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Resistin, a cytokine expressed in adipocytes, has been associated with poor clinical outcomes in heart failure and cardiovascular disease, Li Gao, MD, of Johns Hopkins University, Baltimore, Maryland, and colleagues wrote. While mouse studies have shown that human resistin drives pulmonary vascular remodeling and the development of PAH, the role of resistin as a biomarker for PAH remains unclear.
In a study published in Respiratory Research, the researchers reviewed biospecimens and clinical and genetic data from 1121 adults with PAH, 808 with idiopathic PAH (IPAH), and 313 with scleroderma-associated PAH (SSc-PAH). They examined the associations between serum resistin levels and PAH outcomes in multivariate regression models, using machine-learning algorithms to develop models to predict mortality.
Resistin levels were significantly higher in all patients with PAH and patients with the two subtypes than in control participants (all P < .0001). Resistin was also associated with significant discriminative properties, with area under the curve (AUC) measures of 0.84, 0.82, and 0.91 for PAH overall, IPAH, and SSc-PAH, respectively.
Elevated resistin levels (defined as > 4.54 ng/mL) were significantly associated with an increased risk for death (hazard ratio, 2.6; P < .0087) as well as with older age and shorter distance on the 6-minute walk test (P = .001 for both) and reduced cardiac capacity based on the New York Heart Association functional class (P < .014).
Survival models derived from machine learning confirmed the prognostic value of resistin for mortality in PAH as seen in the random forest model, with an AUC of 0.70. “When we used the AUC values of the ROC curve as criteria to evaluate how well resistin levels discerned the presence of PAH, all three tests had excellent discriminative ability (AUCs were 0.84, 0.82, and 0.91 for all PAH, IPAH, and SSc-PAH, respectively),” the researchers wrote.
The researchers also evaluated three RETN genetic variants (rs7408174, rs3219175, and rs3745367) for a specific association with serum resistin levels and measures of PAH severity. Resistin levels were highest among individuals who were carriers of either the rs3219175 or rs3745367 mutation, the researchers noted.
The findings were limited by several factors, including missing data on the 6-minute walk test from several centers, which led to the elimination of that item from the survival analysis. Other limitations included the inability to control for PAH therapy at the time of assessment and the collection of serum at a different time from other clinical variables.
However, “our study provides evidence to support the use of circulating biomarkers as objective and accessible tools for noninvasive PAH risk stratification,” the researchers said. Additional research is needed to strengthen the association, but the findings suggest that resistin represents a novel biomarker for PAH prognostication and risk stratification and may have implications for the development of new treatments.
Biomarker Research Expands Diagnosis and Treatment Horizons
“It is a dynamic time in PAH research and clinical management, given the recent approval and use of the BMP/TGF beta balancing agent sotatercept (Winrevair) as an effective agent to target the molecular origins of this disease,” Stephen Chan, MD, professor of medicine and director of the Vascular Medicine Institute at the University of Pittsburgh, Pittsburgh, Pennsylvania, said in an interview.
The growing number of medications that can be used to treat patients with PAH will likely be more effective if patients are identified and treated early, said Dr. Chan, who was not involved in the study.
However, the time to diagnosis for patients with PAH is still more than 3 years from the start of symptoms, he said. Factors contributing to the delay include the requirement of an invasive cardiac catheterization procedure to make the final diagnosis, the status of PAH as a borderline orphan disease, and the often nonspecific nature of the initial symptoms of PAH.
Consequently, “there is an unmet need to develop effective and preferably noninvasive tools to aid in early diagnosis of PAH,” Dr. Chan added.
The power of the study is in the number of patients included, as much of previous PAH research has involved small studies of patients that could not be replicated or did not generalize to the larger patient population, Dr. Chan said.
The use of the PAH Biobank allows researchers to access a larger population of patients with PAH. “With that in mind, it is not surprising that some markers would emerge as potentially powerful and clinically meaningful,” he said.
“Currently, we do not have a reliable blood-based biomarker that we use in clinical PAH practice, although there are emerging studies that suggest other markers such as metabolites, RNA molecules, and proteins that may serve in the same capacity. If these studies turn out to be reproducible, generalizable, and specific to PAH in larger populations, measuring resistin could be helpful in making early diagnosis, particularly in areas that do not have invasive catheterization facilities (and globally) and for nonspecialists who are puzzled about the nonspecificity of initial symptoms of PAH,” Dr. Chan said.
Resistin could also be incorporated into existing risk stratification scores, such as the REVEAL risk score, that are already used in PAH clinical practice as guidance for when and how to use currently approved medications, he added.
Limitations of the study included the focus only on resistin alone, not in combination with other molecules that might perform better. Also, no independent validation cohort was used, he noted. “While PAH Biobank certainly offered larger numbers than we typically see, we would have to see validation in large independent cohorts for us to be convinced that measurements of resistin should be used in clinical practice.”
Resistin is not specific to PAH, which makes interpretation of the results more complicated, said Dr. Chan. “In this study, the authors used a smaller healthy control cohort of 50 patients as a comparison to their PAH cohort. However, they did not compare their PAH cohort with other cohorts that represent these other ‘resistin-relevant diseases’ and thus do not know whether they can distinguish PAH from any of these other diseases based on simply the resistin levels.” The frequency of comorbidities in patients with PAH, such as obesity, other inflammatory diseases, and cardiovascular disease, could confound the resistin levels.
The study was supported by the National Institutes of Health. Neither the researchers nor Dr. Chan had financial conflicts to disclose.
A version of this article first appeared on Medscape.com.
Resistin, a cytokine expressed in adipocytes, has been associated with poor clinical outcomes in heart failure and cardiovascular disease, Li Gao, MD, of Johns Hopkins University, Baltimore, Maryland, and colleagues wrote. While mouse studies have shown that human resistin drives pulmonary vascular remodeling and the development of PAH, the role of resistin as a biomarker for PAH remains unclear.
In a study published in Respiratory Research, the researchers reviewed biospecimens and clinical and genetic data from 1121 adults with PAH, 808 with idiopathic PAH (IPAH), and 313 with scleroderma-associated PAH (SSc-PAH). They examined the associations between serum resistin levels and PAH outcomes in multivariate regression models, using machine-learning algorithms to develop models to predict mortality.
Resistin levels were significantly higher in all patients with PAH and patients with the two subtypes than in control participants (all P < .0001). Resistin was also associated with significant discriminative properties, with area under the curve (AUC) measures of 0.84, 0.82, and 0.91 for PAH overall, IPAH, and SSc-PAH, respectively.
Elevated resistin levels (defined as > 4.54 ng/mL) were significantly associated with an increased risk for death (hazard ratio, 2.6; P < .0087) as well as with older age and shorter distance on the 6-minute walk test (P = .001 for both) and reduced cardiac capacity based on the New York Heart Association functional class (P < .014).
Survival models derived from machine learning confirmed the prognostic value of resistin for mortality in PAH as seen in the random forest model, with an AUC of 0.70. “When we used the AUC values of the ROC curve as criteria to evaluate how well resistin levels discerned the presence of PAH, all three tests had excellent discriminative ability (AUCs were 0.84, 0.82, and 0.91 for all PAH, IPAH, and SSc-PAH, respectively),” the researchers wrote.
The researchers also evaluated three RETN genetic variants (rs7408174, rs3219175, and rs3745367) for a specific association with serum resistin levels and measures of PAH severity. Resistin levels were highest among individuals who were carriers of either the rs3219175 or rs3745367 mutation, the researchers noted.
The findings were limited by several factors, including missing data on the 6-minute walk test from several centers, which led to the elimination of that item from the survival analysis. Other limitations included the inability to control for PAH therapy at the time of assessment and the collection of serum at a different time from other clinical variables.
However, “our study provides evidence to support the use of circulating biomarkers as objective and accessible tools for noninvasive PAH risk stratification,” the researchers said. Additional research is needed to strengthen the association, but the findings suggest that resistin represents a novel biomarker for PAH prognostication and risk stratification and may have implications for the development of new treatments.
Biomarker Research Expands Diagnosis and Treatment Horizons
“It is a dynamic time in PAH research and clinical management, given the recent approval and use of the BMP/TGF beta balancing agent sotatercept (Winrevair) as an effective agent to target the molecular origins of this disease,” Stephen Chan, MD, professor of medicine and director of the Vascular Medicine Institute at the University of Pittsburgh, Pittsburgh, Pennsylvania, said in an interview.
The growing number of medications that can be used to treat patients with PAH will likely be more effective if patients are identified and treated early, said Dr. Chan, who was not involved in the study.
However, the time to diagnosis for patients with PAH is still more than 3 years from the start of symptoms, he said. Factors contributing to the delay include the requirement of an invasive cardiac catheterization procedure to make the final diagnosis, the status of PAH as a borderline orphan disease, and the often nonspecific nature of the initial symptoms of PAH.
Consequently, “there is an unmet need to develop effective and preferably noninvasive tools to aid in early diagnosis of PAH,” Dr. Chan added.
The power of the study is in the number of patients included, as much of previous PAH research has involved small studies of patients that could not be replicated or did not generalize to the larger patient population, Dr. Chan said.
The use of the PAH Biobank allows researchers to access a larger population of patients with PAH. “With that in mind, it is not surprising that some markers would emerge as potentially powerful and clinically meaningful,” he said.
“Currently, we do not have a reliable blood-based biomarker that we use in clinical PAH practice, although there are emerging studies that suggest other markers such as metabolites, RNA molecules, and proteins that may serve in the same capacity. If these studies turn out to be reproducible, generalizable, and specific to PAH in larger populations, measuring resistin could be helpful in making early diagnosis, particularly in areas that do not have invasive catheterization facilities (and globally) and for nonspecialists who are puzzled about the nonspecificity of initial symptoms of PAH,” Dr. Chan said.
Resistin could also be incorporated into existing risk stratification scores, such as the REVEAL risk score, that are already used in PAH clinical practice as guidance for when and how to use currently approved medications, he added.
Limitations of the study included the focus only on resistin alone, not in combination with other molecules that might perform better. Also, no independent validation cohort was used, he noted. “While PAH Biobank certainly offered larger numbers than we typically see, we would have to see validation in large independent cohorts for us to be convinced that measurements of resistin should be used in clinical practice.”
Resistin is not specific to PAH, which makes interpretation of the results more complicated, said Dr. Chan. “In this study, the authors used a smaller healthy control cohort of 50 patients as a comparison to their PAH cohort. However, they did not compare their PAH cohort with other cohorts that represent these other ‘resistin-relevant diseases’ and thus do not know whether they can distinguish PAH from any of these other diseases based on simply the resistin levels.” The frequency of comorbidities in patients with PAH, such as obesity, other inflammatory diseases, and cardiovascular disease, could confound the resistin levels.
The study was supported by the National Institutes of Health. Neither the researchers nor Dr. Chan had financial conflicts to disclose.
A version of this article first appeared on Medscape.com.
Resistin, a cytokine expressed in adipocytes, has been associated with poor clinical outcomes in heart failure and cardiovascular disease, Li Gao, MD, of Johns Hopkins University, Baltimore, Maryland, and colleagues wrote. While mouse studies have shown that human resistin drives pulmonary vascular remodeling and the development of PAH, the role of resistin as a biomarker for PAH remains unclear.
In a study published in Respiratory Research, the researchers reviewed biospecimens and clinical and genetic data from 1121 adults with PAH, 808 with idiopathic PAH (IPAH), and 313 with scleroderma-associated PAH (SSc-PAH). They examined the associations between serum resistin levels and PAH outcomes in multivariate regression models, using machine-learning algorithms to develop models to predict mortality.
Resistin levels were significantly higher in all patients with PAH and patients with the two subtypes than in control participants (all P < .0001). Resistin was also associated with significant discriminative properties, with area under the curve (AUC) measures of 0.84, 0.82, and 0.91 for PAH overall, IPAH, and SSc-PAH, respectively.
Elevated resistin levels (defined as > 4.54 ng/mL) were significantly associated with an increased risk for death (hazard ratio, 2.6; P < .0087) as well as with older age and shorter distance on the 6-minute walk test (P = .001 for both) and reduced cardiac capacity based on the New York Heart Association functional class (P < .014).
Survival models derived from machine learning confirmed the prognostic value of resistin for mortality in PAH as seen in the random forest model, with an AUC of 0.70. “When we used the AUC values of the ROC curve as criteria to evaluate how well resistin levels discerned the presence of PAH, all three tests had excellent discriminative ability (AUCs were 0.84, 0.82, and 0.91 for all PAH, IPAH, and SSc-PAH, respectively),” the researchers wrote.
The researchers also evaluated three RETN genetic variants (rs7408174, rs3219175, and rs3745367) for a specific association with serum resistin levels and measures of PAH severity. Resistin levels were highest among individuals who were carriers of either the rs3219175 or rs3745367 mutation, the researchers noted.
The findings were limited by several factors, including missing data on the 6-minute walk test from several centers, which led to the elimination of that item from the survival analysis. Other limitations included the inability to control for PAH therapy at the time of assessment and the collection of serum at a different time from other clinical variables.
However, “our study provides evidence to support the use of circulating biomarkers as objective and accessible tools for noninvasive PAH risk stratification,” the researchers said. Additional research is needed to strengthen the association, but the findings suggest that resistin represents a novel biomarker for PAH prognostication and risk stratification and may have implications for the development of new treatments.
Biomarker Research Expands Diagnosis and Treatment Horizons
“It is a dynamic time in PAH research and clinical management, given the recent approval and use of the BMP/TGF beta balancing agent sotatercept (Winrevair) as an effective agent to target the molecular origins of this disease,” Stephen Chan, MD, professor of medicine and director of the Vascular Medicine Institute at the University of Pittsburgh, Pittsburgh, Pennsylvania, said in an interview.
The growing number of medications that can be used to treat patients with PAH will likely be more effective if patients are identified and treated early, said Dr. Chan, who was not involved in the study.
However, the time to diagnosis for patients with PAH is still more than 3 years from the start of symptoms, he said. Factors contributing to the delay include the requirement of an invasive cardiac catheterization procedure to make the final diagnosis, the status of PAH as a borderline orphan disease, and the often nonspecific nature of the initial symptoms of PAH.
Consequently, “there is an unmet need to develop effective and preferably noninvasive tools to aid in early diagnosis of PAH,” Dr. Chan added.
The power of the study is in the number of patients included, as much of previous PAH research has involved small studies of patients that could not be replicated or did not generalize to the larger patient population, Dr. Chan said.
The use of the PAH Biobank allows researchers to access a larger population of patients with PAH. “With that in mind, it is not surprising that some markers would emerge as potentially powerful and clinically meaningful,” he said.
“Currently, we do not have a reliable blood-based biomarker that we use in clinical PAH practice, although there are emerging studies that suggest other markers such as metabolites, RNA molecules, and proteins that may serve in the same capacity. If these studies turn out to be reproducible, generalizable, and specific to PAH in larger populations, measuring resistin could be helpful in making early diagnosis, particularly in areas that do not have invasive catheterization facilities (and globally) and for nonspecialists who are puzzled about the nonspecificity of initial symptoms of PAH,” Dr. Chan said.
Resistin could also be incorporated into existing risk stratification scores, such as the REVEAL risk score, that are already used in PAH clinical practice as guidance for when and how to use currently approved medications, he added.
Limitations of the study included the focus only on resistin alone, not in combination with other molecules that might perform better. Also, no independent validation cohort was used, he noted. “While PAH Biobank certainly offered larger numbers than we typically see, we would have to see validation in large independent cohorts for us to be convinced that measurements of resistin should be used in clinical practice.”
Resistin is not specific to PAH, which makes interpretation of the results more complicated, said Dr. Chan. “In this study, the authors used a smaller healthy control cohort of 50 patients as a comparison to their PAH cohort. However, they did not compare their PAH cohort with other cohorts that represent these other ‘resistin-relevant diseases’ and thus do not know whether they can distinguish PAH from any of these other diseases based on simply the resistin levels.” The frequency of comorbidities in patients with PAH, such as obesity, other inflammatory diseases, and cardiovascular disease, could confound the resistin levels.
The study was supported by the National Institutes of Health. Neither the researchers nor Dr. Chan had financial conflicts to disclose.
A version of this article first appeared on Medscape.com.