Use Of Blood-based Biomarkers Research Articles

Utilization of fluid-based biomarkers as endpoints in disease-modifying clinical trials for Alzheimer’s disease: a systematic review

BackgroundClinical trials in Alzheimer’s disease (AD) had high failure rates for several reasons, including the lack of biological endpoints. Fluid-based biomarkers may present a solution to measure biologically relevant endpoints. It is currently unclear to what extent fluid-based biomarkers are applied to support drug development.MethodsWe systematically reviewed 272 trials (clinicaltrials.gov) with disease-modifying therapies starting between 01–01-2017 and 01–01-2024 and identified which CSF and/or blood-based biomarker endpoints were used per purpose and trial type.ResultsWe found that 44% (N = 121) of the trials employed fluid-based biomarker endpoints among which the CSF ATN biomarkers (Aβ (42/40), p/tTau) were used most frequently. In blood, inflammatory cytokines, NFL, and pTau were most frequently employed. Blood- and CSF-based biomarkers were used approximately equally. Target engagement biomarkers were used in 26% (N = 72) of the trials, mainly in drugs targeting inflammation and amyloid. Lack of target engagement markers is most prominent in synaptic plasticity/neuroprotection, neurotransmitter receptor, vasculature, epigenetic regulators, proteostasis and, gut-brain axis targeting drugs. Positive biomarker results did not always translate to cognitive effects, most commonly the small significant reductions in CSF tau isoforms that were seen following anti-Tau treatments. On the other hand, the positive anti-amyloid trials results on cognitive function were supported by clear effect in most fluid markers.ConclusionsAs the field moves towards primary prevention, we expect an increase in the use of fluid-based biomarkers to determine disease modification. Use of blood-based biomarkers will rapidly increase, but CSF markers remain important to determine brain-specific treatment effects. With improving techniques, new biomarkers can be found to diversify the possibilities in measuring treatment effects and target engagement. It remains important to interpret biomarker results in the context of the trial and be aware of the performance of the biomarker. Diversifying biomarkers could aid in the development of surrogacy biomarkers for different drug targets.

The Bio-Hermes Study: Biomarker database developed to investigate blood-based and digital biomarkers in community-based, diverse populations clinically screened for Alzheimer's disease.

Alzheimer's disease (AD) trial participants are often screened for eligibility by brain amyloid positron emission tomography/cerebrospinal fluid (PET/CSF), which is inefficient as many are not amyloid positive. Use of blood-based biomarkers may reduce screen failures. We recruited 755 non-Hispanic White, 115 Hispanic, 112 non-Hispanic Black, and 19 other minority participants across groups of cognitively normal (n=417), mild cognitive impairment (n=312), or mild AD (n=272) participants. Plasma amyloid beta (Aβ)40, Aβ42, Aβ42/Aβ40, total tau, phosphorylated tau (p-tau)181, and p-tau217 were measured; amyloid PET/CSF (n=956) determined amyloid positivity. Clinical, blood biomarker, and ethnicity/race differences associated with amyloid status were evaluated. Greater impairment, older age, and carrying an apolipoprotein E (apoE) ε4 allele were associated with greater amyloid burden. Areas under the receiver operating characteristic curve for amyloid status of plasma Aβ42/Aβ40, p-tau181, and p-tau217 with amyloid positivity were ≥ 0.7117 for all ethnoracial groups (p-tau217, ≥0.8128). Age and apoE ε4 adjustments and imputation of biomarker values outside limit of quantitation provided small improvement in predictive power. Blood-based biomarkers are highly associated with amyloid PET/CSF results in diverse populations enrolled at clinical trial sites. Amyloid beta (Aβ)42/Aβ40, phosphorylated tau (p-tau)181, and p-tau 217 blood-based biomarkers predicted brain amyloid positivity. P-tau 217 was the strongest predictor of brain amyloid positivity. Biomarkers from diverse ethnic, racial, and clinical cohorts predicted brain amyloid positivity. Community-based populations have similar Alzheimer's disease (AD) biomarker levels as other populations. A prescreen process with blood-based assays may reduce the number of AD trial screen failures.

Biomarkers in Endurance Exercise: Individualized Regulation and Predictive Value.

The high interindividual variability of exercise response complicates the efficient use of blood-based biomarkers in sports. To address this problem, a useful algorithm to characterize the individual regulation and predictive value of different candidate markers will be developed. Forty-nine participants completed two identical exercise trials. Blood samples were collected before, immediately after, 3 hours after, and 24 hours after completion of exercise. Plasma concentrations of interleukin (IL-) 1RA, IL-6, IL-8, IL-10, IL-15, creatine kinase (CK), cortisol, c-reactive protein (CRP), lactate dehydrogenase (LDH), and thiobarbituric acid reactive substances (TBARS) were measured. Individualized regulation was analyzed using k-means clustering and a Group Assignment Quality (GAQ) score. Regression trees with a bootstrapped-aggregated approach were used to assess the predictive qualities of the markers. For most of the markers studied, a distinction can be made between individuals who show a stronger or weaker response to a particular endurance training program. The regulation of IL-6, IL-8, IL-10, and CK exhibited a high degree of stability within the individuals. Regarding the predictive power of the markers, for all dependent variables, the most accurate predictions were obtained for cortisol and IL-8 based on the baseline value. For CK, a good prediction of recovery of maximal strength and subjective feeling of exhaustion can be made. For IL-1RA and TBARS, especially their reregulation can be predicted if the baseline level is known. Focusing individual variations in biomarker responses, our results suggest the combined use of IL-6, IL-8, IL-10, and CK for the personalized management of stress and recovery cycles following endurance exercise.

Considerations for Use of Blood-Based Biomarkers in Epidemiologic Dementia Research.

Dementia represents a growing public health burden with large social, racial, and ethnic disparities. The etiology of dementia is poorly understood, and the lack of robust biomarkers in diverse, population-representative samples is a barrier to moving dementia research forward. Existing biomarkers and other measures of pathology-derived from neuropathology, neuroimaging, and cerebrospinal fluid samples-are commonly collected from predominantly White and highly educated samples drawn from academic medical centers in urban settings. Blood-based biomarkers are noninvasive and less expensive, offering promise to expand our understanding of the pathophysiology of dementia, including in participants from historically excluded groups. Although largely not yet approved by the Food and Drug Administration or used in clinical settings, blood-based biomarkers are increasingly included in epidemiologic studies on dementia. Blood-based biomarkers in epidemiologic research may allow the field to more accurately understand the multifactorial etiology and sequence of events that characterize dementia-related pathophysiological changes. As blood-based dementia biomarkers continue to be developed and incorporated into research and practice, we outline considerations for using them in dementia epidemiology, and illustrate key concepts with Alzheimer's Disease Neuroimaging Initiative (2003-present) data. We focus on measurement, including both validity and reliability, and on the use of dementia blood-based biomarkers to promote equity in dementia research and cognitive aging. This article is part of a Special Collection on Mental Health.

Blood-Brain Barrier Dysfunction and Aβ42/40 Ratio Dose-Dependent Modulation with the ApoE Genotype within the ATN Framework.

The definition of Alzheimer's disease (AD) now considers the presence of the markers of amyloid (A), tau deposition (T), and neurodegeneration (N) essential for diagnosis. AD patients have been reported to have increased blood-brain barrier (BBB) dysfunction, but that has not been tested within the ATN framework so far. As the field is moving towards the use of blood-based biomarkers, the relationship between BBB disruption and AD-specific biomarkers requires considerable attention. Moreover, other factors have been previously implicated in modulating BBB permeability, including age, gender, and ApoE status. A total of 172 cognitively impaired individuals underwent cerebrospinal fluid (CSF) analysis for AD biomarkers, and data on BBB dysfunction, demographics, and ApoE status were collected. Our data showed that there was no difference in BBB dysfunction across different ATN subtypes, and that BBB damage was not correlated with cognitive impairment. However, patients with BBB disruption, if measured with a high Qalb, had low Aβ40 levels. ApoE status did not affect BBB function but had a dose-dependent effect on the Aβ42/40 ratio. These results might highlight the importance of understanding dynamic changes across the BBB in future studies in patients with AD.

Improving Traditional Post Mortem Healthcare—The Cross-Sectional Use of Blood-Based Biomarkers

Many tools of clinical medicine, such as clinical chemistry and diagnostic imaging, are prioritized for clinical diagnosis over post mortem diagnosis. Indeed, it is reasonable that the assessment of a patient’s functional status should take priority over the post mortem, cross-sectional use of diagnostic tests and laboratory equipment. In addition, these tools are sometimes expensive, and their use does not always have a reasonable cost–benefit ratio. However, some post mortem observations, such as inflammation, pulmonary edema, or infiltration and cerebral swelling, cannot be explained without using immunohistochemical markers for post mortem diagnosis. Introducing blood-based biomarkers into post mortem care could significantly reduce the rates of inconclusive post mortems and discrepancies in autopsy findings and clinical diagnoses. This is particularly relevant in relation to vascular pathology, considering the significant burden that vascular diseases represent for overall mortality. Expanding traditional autopsies with blood-based (circulating) biomarkers to avoid invasive post mortem examination would have cultural, religious, and potentially economic advantages. All of the target molecules were discussed in the context of the processes they up-regulate or down-regulate, which turned out to be the final cause of death. Ultimately, it is evident that further studies are needed to provide concrete validation for using a combination of markers for each case to reach a post mortem diagnosis with or without clinical records.

Biomarkers of Neurological Injury for Emerging Viral Threats and Post Viral Disease

Abstract Neurotropic viral infection and the ensuant immune response are a significant cause of morbidity and mortality worldwide, which can range in severity from mild to permanent central nervous system (CNS) damage and death. Encephalitic alphaviruses include Venezuelan and eastern equine encephalitis viruses (VEEV and EEEV; Alphavirus; Togaviridae). Injury to the CNS is an important determinant of poor outcome and tools to predict this outcome are lacking. Neurons are the primary target cells of encephalitic alphaviruses where cytopathology plays a major role in CNS dysfunction. Proteins are released following cell death, such as ubiquitin carboxy-terminal hydrolase L1 (UCH-L1) and glial fibrillary acidic protein (GFAP) are neuromarkers of CNS tissue injury which could serve as biomarkers to assess injury severity, monitor disease progression, direct treatment, and as reliable endpoints to help develop novel medical countermeasures. Recent advances in the use of blood-based biomarkers for diagnosis of traumatic brain injury (TBI) which have FDA approved assays have provided a scientific foundation for expanding the biomarker technology to brain damage caused by other CNS pathologies like viral encephalitis. Here we evaluated the ability to detect these biomarkers for encephalitic alphaviruses, encephalitis of unknown origin, and hospitalized patients with severe coronavirus disease (COVID-19). Higher levels of specific biomarkers were detected in patients diagnosed with alphavirus or unknown encephalitis which may be useful in prognosis and treatment guidance of post viral disease. Collectively, our results suggest that these blood-based biomarkers may be a good indicator for brain injury resulting from viral infection.

Blood-based biomarkers in Alzheimer's disease: a mini-review.

Alzheimer's disease (AD) is the most common cause of dementia and has far reaching consequences for patients and their caregivers. Early detection and treatment are key factors in limiting the impact of the disease. However, a definitive diagnosis of AD requires an examination of brain tissue during an autopsy. Although a plethora of biomarkers such as neuroimaging, electrophysiological, and cerebrospinal fluid (CSF) biomarkers are available, their utility is limited to research due to their poor reach and prohibitive cost. In order for biomarkers to be widely used, they need to be accessible, affordable, and conducive for the patient population or disease stage. Blood-based biomarkers may not only be less expensive and more accessible compared to neuroimaging or CSF tests, but they are also preferred by patients with AD as they are much less invasive. In this mini-review article, we expand on the rationale for the use of blood-based biomarkers, review currently available biomarkers and discuss the need for the standardization of these biomarkers. We contrast the blood-based biomarkers with other available biomarkers and discuss the advantages of using a panel of blood-based biomarkers to strengthen their accuracy.

Tau and Amyloid-β Peptides in Serum of Patients With Parkinson's Disease: Correlations With CSF Levels and Clinical Parameters.

Relevance of blood-based biomarkers is increasing into the neurodegenerative diseases field, but data on Parkinson's disease (PD) remain still scarce. In this study, we used the SiMoA technique to measure serum content of total tau protein and amyloid-β peptides (Aβ-42, Aβ-40) in 22 PD patients and ten control subjects. Serum levels of each biomarker were correlated with the respective CSF levels in both the groups; in PD patients, also the correlations between serum biomarkers and main clinical parameters were tested (motor, non-motor, cognitive scores and levodopa equivalent daily dose). Serum biomarkers did not exhibit quantitative differences between patients and controls; however, only PD patients had inter-fluids (serum-CSF) associations in tau and amyloid-β-42 levels. Moreover, serum content of tau protein was inversely correlated with cognitive performances (MoCA score). These findings, albeit preliminary, indicate that brain-derived peptides may change in parallel in both peripheral blood and CSF of PD patients, eventually even in association with some clinical features. Further studies are now needed to validate the use of blood-based biomarkers in PD.

2021 marks a new era for Alzheimer's therapeutics

2021 marks a new era for Alzheimer's therapeutics

Plasma p-tau181 shows stronger network association to Alzheimer's disease dementia than neurofilament light and total tau.

We examined the ability of plasma hyperphosphorylated tau (p-tau)181 to detect cognitive impairment due to Alzheimer's disease (AD) independently and in combination with plasma total tau (t-tau) and neurofilament light (NfL). Plasma samples were analyzed using the Simoa platform for 235 participants with normal cognition (NC), 181 with mild cognitive impairment due to AD (MCI), and 153 with AD dementia. Statistical approaches included multinomial regression and Gaussian graphical models (GGMs) to assess a network of plasma biomarkers, neuropsychological tests, and demographic variables. Plasma p-tau181 discriminated AD dementia from NC, but not MCI, and correlated with dementia severity and worse neuropsychological test performance. Plasma NfL similarly discriminated diagnostic groups. Unlike plasma NfL or t-tau, p-tau181 had a direct association with cognitive diagnosis in a bootstrapped GGM. These results support plasma p-tau181 for the detection of AD dementia and the use of blood-based biomarkers for optimal disease detection.

Biochemical and hematological biomarkers of reproductive failure in bottlenose dolphins Tursiops truncatus.

The physiological demands of pregnancy inevitably result in alterations in both biochemical and hematological parameters as fetal development occurs. The shifts observed in successful pregnancy in bottlenose dolphins Tursiops truncatus to support both fetal physiological needs and maternal basal requirements have been established according to each trimester. Detecting aberrations in blood-based biomarkers could help facilitate diagnosis of gestational abnormalities, improve our understanding of factors influencing reproductive outcomes and aid in prediction of reproductive failure. This study retrospectively analyzed 263 blood samples from 15 bottlenose dolphins in 21 failed pregnancies over 28 yr (1989-2017). Most samples remained within normal pregnancy reference ranges; however, significant shifts were observed between trimesters. Hematological alterations, compared to successful pregnancy reference ranges from previously published data, were consistent across failed pregnancies and included an increased prevalence of elevated 2nd and 3rd trimester neutrophils, elevated 2nd trimester monocytes and decreased 3rd trimester eosinophils. In addition, low hematocrit and low red blood cells were more prevalent in the 2nd trimester. Biochemical shifts included an increased prevalence of elevated creatine phosphokinase in the 3rd trimester outside of the normal reference ranges. Across failed pregnancies, calcium and iron were decreased in the 3rd trimester. Significantly decreased progesterone in the 3rd trimester was a negative prognostic indicator of pregnancy outcome with decreasing 3rd trimester progesterone associated with failed pregnancy. This study demonstrates the use of blood-based biomarkers as possible predictors of pregnancy outcome in bottlenose dolphins.

Combining Select Blood-Based Biomarkers with Neuropsychological Assessment to Detect Mild Cognitive Impairment among Mexican Americans.

Recent work has supported use of blood-based biomarkers in detection of amnestic mild cognitive impairment (MCI). Inclusion of neuropsychological measures has shown promise in enhancing utility of biomarkers to detect disease. The present study sought to develop cognitive-biomarker profiles for detection of MCI. Data were analyzed on 463 participants (normal control n = 378; MCI n = 85) from HABLE. Random forest analyses determined proteomic profile of MCI. Separate linear regression analyses determined variance accounted for by select biomarkers per neuropsychological measure. When neuropsychological measure with the least shared variance was identified, it was then combined with select biomarkers to create a biomarker-cognitive profile. The biomarker-cognitive profile was 90% accurate in detecting MCI. Among amnestic MCI cases, the detection accuracy of the biomarker-cognitive profile was 92% and increased to 94% with demographic variables. The biomarker-cognitive profile for MCI was highly accurate in its detection with use of only five biomarkers.

Novel Approach for Detecting the Neurological or Behavioral Impact of Physiological Episodes (PEs) in Military Aircraft Crews.

Military and civil aviation have documented physiological episodes among aircrews. Therefore, continued efforts are being made to improve the internal environment. Studies have shown that exposures to many organic compounds present in emissions are known to cause a variety of physiological symptoms. We hypothesize that these compounds may reversibly inhibit acetylcholinesterase, which may disrupt synaptic signaling. As a result, neural proteins leak through the damaged blood-brain barrier into the blood and in some, elicit an autoimmune response. Neural-specific autoantibodies of immunoglobulin-G (IgG) class were estimated by the Western blotting technique in the sera of 26 aircrew members and compared with the sera of 19 normal healthy nonaircrew members, used as controls. We found significantly elevated levels of circulating IgG-class autoantibodies to neurofilament triplet proteins, tubulin, microtubule-associated tau proteins (Tau), microtubule-associated protein-2, myelin basic protein, and glial fibrillary acidic protein, but not S100 calcium-binding protein B compared to healthy controls. Repetitive physiological episodes may initiate cellular injury, leading to neuronal degeneration in selected individuals. Diagnosis and intervention should occur at early postinjury periods. Use of blood-based biomarkers to assess subclinical brain injury would help in both diagnosis and treatment.

Blood-based tumor biomarkers in lung cancer for detection and treatment.

The therapeutic landscape of lung cancer has expanded significantly over the past decade. Advancements in molecularly targeted therapies, strategies to discover and treat resistance mutations, and development of personalized cancer treatments in the context of tumor heterogeneity and dynamic tumor biology have made it imperative to obtain tumor samples on several different occasions through the course of patient treatment. While this approach is critical to the delivery of optimal cancer treatment, it is fraught with a number of barriers including the need for invasive procedures with associated complications, access to limited amount of tissue, logistical delays in obtaining the biopsy, high healthcare cost, and in many cases inability to obtain tissue because of technically difficult location of the tumor. Given multiple limitations of obtaining tissue samples, the use of blood-based biomarkers ("liquid biopsies") may enable earlier diagnosis of cancer, lower costs by avoiding complex invasive procedures, tailoring molecular targeted treatments, improving patient convenience, and ultimately supplement clinical oncologic decision-making. In this paper, we review various blood-based biomarkers including circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), tumor derived exosomes, tumor educated platelets (TEPs), and microRNA; and highlight current evidence for their use in detection and treatment of lung cancer.

The Need for Predictive, Prognostic, Objective and Complementary Blood-Based Biomarkers in Osteoarthritis (OA)

Osteoarthritis (OA) has traditionally been viewed as a non-inflammatory arthropathy and has not been considered a ‘serious disease’. However, this view has radically changed in recent years, due to the complexity and heterogeneity of the patient populations, spiralling socio-economical costs and long-term impact on the quality of life of affected individuals. There is an acute need for objective and non-invasive diagnostic biomarkers in OA, markers that can stratify patient subtypes and thereby direct therapeutic treatments at an earlier disease stage (read personal health care (PHC)) (Conaghan, 2013). Increased interest in the development of new diagnostic and prognostic tests for early forms of OA may incorporate the use of blood-based biomarkers; however, both research and regulated development and approval are still needed to reach a diagnostically important significant point where a given biomarker will benefit the clinical management of the patient.

Can the use of blood-based biomarkers in addition to anthropometric indices substantially improve the prediction of visceral fat volume as measured by magnetic resonance imaging?

To investigate whether blood-based biomarkers can improve the prediction of visceral fat volume as measured by magnetic resonance imaging (MRI) and thus be used as proxies of visceral adiposity in large-scale epidemiological studies. Whole-body MRI was performed to determine overall and regional body compartments in 542 participants aged 48-80 years (52% men) of the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition. Anthropometric measures were taken, and clinical chemistry profiles including 15 routine biomarkers were obtained. Furthermore, nine novel biomarkers of visceral fat were assayed in a discovery sample of 100 participants. Multivariable regression models were calculated to assess associations between anthropometric variables, biomarkers, and visceral fat volume. The proportion of variance in visceral fat volume explained by anthropometric measures was 65.2% in women and 60.8% in men. By using blood-based biomarkers in addition to anthropometric indices, the variance in visceral fat volume explained could be increased by 4.8% in women and 4.0% in men. After backward selection, HbA1c, triglycerides, and adiponectin remained in the final multivariable regression model in women, while in men hsCRP, leukocytes, AST (GOT), GGT, LDL, and adiponectin remained in the final model. In the present study, blood-based biomarkers moderately improved the prediction of visceral fat volume. This finding suggests that the underestimation of true associations between visceral fat and disease outcomes in epidemiological studies remains critical, even when using comprehensive sets of anthropometric and biomarker variables as proxies of visceral adiposity.

Use of blood-based biomarkers for early diagnosis and surveillance of colorectal cancer.

Early screening for colorectal cancer (CRC) holds the key to combat and control the increasing global burden of CRC morbidity and mortality. However, the current available screening modalities are severely inadequate because of their high cost and cumbersome preparatory procedures that ultimately lead to a low participation rate. People simply do not like to have colonoscopies. It would be ideal, therefore, to develop an alternative modality based on blood biomarkers as the first line screening test. This will allow for the differentiation of the general population from high risk individuals. Colonoscopy would then become the secondary test, to further screen the high risk segment of the population. This will encourage participation and therefore help to reach the goal of early detection and thereby reduce the anticipated increasing global CRC incidence rate. A blood-based screening test is an appealing alternative as it is non-invasive and poses minimal risk to patients. It is easy to perform, can be repeated at shorter intervals, and therefore would likely lead to a much higher participation rate. This review surveys various blood-based test strategies currently under investigation, discusses the potency of what is available, and assesses how new technology may contribute to future test design.

Ischemic Stroke Biomarkers in Blood

Ischemic stroke is a leading cause of adult disability and mortality. With over 15 million strokes occurring every year in the world, methods to better identify patients at risk for stroke are needed, as are methods to improve patient diagnosis and prognosis when stroke occurs. Use of blood-based biomarkers is one method that has been evaluated to predict risk of stroke, diagnose stroke and its causes, predict stroke severity and outcome, and guide prevention therapy. Markers that have been identified include a variety of proteins, nucleic acids and lipids that relate to stroke pathophysiology. The role of blood biomarkers in ischemic stroke is still being defined, and further study is needed to develop blood biomarkers for clinical stroke use. In this review, the authors provide a summary of biomarkers that have been divided by their potential clinical application.

Finding a pathological diagnosis for Alzheimer's disease: Are inflammatory molecules the answer?

Conventional diagnostic tools for Alzheimer's disease (AD) are currently based on a number of clinical criteria, and a definitive diagnosis still relies on pathological evaluation at autopsy. Moreover, neurodegenerative changes are believed to begin years before clinical presentation. There is therefore an essential need for a reliable AD biomarker to aid in the identification of preclinical disease, early diagnosis, prediction of disease progression and treatment response. There is mounting evidence that chronic inflammatory processes play a fundamental role in the progression of neuropathological changes in AD. Clinical and experimental evidence supports the involvement of inflammatory changes in the early stages of AD, even before the appearance of amyloid deposits. Therefore biomarkers that reflect the inflammatory process in AD hold promise. Tests based on these should preferably be reliable, noninvasive and costeffective, which has led to an increasing focus on the use of blood-based biomarkers. This review considers the current progress in AD inflammatory biomarker research followed by a detailed analysis of two leading putative inflammatory biomarkers: α-2-macroglobulin and clusterin.