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New research provides more evidence that
In a cross-sectional study of adults with and those without cognitive impairment, chronic kidney disease was associated with increased plasma concentrations of phosphorylated tau (p-tau) 217 and 181.
However, there were no associations between chronic kidney disease and the ratio of p-tau217 to unphosphorylated tau 217 (pT217/T217), and the associations with p-tau181 to unphosphorylated tau 181 (pT181/T181) were attenuated in patients with cognitive impairment.
“These novel findings suggest that plasma measures of the phosphorylated to unphosphorylated tau ratios are more accurate than p-tau forms alone as they correlate less with individual difference in glomerular filtration rate or impaired kidney function,” reported an investigative team led by Oskar Hansson, MD, PhD, with Lund University in Sweden.
“Thus, to mitigate the effects of non-Alzheimer’s–related comorbidities like chronic kidney disease on the performance of plasma Alzheimer’s disease biomarkers, certain tau ratios, and specifically pT217/T217, should be considered for implementation in clinical practice and drug trials,” they added.
The study was published online in JAMA Neurology to coincide with a presentation at the International Conference on Alzheimer’s and Parkinson’s Diseases in Gothenburg, Sweden.
Skewed tau levels
Plasma biomarkers of amyloid-beta (Abeta) and tau pathologies, and in particular variants in p-tau217 and p-tau181, have shown promise for use in Alzheimer’s disease diagnosis and prognosis. However, previous reports have suggested that chronic kidney disease might influence plasma p-tau217 and p-tau181 concentrations, potentially decreasing their usefulness in the diagnostic workup of dementia.
Researchers investigated associations of chronic kidney disease with plasma ratios of p-tau217 and p-tau181 to the corresponding unphosphorylated peptides in Alzheimer’s disease.
The data came from 473 older adults, with and without cognitive impairment, from the Swedish BioFinder-2 study who had plasma tau assessments and chronic kidney disease status established within 6 months of plasma collection.
The researchers found that lower estimated glomerular filtration rate levels (indicative of kidney dysfunction) were associated with higher plasma concentrations of phosphorylated and unphosphorylated tau peptides measured simultaneously using the tau immunoprecipitation mass spectrometry assay.
However, the correlations with estimated glomerular filtration rate were nonsignificant for the pT217/T217 ratio in individuals with cognitive impairment and were significantly attenuated for pT217/T217 in cognitively unimpaired individuals and for pT181/T181 in both cognitively unimpaired and impaired individuals.
“Importantly, we demonstrate that there were no significant associations between chronic kidney disease and the pT217/T217 ratio and changes in plasma pT181/T181 associated with chronic kidney disease were small or nonsignificant,” the researchers noted.
“Our results indicate that by using p-tau/tau ratios we may be able to reduce the variability in plasma p-tau levels driven by impaired kidney function and consequently such ratios are more robust measures of brain p-tau pathology in individuals with both early- and later-stage Alzheimer’s disease,” they added.
The researchers believe this is likely true for the ratios of other related proteins – a view that is supported by findings of attenuated associations of chronic kidney disease with Abeta42/40, compared with Abeta42 and Abeta40 in the current study and in previous studies.
Important clinical implications
Reached for comment, Rebecca Edelmayer, PhD, Alzheimer’s Association senior director of scientific engagement, noted that research continues to indicate that blood biomarkers have “promise for improving, and possibly even redefining, the clinical workup for Alzheimer’s disease.
“Many of the Alzheimer’s blood tests in development today have focused on core blood biomarkers associated with amyloid accumulation and tau tangle formation in the brain,” Dr. Edelmayer said.
“Before these tests can be used more broadly in the clinic, we need to understand all of the variables that may impact the results of various blood biomarkers, including differences that may be driven by race, ethnicity, sex, and underlying health conditions, such as chronic kidney disease.
“This study corroborates other research suggesting that some Alzheimer’s-associated markers can be affected by chronic kidney disease, but by using ratios of amyloid or tau markers, we may be able to minimize these differences in results caused by underlying disease,” Dr. Edelmayer said.
Howard Fillit, MD, cofounder and chief science officer at the Alzheimer’s Drug Discovery Foundation, said, “Using these ratios makes a lot of sense because the ratios wouldn’t change with kidney function. I think this is an important advance in clinical utilization of these tests.”
Dr. Fillit noted that older people often have declining kidney function, which can be easily measured by glomerular filtration rate. Changes in blood levels of these markers with declining kidney function are “not unexpected, but [it’s] important that it’s been demonstrated.
“As we go forward, maybe the future utilization of these tests will be not only recording the ratios but also reporting the ratios in the context of somebody’s glomerular filtration rate. You could imagine a scenario where when the test is done, it’s automatically done alongside of glomerular filtration rate,” Dr. Fillit said in an interview.
The study was supported by Coins for Alzheimer’s Research Trust, the Tracy Family Stable Isotope Labeling Quantitation Center, and the National Institute of Neurological Disorders and Stroke. Dr. Hansson has received support to his institution from ADx, AVID Radiopharmaceuticals, Biogen, Eli Lilly, Eisai, Fujirebio, GE Healthcare, Pfizer, and Roche; consultancy/speaker fees from Amylyx, Alzpath, Biogen, Cerveau, Fujirebio, Genentech, Novartis, Roche, and Siemens; and personal fees from Eli Lilly, Eisai, Bioarctic, and Biogen outside the submitted work. Dr. Edelmayer and Dr. Fillit have disclosed no relevant financial relationships.
A version of this article first appeared on Medscape.com.
New research provides more evidence that
In a cross-sectional study of adults with and those without cognitive impairment, chronic kidney disease was associated with increased plasma concentrations of phosphorylated tau (p-tau) 217 and 181.
However, there were no associations between chronic kidney disease and the ratio of p-tau217 to unphosphorylated tau 217 (pT217/T217), and the associations with p-tau181 to unphosphorylated tau 181 (pT181/T181) were attenuated in patients with cognitive impairment.
“These novel findings suggest that plasma measures of the phosphorylated to unphosphorylated tau ratios are more accurate than p-tau forms alone as they correlate less with individual difference in glomerular filtration rate or impaired kidney function,” reported an investigative team led by Oskar Hansson, MD, PhD, with Lund University in Sweden.
“Thus, to mitigate the effects of non-Alzheimer’s–related comorbidities like chronic kidney disease on the performance of plasma Alzheimer’s disease biomarkers, certain tau ratios, and specifically pT217/T217, should be considered for implementation in clinical practice and drug trials,” they added.
The study was published online in JAMA Neurology to coincide with a presentation at the International Conference on Alzheimer’s and Parkinson’s Diseases in Gothenburg, Sweden.
Skewed tau levels
Plasma biomarkers of amyloid-beta (Abeta) and tau pathologies, and in particular variants in p-tau217 and p-tau181, have shown promise for use in Alzheimer’s disease diagnosis and prognosis. However, previous reports have suggested that chronic kidney disease might influence plasma p-tau217 and p-tau181 concentrations, potentially decreasing their usefulness in the diagnostic workup of dementia.
Researchers investigated associations of chronic kidney disease with plasma ratios of p-tau217 and p-tau181 to the corresponding unphosphorylated peptides in Alzheimer’s disease.
The data came from 473 older adults, with and without cognitive impairment, from the Swedish BioFinder-2 study who had plasma tau assessments and chronic kidney disease status established within 6 months of plasma collection.
The researchers found that lower estimated glomerular filtration rate levels (indicative of kidney dysfunction) were associated with higher plasma concentrations of phosphorylated and unphosphorylated tau peptides measured simultaneously using the tau immunoprecipitation mass spectrometry assay.
However, the correlations with estimated glomerular filtration rate were nonsignificant for the pT217/T217 ratio in individuals with cognitive impairment and were significantly attenuated for pT217/T217 in cognitively unimpaired individuals and for pT181/T181 in both cognitively unimpaired and impaired individuals.
“Importantly, we demonstrate that there were no significant associations between chronic kidney disease and the pT217/T217 ratio and changes in plasma pT181/T181 associated with chronic kidney disease were small or nonsignificant,” the researchers noted.
“Our results indicate that by using p-tau/tau ratios we may be able to reduce the variability in plasma p-tau levels driven by impaired kidney function and consequently such ratios are more robust measures of brain p-tau pathology in individuals with both early- and later-stage Alzheimer’s disease,” they added.
The researchers believe this is likely true for the ratios of other related proteins – a view that is supported by findings of attenuated associations of chronic kidney disease with Abeta42/40, compared with Abeta42 and Abeta40 in the current study and in previous studies.
Important clinical implications
Reached for comment, Rebecca Edelmayer, PhD, Alzheimer’s Association senior director of scientific engagement, noted that research continues to indicate that blood biomarkers have “promise for improving, and possibly even redefining, the clinical workup for Alzheimer’s disease.
“Many of the Alzheimer’s blood tests in development today have focused on core blood biomarkers associated with amyloid accumulation and tau tangle formation in the brain,” Dr. Edelmayer said.
“Before these tests can be used more broadly in the clinic, we need to understand all of the variables that may impact the results of various blood biomarkers, including differences that may be driven by race, ethnicity, sex, and underlying health conditions, such as chronic kidney disease.
“This study corroborates other research suggesting that some Alzheimer’s-associated markers can be affected by chronic kidney disease, but by using ratios of amyloid or tau markers, we may be able to minimize these differences in results caused by underlying disease,” Dr. Edelmayer said.
Howard Fillit, MD, cofounder and chief science officer at the Alzheimer’s Drug Discovery Foundation, said, “Using these ratios makes a lot of sense because the ratios wouldn’t change with kidney function. I think this is an important advance in clinical utilization of these tests.”
Dr. Fillit noted that older people often have declining kidney function, which can be easily measured by glomerular filtration rate. Changes in blood levels of these markers with declining kidney function are “not unexpected, but [it’s] important that it’s been demonstrated.
“As we go forward, maybe the future utilization of these tests will be not only recording the ratios but also reporting the ratios in the context of somebody’s glomerular filtration rate. You could imagine a scenario where when the test is done, it’s automatically done alongside of glomerular filtration rate,” Dr. Fillit said in an interview.
The study was supported by Coins for Alzheimer’s Research Trust, the Tracy Family Stable Isotope Labeling Quantitation Center, and the National Institute of Neurological Disorders and Stroke. Dr. Hansson has received support to his institution from ADx, AVID Radiopharmaceuticals, Biogen, Eli Lilly, Eisai, Fujirebio, GE Healthcare, Pfizer, and Roche; consultancy/speaker fees from Amylyx, Alzpath, Biogen, Cerveau, Fujirebio, Genentech, Novartis, Roche, and Siemens; and personal fees from Eli Lilly, Eisai, Bioarctic, and Biogen outside the submitted work. Dr. Edelmayer and Dr. Fillit have disclosed no relevant financial relationships.
A version of this article first appeared on Medscape.com.
New research provides more evidence that
In a cross-sectional study of adults with and those without cognitive impairment, chronic kidney disease was associated with increased plasma concentrations of phosphorylated tau (p-tau) 217 and 181.
However, there were no associations between chronic kidney disease and the ratio of p-tau217 to unphosphorylated tau 217 (pT217/T217), and the associations with p-tau181 to unphosphorylated tau 181 (pT181/T181) were attenuated in patients with cognitive impairment.
“These novel findings suggest that plasma measures of the phosphorylated to unphosphorylated tau ratios are more accurate than p-tau forms alone as they correlate less with individual difference in glomerular filtration rate or impaired kidney function,” reported an investigative team led by Oskar Hansson, MD, PhD, with Lund University in Sweden.
“Thus, to mitigate the effects of non-Alzheimer’s–related comorbidities like chronic kidney disease on the performance of plasma Alzheimer’s disease biomarkers, certain tau ratios, and specifically pT217/T217, should be considered for implementation in clinical practice and drug trials,” they added.
The study was published online in JAMA Neurology to coincide with a presentation at the International Conference on Alzheimer’s and Parkinson’s Diseases in Gothenburg, Sweden.
Skewed tau levels
Plasma biomarkers of amyloid-beta (Abeta) and tau pathologies, and in particular variants in p-tau217 and p-tau181, have shown promise for use in Alzheimer’s disease diagnosis and prognosis. However, previous reports have suggested that chronic kidney disease might influence plasma p-tau217 and p-tau181 concentrations, potentially decreasing their usefulness in the diagnostic workup of dementia.
Researchers investigated associations of chronic kidney disease with plasma ratios of p-tau217 and p-tau181 to the corresponding unphosphorylated peptides in Alzheimer’s disease.
The data came from 473 older adults, with and without cognitive impairment, from the Swedish BioFinder-2 study who had plasma tau assessments and chronic kidney disease status established within 6 months of plasma collection.
The researchers found that lower estimated glomerular filtration rate levels (indicative of kidney dysfunction) were associated with higher plasma concentrations of phosphorylated and unphosphorylated tau peptides measured simultaneously using the tau immunoprecipitation mass spectrometry assay.
However, the correlations with estimated glomerular filtration rate were nonsignificant for the pT217/T217 ratio in individuals with cognitive impairment and were significantly attenuated for pT217/T217 in cognitively unimpaired individuals and for pT181/T181 in both cognitively unimpaired and impaired individuals.
“Importantly, we demonstrate that there were no significant associations between chronic kidney disease and the pT217/T217 ratio and changes in plasma pT181/T181 associated with chronic kidney disease were small or nonsignificant,” the researchers noted.
“Our results indicate that by using p-tau/tau ratios we may be able to reduce the variability in plasma p-tau levels driven by impaired kidney function and consequently such ratios are more robust measures of brain p-tau pathology in individuals with both early- and later-stage Alzheimer’s disease,” they added.
The researchers believe this is likely true for the ratios of other related proteins – a view that is supported by findings of attenuated associations of chronic kidney disease with Abeta42/40, compared with Abeta42 and Abeta40 in the current study and in previous studies.
Important clinical implications
Reached for comment, Rebecca Edelmayer, PhD, Alzheimer’s Association senior director of scientific engagement, noted that research continues to indicate that blood biomarkers have “promise for improving, and possibly even redefining, the clinical workup for Alzheimer’s disease.
“Many of the Alzheimer’s blood tests in development today have focused on core blood biomarkers associated with amyloid accumulation and tau tangle formation in the brain,” Dr. Edelmayer said.
“Before these tests can be used more broadly in the clinic, we need to understand all of the variables that may impact the results of various blood biomarkers, including differences that may be driven by race, ethnicity, sex, and underlying health conditions, such as chronic kidney disease.
“This study corroborates other research suggesting that some Alzheimer’s-associated markers can be affected by chronic kidney disease, but by using ratios of amyloid or tau markers, we may be able to minimize these differences in results caused by underlying disease,” Dr. Edelmayer said.
Howard Fillit, MD, cofounder and chief science officer at the Alzheimer’s Drug Discovery Foundation, said, “Using these ratios makes a lot of sense because the ratios wouldn’t change with kidney function. I think this is an important advance in clinical utilization of these tests.”
Dr. Fillit noted that older people often have declining kidney function, which can be easily measured by glomerular filtration rate. Changes in blood levels of these markers with declining kidney function are “not unexpected, but [it’s] important that it’s been demonstrated.
“As we go forward, maybe the future utilization of these tests will be not only recording the ratios but also reporting the ratios in the context of somebody’s glomerular filtration rate. You could imagine a scenario where when the test is done, it’s automatically done alongside of glomerular filtration rate,” Dr. Fillit said in an interview.
The study was supported by Coins for Alzheimer’s Research Trust, the Tracy Family Stable Isotope Labeling Quantitation Center, and the National Institute of Neurological Disorders and Stroke. Dr. Hansson has received support to his institution from ADx, AVID Radiopharmaceuticals, Biogen, Eli Lilly, Eisai, Fujirebio, GE Healthcare, Pfizer, and Roche; consultancy/speaker fees from Amylyx, Alzpath, Biogen, Cerveau, Fujirebio, Genentech, Novartis, Roche, and Siemens; and personal fees from Eli Lilly, Eisai, Bioarctic, and Biogen outside the submitted work. Dr. Edelmayer and Dr. Fillit have disclosed no relevant financial relationships.
A version of this article first appeared on Medscape.com.
FROM AD/PD 2023