Role of KCNK3 Dysfunction in Dasatinib-associated PAH and Endothelial Cell Dysfunction.

Pulmonary arterial hypertension (PAH) is severe cardiopulmonary disease that may be triggered by exposure to drugs such as dasatinib or facilitated by genetic predispositions. The incidence of dasatinib-associated PAH is estimated at 0.45%, suggesting individual predispositions. The mechanisms of dasatinib-associated PAH are still incomplete. We discovered a KCNK3 gene (coding for outward K+ channel) variant in a patient with dasatinib-associated PAH, and we investigated the impact of this variant on KCNK3 function. Additionally, we assessed the effects of dasatinib exposure on KCNK3 expression. In control-human in pulmonary arterial smooth muscle cells (hPASMCs) and pulmonary endothelial cells (hPECs), we evaluated the consequence of KCNK3 knockdown on cell migration, mitochondrial membrane potential, ATP production, and in vitro tube formation. Using mass spectrometry, we determined the KCNK3 interactome. Patch-clamp revealed that the KCNK3 variant represents a loss-of-function variant. Dasatinib contributed to pulmonary artery constriction by decreasing KCNK3 function and expression. In control-hPASMCs, KCNK3 knockdown promotes mitochondrial membrane depolarization and glycolytic shift. Dasatinib exposure or KCNK3 knockdown reduced the number of caveolae in hPECs. Moreover, KCNK3 knockdown in control-hPECs reduced migration, proliferation, and in vitro tubulogenesis. Using proximity labeling and mass spectrometry, we identified the KCNK3 interactome, revealing that KCNK3 interacts with various proteins across different cellular compartments. We identified a novel pathogenic variant in the KCNK3 and showed that dasatinib downregulates KCNK3, emphasizing the relationship between dasatinib-associated PAH and KCNK3 dysfunction. We demonstrated that loss of KCNK3-dependent signaling contributes to endothelial dysfunction in PAH and glycolytic switch of hPASMCs.

Chronic interstitial lung disease associated with systemic lupus erythematosus: A multicentric study of 89 cases.

BACKGROUND AND OBJECTIVE: Chronic interstitial lung disease (ILD) occurs rarely with systemic lupus erythematosus (SLE) as compared with other connective tissue diseases. This multicentric retrospective study of patients with SLE-ILD from the OrphaLung and French SLE networks during 2005-2020 aimed to describe the characteristics of patients with SLE-ILD and analyse factors associated with prognosis. METHODS: We analysed data for 89 patients with SLE-ILD (82 women, 92.1%) (median age at SLE diagnosis: 35 years [interquartile range 27-47]). All patients met the 2019 EULAR/ACR criteria for the diagnosis of SLE. RESULTS: Forty two (47.2%) patients were positive for anti-ribonuclear protein antibodies and 45 (50.6%) for anti SSA/Ro antibodies. A total of 58 (65.2%) patients had another connective tissue disease: Sjögren's syndrome (n = 33, 37.1%), systemic sclerosis (n = 14, 15.7%), inflammatory myopathy (n = 6, 6.7%), or rheumatoid arthritis (n = 6, 6.7%). ILD was diagnosed along with SLE in 25 (28.1%) patients and at a median of 6 (0-14) years after the SLE diagnosis. The most frequent CT pattern was suggestive of non-specific interstitial pneumonia (n = 41, 46.0%) with or without superimposed organizing pneumonia. After a median follow-up of 86.5 [39.5-161.2] months, 18 (20.2%) patients had died and 6 (6.7%) underwent lung transplantation. The median 5-year and 10-year transplantation-free survival were 96% (92-100) and 87% (78-97). In total, 44 (49.4%) patients showed ILD progression. Cutaneous manifestations and Raynaud's phenomenon were associated with better survival. Only forced vital capacity was significantly associated with survival and ILD progression. CONCLUSION: ILD is a rare manifestation of SLE with good overall prognosis but with possible risk of ILD progression. Patients with SLE-ILD frequently have another connective tissue disease.

Updated Clinical Classification and Hemodynamic Definitions of Pulmonary Hypertension and Its Clinical Implications.

Pulmonary hypertension (PH) refers to a pathologic elevation of the mean pulmonary artery pressure (mPAP) and is associated with increased morbidity and mortality in a wide range of medical conditions. These conditions are classified according to similarities in pathophysiology and management in addition to their invasive hemodynamic profiles. The 2022 ESC/ERS guidelines for the diagnosis and treatment of pulmonary hypertension present the newest clinical classification system and includes significant updates to the hemodynamic definitions. Pulmonary hypertension is now hemodynamically defined as an mPAP > 20 mmHg, reduced from the previous threshold of ≥25 mmHg, due to important insights from both normative and prognostic data. Pulmonary vascular resistance has been extended into the definition of pre-capillary pulmonary hypertension, with an updated threshold of >2 Wood Units (WU), to help differentiate pulmonary vascular disease from other causes of increased mPAP. Exercise pulmonary hypertension has been reintroduced into the hemodynamic definitions and is defined by an mPAP/cardiac output slope of >3 mmHg/L/min between rest and exercise. While these new hemodynamic thresholds will have a significant impact on the diagnosis of pulmonary hypertension, no evidence-based treatments are available for patients with mPAP between 21-24 mmHg and/or PVR between 2-3 WU or with exercise PH. This review highlights the evidence underlying these major changes and their implications on the diagnosis and management of patients with pulmonary hypertension.

Survival and response to pulmonary vasodilator therapies in patients with chronic obstructive pulmonary disease and pulmonary vascular phenotype.

BACKGROUND: The aim of the study was to describe and investigate the effect of pulmonary arterial hypertension (PAH) therapies in a cohort of patients with severe precapillary pulmonary hypertension (PH) associated with chronic obstructive pulmonary disease (COPD; PH-COPD), and to assess factors predictive of treatment response and mortality. MATERIAL AND METHODS: We retrospectively included patients with severe incident PH-COPD who received PAH therapy and underwent RHC at diagnosis and on treatment. RESULTS: From 2015 to 2022, 35 severe PH-COPD patients, with clinical features of pulmonary vascular phenotype, were included. Seventeen (48.5%) patients were treated with combined PAH therapy. PAH therapy led to a significant improvement in hemodynamics (PVR -3.5 Wood Units (-39.3%); p < 0.0001), and in the simplified four-strata risk-assessment score, which improved by at least one category in 21 (60%) patients. This effect was more pronounced in patients on dual therapy. Kaplan-Meier estimated survival rates at 1, 3 and 5 years were 94%, 65% and 42% respectively. Univariate analysis showed a significant reduction in survival in patients with a higher simplified risk score at follow-up (Hazard ratio (HR) 2.88 [1.16-7.15]; p = 0.02). Hypoxemia <50 mmHg was correlated to mortality in multivariate analysis (HR 4.33 [1.08-17.42]; p = 0.04). CONCLUSIONS: Our study confirms the poor prognosis of patients with COPD and a pulmonary vascular phenotype and the potential interest of combined PAH therapy in this population, with good tolerability and greater clinical and hemodynamic improvement than monotherapy. Using the simplified risk score during follow-up could be of interest in this population.

Pulmonary vascular phenotype identified in patients with GDF2 (BMP9) or BMP10 variants: an international multicentre study.

BACKGROUND: Bone morphogenetic proteins 9 and 10 (BMP9 and BMP10), encoded by GDF2 and BMP10, respectively, play a pivotal role in pulmonary vascular regulation. GDF2 variants have been reported in pulmonary arterial hypertension (PAH) and hereditary haemorrhagic telangiectasia (HHT). However, the phenotype of GDF2 and BMP10 carriers remains largely unexplored. METHODS: We report the characteristics and outcomes of PAH patients in GDF2 and BMP10 carriers from the French and Dutch pulmonary hypertension registries. A literature review explored the phenotypic spectrum of these patients. RESULTS: 26 PAH patients were identified: 20 harbouring heterozygous GDF2 variants, one homozygous GDF2 variant, four heterozygous BMP10 variants, and one with both GDF2 and BMP10 variants. The prevalence of GDF2 and BMP10 variants was 1.3% and 0.4%, respectively. Median age at PAH diagnosis was 30 years, with a female/male ratio of 1.9. Congenital heart disease (CHD) was present in 15.4% of the patients. At diagnosis, most of the patients (61.5%) were in New York Heart Association Functional Class III or IV with severe haemodynamic compromise (median (range) pulmonary vascular resistance 9.0 (3.3-40.6) WU). Haemoptysis was reported in four patients; none met the HHT criteria. Two patients carrying BMP10 variants underwent lung transplantation, revealing typical PAH histopathology. The literature analysis showed that 7.6% of GDF2 carriers developed isolated HHT, and identified cardiomyopathy and developmental disorders in BMP10 carriers. CONCLUSIONS: GDF2 and BMP10 pathogenic variants are rare among PAH patients, and occasionally associated with CHD. HHT cases among GDF2 carriers are limited according to the literature. BMP10 full phenotypic ramifications warrant further investigation.

4D flow cardiac MRI to assess pulmonary blood flow in patients with pulmonary arterial hypertension associated with congenital heart disease.

PURPOSE: The purpose of this study was to evaluate the accuracy of four-dimensional flow cardiac magnetic resonance imaging (4D flow MRI) compared to right heart catheterization in measuring pulmonary flow (Qp), systemic flow (Qs) and pulmonary-to-systemic flow ratio (Qp/Qs) in patients with pulmonary arterial hypertension associated with congenital heart disease (PAH-CHD). MATERIALS AND METHODS: The study was registered on Clinical-trial.gov (NCT03928002). Sixty-four patients with PAH-CHD who underwent 4D flow MRI were included. There were 16 men and 48 women with a mean age of 45.3 ± 13.7 (standard deviation [SD]) years (age range: 21-77 years). Fifty patients (50/64; 78%) presented with pre-tricuspid shunt. Qp (L/min), Qs (L/min) and Qp/Qs were measured invasively using direct Fick method during right heart catheterization and compared with measurements assessed by 4D flow MRI within a 24-48-hour window. RESULTS: The average mean pulmonary artery pressure was 51 ± 17 (SD) mm Hg with median pulmonary vascular resistance of 8.8 Wood units (Q1, Q3: 5.3, 11.7). A strong linear correlation was found between Qp measurements obtained with 4D flow MRI and those obtained with the Fick method (r = 0.96; P < 0.001). Bland Altman analysis indicated a mean difference of 0.15 ± 0.48 (SD) L/min between Qp estimated by 4D flow MRI and by right heart catheterization. A strong correlation was found between Qs and Qp/Qs measured by 4D flow MRI and those obtained with the direct Fick method (r = 0.85 and r = 0.92; P < 0.001 for both). CONCLUSION: Qp as measured by 4D flow MRI shows a strong correlation with measurements derived from the direct Fick method. Further investigation is needed to develop less complex and standardized methods for measuring essential PAH parameters, such as pulmonary arterial pressures and pulmonary vascular resistance.

Sarcoidosis-Associated Pulmonary Hypertension.

Pulmonary hypertension is a life-threatening complication of advanced sarcoidosis. Many mechanisms can cause an elevation of pulmonary pressure in sarcoidosis, leading to precapillary or postcapillary pulmonary hypertension. Sarcoidosis-associated pulmonary hypertension contributes to severe exertional dyspnea, reduced exercise capacity, and notably compromised the survival. Despite the critical functional and prognostic implications of pulmonary hypertension in sarcoidosis, there is a scarcity of specific guidelines on the management of these patients due to a lack of evidence. Hence, further research is required to identify subgroups of patients who may benefit from pulmonary arterial hypertension-targeted therapies and/or immunosuppressive therapies.

Pulmonary veno-occlusive disease: illustrative cases and literature review.

Pulmonary veno-occlusive disease (PVOD), also known as "pulmonary arterial hypertension (PAH) with overt features of venous/capillary involvement", is a rare cause of PAH characterised by substantial small pulmonary vein and capillary involvement, leading to increased pulmonary vascular resistance and right ventricular failure. Environmental risk factors have been associated with the development of PVOD, such as occupational exposure to organic solvents and chemotherapy, notably mitomycin. PVOD may also be associated with a mutation in the EIF2AK4 gene in heritable forms of disease. Distinguishing PVOD from PAH is critical for guiding appropriate management. Chest computed tomography typically displays interlobular septal thickening, ground-glass opacities and mediastinal lymphadenopathy. Life-threatening pulmonary oedema is a complication of pulmonary vasodilator therapy that can occur with any class of PAH drugs in PVOD. Early referral to a lung transplant centre is essential due to the poor response to therapy when compared with other forms of PAH. Histopathological analysis of lung explants reveals microvascular remodelling with typical fibrous veno-occlusive lesions. This review covers the main features distinguishing PVOD from PAH and two clinical cases that illustrate the challenges of PVOD management.

Outcomes and risk assessment in pulmonary veno-occlusive disease.

Introduction: Pulmonary veno-occlusive disease (PVOD) is a rare and severe subtype of pulmonary arterial hypertension (PAH). Although European Society of Cardiology/European Respiratory Society (ESC/ERS) guidelines advise assessing PAH severity at baseline and during follow-up, no existing risk assessment methods have been validated for PVOD. This study aimed to identify prognostic factors, examine the impact of treatment strategies and evaluate risk assessment methods for PVOD patients. Methods: The study analysed all incident PVOD patients included in the French Pulmonary Hypertension Registry between 2006 and 2021. Survival was assessed based on initial treatment strategy and risk status and compared to a matched (age, sex, pulmonary vascular resistance) PAH group. Six risk assessment methods (number of four low-risk and three noninvasive low-risk variables, ESC/ERS guidelines three-strata and four-strata models, REVEAL 2.0 and Lite 2) were applied at baseline and early follow-up, and their accuracy was compared using Harrell's c-statistic. Results: Among the 327 included PVOD patients, survival rates at 1, 3 and 5 years were 86%, 50% and 27%, respectively. Multivariate analysis showed that only 6-min walk distance was associated with survival, with no significant difference based on initial treatment strategy. All six risk assessment methods could discriminate mortality risk, and the ESC/ERS four-strata model was the most accurate at both baseline and follow-up (C-index 0.64 and 0.74). PVOD survival rates were consistently lower than PAH when comparing baseline risk status using the ESC/ERS four-strata model. Conclusion: PVOD is associated with poor outcomes, and initial treatment strategies do not significantly affect survival. Risk assessment methods can be useful in predicting survival for PVOD patients.

Radiological pulmonary sequelae after COVID-19 and correlation with clinical and functional pulmonary evaluation: results of a prospective cohort.

OBJECTIVES: Whether COVID-19 leads to long-term pulmonary sequelae or not remains unknown. The aim of this study was to assess the prevalence of persisting radiological pulmonary fibrotic lesions in patients hospitalized for COVID-19. MATERIALS AND METHODS: We conducted a prospective single-center study among patients hospitalized for COVID-19 between March and May 2020. Patients with residual symptoms or admitted into intensive care units were investigated 4 months after discharge by a chest CT (CCT) and pulmonary function tests (PFTs). The primary endpoint was the rate of persistent radiological fibrotic lesions after 4 months. Secondary endpoints included further CCT evaluation at 9 and 16 months, correlation of fibrotic lesions with clinical and PFT evaluation, and assessment of predictive factors. RESULTS: Among the 1151 patients hospitalized for COVID-19, 169 patients performed a CCT at 4 months. CCTs showed pulmonary fibrotic lesions in 19% of the patients (32/169). These lesions were persistent at 9 months and 16 months in 97% (29/30) and 95% of patients (18/19) respectively. There was no significant clinical difference based on dyspnea scale in patients with pulmonary fibrosis. However, PFT evaluation showed significantly decreased diffusing lung capacity for carbon monoxide (p < 0.001) and total lung capacity (p < 0.001) in patients with radiological lesions. In multivariate analysis, the predictive factors of radiological pulmonary fibrotic lesions were pulmonary embolism (OR = 9.0), high-flow oxygen (OR = 6.37), and mechanical ventilation (OR = 3.49). CONCLUSION: At 4 months, 19% of patients investigated after hospitalization for COVID-19 had radiological pulmonary fibrotic lesions; they persisted up to 16 months. CLINICAL RELEVANCE STATEMENT: Whether COVID-19 leads to long-term pulmonary sequelae or not remains unknown. The aim of this study was to assess the prevalence of persisting radiological pulmonary fibrotic lesions in patients hospitalized for COVID-19. The prevalence of persisting lesions after COVID-19 remains unclear. We assessed this prevalence and predictive factors leading to fibrotic lesions in a large cohort. The respiratory clinical impact of these lesions was also assessed. KEY POINTS: • Nineteen percent of patients hospitalized for COVID-19 had radiological fibrotic lesions at 4 months, remaining stable at 16 months. • COVID-19 fibrotic lesions did not match any infiltrative lung disease pattern. • COVID-19 fibrotic lesions were associated with pulmonary function test abnormalities but did not lead to clinical respiratory manifestation.

Thirty years of surgical management of pediatric pulmonary hypertension: Mid-term outcomes following reverse Potts shunt and transplantation.

BACKGROUND: Reverse Potts shunt (RPS) and lung or heart-lung transplantation are life-extending surgical interventions for pediatric patients with severe pulmonary arterial hypertension (PAH). Robust criteria for identifying patients who will benefit from these procedures remain elusive. Based on 30 years of experience, we sought to refine the surgical indications. METHODS: This single-center retrospective cohort study included 61 consecutive pediatric patients with PAH managed by RPS (2004-2020) or transplantation (1988-2020). Their mid-term outcomes were assessed. RESULTS: Compared with the 20 patients managed by RPS, the 41 transplant waitlist patients, of whom 28 were transplanted, were older (14.9 vs 8.0 years, P = .0001), had worse right ventricular impairment (tricuspid annular plane systolic excursion, 12.5 mm vs 18.0 mm, P = .03), and were managed later in the evolution of the disease (6.0 vs 1.7 years, P = .002). After implementation of a high-priority allocation program in 2007, waitlist mortality decreased from 52.6% to 13.6% (P = .02) and 5-year survival increased from 57.1% to 74.7% after RPS and 55.6% to 77.2% after transplantation. At a median follow-up of 8.6 years after RPS and 5.9 years after transplantation, functional capacity had improved significantly, and PAH-specific drug requirements had diminished markedly in the RPS group. Two patients successfully underwent double-lung transplant 6 and 9 years after RPS. CONCLUSIONS: In selected children with suprasystemic PAH, RPS is associated with functional capacity improvements and decreased pharmacotherapy needs over the midterm. RPS deserves consideration earlier in the course of pediatric PAH, with transplantation being performed in the event of refractory RV failure.

Pulmonary hypertension associated with diazoxide: the SUR1 paradox.

The ATP-sensitive potassium channels and their regulatory subunits, sulfonylurea receptor 1 (SUR1/Kir6.2) and SUR2/Kir6.1, contribute to the pathophysiology of pulmonary hypertension (PH). Loss-of-function pathogenic variants in the ABCC8 gene, which encodes for SUR1, have been associated with heritable pulmonary arterial hypertension. Conversely, activation of SUR1 and SUR2 leads to the relaxation of pulmonary arteries and reduces cell proliferation and migration. Diazoxide, a SUR1 activator, has been shown to alleviate experimental PH, suggesting its potential as a therapeutic option. However, there are paradoxical reports of diazoxide-induced PH in infants. This review explores the role of SUR1/2 in the pathophysiology of PH and the contradictory effects of diazoxide on the pulmonary vascular bed. Additionally, we conducted a comprehensive literature review of cases of diazoxide-associated PH and analysed data from the World Health Organization pharmacovigilance database (VigiBase). Significant disproportionality signals link diazoxide to PH, while no other SUR activators have been connected with pulmonary vascular disease. Diazoxide-associated PH seems to be dose-dependent and potentially related to acute effects on the pulmonary vascular bed. Further research is required to decipher the differing pulmonary vascular consequences of diazoxide in different age populations and experimental models.

Proteomic biomarkers for survival in systemic sclerosis-associated pulmonary hypertension.

BACKGROUND: Interstitial lung disease (ILD) and pulmonary hypertension (PH) represent the major causes of mortality in systemic sclerosis (SSc). Patients with systemic sclerosis and combined PH and ILD (SSc-PH-ILD) generally have a poor prognosis. Predictors of survival and of potential benefit of treatment are lacking in patients with SSc-PH-ILD. OBJECTIVE: To identify specific plasma protein expression patterns associated with survival in patients with SSc-PH-ILD. MATERIALS AND METHODS: Post-hoc analysis of a prospective multicenter French study in patients with PH-ILD. An untargeted proteomic analysis using mass spectrometry was performed to identify plasma protein changes associated with long-term overall survival in patients with SSc-PH-ILD. RESULTS: Thirty two patients were included in the analysis, of whom 13 died during follow-up (median survival: 76.5 months). At baseline, survivors had less severe hemodynamic impairment [pulmonary vascular resistance of 4.4 Wood Units (IQR 3-5.2) vs. 6.2 Wood Units (IQR 4.2-10.7)] and higher carbon monoxide diffusing capacity [median 39% (IQR 35-44%) vs. 25% (IQR 22-30.5%)], than the 13 patients who died. Seven proteins, associated with haemostasis and fibrosis, were differentially expressed according to patients' survival. In the survivor group, two proteins were increased (ADAMTS13, SERPIND1) and five were decreased (PTGDS, OLFM1, C7, IGFBP7, FBN1) compared to the non-survivor groups. CONCLUSION: The prognosis of SSc-PH-ILD patients is poor. This proteomic approach found 7 plasma proteins (involved in haemostasis and fibrosis pathways) associated with survival. These potential biomarkers may be good candidates to prognostic enrichment.

Pharmacological management of connective tissue disease-associated pulmonary arterial hypertension.

INTRODUCTION: Pulmonary arterial hypertension (PAH) is a severe, progressive pulmonary vasculopathy (Group 1 Pulmonary Hypertension (PH)) that complicates the course of many connective tissue diseases (CTD). Detailed testing is required to differentiate PAH from other types of PH caused by CTD such as left heart disease (Group 2 PH), pulmonary parenchymal disease (Group 3 PH), and chronic thromboembolic pulmonary hypertension (Group 4 PH). PAH is most frequently seen in systemic sclerosis but can also be seen with systemic lupus erythematosus, mixed CTD, and primary Sjogren's syndrome. AREAS COVERED: This review discusses the epidemiology of CTD-associated PAH, outlines the complex diagnosis approach, and finishes with an in-depth discussion on the current treatment paradigm. Focus is placed on challenges faced in the treatment of CTD-associated PAH, (decreased efficacy and poorer tolerance of pharmacological therapies) and includes a discussion on the future investigational treatments. EXPERT OPINION: Despite significant advances over the past decades with more aggressive treatment algorithms, CTD-associated PAH patients continue to have poorer survival compared to those with idiopathic PAH. This review highlights factors leading to disparate outcomes compared to other forms of PAH, and discusses on further improvements that may increase quality of life and survival for CTD-associated PAH patients.

KCNK3 channel is important for the ventilatory response to hypoxia in rats.

To clarify the contribution of KCNK3/TASK-1 channel chemoreflex in response to hypoxia and hypercapnia, we used a unique Kcnk3-deficient rat. We assessed ventilatory variables using plethysmography in Kcnk3-deficient and wild-type rats at rest in response to hypoxia (10% O2) and hypercapnia (4% CO2). Immunostaining for C-Fos, a marker of neuronal activity, was performed to identify the regions of the respiratory neuronal network involved in the observed response.Under basal conditions, we observed increased minute ventilation in Kcnk3-deficient rats, which was associated with increased c-Fos positive cells in the ventrolateral region of the medulla oblongata. Kcnk3-deficient rats show an increase in ventilatory response to hypoxia without changes in response to hypercapnia. In Kcnk3-deficient rats, linked to an increased hypoxia response, we observed a greater increase in c-Fos-positive cells in the first central relay of peripheral chemoreceptors and Raphe Obscurus. This study reports that KCNK3/TASK-1 deficiency in rats induces an inadequate peripheral chemoreflex, alternating respiratory rhythmogenesis, and hypoxic chemoreflex.

Updated Hemodynamic Definition and Classification of Pulmonary Hypertension.

Pulmonary hypertension (PH) is a pathophysiological manifestation of a heterogeneous group of diseases characterized by abnormally elevated pulmonary arterial pressures diagnosed on right heart catheterization. The 2022 European Society of Cardiology (ESC) and European Respiratory Society (ERS) Guidelines for the diagnosis and treatment of PH provides a new hemodynamic definition to define PH by lowering the threshold of the mean pulmonary artery pressure (mPAP) to 20 mm Hg. Precapillary PH is thus now defined as a mPAP >20 mm Hg together with a normal pulmonary artery wedge pressure (<15 mm Hg) and an increased pulmonary vascular resistance (>2 Wood Units). The ESC/ERS 2022 Guidelines also introduce a revised clinical classification of PH while retaining its previous distinction between the five groups according to the underlying pathophysiology.