KIF15 missense variant is associated with the early onset of idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) has an unknown aetiology and limited treatment options. A recent meta-analysis identified three novel causal variants in the TERT, SPDL1, and KIF15 genes. This observational study aimed to investigate whether the aforementioned variants cause clinical phenotypes in a well-characterised IPF cohort. METHODS: The study consisted of 138 patients with IPF who were diagnosed and treated at the Helsinki University Hospital and genotyped in the FinnGen FinnIPF study. Data on > 25 clinical parameters were collected by two pulmonologists who were blinded to the genetic data for patients with TERT loss of function and missense variants, SPDL1 and KIF15 missense variants, and a MUC5B variant commonly present in patients with IPF, or no variants were separately analysed. RESULTS: The KIF15 missense variant is associated with the early onset of the disease, leading to progression to early-age transplantation or death. In patients with the KIF15 variant, the median age at diagnosis was 54.0 years (36.5-69.5 years) compared with 72.0 years (65.8-75.3 years) in the other patients (P = 0.023). The proportion of KIF15 variant carriers was 9- or 3.6-fold higher in patients aged < 55 or 65 years, respectively. The variants for TERT and MUC5B had similar effects on the patient's clinical course, as previously described. No distinct phenotypes were observed in patients with the SPDL1 variant. CONCLUSIONS: Our study indicated the potential of KIF15 to be used in the genetic diagnostics of IPF. Further studies are needed to elucidate the biological mechanisms of KIF15 in IPF.

Dyspnea Associates With a Widely Impaired Quality of Life in Idiopathic Pulmonary Fibrosis Patients: A Longitudinal Study Using 15D.

Background: Research on health-related quality of life (HRQoL) is crucial for developing comprehensive palliative care in idiopathic pulmonary fibrosis (IPF). Objectives: To study IPF patients' HRQoL compared with general population and its association with dyspnea in a longitudinal follow-up. Design: Assessment of IPF patients' HRQoL by a generic tool. Comparison of baseline data with the general population and a 30-month follow-up with 6 months intervals. Setting/Subjects: In total, 246 IPF patients were recruited from the Finnish nationwide real-life study, FinnishIPF. Measurements: Modified Medical Research Council (MMRC) dyspnea scale for dyspnea and the generic HRQoL tool 15D for the total and dimensional HRQoL were used. Results: At baseline, the mean 15D total score was lower (0.786, standard deviation [SD] 0.116) in IPF patients than in the general population (0.871, SD 0.043) (p < 0.001) and among the IPF patients with MMRC ≥2 compared with those with MMRC <2 (p < 0.001). In patients with MMRC ≥2, significant impairment compared with general population existed in 11 dimensions of HRQoL, such as breathing, usual activities, and sexual activity, whereas this was true in only 4 dimensions in MMRC <2 category. Mental function was not impaired in either group. During the follow-up, 15D total score decreased in both MMRC categories (p < 0.001) but stayed constantly worse in the MMRC ≥2 group. Seven and two dimensions of HRQoL significantly declined in the categories of MMRC <2 and MMRC ≥2, respectively. Conclusions: Patients with IPF, especially if dyspnea limits everyday life, suffer from widely impaired HRQoL, although self-assessed mental capability is preserved. Integrated palliative care is supported to face the multiple needs of IPF patients.

Inhibition of Vascular Endothelial Growth Factor Receptors 1 and 2 Attenuates Natural Killer Cell and Innate Immune Responses in an Experimental Model for Obliterative Bronchiolitis.

Obliterative bronchiolitis (OB) after lung transplantation is a nonreversible, life-threatening complication. Herein, the role of vascular endothelial growth factor receptor (Vegfr)-1 and -2 was investigated in the development of obliterative airway disease (OAD), an experimental model for OB. The nonimmunosuppressed recipients underwent transplantation with fully major histocompatibility complex mismatched heterotopic tracheal allografts and received Vegfr1 and -2-specific monoclonal antibodies either alone or in combination, or rat IgG as a control. The treatment with Vegfr1- or -2-blocking antibody significantly decreased intragraft mRNA expression of natural killer cell activation markers early after transplantation. This was followed by reduced infiltration of Cd11b+ cells and Cd4+ T cells as well as down-regulated mRNA expression of proinflammatory chemokines and profibrotic growth factors. However, blocking of both Vegfr1 and -2 was necessary to reduce luminal occlusion. Furthermore, concomitant inhibition of the calcineurin activation pathway almost totally abolished the development of OAD. This study proposes that blocking of Vegf receptors blunted natural killer cell and innate immune responses early after transplantation and attenuated the development of OAD. The results of this study suggest that further studies on the role of Vegfr1 and -2 blocking in development of obliterative airway lesions might be rewarding.

Disposal of iron by a mutant form of lipocalin 2.

Iron overload damages many organs. Unfortunately, therapeutic iron chelators also have undesired toxicity and may deliver iron to microbes. Here we show that a mutant form (K3Cys) of endogenous lipocalin 2 (LCN2) is filtered by the kidney but can bypass sites of megalin-dependent recapture, resulting in urinary excretion. Because K3Cys maintains recognition of its cognate ligand, the iron siderophore enterochelin, this protein can capture and transport iron even in the acidic conditions of urine. Mutant LCN2 strips iron from transferrin and citrate, and delivers it into the urine. In addition, it removes iron from iron overloaded mice, including models of acquired (iron-dextran or stored red blood cells) and primary (Hfe-/-) iron overload. In each case, the mutants reduce redox activity typical of non-transferrin-bound iron. In summary, we present a non-toxic strategy for iron chelation and urinary elimination, based on manipulating an endogenous protein:siderophore:iron clearance pathway.

Serum neutrophil gelatinase-associated lipocalin and recovery of kidney graft function after transplantation.

BACKGROUND: Neutrophil gelatinase-associated lipocalin (NGAL) is a marker for acute kidney injury. We studied whether serum NGAL predicts delayed graft function (DGF) and recovery of kidney function after transplantation. METHODS: Serum NGAL was analyzed using commercial ELISA and point-of-care (POC) (Triage®, Biosite) methods. Serum samples were collected from 176 consecutive, deceased-donor kidney recipients just before transplant surgery and on day 1 and 14 after transplantation. The first 132 samples were analyzed with both methods and the remaining samples with the POC method. RESULTS: The correlation between the ELISA and POC methods was 0.89, p < 0.0001 and hence the POC method was used for the remaining analyses. DGF was seen in 66/176 patients. Day 1 sNGAL was significantly higher in DGF (588 ng/ml, SD 189.6) compared to early graft function (355 ng/ml, SD 166.2, p < 0.0001) and this difference persisted on day 14. Day 1 sNGAL predicted DGF with an area under the curve (AUC) of 0.853 (CI 0.792-0.914, p < 0.0001). At the optimal cutoff level of 423 ng/ml the sensitivity was 87% and the specificity 77%. In a multivariate analysis, day 1 sNGAL emerged as an independent predictor of DGF. The sNGAL also predicted DGF lasting longer than 14 days with an AUC of 0.825 (CI 0.751-0.899, p < 0.0001). At the optimal cutoff level of 486 ng/ml, the sensitivity was 80% and specificity 75%. CONCLUSION: Serum NGAL predicts clinically significant DGF and is useful in the care of kidney transplant recipients.

Neutrophil gelatinase-associated lipocalin associated with irreversibility of pre-liver transplant kidney dysfunction.

Kidney outcomes in early post-liver transplantation (LT) are crucial for long-term prognosis, but difficult to predict. Among 203 adult LT patients, we studied the value of plasma neutrophil gelatinase-associated lipocalin (NGAL) measured pre-LT for predicting acute kidney injury (AKI), kidney-replacement therapy within three months, and kidney dysfunction at three months post-LT. Glomerular filtration rate (GFR) was estimated by creatinine-based and cystatin C-based equations. Highest NGAL levels were among patients on pre-LT kidney-replacement therapy, whereas NGAL exceeded 200 µg/L in only three (2%) patients with pre-LT GFR >60 mL/min. Pre-LT NGAL >260 µg/L predicted GFR <60 mL/min at three months post-LT (OR 17.8, 95% CI 2.1-153) independently of 19 other variables reflecting recipient characteristics, liver and kidney function, perioperative hemodynamic stress, and immunosuppression. Of 81 patients with pre-LT GFR <60 mL/min, 48% had GFR <60 mL/min at three months, and an NGAL level >260 µg/L predicted this outcome with 90% specificity and 46% sensitivity. NGAL failed to predict post-LT AKI or need for temporary kidney-replacement therapy. In conclusion, NGAL independently predicted irreversibility of pre-LT kidney dysfunction and could thus help in optimizing patient care and in the decision to perform combined liver-kidney transplantation. Pre-LT NGAL was not useful in patients with preserved pre-LT kidney function or in predicting post-LT AKI.

NGAL-Siderocalin in kidney disease.

Kidney damage induces the expression of a myriad of proteins in the serum and in the urine. The function of these proteins in the sequence of damage and repair is now being studied in genetic models and by novel imaging techniques. One of the most intensely expressed proteins is lipocalin2, also called NGAL or Siderocalin. While this protein has been best studied by clinical scientists, only a few labs study its underlying metabolism and function in tissue damage. Structure-function studies, imaging studies and clinical studies have revealed that NGAL-Siderocalin is an endogenous antimicrobial with iron scavenging activity. This review discusses the "iron problem" of kidney damage, the tight linkage between kidney damage and NGAL-Siderocalin expression and the potential roles that NGAL-Siderocalin may serve in the defense of the urogenital system. This article is part of a Special Issue entitled: Cell Biology of Metals.

Deceased donor neutrophil gelatinase-associated lipocalin and delayed graft function after kidney transplantation: a prospective study.

INTRODUCTION: Expanding the criteria for deceased organ donors increases the risk of delayed graft function (DGF) and complicates kidney transplant outcome. We studied whether donor neutrophil gelatinase-associated lipocalin (NGAL), a novel biomarker for acute kidney injury, could predict DGF after transplantation. METHODS: We included 99 consecutive, deceased donors and their 176 kidney recipients. For NGAL detection, donor serum and urine samples were collected before the donor operation. The samples were analyzed using a commercial enzyme-linked immunosorbent assay kit (serum) and the ARCHITECT method (urine). RESULTS: Mean donor serum NGAL (S-NGAL) concentration was 218 ng/mL (range 27 to 658, standard deviation (SD) 145.1) and mean donor urine NGAL (U-NGAL) concentration was 18 ng/mL (range 0 to 177, SD 27.1). Donor S-NGAL and U-NGAL concentrations correlated directly with donor plasma creatinine levels and indirectly with estimated glomerular filtration rate (eGFR) calculated using the modification of diet in renal disease equation for glomerular filtration rate. In transplantations with high (greater than the mean) donor U-NGAL concentrations, prolonged DGF lasting longer than 14 days occurred more often than in transplantations with low (less than the mean) U-NGAL concentration (23% vs. 11%, P = 0.028), and 1-year graft survival was worse (90.3% vs. 97.4%, P = 0.048). High U-NGAL concentration was also associated with significantly more histological changes in the donor kidney biopsies than the low U-NGAL concentration. In a multivariate analysis, U-NGAL, expanded criteria donor status and eGFR emerged as independent risk factors for prolonged DGF. U-NGAL concentration failed to predict DGF on the basis of receiver operating characteristic curve analysis. CONCLUSIONS: This first report on S-NGAL and U-NGAL levels in deceased donors shows that donor U-NGAL, but not donor S-NGAL, measurements give added value when evaluating the suitability of a potential deceased kidney donor.

Urine neutrophil gelatinase-associated lipocalin is a marker of graft recovery after kidney transplantation.

Delayed graft function (DGF), especially long-lasting DGF, complicates kidney transplant outcome. Neutrophil gelatinase-associated lipocalin (NGAL) is an acute kidney injury marker; therefore, we tested whether urine NGAL could predict DGF, prolonged DGF (lasting over 14 days), or the quality of kidney function in transplant recipients without DGF (non-DGF). We collected urine samples from 176 recipients transplanted with deceased donor kidneys before and various days after transplantation. A total of 70 transplantations had DGF, of which 26 were prolonged. Patients who developed DGF had a significantly slower decrease in urinary NGAL compared with those without DGF, such that day 1 NGAL predicted DGF (area under the curve (AUC) 0.75) and predicted DGF in 15 of 112 cases with day 1 urine output over 1 l (AUC 0.70) and in 19 of 86 cases with a day 1 decrease in creatinine over 50 µmol/l (AUC 0.74). The urinary NGAL level on day 1 predicted prolonged DGF (AUC 0.75), which had significantly worse 1-year graft survival (73%), compared with shorter DGF (100%). In non-DGF, high day 3 NGAL (greater than the mean) was associated with significantly worse kidney function at 3 weeks compared with low NGAL, but not at 3 months and 1 year. NGAL did not correlate with long-term function in DGF. Hence, day 1 urinary NGAL predicted DGF even when it was not clinically expected early on, and importantly, it predicted prolonged DGF that led to worse graft survival.

VEGFR-1 and -2 regulate inflammation, myocardial angiogenesis, and arteriosclerosis in chronically rejecting cardiac allografts.

OBJECTIVE: Interplay between inflammation and angiogenesis is important in pathological reparative processes such as arteriosclerosis. We investigated how the two vascular endothelial growth factor receptors VEGFR-1 and -2 regulate these events in chronically rejecting cardiac allografts. METHODS AND RESULTS: Chronic rejection in mouse cardiac allografts induced primitive myocardial, adventitial, and intimal angiogenesis with endothelial expression of CD31, stem cell marker c-kit, and VEGFR-2. Experiments using marker gene mice or rats as cardiac allograft recipients revealed that replacement of cardiac allograft endothelial cells with recipient bone marrow- or non-bone marrow-derived cells was rare and restricted only to sites with severe injury. Targeting VEGFR-1 with neutralizing antibodies in mice reduced allograft CD11b+ myelomonocyte infiltration and allograft arteriosclerosis. VEGFR-2 inhibition prevented myocardial c-kit+ and CD31+ angiogenesis in the allograft, and decreased allograft inflammation and arteriosclerosis. CONCLUSIONS: These results suggest interplay of inflammation, primitive donor-derived myocardial angiogenesis, and arteriosclerosis in transplanted hearts, and that targeting VEGFR-1 and -2 differentially regulate these pathological reparative processes.

Role of platelet-derived growth factor and vascular endothelial growth factor in obliterative airway disease.

RATIONALE: Platelet-derived growth factor (PDGF) is an important smooth muscle cell mitogen, and vascular endothelial growth factor (VEGF) is a known angiogenic and proinflammatory growth factor. We hypothesized that specific therapy aimed at these growth factors might inhibit the development of experimental obliterative airway disease (OAD). METHODS: In fully mismatched rat tracheal allografts, we used imatinib and PTK/ZK, either alone or in combination, to block PDGF and VEGF receptor protein tyrosine kinase (RTK) action, respectively. Prophylaxis was initiated at the time of transplantation. Early treatment was commenced on Day 7 during the inflammatory phase and late treatment on Day 14 during the fibroproliferative phase of OAD. No immunosuppression was administered. MEASUREMENTS AND MAIN RESULTS: Prophylaxis with either PTK/ZK or imatinib alone significantly reduced OAD, and combined prophylaxis completely prevented its development. Early treatment with PTK/ZK and imatinib also effectively reduced the development of OAD. Late treatment failed to show significant efficacy. Blocking VEGF RTK action with PTK/ZK reduced the activation of allograft blood vessels and the number of lymph vessels in the allograft airway wall, and significantly diminished allograft inflammation, whereas PDGF blockade with imatinib inhibited the growth of smooth muscle cells in the proliferating lesion. CONCLUSIONS: Combined prophylactic PDGF and VEGF RTK blockade completely prevents the development of OAD. Also, when early treatment with PTK/ZK and imatinib is commenced during the inflammatory phase of OAD development, it significantly attenuates the development of tracheal occlusion, suggesting that these drugs could potentially be used to treat bronchiolitis obliterans syndrome in its early phase.