We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
To save content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about saving content to .
To save content items to your Kindle, first ensure coreplatform@cambridge.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Current neurobiological models of post-traumatic stress disorder (PTSD) assume excessive medial frontal activation and hypoactivation of cortico-limbic regions as neural markers of post-traumatic dissociation. Script-driven imagery is an established experimental paradigm that is used to study acute dissociative reactions during trauma exposure. However, there is a scarcity of experimental research investigating neural markers of dissociation; findings from existing script-driven neuroimaging studies are inconsistent and based on small sample sizes.
Aims
The current aim was to identify the neural correlates of acute post-traumatic dissociation by employing the script-driven imagery paradigm in combination with functional magnetic resonance imaging.
Method
Functional neuroimaging data was acquired in 51 female patients with PTSD with a history of interpersonal childhood trauma. Blood-oxygen-level-dependent response during the traumatic (versus neutral) autobiographical memory recall was analysed, and the derived activation clusters were correlated with dissociation measures.
Results
During trauma recall, enhanced activation in the cerebellum, occipital gyri, supramarginal gyrus and amygdala was identified. None of the derived clusters correlated significantly with dissociative symptoms, although patients reported increased levels of acute dissociation following the paradigm.
Conclusions
The present study is one of the largest functional magnetic resonance imaging investigations of dissociative neural biomarkers in patients with PTSD undergoing experimentally induced trauma confrontation to elicit symptom-specific brain reactivity. In light of the current reproducibility crisis prominent in neuroimaging research owing to costly and time-consuming data acquisition, the current (null) findings highlight the difficulty of extracting reliable neurobiological biomarkers for complex subjective experiences such as dissociation.
The multiplicity and complexity of the neuronal connections in the central nervous system make it difficult to disentangle circuits that play an essential role in the development or treatment of (neuro)psychiatric disorders. By choosing the evolutionary development of the forebrain as a starting point, a certain order in the connections can be created. The dorsal diencephalic connection (DDC) system can be applied for the development of biomarkers that can predict treatment response.
Materials and methods:
After providing a brief introduction to the theory, we examined neuroanatomical publications on the connectivity of the DDC system. We then searched for neurochemical components that are specific for the habenula.
Results and discussion:
The best strategy to find biomarkers that reflect the function of the habenular connection is to use genetic variants of receptors, transporters or enzymes specific to this complex. By activating these with probes and measuring the response in people with different functional genotypes, the usefulness of biomarkers can be assessed.
Conclusions:
The most promising biomarkers in this respect are those linked to activation or inhibition of the nicotine receptor, dopamine D4 receptor, μ-opioid receptor and also those of the functioning of habenular glia cells (astrocytes and microglia).
Higher inflammation has been linked to poor physical and mental health outcomes, and mortality, but few studies have rigorously examined whether changes in perceived stress and depressive symptoms are associated with increased inflammation within family caregivers and non-caregivers in a longitudinal design.
Design:
Longitudinal Study.
Setting:
REasons for Geographic And Racial Differences in Stroke cohort study.
Participants:
Participants included 239 individuals who were not caregivers at baseline but transitioned to providing substantial and sustained caregiving over time. They were initially matched to 241 non-caregiver comparisons on age, sex, race, education, marital status, self-rated health, and history of cardiovascular disease. Blood was drawn at baseline and approximately 9.3 years at follow-up for both groups.
Measurements:
Perceived Stress Scale, Center for Epidemiological Studies-Depression, inflammatory biomarkers, including high-sensitivity C-reactive protein, D dimer, tumor necrosis factor alpha receptor 1, interleukin (IL)-2, IL-6, and IL-10 taken at baseline and follow-up.
Results:
Although at follow-up, caregivers showed significantly greater worsening in perceived stress and depressive symptoms compared to non-caregivers, there were few significant associations between depressive symptoms or perceived stress on inflammation for either group. Inflammation, however, was associated with multiple demographic and health variables, including age, race, obesity, and use of medications for hypertension and diabetes for caregivers and non-caregivers.
Conclusions:
These findings illustrate the complexity of studying the associations between stress, depressive symptoms, and inflammation in older adults, where these associations may depend on demographic, disease, and medication effects. Future studies should examine whether resilience factors may prevent increased inflammation in older caregivers.
Phase 1 clinical trials are the entrance to the further clinical development of new compounds. The chapter describes the regulatory background and highlights most important issues about selection of the maximum recommended starting dose, dose escalation steps, and definition of maximum tolerated dose, or maximum applied dose in a study considering actual guidelines. There is an overview about selection of subject populations and frequently used trial designs. The principles of single-ascending-dose and multiple-ascending-dose tolerance studies are described with a few examples of studies in Alzheimer’s disease (AD). The safety assessment is important in clinical practice, as AD drugs will be used over many years, so excellent tolerability is a must! In Phase 1, a careful assessment of pharmacokinetic (PK) properties of a new compound forms the basis for dose selection in Phase 2 and 3 studies and supports the decision on the treatment regimen. The importance of inclusion of different biomarkers in these studies to allow assessment of pharmacodynamic and PK relationship and to potentially identify first signals in human studies indicating therapeutic usefulness in the indication.
There has been a rapid development of cerebrospinal fluid (CSF) and also blood biomarkers in the field of Alzheimer’s disease (AD) clinical research and drug development. Clinical research studies support that the core AD CSF biomarkers amyloid beta (Aβ42 and Aβ42/40 ratio), total-tau (t-tau), and hyperphosphorylated tau (p-tau) reflect key elements of AD pathophysiology. The “Alzheimer CSF profile”, decreased Aβ42/40 ratio together with increased t-tau and p-tau, has high diagnostic value, and high concordance with amyloid PET. These biomarkers have undergone thorough standardization and are today available on fully automated laboratory analyzers. Recent technical developments in the field of ultrasensitive immunoassays and mass spectrometry methods also allow for measurement of these AD biomarkers in blood samples. Blood neurofilament light may also be a biomarker to grade axonal degeneration in AD and other neurodegenerative disorders. These biomarkers are important in AD drug development, for screening tools and diagnostic markers, and the verification of target engagement of candidate molecules in early trials and identification of downstream drug effects in late-stage trials.
Phase 2 in drug development is a crucial phase that can make or break success. The goals in Phase 2 are to determine safety, dosage and efficacy. In this chapter elements of planning, design, biomarker use and clinical outcomes are highlighted and some good and bad examples are given, emphasizing the importance of conducting a proper Phase 2.
Academic investigators have played key roles in Alzheimer’s disease drug development. This work has been highly collaborative, with innovations in trial design, population characteristics, outcome measures, biomarker utilization and regulatory pathways arising from interactions among academics, industry scientists, regulators, and other stakeholders. The National Institute on Aging (NIA) has funded much of this work, along with the Alzheimer’s Association and other philanthropic organizations. The NIA Alzheimer’s Clinical Trials Consortium (ACTC) supports a nationwide infrastructure to continue academic efforts on trial methodology and the implementation of innovative studies in age-related neurodegenerative disorders. ACTC, with the University of Southern California, Harvard University and the Mayo Clinic, expert trialists from across the country and 35 primary trial sites, conducts a number of multicenter randomized controlled trials. Public-private partnerships are encouraged. Additional innovations include a focus on diversity and inclusion in trial recruitment, involvement of research participants in guiding trial design, and training the next generation of trialists.
While Alzheimer’s disease (AD) remains one of the very few common chronic diseases of aging and old age without any effective treatments to slow or prevent the illness, an historical perspective can provide the context for why this is true. The same historical perspective demonstrates that this lag is primarily a frame shift in time, rather than due to excess difficulties in developing drugs for the disease. Indeed, the historical perspective suggests that today, we are “right on time” for an explosion in new drugs for the disease after 40 years of rapid progress in basic and clinical research. The first drugs (cholinergic agents) for AD were approved after only about 15-20 years of research in the field, including the time needed for basic discovery, clinical development and regulatory approval. Today, after 40 years of AD research, many disease-modifying drugs are in clinical development. Considering that cancer, diabetes and hypertension research began more than 80-100 years ago, the rapid progress in AD research can actually be viewed as impressive progress.
The Alzheimer’s Disease Neuroimaging Initiative (ADNI) is a longitudinal, observational study initiated in 2004 with the aim to develop and validate biomarkers for Alzheimer’s disease (AD) trials. From its inception, ADNI has been a model of a public–private partnership, with industry partners involved not only through financial support but in a guidance capacity. Through the development of standardized methods, ADNI has collected imaging and fluid biomarker data from cognitively normal, early and late mild cognitive impairment, and AD participants which is available to qualified researchers without embargo. Moreover, these methods have been incorporated into companion studies worldwide. The data that have been collected have provided important insights into the progression of AD pathology over time, assists in understanding which biomarkers may be most useful in clinical trials and have facilitated the design of studies of disease-modifying therapies.
Progress in developing personalised care for mental disorders is supported by numerous proof-of-concept machine learning studies in the area of risk assessment, diagnostics and precision prescribing. Most of these studies primarily use clinical data, but models might benefit from additional neuroimaging, blood and genetic data to improve accuracy. Combined, multimodal models might offer potential for stratification of patients for treatment. Clinical implementation of machine learning is impeded by a lack of wider generalisability, with efforts primarily focused on psychosis and dementia. Studies across all diagnostic groups should work to test the robustness of machine learning models, which is an essential first step to clinical implementation, and then move to prospective clinical validation. Models need to exceed clinicians’ heuristics to be useful, and safe, in routine decision-making. Engagement of clinicians, researchers and patients in digitalisation and ‘big data’ approaches are vital to allow the generation and accessibility of large, longitudinal, prospective data needed for precision psychiatry to be applied into real-world psychiatric care.
This study seeks to identify Alzheimer’s and related dementias (ADRD) biomarkers associated with postoperative delirium (POD) via meta-analysis.
Design:
A comprehensive search was conducted. Studies met the following inclusion criteria: >18 years of age, identified POD with standardized assessment, and biomarker measured in the AT(N)-X (A = amyloid, T = tau, (N)=neurodegeneration, X-Other) framework. Exclusion criteria: focus on prediction of delirium, delirium superimposed on dementia, other neurologic or psychiatric disorders, or terminal delirium. Reviewers extracted and synthesized data for the meta-analysis.
Setting:
Meta-analysis.
Participants:
Patients with POD.
Measurements:
Primary outcome: association between POD and ATN-X biomarkers. Secondary outcomes involved sample heterogeneity.
Results
28 studies were included in this meta-analysis. Studies focused on inflammatory and neuronal injury biomarkers; there were an insufficient number of studies for amyloid and tau biomarker analysis. Two inflammatory biomarkers (IL-6, and CRP) showed a significant relationship with POD (IL-6 n = 10, standardized mean difference (SMD): 0.53, 95% CI: 0.36–0.70; CRP n = 14, SMD: 0.53, 95% CI: 0.33–0.74). Two neuronal injury biomarkers (blood-based S100B and NfL) were positively associated with POD (S100B n = 5, SMD: 0.40, 95% CI: 0.11–0.69; NFL n = 2, SMD: 0.93, 95% CI: 0.28–1.57). Of note, many analyses were impacted by significant study heterogeneity.
Conclusions
This meta-analysis identified an association between certain inflammatory and neuronal injury biomarkers and POD. Future studies will need to corroborate these relationships and include amyloid and tau biomarkers in order to better understand the relationship between POD and ADRD.
Precision medicine in psychiatry is based on the identification of homogeneous subgroups of patients with the help of biosignatures—sets of biomarkers—in order to enhance diagnosis, stratification of patients, prognosis, evaluation, and prediction of treatment response. Within the broad domain of biomarker discovery, we propose retinal electrophysiology as a tool for identification of biosignatures. The retina is a window to the brain and provides an indirect access to brain functioning in psychiatric disorders. The retina is organized in layers of specialized neurons which share similar functional properties with brain neurons. The functioning of these neurons can be evaluated by electrophysiological techniques named electroretinogram (ERG). Since the study of retinal functioning gives a unique opportunity to have an indirect access to brain neurons, retinal dysfunctions observed in psychiatric disorders inform on brain abnormalities. Up to now, retinal dysfunctions observed in psychiatric disorders provide indicators for diagnosis, identification of subgroups of patients, prognosis, evaluation, and prediction of treatment response. The use of signal processing and machine learning applied on ERG data enhances retinal markers extraction, thus providing robust, reproducible, and reliable retinal electrophysiological markers to identify biosignatures in precision psychiatry. We propose that retinal electrophysiology may be considered as a new approach in the domain of electrophysiology and could now be added to the routine evaluations in psychiatric disorders. Retinal electrophysiology may provide, in combination with other approaches and techniques, sets of biomarkers to produce biosignatures in mental health.
Castration of male piglets in the United States is conducted without analgesics because no Food and Drug Administration (FDA) approved products are labeled for pain control in swine. The absence of approved products is primarily due to a wide variation in how pain is measured in suckling piglets and the lack of validated pain-specific outcomes individually indistinct from other biological responses, such as general stress or inflammation responses with cortisol. Simply put, to measure pain mitigation, measurement of pain must be specific, quantifiable, and defined. Therefore, given the need for mitigating castration pain, a consortium of researchers, veterinarians, industry, and regulatory agencies was formed to identify potential animal-based outcomes and develop a methodology, based on the known scientific research, to measure pain and the efficacy of mitigation strategies. The outcome-based measures included physiological, neuroendocrine, behavioral, and production parameters. Ultimately, this consortium aims to provide a validated multimodal methodology to demonstrate analgesic drug efficacy for piglet castration.
Measurable outcomes were selected based on published studies suggesting their validity, reliability, and sensitivity for the direct or indirect measurement of pain associated with surgical castration in piglets. Outcomes to be considered are observation of pain behaviors (i.e. ethogram defined behaviors and piglet grimace scale), gait parameters measured with a pressure mat, infrared thermography of skin temperature of the cranium and periphery of the eye, and blood biomarkers. Other measures include body weight and mortality rate.
This standardized measurement of the outcome variable's primary goal is to facilitate consistency and rigor by developing a research methodology utilizing endpoints that are well-defined and reliably measure pain in piglets. The resulting methodology will facilitate and guide the evaluation of the effectiveness of comprehensive analgesic interventions for 3- to 5-day-old piglets following surgical castration.
The search for biomarkers for autism spectrum disorder (henceforth autism) has received a lot of attention due to their potential clinical relevance. The clinical and aetiological heterogeneity of autism suggests the presence of subgroups. The lack of identification of a valid diagnostic biomarker for autism, and the inconsistencies seen in studies assessing differences between autism and typically developing control groups, may be partially explained by the vast heterogeneity observed in autism. The focus now is to better understand the clinical and biological heterogeneity and identify stratification biomarkers, which are measures that describe subgroups of individuals with shared biology. Using stratification approaches to assess treatment within pre-defined subgroups could clarify who may benefit from different treatments and therapies, and ultimately lead to more effective individualised treatment plans.
In the burgeoning demand for optimization of cheese production, ascertaining cheese flavour formation during the cheese making process has been the focal point of determining cheese quality. In this research reflection, we have highlighted how valuable volatile organic compound (VOC) analysis has been in assessing contingent cheese flavour compounds arising from non-starter lactic acid bacteria (NSLAB) along with starter lactic acid bacteria (SLAB), and whether VOC analysis associated with other high-throughput data might help provide a better understanding the cheese flavour formation during cheese process. It is widely known that there is a keen interest to merge all omics data to find specific biomarkers and/or to assess aroma formation of cheese. Towards that end, results of VOC analysis have provided valuable insights into the cheese flavour profile. In this review, we are pinpointing the effective use of flavour compound analysis to perceive flavour-forming ability of microbial strains that are convenient for dairy production, intertwining microbiome and metabolome to unveil potential biomarkers that occur during cheese ripening. In doing so, we summarised the functionality and integration of aromatic compound analysis in cheese making and gave reflections on reconsidering what the role of flavour-based analysis might have in the future.
Major depressive disorder (MDD) is the main cause of disability worldwide, its outcome is poor, and its underlying mechanisms deserve a better understanding. Recently, peripheral acetyl-l-carnitine (ALC) has been shown to be lower in patients with major depressive episodes (MDEs) than in controls. l-Carnitine is involved in mitochondrial function and ALC is its short-chain acetyl-ester. Our first aim was to compare the plasma levels of l-carnitine and ALC, and the l-carnitine/ALC ratio in patients with a current MDE and healthy controls (HCs). Our second aim was to assess their changes after antidepressant treatment.
Methods
l-Carnitine and ALC levels and the carnitine/ALC ratio were measured in 460 patients with an MDE in a context of MDD and in 893 HCs. Depressed patients were re-assessed after 3 and 6 months of antidepressant treatment for biology and clinical outcome.
Results
As compared to HC, depressed patients had lower ALC levels (p < 0.00001), higher l-carnitine levels (p < 0.00001) and higher l-carnitine/ALC ratios (p < 0.00001). ALC levels increased [coefficient: 0.18; 95% confidence interval (CI) 0.12–0.24; p < 0.00001], and l-carnitine levels (coefficient: −0.58; 95% CI −0.75 to −0.41; p < 0.00001) and l-carnitine/ALC ratios (coefficient: −0.41; 95% CI −0.47 to −0.34; p < 0.00001), decreased after treatment. These parameters were completely restored after 6 months of antidepressant. Moreover, the baseline l-carnitine/ALC ratio predicted remission after 3 months of treatment (odds ratio = 1.14; 95% CI 1.03–1.27; p = 0.015).
Conclusions
Our data suggest a decreased mitochondrial metabolism of l-carnitine into ALC during MDE. This decreased mitochondrial metabolism is restored after a 6-month antidepressant treatment. Moreover, the magnitude of mitochondrial dysfunction may predict remission after 3 months of antidepressant treatment. New strategies targeting mitochondria should be explored to improve treatments of MDD.
Mars is a primary target of astrobiological interest: its past environmental conditions may have been favourable to the emergence of a prebiotic chemistry and, potentially, biological activity. In situ exploration is currently underway at the Mars surface, and the subsurface (2 m depth) will be explored in the future ESA ExoMars mission. In this context, BIOlogy and Mars EXperiment was performed to evaluate the stability and detectability of organic biomarkers under space and Mars-like conditions. Our data suggested that some target molecules, namely melanin, azelaic acid and nucleic acids, can be detected even after 16 months exposure to Low Earth Orbit conditions by multidisciplinary approaches. We used the same techniques as onboard the ExoMars rover, as Raman and infrared spectroscopies and gas chromatograph-mass spectrometer, and polymerase chain reaction even if this is not planned for the imminent mission to Mars. These results should be taken into account for future Mars exploration.
The identification of potential biomarkers is crucial to improve the management and treatment of mood disorders. Glycogen synthase kinase-3 (GSK-3) is a multifunctional enzyme with an important role in the etiology of mood disorders. Recent findings suggested GSK-3 as a putative biomarker in mood disorders.
Objectives
The aims of the study are: - to evaluate GSK3 as potential biomarker for differential diagnosis (MDD and BD); - to analyze the regulation of GSK3 by psychopharmacological treatments.
Methods
Patients included fulfill the following criteria: (a) principal diagnosis of MDD or BD (DSM-5); (b) age ≥ 18 years; (c) drug-free for at least 4 weeks before the inclusion. For each patient included a healthy control is enrolled, matched by gender and age. All included subjects at the study entry point (t0) are assessed through: - semistructured clinical interview and clinical rating scales (Hamilton Depression Rating Scale, Hamilton Anxiety Rating Scale; Young Mania Rating Scale, Clinical Global Impression) - blood draw, to measure GSK-3 levels Patients with MDD or BD are assessed again after 1 week (T1) and after 2 month (T2) of specific pharmacological treatment.
Results
So far, we enrolled 16 patients and 16 healthy controls. The enrollment is still ongoing.
Conclusions
We expect to find GSK-3 levels differently expressed between healthy controls, patients with DDM and patients with BD. This finding would be crucial as it could contribute to the improvement of differential diagnosis. Moreover, we expect to observe a change in GSK-3 levels after psychopharmacological treatments.
Depression or Major Depressive Disorder (MDD) is the most prevalent psychiatric disorder and a leading cause of disability worldwide. Currently affecting around 300 million people worldwide, depression is a major clinical, emotional, and socioeconomic strain for society. There is a growing interest in the biological underpinnings of depression, which are reflected by altered levels of biomarkers.
Objectives
The aim of the study was to present an up-to-date review of potential MDD biomarkers.
Methods
PubMed, Scopus, and Web of Science databases were searched.
Results
Enhanced inflammation has been reported in MDD, as reflected by increased concentrations of inflammatory markers –
interleukin-6, C-reactive protein, tumor necrosis factor-α, and soluble interleukin-2 receptor. Dysregulation of the hypothalamus-pituitary-adrenals axis, along with increased cortisol levels, have also been reported in MDD. Oxidative and nitrosative stress also plays an important role in the pathophysiology of MDD. Notably, increased levels of lipid peroxidation markers are characteristic of MDD. Kynurenine metabolites, increased glutamate and decreased total cholesterol are also features of MDD. Finally, alterations in growth factors, with a significant decrease in brain-derived neurotrophic factor and an increase in fibroblast growth factor-2 and insulin-like growth factor-1 concentrations have also been found in MDD.
Conclusions
A group of substances holds promise as reliable biomarkers for MDD. However, biomarker research in depression faces many difficulties, such as insufficient understanding of MDD etiopathogenesis, substantial heterogeneity of the disorder and low specificity of biomarkers. The construction of biomarker panels and their evaluation with use of new technologies may have the potential to overcome the above mentioned obstacles.
There is growing evidence that generalised joint hypermobility (GJH) is associated with several psychiatric conditions. There are no previous studies on adult ADHD.
Objectives
To evaluate, in a large Swedish sample, if generalised joint hypermobility and adult ADHD are associated.
Methods
431 adults with ADHD and 417 controls were included. GJH was assessed by the Beighton Score, a physical examination, and the 5PQ, a self-report screening tool. Exploratively, reported musculoskeletal symptoms and abnormal skin manifestations suggestive of symptomatic GJH (e.g. Ehlers-Danlos syndrome), were assessed to differentiate this group from the general GJH group. Logistic regressions determined the influence of an ADHD diagnosis and known covariates (age, sex and ethnicity) on GJH and symptomatic GJH respectively.
Results
ADHD was associated to GJH, as defined by the Beighton Score and the 5PQ, with adjusted odds ratios of 4.65 (CI 95% 3.01-7.18, p<.005) and 1.86 (CI 95% 1.39-2.48, p<.005), respectively. Likewise, ADHD and symptomatic GJH were associated with adjusted odds ratios of 6.94 (CI 95% 4.05-11.89, p<.005) and 2.66 (CI 95% 1.94-3.66, p<.005).
Conclusions
GJH and adult ADHD are associated conditions. Symptomatic GJH, defined as additional symptoms of pain and/or skin manifestations, has a considerably stronger link to adult ADHD than unspecific GJH has. GJH may represent a marker of an underlying systemic disorder with physical manifestations in connective tissue as well as behavioural manifestations including hyperactivity, impulsiveness and inattentiveness. Future studies should investigate if this represents a novel subtype of ADHD and if symptomatic GJH affects the ADHD management.