ABSTRACT
BACKGROUND: Individuals with chronic obstructive pulmonary disease (COPD) are often at risk for or have comorbid cardiovascular disease and are likely to die of cardiovascular-related causes. OBJECTIVES: To prioritize a list of research topics related to diagnosis and management of patients with COPD and comorbid cardiovascular diseases (heart failure, atherosclerotic vascular disease and atrial fibrillation) by summarizing existing evidence and using consensus-based methods. METHODS: A literature search was performed. References were reviewed by committee co-chairs. An international, multidisciplinary committee, including a patient advocate, met virtually to review evidence and identify research topics. A modified Delphi approach was used to prioritize topics in real-time based on their potential for advancing the field. RESULTS: Gaps spanned the translational science spectrum from basic science to implementation: 1) disease mechanisms, 2) epidemiology, 3) subphenotyping, 4) diagnosis and management, 5) clinical trials, 6) care delivery, 7) medication access, adherence and side effects, 8) risk factor mitigation, 9) cardiac and pulmonary rehabilitation, and 10) health equity. Seventeen experts participated and quorum was achieved for all votes (>80%). Of 17 topics, ≥70% agreement was achieved for 12 topics after 2 rounds of voting. Range of summative Likert score was -15 to 25. Highest priority was "Conduct pragmatic clinical trials with patient-centered outcomes that collect both pulmonary and cardiac data elements." Health equity was identified as an important topic that should be embedded within all research. CONCLUSIONS: We propose a prioritized research agenda with the purpose of stimulating high-impact research that will hopefully improve outcomes among people with COPD and cardiovascular disease.
ABSTRACT
OBJECTIVE: Olfactory dysfunction is a "canary in the coalmine" for aging conditions. We evaluated olfactory dysfunction as a biomarker of early frailty in older adults living in the United States. STUDY DESIGN: Prospective, longitudinal, nationally representative study. SETTING: National Social Life, Health and Aging Project (NSHAP). METHODS: We examined data from 1061 community-dwelling older US adults. Odor identification (5-item Sniffin' Stick) and frailty scores were measured at baseline and 5-year follow-up. Multivariate logistic regressions evaluated the association between olfactory dysfunction and frailty at baseline in cross-section and over time in the transition from robust to prefrail to frail, adjusting for confounding factors measured at baseline. RESULTS: Older US adults who were anosmic at baseline were more likely to be frail 5 years later compared to normosmic peers (odds ratio [OR]: 3.83, 95% confidence interval [CI]: 1.10-13.31, P = .035). Examining changes in frailty stage over time, we found that anosmics were more likely to transition from prefrail to frail over 5 years (OR: 3.25, 95% CI: 1.31-8.08, P = .011). Interestingly, hyposmics did not show a similar trajectory toward frailty (P > .05). In contrast, olfactory dysfunction was not associated with frailty in cross-section (OR: 0.90, 95% CI: 0.43-1.89, P = .787, hyposmia; OR: 0.72, 95% CI: 0.15-3.35, P = .673, anosmia). CONCLUSION: Older US adults with anosmia face higher odds of becoming frail over 5 years, especially those in the prefrail stage. Olfactory dysfunction may serve as a surrogate marker for early-stage neurodegenerative diseases, which are strong contributors to frailty.
Subject(s)
Frailty , Independent Living , Olfaction Disorders , Humans , Male , Aged , Female , United States/epidemiology , Prospective Studies , Olfaction Disorders/epidemiology , Longitudinal Studies , Frailty/complications , Aged, 80 and over , Frail Elderly/statistics & numerical data , Geriatric AssessmentSubject(s)
Oxygen Inhalation Therapy , Pulmonary Disease, Chronic Obstructive , Self Report , Humans , Pulmonary Disease, Chronic Obstructive/epidemiology , Pulmonary Disease, Chronic Obstructive/therapy , Oxygen Inhalation Therapy/statistics & numerical data , United States/epidemiology , Male , Female , Aged , Middle Aged , PrevalenceABSTRACT
BACKGROUND: Frailty is prevalent among older adults with asthma or chronic obstructive pulmonary disease (obstructive lung diseases [OLDs]). Frailty and OLD's co-occurrence is associated with increased hospitalization/mortality. Chemosensory dysfunction is closely connected to both OLD and frailty. We evaluated the utility of olfactory decline as a biomarker of frailty in the setting of OLD. METHODS: We performed a prospective, longitudinal, nationally representative study of community-dwelling older US adults in the National Social Life, Health and Aging Project, an omnibus in-home survey. Respondents reported a physician's diagnosis of OLD. Decline in odor identification and sensitivity over 5 years and frailty (adapted fried frailty phenotype criteria) were measured using standard tools. Multivariate logistic regressions evaluated the association between OLD status, olfactory decline, and frailty. RESULTS: We compared individuals with OLD (n = 98; mean age 71.2 years, 59.2% women) and those without OLD (n = 1036; mean age 69.5 years, 58.9% women). Olfactory identification decline was associated with developing frailty over the 5-year follow-up period in individuals with OLD (odds ratio [OR] = 9.1, 95% confidence interval [CI] = 2.1-38.6, p = 0.003). Olfactory decline predicted incidence of frailty in individuals with OLD (identification: OR = 4.8, 95% CI = 1.3-17.5, P = 0.018; sensitivity: OR = 6.1, 95%CI = 1.2-31.0, p = 0.030) but not in those without OLD adjusting for demographics, heavy alcohol use, current smoking, and comorbidity. Results were robust to different thresholds for olfactory decline and frailty development. CONCLUSIONS: Older adults with OLD who experience olfactory decline face higher odds of developing frailty. Use of olfactory decline as a biomarker to identify frailty could allow earlier intervention and decrease adverse outcomes for high-risk older adults with OLD.
Subject(s)
Asthma , Frailty , Humans , Female , Adult , Middle Aged , Aged , Male , Frailty/epidemiology , Frailty/diagnosis , Prospective Studies , Smell , BiomarkersABSTRACT
Lung cancer remains the leading cause of cancer-related mortality for men and women in the United States. Screening for lung cancer with annual low-dose CT is saving lives, and the continued implementation of lung screening can save many more. In 2015, the CMS began covering annual lung screening for those who qualified based on the original United States Preventive Services Task Force (USPSTF) lung screening criteria, which included patients 55 to 77 year of age with a 30 pack-year history of smoking, who were either currently using tobacco or who had smoked within the previous 15 years. In 2021, the USPSTF issued new screening guidelines, decreasing the age of eligibility to 80 years of age and pack-years to 20. Lung screening remains controversial for those who do not meet the updated USPSTF criteria, but who have additional risk factors for the development of lung cancer. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.
Subject(s)
Early Detection of Cancer , Lung Neoplasms , Male , Humans , Female , United States , Adult , Lung Neoplasms/diagnostic imaging , Societies, Medical , Evidence-Based Medicine , Diagnostic Imaging/methodsABSTRACT
Older adults suffering from chronic pulmonary diseases, such as chronic obstructive pulmonary disease and interstitial lung disease, and critical illnesses, such as sepsis and acute respiratory failure, are more vulnerable to adverse outcomes like disability and greater side effects from treatments. In this update, we discuss recent practice-changing clinical trials and observational studies in Pulmonary & Critical Care Medicine that have advanced our understanding of the diagnosis or management of older adults with chronic lung diseases or critical illnesses.
Subject(s)
Geriatrics , Lung Diseases , Pulmonary Disease, Chronic Obstructive , Humans , Aged , Critical Illness/therapy , Lung Diseases/therapy , Critical CareABSTRACT
RATIONALE: Chronic obstructive pulmonary disease (COPD) predominantly affects older adults. However, the co-morbid occurrence of geriatric conditions has been understudied. OBJECTIVE: Characterize the prevalence of geriatric conditions among community-dwelling U.S. older adults with self-reported COPD. METHODS: We conducted a nationally representative, cross-sectional study of 3,005 U.S. community-dwelling older adults (ages 57-85 years) from the National Social Life, Health, and Aging Project (NSHAP). We evaluated the prevalence of select geriatric conditions (multimorbidity, functional disability, impaired physical function, low physical activity, modified frailty assessment, falls, polypharmacy, and urinary incontinence) and psychosocial measures (frequency of socializing, sexual activity in the last year, loneliness, cognitive impairment, and depressive symptoms) among individuals with self-reported COPD as compared to those without. Using multivariate logistic and linear regressions, we investigated the relationships between COPD and these geriatric physical and psychosocial conditions. MAIN RESULTS: Self-reported COPD prevalence was 10.7%, similar to previous epidemiological studies. Individuals with COPD had more multimorbidity [modified Charlson score 2.6 (SD 1.9) vs. 1.6 (SD 1.6)], more functional disability (58.1 vs. 29.6%; adjusted OR 3.1, 95% CI 2.3, 4.3), falls in the last year (28.4 vs. 20.8%; adjusted OR 1.4, 95% CI 1.01, 2.0), impaired physical function (75.8 vs. 56.6%; adjusted OR 2.1, 95% CI 1.1, 3.7), more frequently reported extreme low physical activity (18.7 vs. 8.1%; adjusted OR 2.3, 95% CI 1.5, 3.5) and higher frailty prevalence (16.0 vs. 2.7%; adjusted OR 6.3, 95% CI 3.0,13.0) than those without COPD. They experienced more severe polypharmacy (≥10 medications, 37.5 vs. 16.1%; adjusted OR 2.9, 95% CI 2.0, 4.2). They more frequently reported extreme social disengagement and were lonelier, but the association with social measures was eliminated when relationship status was accounted for, as those with COPD were less frequently partnered. They more frequently endorsed depressive symptoms (32.0 vs. 18.9%, adjusted OR 1.9, 95% CI 1.4, 2.7). There was no noted difference in cognitive impairment between the two populations. CONCLUSIONS: Geriatric conditions are common among community-dwelling older adults with self-reported COPD. A "beyond the lung" approach to COPD care should center on active management of geriatric conditions, potentially leading to improved COPD management, and quality of life.
ABSTRACT
Rationale: Identifying patients hospitalized for acute exacerbations of COPD (AECOPD) who are at high risk for readmission is challenging. Traditional markers of disease severity such as pulmonary function have limited utility in predicting readmission. Handgrip strength, a component of the physical frailty phenotype, may be a simple tool to help predict readmission. Objective(s): To investigate if handgrip strength, a component of the physical frailty phenotype and surrogate for weakness, is a predictive biomarker of COPD readmission. Methods: This was a prospective, observational study of patients admitted to the inpatient general medicine unit at the University of Chicago Medicine, US. This study evaluated age, sex, ethnicity, degree of obstructive lung disease by spirometry (FEV1 percent predicted), and physical frailty phenotype (components include handgrip strength and walk speed). The primary outcome was all-cause hospital readmission within 30 days of discharge. Results: Of 381 eligible patients with AECOPD, 70 participants agreed to consent to participate in this study. Twelve participants (17%) were readmitted within 30 days of discharge. Weak grip at index hospitalization, defined as grip strength lower than previously established cut-points for sex and body mass index (BMI), was predictive of readmission (OR 11.2, 95% CI 1.3, 93.2, p = 0.03). Degree of airway obstruction (FEV1 percent predicted) did not predict readmission (OR 1.0, 95% CI 0.95, 1.1, p = 0.7). No non-frail patients were readmitted. Conclusions: At a single academic center weak grip strength was associated with increased 30-day readmission. Future studies should investigate whether geriatric measures can help risk-stratify patients for likelihood of readmission after admission for AECOPD.
ABSTRACT
Idiopathic pulmonary fibrosis is a fatal interstitial lung disease characterized by the TGF-ß (transforming growth factor-ß)-dependent differentiation of lung fibroblasts into myofibroblasts, which leads to excessive deposition of collagen proteins and progressive scarring. We have previously shown that synthesis of collagen by myofibroblasts requires de novo synthesis of glycine, the most abundant amino acid found in collagen protein. TGF-ß upregulates the expression of the enzymes of the de novo serine-glycine synthesis pathway in lung fibroblasts; however, the transcriptional and signaling regulators of this pathway remain incompletely understood. Here, we demonstrate that TGF-ß promotes accumulation of ATF4 (activating transcription factor 4), which is required for increased expression of the serine-glycine synthesis pathway enzymes in response to TGF-ß. We found that induction of the integrated stress response (ISR) contributes to TGF-ß-induced ATF4 activity; however, the primary driver of ATF4 downstream of TGF-ß is activation of mTORC1 (mTOR Complex 1). TGF-ß activates the PI3K-Akt-mTOR pathway, and inhibition of PI3K prevents activation of downstream signaling and induction of ATF4. Using a panel of mTOR inhibitors, we found that ATF4 activation is dependent on mTORC1, independent of mTORC2. Rapamycin, which incompletely and allosterically inhibits mTORC1, had no effect on TGF-ß-mediated induction of ATF4; however, Rapalink-1, which specifically targets the kinase domain of mTORC1, completely inhibited ATF4 induction and metabolic reprogramming downstream of TGF-ß. Our results provide insight into the mechanisms of metabolic reprogramming in myofibroblasts and clarify contradictory published findings on the role of mTOR inhibition in myofibroblast differentiation.
Subject(s)
Activating Transcription Factor 4/metabolism , Fibroblasts/metabolism , Lung/cytology , Mechanistic Target of Rapamycin Complex 1/metabolism , Transforming Growth Factor beta/pharmacology , Collagen/biosynthesis , Fibroblasts/drug effects , Glycine/metabolism , Glycolysis/drug effects , Humans , Mitochondria/drug effects , Mitochondria/metabolism , Oxygen Consumption/drug effects , Phosphatidylinositol 3-Kinases/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Serine/metabolism , Signal Transduction/drug effects , Stress, Physiological , TOR Serine-Threonine Kinases/metabolismABSTRACT
Coronavirus disease 2019 (COVID-19) continues to impact older adults disproportionately, from severe illness and hospitalization to increased mortality risk. Concurrently, concerns about potential shortages of healthcare professionals and health supplies to address these needs have focused attention on how resources are ultimately allocated and used. Some strategies misguidedly use age as an arbitrary criterion, inappropriately disfavoring older adults. This statement represents the official policy position of the American Geriatrics Society (AGS). It is intended to inform stakeholders including hospitals, health systems, and policymakers about ethical considerations to consider when developing strategies for allocating scarce resources during an emergency involving older adults. Members of the AGS Ethics Committee collaborated with interprofessional experts in ethics, law, nursing, and medicine (including geriatrics, palliative care, emergency medicine, and pulmonology/critical care) to conduct a structured literature review and examine relevant reports. The resulting recommendations defend a particular view of distributive justice that maximizes relevant clinical factors and deemphasizes or eliminates factors placing arbitrary, disproportionate weight on advanced age. The AGS positions include (1) avoiding age per se as a means for excluding anyone from care; (2) assessing comorbidities and considering the disparate impact of social determinants of health; (3) encouraging decision makers to focus primarily on potential short-term (not long-term) outcomes; (4) avoiding ancillary criteria such as "life-years saved" and "long-term predicted life expectancy" that might disadvantage older people; (5) forming and staffing triage committees tasked with allocating scarce resources; (6) developing institutional resource allocation strategies that are transparent and applied uniformly; and (7) facilitating appropriate advance care planning. The statement includes recommendations that should be immediately implemented to address resource allocation strategies during COVID-19, aligning with AGS positions. The statement also includes recommendations for post-pandemic review. Such review would support revised strategies to ensure that governments and institutions have equitable emergency resource allocation strategies, avoid future discriminatory language and practice, and have appropriate guidance to develop national frameworks for emergent resource allocation decisions. J Am Geriatr Soc 68:1136-1142, 2020.
Subject(s)
Betacoronavirus , Coronavirus Infections , Geriatrics/standards , Health Care Rationing/standards , Health Planning Guidelines , Pandemics , Pneumonia, Viral , Aged , Aged, 80 and over , COVID-19 , Female , Humans , Male , SARS-CoV-2 , United States/epidemiologyABSTRACT
Coronavirus disease 2019 (COVID-19) continues to impact older adults disproportionately with respect to serious consequences ranging from severe illness and hospitalization to increased mortality risk. Concurrently, concerns about potential shortages of healthcare professionals and health supplies to address these issues have focused attention on how these resources are ultimately allocated and used. Some strategies, for example, misguidedly use age as an arbitrary criterion that disfavors older adults in resource allocation decisions. This is a companion article to the American Geriatrics Society (AGS) position statement, "Resource Allocation Strategies and Age-Related Considerations in the COVID-19 Era and Beyond." It is intended to inform stakeholders including hospitals, health systems, and policymakers about ethical considerations that should be considered when developing strategies for allocation of scarce resources during an emergency involving older adults. This review presents the legal and ethical background for the position statement and discusses these issues that informed the development of the AGS positions: (1) age as a determining factor, (2) age as a tiebreaker, (3) criteria with a differential impact on older adults, (4) individual choices and advance directives, (5) racial/ethnic disparities and resource allocation, and (6) scoring systems and their impact on older adults. It also considers the role of advance directives as expressions of individual preferences in pandemics. J Am Geriatr Soc 68:1143-1149, 2020.
Subject(s)
Betacoronavirus , Coronavirus Infections , Geriatrics/ethics , Health Care Rationing/ethics , Pandemics , Pneumonia, Viral , Aged , Aged, 80 and over , COVID-19 , Female , Humans , Male , SARS-CoV-2 , United States/epidemiologySubject(s)
Atrophy/physiopathology , Diaphragm/diagnostic imaging , Diaphragm/physiopathology , Disease Progression , Idiopathic Pulmonary Fibrosis/diagnostic imaging , Idiopathic Pulmonary Fibrosis/genetics , Idiopathic Pulmonary Fibrosis/physiopathology , Aged , Genetic Predisposition to Disease , Humans , MaleABSTRACT
Idiopathic pulmonary fibrosis (IPF) is characterized by the transforming growth factor (TGF)-ß-dependent differentiation of lung fibroblasts into myofibroblasts, leading to excessive deposition of extracellular matrix proteins, which distort lung architecture and function. Metabolic reprogramming in myofibroblasts is emerging as an important mechanism in the pathogenesis of IPF, and recent evidence suggests that glutamine metabolism is required in myofibroblasts, although the exact role of glutamine in myofibroblasts is unclear. In the present study, we demonstrate that glutamine and its conversion to glutamate by glutaminase are required for TGF-ß-induced collagen protein production in lung fibroblasts. We found that metabolism of glutamate to α-ketoglutarate by glutamate dehydrogenase or the glutamate-pyruvate or glutamate-oxaloacetate transaminases is not required for collagen protein production. Instead, we discovered that the glutamate-consuming enzymes phosphoserine aminotransferase 1 (PSAT1) and aldehyde dehydrogenase 18A1 (ALDH18A1)/Δ1-pyrroline-5-carboxylate synthetase (P5CS) are required for collagen protein production by lung fibroblasts. PSAT1 is required for de novo glycine production, whereas ALDH18A1/P5CS is required for de novo proline production. Consistent with this, we found that TGF-ß treatment increased cellular concentrations of glycine and proline in lung fibroblasts. Our results suggest that glutamine metabolism is required to promote amino acid biosynthesis and not to provide intermediates such as α-ketoglutarate for oxidation in mitochondria. In support of this, we found that inhibition of glutaminolysis has no effect on cellular oxygen consumption and that knockdown of oxoglutarate dehydrogenase has no effect on the ability of fibroblasts to produce collagen protein. Our results suggest that amino acid biosynthesis pathways may represent novel therapeutic targets for treatment of fibrotic diseases, including IPF.
Subject(s)
Collagen/metabolism , Fibroblasts/metabolism , Glutaminase/metabolism , Glutamine/metabolism , Cell Differentiation , Cells, Cultured , Humans , Lung/pathology , Myofibroblasts/metabolism , Transforming Growth Factor beta/metabolismABSTRACT
BACKGROUND: Mortality is similarly high among individuals with usual interstitial pneumonia (UIP) due to idiopathic pulmonary fibrosis (IPF) and interstitial pneumonia with autoimmune features (IPAF). Circulating anti-nuclear antibodies (ANA) are commonly found in this patient population, suggesting possible aberrant immune activation. Because an environment of oxidative stress can result from immunologic activation, we hypothesized that ANA positive patients with UIP would have improved outcome when exposed to the antioxidant N-acetylcysteine (NAC) compared to ANA negative patients. METHODS: A single center, retrospective cohort analysis was performed. Patients with UIP due to IPF and IPAF were stratified according to ANA status to and NAC exposure. Transplant-free survival (TFS) was assessed using the Kaplan-Meier estimator and multivariable Cox regression adjusted for diagnosis, gender/age/physiology score, immunosuppressant exposure and anti-fibrotic exposure. RESULTS: Of 293 individuals with UIP due to IPF (74%) or IPAF (26%), NAC exposure was documented in 58 (19.8%). Among NAC exposed individuals, 33 (56.9%) were ANA seropositive and 25 (43.1%) were seronegative. NAC exposure was associated with improved TFS survival among ANA seropositive individuals in unadjusted analysis (plogrank = 0.02) and after multi-variable adjustment (HR 0.51, 95% CI 0.30-0.87; p = 0.01). There was no association between NAC exposure and TFS in ANA seronegative individuals (HR 1.26, 95% CI 0.69-2.32; p = 0.45). Formal interaction testing confirmed NAC*ANA interaction (p = 0.04) and sensitivity analysis demonstrated an increasing effect size associated with NAC therapy as ANA titer increased. Among patients with available genetic data, a marginally higher proportion of ANA positive patients (p = 0.08) carried the rs3750920 (TOLLIP) genotype previously shown to predict favorable outcome in NAC exposed patients. CONCLUSION: NAC exposure is associated with improved transplant-free survival ANA positive patients with UIP. These findings support the prospective collection of ANA data in in future NAC clinical trials performed in patients with UIP.
Subject(s)
Acetylcysteine/therapeutic use , Free Radical Scavengers/therapeutic use , Idiopathic Pulmonary Fibrosis/drug therapy , Aged , Antibodies, Antinuclear/immunology , Cohort Studies , Female , Humans , Idiopathic Pulmonary Fibrosis/immunology , Idiopathic Pulmonary Fibrosis/mortality , Kaplan-Meier Estimate , Lung Transplantation/statistics & numerical data , Male , Middle Aged , Multivariate Analysis , Proportional Hazards Models , Retrospective Studies , Survival RateABSTRACT
Organ fibrosis, including idiopathic pulmonary fibrosis, is associated with significant morbidity and mortality. Because currently available therapies have limited effect, there is a need to better understand the mechanisms by which organ fibrosis occurs. We have recently reported that transforming growth factor (TGF)-ß, a key cytokine that promotes fibrogenesis, induces the expression of the enzymes of the de novo serine and glycine synthesis pathway in human lung fibroblasts, and that phosphoglycerate dehydrogenase (PHGDH; the first and rate-limiting enzyme of the pathway) is required to promote collagen protein synthesis downstream of TGF-ß. In this study, we investigated whether inhibition of de novo serine and glycine synthesis attenuates lung fibrosis in vivo. We found that TGF-ß induces mRNA and protein expression of PHGDH in murine fibroblasts. Similarly, intratracheal administration of bleomycin resulted in increased expression of PHGDH in mouse lungs, localized to fibrotic regions. Using a newly developed small molecule inhibitor of PHGDH (NCT-503), we tested whether pharmacologic inhibition of PHGDH could inhibit fibrogenesis both in vitro and in vivo. Treatment of murine and human lung fibroblasts with NCT-503 decreased TGF-ß-induced collagen protein synthesis. Mice treated with the PHGDH inhibitor beginning 7 days after intratracheal instillation of bleomycin had attenuation of lung fibrosis. These results indicate that the de novo serine and glycine synthesis pathway is necessary for TGF-ß-induced collagen synthesis and bleomycin-induced pulmonary fibrosis. PHGDH and other enzymes in the de novo serine and glycine synthesis pathway may be a therapeutic target for treatment of fibrotic diseases, including idiopathic pulmonary fibrosis.
Subject(s)
Airway Remodeling/drug effects , Bleomycin , Enzyme Inhibitors/pharmacology , Fibroblasts/drug effects , Idiopathic Pulmonary Fibrosis/prevention & control , Lung/drug effects , Phosphoglycerate Dehydrogenase/antagonists & inhibitors , Animals , Collagen/metabolism , Disease Models, Animal , Fibroblasts/enzymology , Fibroblasts/pathology , Glycine/metabolism , Humans , Idiopathic Pulmonary Fibrosis/chemically induced , Idiopathic Pulmonary Fibrosis/enzymology , Idiopathic Pulmonary Fibrosis/pathology , Lung/enzymology , Lung/pathology , Male , Mice , Mice, Inbred C57BL , NIH 3T3 Cells , Phosphoglycerate Dehydrogenase/metabolism , Serine/metabolism , Signal Transduction/drug effects , Transforming Growth Factor beta/pharmacologyABSTRACT
BACKGROUND: The current interstitial lung disease (ILD) classification has overlapping clinical presentations and outcomes. Cluster analysis modeling is a valuable tool in identifying distinct clinical phenotypes in heterogeneous diseases. However, this approach has yet to be implemented in ILD. METHODS: Using cluster analysis, novel ILD phenotypes were identified among subjects from a longitudinal ILD cohort, and outcomes were stratified according to phenotypic clusters compared with subgroups according to current American Thoracic Society/European Respiratory Society ILD classification criteria. RESULTS: Among subjects with complete data for baseline variables (N = 770), four clusters were identified. Cluster 1 (ie, younger white obese female subjects) had the highest baseline FVC and diffusion capacity of the lung for carbon monoxide (Dlco). Cluster 2 (ie, younger African-American female subjects with elevated antinuclear antibody titers) had the lowest baseline FVC. Cluster 3 (ie, elderly white male smokers with coexistent emphysema) had intermediate FVC and Dlco. Cluster 4 (ie, elderly white male smokers with severe honeycombing) had the lowest baseline Dlco. Compared with classification according to ILD subgroup, stratification according to phenotypic clusters was associated with significant differences in monthly FVC decline (Cluster 4, -0.30% vs Cluster 2, 0.01%; P < .0001). Stratification by using clusters also independently predicted progression-free survival (P < .001) and transplant-free survival (P < .001). CONCLUSIONS: Among adults with diverse chronic ILDs, cluster analysis using baseline characteristics identified four distinct clinical phenotypes that might better predict meaningful clinical outcomes than current ILD diagnostic criteria.
Subject(s)
Lung Diseases, Interstitial/classification , Aged , Chronic Disease , Cluster Analysis , Female , Humans , Longitudinal Studies , Male , Middle Aged , Phenotype , Pulmonary Fibrosis/pathologyABSTRACT
CONTEXT: - Patients with idiopathic interstitial pneumonia may display evidence of autoimmunity without meeting criteria for a defined connective tissue disease. A recent European Respiratory Society/American Thoracic Society statement proposed research criteria for interstitial pneumonia with autoimmune features (IPAF), which includes findings from the clinical, serologic, and morphologic domains. OBJECTIVES: - To investigate the importance of histopathologic criteria within the morphologic domain and to report our methodology for identifying these features. DESIGN: - Patients with idiopathic interstitial pneumonia at the University of Chicago who underwent surgical lung biopsy or lung transplantation were assessed for IPAF histopathologic features, using the initial pathology interpretation in the electronic records. A focused rereview of available slides by a pulmonary pathologist was then performed for patients who failed to meet IPAF criteria on initial pathology assessment. RESULTS: - Of 422 patients with idiopathic interstitial pneumonia, 176 (41.7%) underwent surgical lung biopsy or lung transplant. Forty-six of those 176 patients (26.1%) met IPAF criteria by initial pathology interpretation and a positive clinical or serologic feature. Of the remaining 130 patients, 73 (56.2%) met either the clinical or serologic domains without meeting the morphologic domain, whereas 36 (27.7%) had slides available for pathology rereview. This rereview demonstrated nonspecific interstitial pneumonia in 8 of 36 patients (22.2%) and lymphoplasmacytic infiltrates in 6 of 36 patients (16.7%), resulting in an additional 7 of 36 patients (19.4%) with idiopathic interstitial pneumonia that met the IPAF criteria. In IPAF, pulmonary vasculopathy was the most prevalent finding (45 of 84; 53.6%) and predicted increased mortality (hazard ratio, 2.5; P = .04). CONCLUSIONS: - Using a methodological approach to identifying IPAF pathology, we demonstrate a significant increase in the number of patients meeting IPAF criteria because of focused pathologic review and highlight the prognostic value of the IPAF pathologic findings.
Subject(s)
Autoimmunity , Idiopathic Interstitial Pneumonias/diagnosis , Pathology, Clinical/methods , Adult , Aged , Female , Humans , Male , Middle AgedABSTRACT
TGF-ß promotes excessive collagen deposition in fibrotic diseases such as idiopathic pulmonary fibrosis (IPF). The amino acid composition of collagen is unique due to its high (33%) glycine content. Here, we report that TGF-ß induces expression of glycolytic genes and increases glycolytic flux. TGF-ß also induces the expression of the enzymes of the de novo serine synthesis pathway (phosphoglycerate dehydrogenase (PHGDH), phosphoserine aminotransferase 1 (PSAT1), and phosphoserine phosphatase (PSPH)) and de novo glycine synthesis (serine hydroxymethyltransferase 2 (SHMT2)). Studies in fibroblasts with genetic attenuation of PHGDH or SHMT2 and pharmacologic inhibition of PHGDH showed that these enzymes are required for collagen synthesis. Furthermore, metabolic labeling experiments demonstrated carbon from glucose incorporated into collagen. Lungs from humans with IPF demonstrated increased expression of PHGDH and SHMT2. These results indicate that the de novo serine synthesis pathway is necessary for TGF-ß-induced collagen production and suggest that this pathway may be a therapeutic target for treatment of fibrotic diseases including IPF.
Subject(s)
Collagen/metabolism , Fibroblasts/metabolism , Glycine Hydroxymethyltransferase/metabolism , Idiopathic Pulmonary Fibrosis/metabolism , Phosphoglycerate Dehydrogenase/metabolism , Serine/biosynthesis , Transforming Growth Factor beta/pharmacology , Cells, Cultured , Fibroblasts/cytology , Fibroblasts/drug effects , Gene Expression Regulation/drug effects , Glycine Hydroxymethyltransferase/genetics , Glycolysis , Humans , Idiopathic Pulmonary Fibrosis/drug therapy , Idiopathic Pulmonary Fibrosis/pathology , Lung/cytology , Lung/drug effects , Lung/metabolism , Phosphoglycerate Dehydrogenase/geneticsABSTRACT
BACKGROUND: Azathioprine is a commonly prescribed therapy for connective tissue disease-associated interstitial lung disease (CTD-ILD). Combination therapy that included azathioprine was recently shown to increase the risk of death and hospitalization in patients with idiopathic pulmonary fibrosis. Whether azathioprine increases the risk of adverse outcomes in patients with fibrotic CTD-ILD, including those with CTD-associated usual interstitial pneumonia (UIP), remains unknown. METHODS: A retrospective cohort analysis was performed to determine the combined incidence rate of death, transplant and respiratory hospitalization associated with azathioprine exposure. A fibrotic CTD-ILD cohort treated with mycophenolate mofetil served as a comparator group. Incidence rates were compared with an incidence rate ratio (IRR) generated by negative binomial regression. Longitudinal pulmonary function response was then assessed using mixed effects linear regression models. RESULTS: Fifty-four patients were treated with azathioprine and forty-three with mycophenolate. Medication discontinuation due to non-respiratory side effects occurred in 27% and 5% of the azathioprine and mycophenolate cohorts, respectively. The combined incidence rate of adverse outcomes was 0.015 and 0.013 for azathioprine and mycophenolate, respectively (IRR 1.23; 95% CI 0.49-3.12; p = 0.66). Similar incidence rates were observed among those with CTD-UIP (IRR 0.83; 95% CI 0.21-3.31; p = 0.79). Both groups demonstrated pulmonary function stability over time, with the azathioprine group demonstrating a marginal improvement. CONCLUSIONS: A significant minority of patients could not tolerate azathioprine due to non-respiratory side effects. Of those who did tolerate azathioprine, a similar incidence of adverse outcomes was observed as those treated with mycophenolate. Both therapies were associated with stability in pulmonary function.