

Megalin-related mechanism of hemolysis-induced acute kidney injury and the therapeutic strategy.

Hemolysis-induced acute kidney injury (AKI) is attributed to heme-mediated proximal tubule epithelial cell (PTEC) injury and tubular cast formation due to intratubular protein condensation. Megalin is a multiligand endocytic receptor for proteins, peptides, and drugs in PTECs and mediates the uptake of free hemoglobin and the heme-scavenging protein α1-microglobulin. However, understanding of how megalin is involved in the development of hemolysis-induced AKI remains elusive. Here, we investigated the megalin-related pathogenesis of hemolysis-induced AKI and a therapeutic strategy using cilastatin, a megalin blocker. A phenylhydrazine-induced hemolysis model developed in kidney-specific mosaic megalin knockout (MegKO) mice confirmed megalin-dependent PTEC injury revealed by the co-expression of kidney injury molecule-1 (KIM-1). In the hemolysis model in kidney-specific conditional MegKO mice, the uptake of hemoglobin and α1-microglobulin as well as KIM-1 expression in PTECs was suppressed, but tubular cast formation was augmented, likely due to the nonselective inhibition of protein reabsorption in PTECs. Quartz crystal microbalance analysis revealed that cilastatin suppressed the binding of megalin with hemoglobin and α1-microglobulin. Cilastatin also inhibited the specific uptake of fluorescent hemoglobin by megalin-expressing rat yolk sac tumor-derived L2 cells. In a mouse model of hemolysis-induced AKI, repeated cilastatin administration suppressed PTEC injury by inhibiting the uptake of hemoglobin and α1-microglobulin and also prevented cast formation. Hemopexin, another heme-scavenging protein, was also found to be a novel ligand of megalin, and its binding to megalin and uptake by PTECs in the hemolysis model were suppressed by cilastatin. Mass spectrometry-based semiquantitative analysis of urinary proteins in cilastatin-treated C57BL/6J mice indicated that cilastatin suppressed the reabsorption of a limited number of megalin ligands in PTECs, including α1-microglobulin and hemopexin. Collectively, cilastatin-mediated selective megalin blockade is an effective therapeutic strategy to prevent both heme-mediated PTEC injury and cast formation in hemolysis-induced AKI. © 2024 The Pathological Society of Great Britain and Ireland.

Therapeutic α-1-microglobulin ameliorates kidney ischemia-reperfusion injury.

α-1-Microglobulin (A1M) is a circulating glycoprotein with antioxidant, heme-binding, and mitochondrial protection properties. The investigational drug RMC-035, a modified therapeutic A1M protein, was assessed for biodistribution and pharmacological activity in a broad set of in vitro and in vivo experiments, supporting its clinical development. Efficacy and treatment posology were assessed in various models of kidney ischemia and reperfusion injury (IRI). Real-time glomerular filtration rate (GFR), functional renal biomarkers, tubular injury biomarkers (NGAL and KIM-1), and histopathology were evaluated. Fluorescently labeled RMC-035 was used to assess biodistribution. RMC-035 demonstrated consistent and reproducible kidney protection in rat IRI models as well as in a model of IRI imposed on renal impairment and in a mouse IRI model, where it reduced mortality. Its pharmacological activity was most pronounced with combined dosing pre- and post-ischemia and weaker with either pre- or post-ischemia dosing alone. RMC-035 rapidly distributed to the kidneys via glomerular filtration and selective luminal uptake by proximal tubular cells. IRI-induced expression of kidney heme oxygenase-1 was inhibited by RMC-035, consistent with its antioxidative properties. RMC-035 also dampened IRI-associated inflammation and improved mitochondrial function, as shown by tubular autofluorescence. Taken together, the efficacy of RMC-035 is congruent with its targeted mechanism(s) and biodistribution profile, supporting its further clinical evaluation as a novel kidney-protective therapy.NEW & NOTEWORTHY A therapeutic A1M protein variant (RMC-035) is currently in phase 2 clinical development for renal protection in patients undergoing open-chest cardiac surgery. It targets several key pathways underlying kidney injury in this patient group, including oxidative stress, heme toxicity, and mitochondrial dysfunction. RMC-035 is rapidly eliminated from plasma, distributing to kidney proximal tubules, and demonstrates dose-dependent efficacy in numerous models of ischemia-reperfusion injury, particularly when administered before ischemia. These results support its continued clinical evaluation.

Hematological and renal toxicity in mice after three cycles of high activity [177Lu]Lu-PSMA-617 with or without human α1-microglobulin.

Radioligand therapy with [177Lu]Lu-PSMA-617 can be used to prolong life and reduce tumor burden in terminally ill castration resistant prostate cancer patients. Still, accumulation in healthy tissue limits the activity that can be administered. Therefore, fractionated therapy is used to lower toxicity. However, there might be a need to reduce toxicity even further with e.g. radioprotectors. The aim of this study was to (i). establish a preclinical mouse model with fractionated high activity therapy of three consecutive doses of 200 MBq [177Lu]Lu-PSMA-617 in which we aimed to (ii). achieve measurable hematotoxicity and nephrotoxicity and to (iii). analyze the potential protective effect of co-injecting recombinant α1-microglobulin (rA1M), a human antioxidant previously shown to have radioprotective effects. In both groups, three cycles resulted in increased albuminuria for each cycle, with large individual variation. Another marker of kidney injury, serum blood urea nitrogen (BUN), was only significantly increased compared to control animals after the third cycle. The number of white and red blood cells decreased significantly and did not reach the levels of control animals during the experiment. rA1M did reduce absorbed dose to kidney but did not show significant protection here, but future studies are warranted due to the recent clinical studies showing a significant renoprotective effect in patients.

iTRAQ-based mass spectrometry screen to identify serum biomarkers in systemic lupus erythematosus.

OBJECTIVE: Systemic lupus erythematosus (SLE) is a complex systemic autoimmune disorder with no reliable serum biomarkers currently available other than autoantibodies. METHODS: In the present study, isobaric tags for relative and absolute quantitation-based mass spectrometry was used to screen the sera of patients with SLE to uncover potential disease biomarkers. RESULTS: 85 common proteins were identified, with 16 being elevated (≥1.3) and 23 being decreased (≤0.7) in SLE. Of the 16 elevated proteins, serum alpha-1-microglobulin/bikunin precursor (AMBP), zinc alpha-2 glycoprotein (AZGP) and retinol-binding protein 4 (RBP4) were validated in independent cross-sectional cohorts (Cohort I, N=52; Cohort II, N=117) using an orthogonal platform, ELISA. Serum AMBP, AZGP and RBP4 were validated to be significantly elevated in both patients with inactive SLE and patients with active SLE compared with healthy controls (HCs) (p<0.05, fold change >2.5) in Cohort I. All three proteins exhibited good discriminatory power for distinguishing active SLE and inactive SLE (area under the curve=0.82-0.96), from HCs. Serum AMBP exhibited the largest fold change in active SLE (5.96) compared with HCs and correlated with renal disease activity. The elevation in serum AMBP was validated in a second cohort of patients with SLE of different ethnic origins, correlating with serum creatinine (r=0.60, p<0.001). CONCLUSION: Since serum AMBP is validated to be elevated in SLE and correlated with renal disease, the clinical utility of this novel biomarker warrants further analysis in longitudinal cohorts of patients with lupus and lupus nephritis.

Association between decreased cord blood inter-alpha inhibitor levels and neonatal encephalopathy at birth.

BACKGROUND: Inter-alpha inhibitor proteins (IAIPs) are structurally related proteins found in the systemic circulation with immunomodulatory anti-inflammatory properties. Reduced levels are found in inflammatory related conditions including sepsis and necrotizing enterocolitis, and in neonatal rodents after exposure to hypoxia ischemia. In the current study, cord blood IAIP levels were measured in neonates with and without exposure to hypoxic-ischemic encephalopathy (HIE). METHODS: This is a prospective cohort study including infants born ≥36 weeks over a one-year period. Term pregnancies were divided into two groups: a "reference control" (uncomplicated term deliveries), and "moderate to severe HIE" (qualifying for therapeutic hypothermia). IAIPs were quantified using a sensitive ELISA on the cord blood samples. RESULTS: The study included 57 newborns: Reference control group (n = 13) and moderate/severe HIE group (n = 44). Measurement of IAIP cord blood concentrations in moderate to severe HIE group [278.2 (138.0, 366.0) µg/ml] revealed significantly lower IAIP concentrations compared with the control group [418.6 (384.5, 445.0) µg/ml] (p = 0.002). CONCLUSIONS: These findings suggest a potential role for IAIPs as indicators of neonates at risk for HIE. IAIP levels could have diagnostic implications in the management of HIE. Future research is required to explore the relationship between HIE and IAIPs as biomarkers for disease severity. CATEGORY OF STUDY: Translational.

Major endothelial damage markers identified from hemadsorption filters derived from treated patients with septic shock - endoplasmic reticulum stress and bikunin may play a role.

Introduction: In septic patients the damage of the endothelial barrier is decisive leading to circulatory septic shock with disseminated vascular coagulation, edema and multiorgan failure. Hemadsorption therapy leads to rapid resolution of clinical symptoms. We propose that the isolation of proteins adsorbed to hemadsorption devices contributes to the identification of mediators responsible for endothelial barrier dysfunction. Material and methods: Plasma materials enriched to hemadsorption filters (CytoSorb®) after therapy of patients in septic shock were fractionated and functionally characterized for their effect on cell integrity, viability, proliferation and ROS formation by human endothelial cells. Fractions were further studied for their contents of oxidized nucleic acids as well as peptides and proteins by mass spectrometry. Results: Individual fractions exhibited a strong effect on endothelial cell viability, the endothelial layer morphology, and ROS formation. Fractions with high amounts of DNA and oxidized DNA correlated with ROS formation in the target endothelium. In addition, defined proteins such as defensins (HNP-1), SAA1, CXCL7, and the peptide bikunin were linked to the strongest additive effects in endothelial damage. Conclusion: Our results indicate that hemadsorption is efficient to transiently remove strong endothelial damage mediators from the blood of patients with septic shock, which explains a rapid clinical improvement of inflammation and endothelial function. The current work indicates that a combination of stressors leads to the most detrimental effects. Oxidized ssDNA, likely derived from mitochondria, SAA1, the chemokine CXCL7 and the human neutrophil peptide alpha-defensin 1 (HNP-1) were unique for their significant negative effect on endothelial cell viability. However, the strongest damage effect occurred, when, bikunin - cleaved off from alpha-1-microglobulin was present in high relative amounts (>65%) of protein contents in the most active fraction. Thus, a relevant combination of stressors appears to be removed by hemadsorption therapy which results in fulminant and rapid, though only transient, clinical restitution.

Neuroprotective efficacy of hypothermia and Inter-alpha Inhibitor Proteins after hypoxic ischemic brain injury in neonatal rats.

Therapeutic hypothermia is the standard of care for hypoxic-ischemic (HI) encephalopathy. Inter-alpha Inhibitor Proteins (IAIPs) attenuate brain injury after HI in neonatal rats. Human (h) IAIPs (60 â€‹mg/kg) or placebo (PL) were given 15 â€‹min, 24 and 48 â€‹h to postnatal (P) day-7 rats after carotid ligation and 8% oxygen for 90 â€‹min with (30 â€‹°C) and without (36 â€‹°C) exposure to hypothermia 1.5 â€‹h after HI for 3 â€‹h. Hemispheric volume atrophy (P14) and neurobehavioral tests including righting reflex (P8-P10), small open field (P13-P14), and negative geotaxis (P14) were determined. Hemispheric volume atrophy in males was reduced (P â€‹< â€‹0.05) by 41.9% in the normothermic-IAIP and 28.1% in the hypothermic-IAIP compared with the normothermic-PL group, and in females reduced (P â€‹< â€‹0.05) by 30.3% in the normothermic-IAIP, 45.7% in hypothermic-PL, and 55.2% in hypothermic-IAIP compared with the normothermic-PL group after HI. Hypothermia improved (P â€‹< â€‹0.05) the neuroprotective effects of hIAIPs in females. The neuroprotective efficacy of hIAIPs was comparable to hypothermia in female rats (P â€‹= â€‹0.183). Treatment with hIAIPs, hypothermia, and hIAIPs with hypothermia decreased (P â€‹< â€‹0.05) the latency to enter the peripheral zone in the small open field test in males. We conclude that hIAIPs provide neuroprotection from HI brain injury that is comparable to the protection by hypothermia, hypothermia increases the effects of hIAIPs in females, and hIAIPs and hypothermia exhibit some sex-related differential effects.

Japanese Study of the Effects of AMG (α1-Microglobulin) Reduction Rates on Survival (JAMREDS): A Protocol of a Multicenter Prospective Observational Cohort Study.

INTRODUCTION: Recent advances in dialysis therapy have made it possible to remove middle molecules. Removal of small-middle molecules, such as ß2-microglobulin, can now be achieved with conventional hemodialysis (HD), and removal of large-middle molecules has become a target, particularly for α1-microglobulin (AMG, 33 kD). The AMG reduction rate has emerged as a target for improvement of various clinical symptoms, but the effects on prognosis have yet to be determined. The "Japanese study of the effects of AMG (α1-microglobulin) reduction rates on survival" (JAMREDS) was started in April 2020, with the goal of determining if the AMG reduction rate associates with the risk of mortality and cardiovascular disease (CVD) events. METHODS: JAMREDS is a prospective observational study in patients on HD to examine the effects of: (1) AMG reduction rate on survival outcome and CVD events; (2) dialysis treatment modalities (HD, intermittent infusion hemodiafiltration(iHDF), pre/post-dilution online HDF) on survival and CVD events (based on AMG reduction rates with treatment mode); and (3) AMG reduction rates on survival and CVD events in patients undergoing each therapy (iHDF, pre/post-dilution online HDF). The number of planned subjects was 4,000 in preplanning. Data are collected using RED-Cap, which is an EDC system. A total of 9,930 patients were enrolled at the beginning of the study at 59 registered facilities. The JAMREDS observation period will continue until the end of 2023, after which the data will be cleaned and confirmed before analysis. CONCLUSION: This study may provide new evidence for the relationship between the amount of removed large-middle molecules (such as AMG) and the mortality and CVD risk. Comparisons with convection volumes will also be of interest.

Targeted Analysis of the Size Distribution of Heavy Chain-Modified Hyaluronan with Solid-State Nanopores.

The glycosaminoglycan hyaluronan (HA) plays important roles in diverse physiological functions where the distribution of its molecular weight (MW) can influence its behavior and is known to change in response to disease conditions. During inflammation, HA undergoes a covalent modification in which heavy chain subunits of the inter-alpha-inhibitor family of proteins are transferred to its structure, forming heavy chain-HA (HC•HA) complexes. While limited assessments of HC•HA have been performed previously, determining the size distribution of its HA component remains a challenge. Here, we describe a selective method for extracting HC•HA from mixtures that yields material amenable to MW analysis with a solid-state nanopore sensor. After demonstrating the approach in vitro, we validate extraction of HC•HA from osteoarthritic human synovial fluid as a model complex biological matrix. Finally, we apply our technique to pathophysiology by measuring the size distributions of HC•HA and total HA in an equine model of synovitis.

Inter-alpha-trypsin inhibitor (IαI) and hyaluronan modifications enhance the innate immune response to influenza virus in the lung.

The inter-alpha-trypsin inhibitor (IαI) complex is composed of the bikunin core protein with a single chondroitin sulfate (CS) attached and one or two heavy chains (HCs) covalently linked to the CS chain. The HCs from IαI can be transferred to hyaluronan (HA) through a TNFα-stimulated gene-6 (TSG-6) dependent process to form an HC•HA matrix. Previous studies reported increased IαI, HA, and HC•HA complexes in mouse bronchoalveolar lavage fluid (BALF) post-influenza infection. However, the expression and incorporation of HCs into the HA matrix of the lungs during the clinical course of influenza A virus (IAV) infection and the biological significance of the HC•HA matrix are poorly understood. The present study aimed to better understand the composition of HC•HA matrices in mice infected with IAV and how these matrices regulate the host pulmonary immune response. In IAV infected mice bikunin, HC1-3, TSG-6, and HAS1-3 all show increased gene expression at various times during a 12-day clinical course. The increased accumulation of IαI and HA was confirmed in the lungs of infected mice using immunohistochemistry and quantitative digital pathology. Western blots confirmed increases in the IαI components in BALF and lung tissue at 6 days post-infection (dpi). Interestingly, HCs and bikunin recovered from BALF and plasma from mice 6 dpi with IAV, displayed differences in the HC composition by Western blot analysis and differences in bikunin's CS chain sulfation patterns by mass spectrometry analysis. This strongly suggests that the IαI components were synthesized in the lungs rather than translocated from the vascular compartment. HA was significantly increased in BALF at 6 dpi, and the HA recovered in BALF and lung tissues were modified with HCs indicating the presence of an HC•HA matrix. In vitro experiments using polyinosinic-polycytidylic acid (poly(I:C)) treated mouse lung fibroblasts (MLF) showed that modification of HA with HCs increased cell-associated HA, and that this increase was due to the retention of HA in the MLF glycocalyx. In vitro studies of leukocyte adhesion showed differential binding of lymphoid (Hut78), monocyte (U937), and neutrophil (dHL60) cell lines to HA and HC•HA matrices. Hut78 cells adhered to immobilized HA in a size and concentration-dependent manner. In contrast, the binding of dHL60 and U937 cells depended on generating a HC•HA matrix by MLF. Our in vivo findings, using multiple bronchoalveolar lavages, correlated with our in vitro findings in that lymphoid cells bound more tightly to the HA-glycocalyx in the lungs of influenza-infected mice than neutrophils and mononuclear phagocytes (MNPs). The neutrophils and MNPs were associated with a HC•HA matrix and were more readily lavaged from the lungs. In conclusion, this work shows increased IαI and HA accumulation and the formation of a HC•HA matrix in mouse lungs post-IAV infection. The formation of HA and HC•HA matrices could potentially create specific microenvironments in the lungs for immune cell recruitment and activation during IAV infection.

Role of inter-alpha-trypsin inhibitor heavy chain 4 and its citrullinated form in experimental arthritis murine models.

Inter-α-trypsin inhibitor heavy chain 4 (ITIH4) is a major protein in serum and reported to be upregulated at the onset of rheumatoid arthritis (RA). Its citrullinated form, cit-ITIH4, is specifically found in the serum and synovial fluid of patients with RA. However, the detailed function of ITIH4 in arthritis remains unknown. The aim of this study was to clarify the role of ITIH4 and cit-ITIH4 using experimental arthritis models. ITIH4 and cit-ITIH4 expression was examined in steady-state mice and two different arthritis models, and their pathological effects were examined in Itih4-deficient mice. In naïve C57BL/6 (WT) mice, ITIH4 was expressed as mRNA in the liver and the lung and was expressed as protein in serum and hepatocytes. In K/BxN serum transferred arthritis (K/BxN-STA) and collagen-induced arthritis (CIA), ITIH4 and cit-ITIH4 in sera were increased before the onset of arthritis, and cit-ITIH4 was further increased at the peak of arthritis. In Itih4-deficient mice, citrullinated proteins in serum and joints, especially 120 kDa protein, were clearly diminished; however, there was no significant difference in arthritis severity between WT and itih-/- mice either in the K/BxN-STA or CIA model. CIA mice also exhibited pulmonary lesions and itih4-/- mice tended to show enhanced inflammatory cell aggregation compared to WT mice. Neutrophils in the lungs of itih4-/- mice were significantly increased compared to WT mice. In summary, ITIH4 itself did not alter the severity of arthritis but may inhibit autoimmune inflammation via suppression of neutrophil recruitment.

Association of alpha globin gene copy number with exhaled nitric oxide in a cross-sectional study of healthy Black adults.

INTRODUCTION: The genetic determinants of fractional exhalation of nitric oxide (FeNO), a marker of lung inflammation, are understudied in Black individuals. Alpha globin (HBA) restricts nitric oxide signalling in arterial endothelial cells via interactions with nitric oxide synthase; however, its role in regulating the release of NO from respiratory epithelium is less well understood. We hypothesised that an HBA gene deletion, common among Black individuals, would be associated with higher FeNO. METHODS: Healthy Black adults were enrolled at four study sites in North Carolina from 2005 to 2008. FeNO was measured in triplicate using a nitric oxide analyzer. The -3.7 kb HBA gene deletion was genotyped using droplet digital PCR on genomic DNA. The association of FeNO with HBA copy number was evaluated using multivariable linear regression employing a linear effect of HBA copy number and adjusting for age, sex and serum immunoglobulin-E levels. Post-hoc analysis employing a recessive mode of inheritance was performed. RESULTS: 895 individuals were in enrolled in the study and 720 consented for future genetic research; 643 had complete data and were included in this analysis. Median (25th, 75th) FeNO was 20 (13, 31) ppb. HBA genotypes were: 30 (4.7%) -a/-a, 197 (30.6%) -a/aa, 405 (63%) aa/aa and 8 (1.2%) aa/aaa. Subjects were 35% male with median age 20 (19, 22) years. Multivariable linear regression analysis revealed no association between FeNO and HBA copy number (ß=-0.005 (95% CI -0.042 to 0.033), p=0.81). In the post-hoc sensitivity analysis, homozygosity for the HBA gene deletion was associated with higher FeNO (ß=0.107 (95% CI 0.003 to 0.212); p=0.045). CONCLUSION: We found no association between HBA copy number and FeNO using a prespecified additive genetic model. However, a post hoc recessive genetic model found FeNO to be higher among subjects homozygous for the HBA deletion.

Longitudinal change of serum inter-alpha-trypsin inhibitor heavy chain H4, and its correlation with inflammation, multiorgan injury, and death risk in sepsis.

BACKGROUND: Inter-alpha-trypsin inhibitor heavy chain H4 (ITIH4) inhibits infection-induced inflammation and multiorgan injury through several methods. The present study aimed to estimate the association of serum ITIH4 with inflammatory cytokines, multiorgan injury, and death risk in sepsis patients. METHODS: Serum samples were collected to detect ITIH4 by enzyme-linked immunosorbent assay in 127 sepsis patients at admission (baseline), day (D)1, D3, and D7 after admission, as well as in 30 healthy controls (HCs). Additionally, 28-day mortality was recorded in sepsis patients. RESULTS: ITIH4 was reduced in sepsis patients versus HCs (median [interquartile range]: 147.9 [78.2-208.8] vs. 318.8 [237.2-511.4] ng/ml) (p < 0.001). In sepsis patients, ITIH4 was associated with the absence of cardiovascular and cerebrovascular disease history (p = 0.021). Additionally, ITIH4 was negatively correlated with tumor necrosis factor-α (p < 0.001), interleukin (IL)-1ß (p < 0.001), IL-6 (p = 0.019), IL-17A (p = 0.002), and C-reactive protein (p = 0.001), but positively related to IL-10 (p = 0.007). Moreover, ITIH4 was also inversely associated with Acute Physiology and Chronic Health Evaluation II score (p = 0.002), Sequential Organ Failure Assessment (SOFA) score (p < 0.001), SOFA-respiratory system score (p = 0.023), and SOFA-renal system score (p = 0.007). Interestingly, ITIH4 gradually increased from baseline to D7 (p < 0.001); besides, ITIH4 at baseline (p = 0.009), D1 (p = 0.002), D3 (p < 0.001), and D7 (p = 0.015) were all decreased in sepsis deaths versus sepsis survivors. CONCLUSION: Serum ITIH4 is raised from baseline to D7 after disease onset, and it reflects the reduction of systemic inflammation, disease severity, and 28-day mortality for sepsis. However, further verification is required.

Longitudinal Change of Serum Inter-α-Trypsin Inhibitor Heavy Chain H4 and its Relation with Inflammation, Disease Recurrence, and Mortality in Acute Ischemic Stroke Patients.

Inter-α-trypsin inhibitor heavy chain H4 (ITIH4) modulates atherosclerosis, lipid, and inflammation, which is involved in the development of acute ischemic stroke. Hence, this study aimed to investigate the longitudinal change and prognostic role of ITIH4 in acute ischemic stroke. In 267 patients with acute ischemic stroke, serum ITIH4 after admission (baseline), the 1st day after admission (D1), D3, D7, and D30, and inflammatory cytokines at baseline were detected by enzyme-linked immunosorbent assay (ELISA). Additionally, serum ITIH4 of 30 controls after enrollment was detected by ELISA. ITIH4 was reduced in acute ischemic stroke patients than controls [median (interquartile range, IQR): 131.0 (95.5-194.3) vs. 418.6 (241.5-506.8) ng/mL] (P < 0.001). Among acute ischemic stroke patients, ITIH4 was negatively associated with tumor necrosis factor-alpha (r = -0.211, P = 0.001), interleukin (IL)-1ß (r = -0.164, P = 0.007), IL-6 (r = -0.121, P = 0.049), and IL-17A (r = -0.188, P = 0.002). ITIH4 presented a decreased trend from admission to D3, then increased from D3 to D30 (P < 0.001). The 1-year, 2-year, and 3-year cumulative recurrence rate was 7.5%, 18.0%, and 19.1%, respectively; meanwhile, 1-year, 2-year, and 3-year cumulative death rate was 2.2%, 7.1%, and 7.1%, accordingly. The further analysis presented that ITIH4 at baseline (P = 0.002), D1 (P = 0.049), D3 (P = 0.003), D7 (P < 0.001), and D30 (P < 0.001) was decreased in recurrent patients than non-recurrent patients; besides, ITIH4 at D3 (P = 0.017), D7 (P = 0.004), and D30 (P = 0.002), but not at baseline (P = 0.151) or D1 (P = 0.013), was decreased in deaths than survivors. Serum ITIH4 declines at first and then elevates with time, and its reduction is correlated with higher inflammation, increased risk of recurrence and mortality in acute ischemic stroke patients.