Back to Authors

Jellis, Christine L

0000-0002-8610-0533

Mayo Clinic

Cleveland Clinic Cleveland OH USA.

Citations 7

Endotypes of Vascular Health Predict Transplantation‐Free Survival in Pulmonary Hypertension
Farha, Samar , Hu, Bo , Chen, Ruoying, Barnard, John , Comhair, Suzy , Heresi, Gustavo A. , Parambil, Joseph, Tonelli, Adriano R. , Beck, Gerald J. , Rosenzweig, Erika B. , Finet, J. Emanuel , Grünig, Gabriele , Hill, Nicholas S. , Jellis, Christine , Park, Margaret , Rischard, Franz P., Olman, Mitchell A. , Erzurum, Serpil C. , Dweik, Raed A. , Group, the PVDOMICS Study, Heresi, Gustavo , Tonelli, Adriano , Beck, Gerald J , Rosenzweig, Erika B , DuBrock, Hilary M , Finet, J Emanuel , Frantz, Robert P , Hassoun, Paul M , Hemnes, Anna , Hill, Nicholas S , Horn, Evelyn M , Jellis, Christine L , Leopold, Jane A , Park, Margaret M , Simpson, Catherine E , Tang, W H Wilson , Erzurum, Serpil C , Dweik, Raed A , Barnard, John , Comhair, Suzy , Hu, Bo , Chen, Ruoying, Parambil, Joseph G. , DuBrock, Hilary M. , Frantz, Robert P. , Hassoun, Paul M. , Hemnes, Anna R. , Horn, Evelyn M. , Leopold, Jane A. , Rischard, Franz , Simpson, Catherine E. , Tang, W.H. Wilson , Group, The PVDOMICS Study

Journal of the American Heart Association | July 17, 2026 | Volume: 15 | Issue: 14 | Pages: No page available

10.1161/jaha.125.048795 Get It

Background The current classification of pulmonary hypertension (PH), based largely on expert opinion, has limitations in prognostication and guiding therapies. We hypothesize that novel PH clusters that predict survival will reveal mechanistic phenotypes associated with biomarkers of vascular health across all PH groups. Methods We first identify novel PH clinical clusters by performing unsupervised clustering analysis on the CC‐PH (Cleveland Clinic PH) registry (N=1529). We develop classification models to predict the new PH clusters and then apply them to the multicenter PVDOMICS (Pulmonary Vascular Diseases Phenomics) cohort (N=853) for validation. We compare transplantation‐free survival across the new PH clusters. We quantify metabolites of the arginine‐nitric oxide pathway and D‐dimer levels and calculate global arginine bioavailability (arginine/[ornithine+citrulline]) to assess endothelial function and activation in the new clusters and link these biomarkers to clinical outcomes. Results Clustering analysis identify 3 clear clusters in CC ‐ PH that are validated in PVDOMICS and outperform conventional classifications in predicting transplantation‐free survival. The phenotype associated with the worst survival is characterized by reduced lung diffusion capacity, decreased arginine bioavailability and nitrate levels, and elevated D‐dimer levels, consistent with loss of pulmonary microcirculation and endothelial dysfunction. Conclusions We identify new informative PH phenotypes associated with mortality and defined by biomarkers of endothelial function and activation. Loss of endothelial health and pronounced pulmonary vascular rarefication contribute more substantially to mortality across the spectrum of PH than right heart function. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02980887.
Metabolomics of Right Ventricular Function in Pulmonary Hypertension
Chacon-Barahona, Jonathan , Chung, Samuel J. , Garry, Jonah , Frantz, Robert P. , Hassoun, Paul M. , Mathai, Stephen C. , Simpson, Catherine E. , Beck, Gerald, Hill, Nicholas S. , MUKHERJEE, MONICA, Jacob, Miriam , Park, M H, Finet, J Emanuel, Farha, Samar , Grünig, Gabriele , Kwon, Deborah, Comhair, Suzy , Erzurum, Serpil, Barnard, John, Jellis, Christine , Racanelli, Alexandra Christin, Krumsiek, Jan , hemnes, anna, Horn, Evelyn, Group, on behalf of the PVDOMICS Study, Beck, Gerald J. , Garry, Jonah D , Hassoun, Paul M , Mathai, Stephen C , Simpson, Catherine E , Beck, Gerald J , Hill, Nicholas S , Leopold, Jane A , Waxman, Aaron B. , Rosenzweig, Erika B , Borlaug, Barry A , Mukherjee, Monica , Vanderpool, Rebecca R , Jacob, Miriam , Mehra, Reena , Park, Margaret M , Finet, J Emanuel , Kwon, Deborah H , Comhair, Suzy , Erzurum, Serpil C , Barnard, John , Hu, Bo , Jellis, Christine L , Krumsiek, Jan , Brittain, Evan L , Hemnes, Anna , Horn, Evelyn M , Frantz, Robert P , Chacon-Barahona, Jonathan , Chung, Samuel J. , Rischard, Franz , Leopold, Jane A. , Rosenzweig, Erika B. , Borlaug, Barry A. , Mukherjee, Monica , Vanderpool, Rebecca , Mehra, Reena , Finet, J. Emanuel , Erzurum, Serpil C. , Racanelli, Alexandra C. , Hemnes, Anna R. , Gro, on behalf of the PVDOMICS Study

Circulation Research | April 15, 2026 | Volume: 138 | Issue: 11 | Pages: No page available

10.1161/circresaha.125.327342 Get It

BACKGROUND: The metabolic mechanisms underlying right ventricular (RV) dysfunction are poorly understood, particularly outside of group 1 pulmonary hypertension (PH). We aimed to identify metabolites and pathways associated with RV systolic function and explored whether associations differed by pulmonary vascular resistance, PH group 1 status, and sex. METHODS: We analyzed data from the multicenter PVDOMICS (Pulmonary Vascular Disease Phenomics) cohort. RV systolic function metrics included fractional area change (echo), global longitudinal strain (echo), and ejection fraction (cardiac magnetic resonance). We used linear regression adjusted for age, sex, body mass index, and PH group to assess associations between metabolites and RV function. Pathway enrichment analyses were used to identify pathways significantly associated with RV function. Interaction terms were assessed to determine whether metabolite associations were modified by pulmonary vascular resistance, group 1 PH status, or sex. Least absolute shrinkage and selection operator regression was used to develop metabolite-based scores for RV function, and prognostic performance was assessed. RESULTS: There were 979 participants with plasma metabolomics and RV function data. Linear regression identified 170 metabolites that were significantly associated with all 3 RV metrics. Androgenic steroid, gamma-glutamyl amino acid, polyamine, vitamin A, fatty acid, and sterol pathways are most strongly associated with RV systolic function. Two metabolites interacted with group 1 PH status, and 6 interacted with pulmonary vascular resistance. Four androgenic steroids are associated more strongly with RV systolic function in women compared with men. Metabolite-based scores were prognostically equivalent to RV systolic function metrics and less accurate than REVEAL Lite 2 scores. CONCLUSIONS: We provide a blueprint of metabolites and metabolic pathways associated with RV systolic function across the spectrum of PH. Novel links to vitamin A and glutathione metabolites were observed. We detected few metabolites that associated with RV systolic function differentially by group 1 PH status or degree of pulmonary vascular resistance elevation. Androgenic steroids may associate more strongly with RV systolic function in women compared with men.
Prevalence and Clinical Implications of Excess Adiposity in Group 1 Pulmonary Hypertension
Reddy, Yogesh N.V. , Frantz, Robert P. , Hemnes, Anna R. , Hassoun, Paul M. , Horn, Evelyn M. , Leopold, Jane A. , Rosenzweig, Erika B. , Hill, Nicholas S. , Erzurum, Serpil C. , Beck, Gerald J. , Finet, J. Emanuel , Jellis, Christine , Mathai, Stephen C. , Group, the PVDOMICS Study, Rosenzweig, Erika B , Hill, Nicholas S , Erzurum, Serpil C , Beck, Gerald J , Finet, J Emanuel , Jellis, Christine L , Mathai, Stephen C , Tang, W H Wilson , Borlaug, Barry A , Nishimura, Rick , Frantz, Robert P , Hemnes, Anna , Horn, Evelyn M , Leopold, Jane A , Hassoun, Paul M , Rischard, Franz , Tang, W.H. Wilson , Borlaug, Barry A. , Group, the PVDOMICS Study

Circulation: Heart Failure | December 3, 2025 | Volume: 19 | Issue: 1 | Pages: No page available

10.1161/circheartfailure.125.013591 Get It

BACKGROUND: Although obesity and insulin resistance (IR) are established risk factors for left heart dysfunction, their clinical impact in group 1 pulmonary hypertension (PH) remains unclear. We sought to determine the impact of excess adiposity versus IR on biventricular hemodynamic and functional reserve in group 1 PH. METHODS: Homeostasis model of insulin resistance and adiposity indices (body mass index [BMI], fat mass, waist circumference) were measured among group 1 patients with PH recruited to PVDOMICS (Redefining Pulmonary Hypertension Through Pulmonary Vascular Disease Phenomics). Functional capacity, and dynamic pulmonary capillary wedge pressure (PCWP) and right atrial pressure responses were compared stratified by obesity (BMI≥30 kg/m 2 ) and IR status (HOMA-IR≥2.6) using repeated-measure mixed models. RESULTS: Among patients with group 1 PH (n=418), 158 (38%) had BMI≥30 kg/m 2 (94 [60%] of whom had IR), and 260 (62%) had BMI<30 kg/m 2 (74 [28%] of whom had IR). Among those with waist circumference measurement (n=375), 287 (77%) had excess adiposity by elevated waist/height ratio, with 214 (57%) having elevated waist circumference. Patients with obesity had worse quality of life, exercise capacity and left heart remodeling, along with higher resting/dynamic PCWP, right atrial pressure and cardiac output ( P <0.0001 for all). Higher PCWP response with obesity persisted after adjusting for IR (IR-adjusted PCWP+2.5 mm Hg [95% CI, +1.4 to +3.6]; P <0.0001). All adiposity indices were consistently associated with PCWP response, but IR was not. Similar associations were observed between adiposity indices with higher right atrial pressure and cardiac output. Greater visceral adiposity as measured by body shape index (hazard ratio, 2.01 [95% CI, 1.16–3.47]; P =0.01) or weight-adjusted waist index (hazard ratio, 1.64 [95% CI, 1.10–2.46]; P =0.01) was associated with worse survival. CONCLUSIONS: Excess adiposity is common in group 1 PH, occurring in 4 out of 5 patients by the more sensitive waist/height ratio, in contrast to only 2 out of 5 patients having obesity by traditional BMI criteria. Excess adiposity is associated with higher biventricular filling pressures, cardiac output demand, worse functional status and reduced survival. These data support trials of adipose-reducing therapies in patients with group 1 PH and excess adiposity.
Left Heart Abnormalities in Patients With Lung Disease, OSA, and Chronic Thromboemboli at Risk for or With Known Pulmonary Hypertension
Reddy, Yogesh N.V. , Frantz, Robert P. , Hassoun, Paul M. , Hemnes, Anna R. , Horn, Evelyn M. , Leopold, Jane A. , Rischard, Franz , Rosenzweig, Erika B. , Hill, Nicholas S. , Erzurum, Serpil C. , Beck, Gerald J. , Finet, J. Emanuel , Jellis, Christine , Mathai, Stephen C. , Group, PVDOMICS Study, Hemnes, Anna , Horn, Evelyn M , Jellis, Christine L , Mehra, Reena , Tang, W H Wilson , Borlaug, Barry A , Nishimura, Rick , Rosenzweig, Erika B , Frantz, Robert P , Rischard, Franz P , Leopold, Jane A , Hassoun, Paul M , Mathai, Stephen C , Mehra, Reena , Tang, W.H. Wilson , Borlaug, Barry A. , Group, PVDOMICS Study

Circulation: Heart Failure | May 29, 2025 | Volume: 18 | Issue: 8 | Pages: No page available

10.1161/circheartfailure.125.012912 Get It

BACKGROUND: Patients with lung disease, sleep apnea, and chronic thromboemboli can develop pulmonary hypertension, currently classified as group 3 or 4. Many of these patients also have risk factors for heart failure with preserved ejection fraction (HFpEF), but the optimal approach to identify the disease overlap remains unclear. METHODS: Pretest probability for HFpEF was determined using the HFpEF-ABA (age, body mass index, atrial fibrillation) algorithm among adjudicated group 3 or 4 patients at risk for pulmonary hypertension in the PVDOMICS study (Redefining Pulmonary Hypertension Through Pulmonary Vascular Disease Phenomics). Patients were stratified by current resting right heart catheterization criteria, and in a separate analysis, stratified only by HFpEF-ABA probability into low (<25%), intermediate, and high (≥75%) HFpEF probability groups. RESULTS: Among 598 patients with group 3 disease, 27% (n=161) had elevated pulmonary capillary wedge pressure (PCWP) with postcapillary pulmonary hypertension even at rest, which was associated with the highest exercise PCWP. However, regardless of this resting PCWP-based classification, a larger subset had intermediate-to-high HFpEF-ABA probabilities (32% [n=197] high and 57% [n=358] intermediate HFpEF probability). High HFpEF probability in group 3 disease was associated with higher resting and dynamic PCWP response to NO, fluid, and exercise ( P <0.0001 for all). These changes were comparable with more traditionally defined HFpEF without pulmonary vascular disease (n=61) but less severe than those with combined precapillary and postcapillary pulmonary hypertension HFpEF (n=31; interaction P =0.006). Increasing HFpEF probability in group 3 disease was associated with worse left heart remodeling, quality of life, 6-minute walk distance, and peak VO 2 ( P <0.0001 for all). Findings were replicated in group 4 disease (n=102). CONCLUSIONS: Quantifying pretest probability for HFpEF in patients with sleep apnea, lung disease, or chronic thromboemboli identifies a progressive gradient for dynamic PCWP abnormalities with worse functional status and quality of life. These subclinical left heart abnormalities are not universally detectable by resting right heart catheterization alone and call for further study of whether strategies to prevent or treat HFpEF might improve functional status in these patients with high risk of occult HFpEF.
Dysregulated Tricarboxylic Acid Cycle Metabolism Is Associated With Right Ventricular Maladaptation in Pulmonary Vascular Disease
Rosen, Darin , Kolb, Todd M. , Mathai, Stephen C. , Suresh, Karthik , D’Amico, Rachel, Hsu, Steven , Tedford, Ryan J. , Hemnes, Anna R. , Leopold, Jane A. , Horn, Evelyn M. , Erzurum, Serpil C. , Beck, Gerald J. , Hill, Nicholas S. , Farha, Samar , Grünig, Gabriele , Jellis, Christine , Kwon, Deborah , Park, Margaret , Xiao, L, Fessel, Jeffrey , Fu, Yongping , Postow, Lisa, Schmetter, Barry, Sutliff, R, Tian, Xuefei , Joseloff, Elizabeth, Wong, Brenda , Lawler, Laurie, Maron, B, Haythe, Jennifer , Krishnan, Udhay , Payne, David A., Bergman, Geoffrey , Bastert, K, Devereux, Richard B. , Kim, Ju Youn , Lohman, Julia, Racanelli, Alexandra C. , Ricketts, Michelle L., Sobol, Irina , Singh, Harsimran , Weinsaft, Jonathan W. , Mathai, S.C. , Carey, Kyle A. , Damico, Rachel L. , Enobun, Blessing , Sanni, Y, Brock, Heinz, Durst, Louise A., Head, Denise , Foley, Thomas A. , Gochanour, Benjamin R. , Halbach, H, Krowka, Michael J. , Menon, David K. , Park, Gyu Tae , Redfield, Margaret M. , Rohwer, Kristi, Williamson, Eric E. , Vanderpool, R, Yuan, Jason X.‐J. , Lim, C.S., Abidov, Aiden , Erickson, Harold , Cunningham, James M. , Pugh, Meredith E., Robbins, Ivan M. , Beck, Gerald J. , Aldred, Micheala A. , Asosingh, Kewal, Aylor, Joan, Beck, B, Borowski, A, Collart, Clara, Comhair, S.A.A., Drinko, Jeanne K., Finet, J. Emanuel , Flinn, Aisling M. , Geraci, M, Jacob, Miriam , Kanta, Alexandra, Larive, Brett , Lempel, Jason K. , Li, Minghui , MacKrell, J., Neumann, D., Nawabit, R, Odabashian, Jill, Olman, Mitchell A. , Park, M, Radeva, Milena , Renapurkar, R, Sharp, Jacqueline, Sherer, Stefan, WHW, Tang, Thomas, Jason , Wadih, K, Wells, Simon P. , Wilcox, Jane, Yu, S, Rounds, Sharon , Bull, Todd , Cadigan, John B., Rosen, Darin T , Rosenzweig, Erika B , Rischard, Franz P , Frantz, Robert P , Beck, Gerald J , Hill, Nicholas S , Barnard, John , Grunig, Gabriele , Jellis, Christine L , Kwon, Deborah H , Mehra, Reena , Park, Margaret M , Tang, W H Wilson , Hassoun, Paul M , Simpson, Catherine E , Hemnes, Anna , Horn, Evelyn M , Leopold, Jane A , Tedford, Ryan J , Mathai, Stephen C , Hsu, Steven , Rosenzweig, Erika B. , Rischard, Franz , Frantz, Robert P. , Barnard, John , Mehra, Reena , Tang, W.H. Wilson , Hassoun, Paul M. , Simpson, Catherine E. , Xiao, L, Fu, Y‐P, Gray, Michael P. , Wong, B, Waxman, Aaron B. , Systrom, David M , Brady, David J. , Chung, Wendy K. , Payne, D, Karas, Maria , Lohman, J, Ricketts, M, Balasubramanian, A, Carey, K, Gao, Lei , Halushka, Marc K. , Kass, David A. , Lin, Ting‐Tse , Mukherjee, Monica , Roth, J, Sanni, Y, Weiss, Robert E. , Zimmerman, Stefan L , Behfar, Atta , Borlaug, Barry A. , Brock, H Du, Head, D, Kane, Garvan C. , Sands, T. , Scott, Christopher G. , Terzic, André , Williamson, E, Garcia, Joe G. N. , Lim, C, Desai, Akshay S , Hansen, L, Newman, J, Brittain, Evan L , Cheng, Feixiong , Filippo, F Di, Flinn, A, Hu, Bo , Jaber, Wael A. , Kanta, A, Martín, Maite Velázquez , McCarthy, Kevin , Ramos, J, Wiggins, K, Willard, Belinda B. , Benza, Raymond L. , Fang, James C. , Gomberg‐Maitland, Mardi

Journal of the American Heart Association | May 22, 2025 | Volume: 14 | Issue: 11 | Pages: No page available

10.1161/jaha.124.041127 Get It

Background Right ventricular (RV) maladaptation to elevated pulmonary afterload is the primary determinant of outcomes in pulmonary artery (PA) hypertension; however, the pathobiological mechanisms underlying RV decompensation remain poorly understood. Methods We performed global untargeted metabolomics on plasma from 55 patients who underwent gold‐standard RV‐PA coupling measurements using multibeat pressure volume loop assessment in a single‐center cohort and from 1027 patients with coupling surrogate measurements in a larger multicenter cohort, the PVDOMICS (Pulmonary Vascular Disease Phenomics) study. Age and sex‐adjusted linear regression was performed to identify associations between metabolites and coupling metrics. Additionally, we performed a metabolic flux analysis using gene expression data from RV tissue in an independent cohort of 32 patients. Partial least squares–discriminant analysis was used to identify metabolites and reactions characteristic of the decompensated RV. Results RV‐PA coupling was negatively associated with tricarboxylic acid (TCA) cycle intermediate levels. Specifically, plasma α‐ketoglutarate and fumarate were significantly associated with all coupling metrics in both cohorts. Metabolic flux analysis indicated that decompensated RVs exhibited aberrant TCA cycle activity, including reduced acetyl coenzyme A entry and increased lactate elimination, suggesting a shift from the TCA cycle toward glycolysis at the RV tissue level. Conclusions We identify an association between circulating TCA cycle intermediate levels and RV‐PA uncoupling in 2 independent cohorts, and dysregulated TCA cycle metabolism in decompensated PA hypertension RVs, suggesting that aberrant TCA cycle metabolism could represent a hallmark of RV maladaptation in PA hypertension. Further study of this pathway is warranted to develop novel biomarkers of RV function or RV‐targeted therapies.
Longitudinal cardiac magnetic resonance imaging following clinical response to rilonacept and prior to recurrence upon treatment suspension: a RHAPSODY subgroup analysis
Cremer, Paul , Brucato, Antonio , Lin, David , Kwon, Deborah , Jellis, Christine , Clair, JoAnn , Curtis, Allison , Wang, Sheldon, Paolini, John F. , Luis, Sushil A , Jellis, Christine L , Brucato, Antonio , Cremer, Paul C , Insalaco, Antonella , Luis, Sushil Allen , Klein, Allan L. , Imazio, Massimo

European Heart Journal - Cardiovascular Imaging | August 22, 2024 | Volume: 26 | Issue: 1 | Pages: 72-79

10.1093/ehjci/jeae200 Get It

Abstract Aims In the Phase 3 trial, RHAPSODY, rilonacept effectively resolved active pericarditis recurrences, and long-term treatment led to sustained pericarditis recurrence risk reduction. Prior analysis suggested association between higher late gadolinium enhancement (LGE) at baseline and more rapid recurrence upon rilonacept suspension after 12 weeks of treatment. This subgroup analysis assessed the utility of longitudinal serial cardiac magnetic resonance (CMR) imaging for tracking clinical improvement and predicting post-treatment cessation outcomes to help guide clinical decision-making. Methods and results At an 18-month decision milestone (18MDM) in the RHAPSODY long-term extension, investigators decided if patients would continue rilonacept, suspend rilonacept for off-treatment observation, or discontinue the study. Pericardial thickness, pericardial oedema (T2-short tau inversion recovery, T2-STIR), and LGE were determined at baseline and 18MDM by an imaging core lab blinded to clinical data, and pericarditis recurrence was investigator-assessed. CMR results in patients with data at both baseline and 18MDM (n = 13) showed that pericardial thickness, T2-STIR, and LGE were reduced during rilonacept treatment. Among patients with CMR data who suspended rilonacept at the 18MDM (n = 7), five (71%) had a pericarditis recurrence within 1–4 months of rilonacept suspension, despite all having had none/trace LGE (n = 7) and negative T2-STIR (n = 7) at the 18MDM and two having received prophylactic colchicine. Conclusion Continued clinical improvement during prolonged rilonacept treatment corresponded with improvement on CMR, including reduced pericardial thickness, resolution of pericardial oedema, and resolution of LGE. However, none/trace LGE at 18MDM while on treatment did not predict absence of pericarditis recurrence upon subsequent rilonacept suspension in this size-limited subgroup.
Comprehensive echocardiographic evaluation of the right heart in patients with pulmonary vascular diseases: the PVDOMICS experience
Jellis, Christine , Park, Margaret , Abidov, Aiden , Jiwon, Kim, Kwon, Deborah , Maron, Bradley A. , Mathai, Stephen C. , Rischard, Franz , Vanderpool, Rebecca , Thomas, James D. , Group, the PVDOMICS Study, Jellis, Christine L , Frantz, Robert, Karas, Maria G , Rischard, Franz P , Vanderpool, Rebecca R , Mathai, Stephen C , Borlaug, Barry A. , Brittain, Evan L , Frantz, Robert P. , Hassoun, Paul M. , Horn, Evelyn M. , Jaber, Wael A. , Jiwon, Kim, Karas, Maria , Leopold, Jane A. , Mehra, Reena , Rosenzweig, Erika B. , Tang, W.H. Wilson , Group, the PVDOMICS Study

European Heart Journal - Cardiovascular Imaging | March 24, 2021 | Volume: 23 | Issue: 7 | Pages: 958-969

10.1093/ehjci/jeab065 Get It

Abstract Aims There is a wide spectrum of diseases associated with pulmonary hypertension, pulmonary vascular remodelling, and right ventricular dysfunction. The NIH-sponsored PVDOMICS network seeks to perform comprehensive clinical phenotyping and endophenotyping across these disorders to further evaluate and define pulmonary vascular disease. Methods and results Echocardiography represents the primary non-invasive method to phenotype cardiac anatomy, function, and haemodynamics in these complex patients. However, comprehensive right heart evaluation requires the use of multiple echocardiographic parameters and optimized techniques to ensure optimal image acquisition. The PVDOMICS echo protocol outlines the best practice approach to echo phenotypic assessment of the right heart/pulmonary artery unit. Conclusion Novel workflow processes, methods for quality control, data for feasibility of measurements, and reproducibility of right heart parameters derived from this study provide a benchmark frame of reference. Lessons learned from this protocol will serve as a best practice guide for echocardiographic image acquisition and analysis across the spectrum of right heart/pulmonary vascular disease.