Blood Biomarkers of Neuronal/Axonal and Glial Injury in Human Immunodeficiency Virus-Associated Neurocognitive Disorders.

INTRODUCTION: Approximately half of the people living with HIV (PLWH) experience HIV-associated neurocognitive disorders (HANDs). However, the neuropathogenesis of HAND is complex, and identifying reliable biomarkers has been challenging. METHODS: This study included 132 participants aged 50 and older from greater San Diego County. The participants were divided into three groups: PLWH with HAND (n = 29), PLWH without HAND (n = 73), and seronegatives without cognitive impairment (n = 30). Peripheral blood was collected at the clinical assessment, and plasma levels of neurofilament light chain (NfL), phosphorylated Tau 181 (pTau181), and glial fibrillary acidic protein (GFAP) were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: Plasma levels of NfL (but not pTau181 and GFAP) were significantly associated with HAND at a medium effect size (p = 0.039, Cohen's d = 0.45 for HAND + vs. HAND-). Notably, higher levels of NfL were significantly associated with HAND diagnosis even after adjusting for sex. DISCUSSION: Our data suggest that neuronal degeneration (as evidenced by increased levels of NfL), but not tau pathology or glial degeneration, is related to cognitive status in PLWH. Our results corroborate the view that blood NfL is a promising biomarker of cognitive impairment in PLWH.

Clinical Correlates of Depression and Suicidality in Huntington Disease: An Analysis of the Enroll-HD Observational Study.

BACKGROUND: Depression and suicidality are commonly experienced by Huntington disease (HD) gene carriers. Research on these behavioral symptoms is imperative, not only to increase our understanding of the symptoms and how they relate to HD, but also to contribute to improving patients' care and quality of life. OBJECTIVE: To identify clinical variables associated with a history of depression and suicidality in HD gene carriers. METHOD: We conducted a cross-sectional study of HD gene carriers from the Enroll-HD database PDS4 (periodic data set 4; N = 11,582). Data from baseline visits were obtained, and binary logistic regression models were used to ascertain the effects of clinical variables on the likelihood that HD gene carriers would have previous depression and suicidal ideation/attempts. RESULTS: Approximately 65% (n = 7526) of the HD gene carriers had a history of depression, and ~27% (n = 3152) had previous suicidal ideation/attempts. Female sex; diagnosis of manifest HD; history of perseverative/obsessive behavior, apathy, and psychosis; and previous suicidal ideation/attempts were significantly associated with a history of depression in the HD gene carriers. Medical history of apathy, psychosis, and depression, as well as worse scores on the Total Functional Capacity and Irritability Scales, were significantly associated with previous suicidal ideation/attempts in the HD gene carriers. CONCLUSION: The prevalence of depression and suicidality is high among HD gene carriers. An improved understanding of the risk factors for depression and suicide in HD gene carriers can assist providers in recognizing at-risk individuals and allow providers to implement therapeutic strategies.

Renin-Angiotensin System in Huntington's Disease: Evidence from Animal Models and Human Patients.

The Renin-Angiotensin System (RAS) is expressed in the central nervous system and has important functions that go beyond blood pressure regulation. Clinical and experimental studies have suggested that alterations in the brain RAS contribute to the development and progression of neurodegenerative diseases. However, there is limited information regarding the involvement of RAS components in Huntington's disease (HD). Herein, we used the HD murine model, (BACHD), as well as samples from patients with HD to investigate the role of both the classical and alternative axes of RAS in HD pathophysiology. BACHD mice displayed worse motor performance in different behavioral tests alongside a decrease in the levels and activity of the components of the RAS alternative axis ACE2, Ang-(1-7), and Mas receptors in the striatum, prefrontal cortex, and hippocampus. BACHD mice also displayed a significant increase in mRNA expression of the AT1 receptor, a component of the RAS classical arm, in these key brain regions. Moreover, patients with manifest HD presented higher plasma levels of Ang-(1-7). No significant changes were found in the levels of ACE, ACE2, and Ang II. Our findings provided the first evidence that an imbalance in the RAS classical and counter-regulatory arms may play a role in HD pathophysiology.

Inflammatory and neurotrophic factor plasma levels are related to epilepsy independently of etiology.

OBJECTIVE: Inflammation plays an essential role in epilepsy. Studies indicate that cytokines and neurotrophic factors can act in neuroexcitability and epileptogenesis. We aimed to investigate the association between plasma inflammatory and neurotrophic markers, seizure frequency, and chronic epilepsy subtypes. METHODS: We studied 446 patients with epilepsy and 166 healthy controls. We classified patients according to etiology and seizure frequency. We measured plasma levels of interleukin-1 (IL-1), IL-2, IL-4, IL-6, IL-10, IL-17, interferon-γ (IFNγ), tumor necrosis factor α (TNFα), soluble TNF receptor 1 (sTNFr1), sTNFr2, brain-derived neurotrophic factor (BDNF), neurotrophic factor 3 (NT3), NT4/5, ciliary neurotrophic factor (CNTF), nerve growth factor (NGF), and glial cell line-derived neurotrophic factor (GDNF) by enzyme-linked immunosorbent assay or cytometric bead array. RESULTS: The plasma levels of BDNF, NT3, NGF, and sTNFr2 were higher, whereas IL-2, IL-4, IL-6, IL-10, IL-17, IFNγ, TNFα, CNTF, and sTNFr1 were lower in patients than controls. IL1, GDNF, and NT4/5 were similar between groups. These markers did not correlate with age, sex, and epilepsy duration. The molecule sTNFr2 was the best marker to discriminate patients from controls (area under the curve = .857), also differing between patients with frequent and infrequent seizures. SIGNIFICANCE: This large cohort confirmed that patients with epilepsy have abnormal levels of plasma inflammatory and neurotrophic markers independent of the underlying etiology. Plasma level of sTNFr2 was related to seizure frequency and discriminated people with or without epilepsy with good accuracy, making it a potential biomarker for epilepsy and seizure burden.

Immunological signatures in saliva of systemic lupus erythematosus patients: influence of periodontal condition.

OBJECTIVES: The immune system has an important role in the development of systemic lupus erythematosus (SLE) and chronic periodontitis (CP). Altered cytokines levels characterise both diseases and contributes to periodontal tissue damage in CP and to macrocomplexes deposition with connective tissue destruction in SLE. This study aimed to evaluate the production of salivary cytokines in patients with SLE and its association with periodontal status. METHODS: The sample comprised 70 SLE patients and 70 paired controls. SLE activity and damage were scored using Systemic Lupus Erythematosus Disease Activity Index 2000 and Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index. Subjects were classified as without or with CP. Salivary concentrations of IL-33, MMP2/TIMP2, RANK and OPG were measured by ELISA, while IL-2, IFNγ, TNFα, IL-4, IL-6, IL-10 and IL-17A were determined by Cytometric Bead Array. Linear regression models analysed association among SLE, CP and salivary cytokines. RESULTS: IL-6 and IL-17A concentrations were significantly higher in SLE/CP patients than controls/CP. Concentrations of IL-6, IL-17A and IL-33 were increased in SLE/CP individuals when compared to SLE without CP. Multivariate model revealed association of cumulative dose of corticoids with periodontal damage and of IL-33 salivary concentration with SLE activity. CONCLUSIONS: Our findings suggest that long-term therapy with corticoids would contribute with periodontal destruction in SLE patients. Moreover, the increased levels of IL-6, IL-17A and IL-33 in saliva of SLE subjects with CP may signal it as possible inflammatory pathways in this process.

Decreased percentage of CD4+ lymphocytes expressing chemokine receptors in bipolar disorder.

OBJECTIVE: Although accumulating evidence supports the hypothesis that immune/inflammatory mechanisms are associated with the pathophysiology of bipolar disorder (BD), data about the profile of chemokines (chemotactic cytokines) and chemokine receptors are still scarce. The current study was designed to evaluate the expression of chemokine receptors on lymphocytes of patients with BD in comparison with controls. METHODS: Thirty-three patients with type I BD (N = 21 in euthymia; N = 6 in mania/hypomania; N = 6 in depression) and 22 age- and sex-matched controls were subjected to clinical evaluation and peripheral blood draw. The expression of chemokine receptors CCR3, CCR5, CXCR4, and CXCR3 on CD4+ and CD8+ lymphocytes was assessed by flow cytometry. RESULTS: Patients with BD had decreased percentage of CD4+CXCR3+ (p = 0.024), CD4+CCR3+ (p = 0.042), and CD4+CCR5+ (0.013) lymphocytes in comparison with controls. The percentage of both CD4+ and CD8+ lymphocytes expressing the chemokine receptor CXCR4 was similar in patients with BD and controls. Likewise, the percentages of CD8+CXCR3+, CD8+CCR3+, and CD8+CCR5+ lymphocytes were similar in patients with BD and controls. CONCLUSION: Our findings reinforce the hypothesis that immune pathways, especially involving CD4+ lymphocytes, are involved in the physiopathology of BD.

Neuroimmunology of Huntington's Disease: Revisiting Evidence from Human Studies.

Huntington's disease (HD) is a neurodegenerative disorder characterized by selective loss of neurons in the striatum and cortex, which leads to progressive motor dysfunction, cognitive decline, and psychiatric disorders. Although the cause of HD is well described-HD is a genetic disorder caused by a trinucleotide (CAG) repeat expansion in the gene encoding for huntingtin (HTT) on chromosome 4p16.3-the ultimate cause of neuronal death is still uncertain. Apart from impairment in systems for handling abnormal proteins, other metabolic pathways and mechanisms might contribute to neurodegeneration and progression of HD. Among these, inflammation seems to play a role in HD pathogenesis. The current review summarizes the available evidence about immune and/or inflammatory changes in HD. HD is associated with increased inflammatory mediators in both the central nervous system and periphery. Accordingly, there have been some attempts to slow HD progression targeting the immune system.

Polymorphism in apoptotic BAX (-248G>A) gene but not in anti-apoptotic BCL2 (-938C>A) gene and its protein and mRNA expression are associated with cervical intraepithelial neoplasia.

HPV is associated with cervical cancer and plays a crucial role in tumor formation. Apoptosis is regulated by different pathways involving genes that either promote (BCL2 gene) or inhibit (BAX gene) cell death. Our goal was to determine whether the BCL2-938C>A (rs2279115) and BAX-248G>A (rs4645878) single nucleotide polymorphisms (SNPs) are associated with squamous intraepithelial neoplasia (SIL) risk, and whether their phenotypic expression was impaired in these lesions. Two hundred and thirty-one cases showing SIL were classified as low SIL (LSIL, n = 101) or high SIL (HSIL, n = 130), and control subjects (n = 266) with no gynecologically proven SIL were recruited. No statistical difference in the genotype and allelic frequency of the BCL-2-938C>A polymorphism was observed among the groups. BCL2-938C/A and A/A homozygotes carriers had higher distribution of BCL-2-expressing cells in stroma in the SIL group. BCL2 mRNA-expression was not correlated with BCL2-938C>A SNPs in both groups. We did find a strong association of the BAX GG genotype and risk for SIL. No difference was observed between LSIL and HSIL groups. In BAX-248G/A and A/A homozygote carriers, the number of BAX-expressing cells was lower the epithelium area in SIL. However, mRNA expression was higher in SIL patients than in the control group. In conclusion, our data provide evidence that allele G carriers in the BAX-248G>A promoter SNP may influence the development of SIL. However, this genotype does not influence the SIL outcome. Additionally, we suggest a possible role of HPV infection in the inhibition of the expression of BAX protein, decreasing cell death, and favoring cervical carcinogenesis.

Increased serum levels of interleukin-8 in patients with tension-type headache.

BACKGROUND AND OBJECTIVES: The pathophysiology of tension-type headache is not well understood. Increased peripheral levels of pro-inflammatory cytokines may act as mediators of several chronic pain disorders. The aim of the present study was to investigate the peripheral levels of chemokines in patients with tension-type headache. METHODS: This was a cross sectional study evaluating serum levels of chemokines in age and sex-matched tension-type headache patients, ictally and interictally, and control participants. Beck Depression and Anxiety Inventories were recorded. Serum levels of monocyte chemoattractant protein-1, macrophage inflammatory protein 1α, regulated on activation, normal T cell expressed and secreted, eotaxin, eotaxin-2, interleukin-8, interferon gamma induced protein-10 were measured by enzyme-linked immunosorbent assay. RESULTS: A total of 96 participants (48 tension-type headache, 48 controls) were included. Interleukin-8 levels were significantly increased in patients with tension-type headache when compared to controls (413.8 (123.4-1756.3) and 329 (107.8-955.6), respectively, P = 0.025). Anxiety and depression scores were higher in patients with tension-type headache but interleukin-8 increase in tension-type headache patients persisted after controlling for anxiety and depression symptoms. Patients with headache at the time of assessment had increased monocyte chemoattractant protein-1 levels when compared with patients without headache (2809.3 (1101-6122.2) and 1630.2 (669.3-31056.8), respectively P = 0.026). Patients with episodic and chronic tension-type headache had no significant differences in serum chemokines levels. CONCLUSION: Interleukin-8 was increased in tension-type headache and monocyte chemoattractant protein-1 was higher in tension-type headache patients with headache, suggesting that pro-inflammatory mechanisms may participate in tension-type headache pathophysiology.

Increased interictal serum levels of CXCL8/IL-8 and CCL3/MIP-1α in migraine.

Inflammatory mediators have been studied in migraine pathophysiology; however, their role is not yet well established. The aim of the present study was to investigate interictal chemokine levels and its association with clinical parameters and psychiatric comorbidities in migraine patients compared with controls. This was a cross-sectional study including age and gender matched migraine patients and controls. Beck Depression and Anxiety Inventories, Headache Impact Test, and Allodynia Symptom Checklist were recorded. Chemokines were measured by ELISA. Forty-nine migraine patients and forty-nine controls without headache were included. CXCL8/IL-8 and CCL3/MIP-1α levels were significantly higher among patients with migraine (P = 0.039 and 0.02, respectively) even after controlling for anxiety and depression scores. Chemokine levels were not correlated with migraine impact as well as allodynia scores. CXCL8/IL-8 and CCL3/MIP-1 α levels were raised in migraine, independently of psychiatric comorbidities, migraine impact, and allodynia.

Targeting the Renin-Angiotensin System (RAS) for Neuropsychiatric Disorders.

BACKGROUND: Neuropsychiatric disorders, such as mood disorders, schizophrenia, and Alzheimer's disease (AD) and related dementias, are associated to significant morbidity and mortality worldwide. The pathophysiological mechanisms of neuropsychiatric disorders remain to be fully elucidated, which has hampered the development of effective therapies. The Renin Angiotensin System (RAS) is classically viewed as a key regulator of cardiovascular and renal homeostasis. The discovery that RAS components are expressed in the brain pointed out a potential role for this system in central nervous system (CNS) pathologies. The understanding of RAS involvement in the pathogenesis of neuropsychiatric disorders may contribute to identifying novel therapeutic targets. AIMS: We aim to report current experimental and clinical evidence on the role of RAS in physiology and pathophysiology of mood disorders, schizophrenia, AD and related dementias. We also aim to discuss bottlenecks and future perspectives that can foster the development of new related therapeutic strategies. CONCLUSION: The available evidence supports positive therapeutic effects for neuropsychiatric disorders with the inhibition/antagonism of the ACE/Ang II/AT1 receptor axis or the activation of the ACE2/Ang-(1-7)/Mas receptor axis. Most of this evidence comes from pre-clinical studies and clinical studies lag much behind, hampering a potential translation into clinical practice.

Further evidence for an anti-inflammatory role of artesunate in experimental cerebral malaria.

BACKGROUND: Cerebral malaria (CM) is a clinical syndrome resulting from Plasmodium falciparum infection. A wide range of clinical manifestations follow the disease including cognitive dysfunction, seizures and coma. CM pathogenesis remains incompletely understood and without treatment this condition is invariably fatal. Artesunate has been accepted as the most effective drug for treating severe malaria. Besides its antiparasitic activity, an anti-inflammatory property has also been reported. In the current study, the immunomodulatory role of artesunate was investigated using a Plasmodium berghei ANKA model of CM, trough evaluation of behavioural changes and cytokines expression in hippocampus and in frontal cortex. METHODS: C57Bl/6 mice were infected with P. berghei by intraperitoneal route, using a standardized inoculation of 106 parasitized erythrocytes. Memory function was evaluated using the step-down inhibitory avoidance test. The mRNA expression of IFN-γ, IL-1ß, IL-6 and TNF in the frontal cortex and hippocampus of control and infected mice on day 5 post-infection were estimated by quantitative real time PCR. Plasmodium berghei -infected mice also received intraperitoneally a single dose of artesunate (32 mg/kg) on day 4 post-infection, and 24 hours after treatment behavioural and immunological analysis were performed. The protein levels of cytokines IL-2, IL-6, IL-10, IL-17, IFN-γ, TNF in the serum, frontal cortex and hippocampus of controls and P. berghei -infected mice treated or not treated with artesunate were determined using a cytometric bead array (CBA) kit. The survival and neurological symptoms of CM were also registered. RESULTS: CM mice presented a significant impairment of aversive memory compared to controls on day 5 post-infection. A higher mRNA expression of pro-inflammatory cytokines was found in the hippocampus and frontal cortex of infected mice. A single dose of artesunate was also able to decrease the expression of inflammatory cytokines in the hippocampus and frontal cortex of P. berghei-infected mice. In parallel, a significant improvement in neurological symptoms and survival were observed in artesunate treated mice. CONCLUSIONS: In summary, the current study provided further evidence that CM affects key brain areas related to cognition process. In addition, different patterns of cytokine expression during the course of CM could be modulated by a single administration of the anti-malarial artesunate.

Effects of physical exercise on plasma levels of brain-derived neurotrophic factor and depressive symptoms in elderly women--a randomized clinical trial.

OBJECTIVES: To investigate the effect of 2 standardized exercise programs, muscle strength exercises (SE) and aerobic exercises (AE), on the plasma levels of brain-derived neurotrophic factor (BDNF) and depressive symptoms in 451 elderly women. DESIGN: A randomized controlled trial. SETTING: Belo Horizonte/MG-Brazil. PARTICIPANTS: Community-dwelling older women (N=451; age, 65-89y). INTERVENTION: The participants were divided into 2 groups: SE and AE. Both protocols lasted 10 weeks, and 30 sessions (1-h sessions) in total were performed 3 times a week under the direct supervision of physical therapists. MAIN OUTCOME MEASURES: Plasma levels of BDNF (enzyme-linked immunosorbent assay) and depressive symptoms (Geriatric Depression Scale). RESULTS: There was a significant difference for BDNF plasma levels between the SE and AE groups (P=.009). Post hoc analysis revealed a pre-post intervention difference in BDNF levels only for the SE group (P=.008). A statistically significant difference was found for the pre- and postintervention Geriatric Depression Scale scores in both groups (P=.001), showing that the effects of both exercise protocols were comparable regarding depressive symptoms (P=.185). CONCLUSIONS: The present findings have demonstrated the positive effect of muscle strengthening and aerobic intervention on depressive symptoms in community-dwelling elderly women. Interestingly, only SE significantly increased the plasma levels of BDNF in our sample. The positive effects of physical exercise on depressive symptoms in the elderly were not mediated by BDNF.

Antipsychotics in Alzheimer's Disease: Current Status and Therapeutic Alternatives.

Psychosis and hyperactive behaviors, such as agitation and wandering, affect a significant proportion of patients with Alzheimer's disease (AD). These symptoms are often treated with antipsychotics, usually in an off-label approach. This mini-review provides an updated perspective on the pharmacological approach for the neuropsychiatric symptoms (NPS) in AD. The results of new studies have provided a better understanding of AD-related NPS management, but high-quality evidence still needs to be obtained. Herein, we argue for a more cautious approach to the use of antipsychotics in AD and highlight the importance of exploring alternative treatments for NPS. By doing so, we can ensure that patients with AD receive optimal care that is both effective and safe.

Role of Oxysterols in the Activation of the NLRP3 Inflammasome as a Potential Pharmacological Approach in Alzheimer's Disease.

Alzheimer's disease (AD), the most prevalent form of dementia, is a complex clinical condition with multifactorial origin posing a major burden to health care systems across the world. Even though the pathophysiological mechanisms underlying the disease are still unclear, both central and peripheral inflammation has been implicated in the process. Piling evidence shows that the nucleotide-binding domain, leucine-rich repeat and pyrin domain-containing protein 3 (NLRP3) inflammasome is activated in AD. As dyslipidemia is a risk factor for dementia, and cholesterol can also activate the inflammasome, a possible link between lipid levels and the NLRP3 inflammasome has been proposed in Alzheimer's. It is also speculated that not only cholesterol but also its metabolites, the oxysterols, may be involved in AD pathology. In this context, mounting data suggest that NLRP3 inflammasome activity can be modulated by different peripheral nuclear receptors, including liver-X receptors, which present oxysterols as endogenous ligands. In light of this, the current review explores whether the activation of NLRP3 by nuclear receptors, mediated by oxysterols, may also be involved in AD and could serve as a potential pharmacological avenue in dementia.

Accelerated epigenetic aging in older adults with HIV disease: associations with serostatus, HIV clinical factors, and health literacy.

The prevalence of older persons with HIV (PWH) disease has increased considerably in the last 20 years, but our understanding of biological factors of aging and their clinical correlates among PWH remains limited. Study participants were 149 persons aged 50 and older, including 107 PWH and 42 seronegatives. All participants completed a blood draw, research medical evaluation, structured psychiatric interview, neurocognitive assessment, questionnaires, and measures of health literacy. Four epigenetic clocks were generated from stored blood samples using standardized laboratory methods. In regression models adjusting for sex and smoking status, PWH had significantly higher epigenetic aging acceleration values than seronegatives on all four indicators. Within the PWH sample, higher levels of epigenetic aging acceleration were moderately associated with lower current CD4 count, AIDS diagnoses, higher scores on the Veterans Aging Cohort Study Index, and lower telomere values. Higher epigenetic aging acceleration indices were also associated with lower health literacy among PWH. PWH experience accelerated aging as measured by a series of epigenetic clocks, which may be linked to immune compromise and risk of all-cause mortality. Health literacy may be a modifiable target for mitigating the risk of accelerated aging among older PWH.

Hearts and Minds: Emotion Recognition and Mentalizing in Parkinson's Disease and Progressive Supranuclear Palsy.

OBJECTIVE: There are scarce data comparing Parkinson's disease (PD) and Progressive Supranuclear Palsy (PSP) in social cognition (SC). We aimed to compare patients with PSP and PD in SC. METHODS: We included three groups: PD (n = 18), PSP (n = 20) and controls (n = 23). Participants underwent neuropsychological exams, including the mini-version of the Social and Emotional Assessment, which is composed of the facial emotion recognition test (FERT) and the modified faux-pas (mFP) test, which assesses Theory of Mind (ToM). RESULTS: Patients with PD scored lower than controls in the FERT, but not in the mFP test. Patients with PSP performed worse than controls in both the mFP and FERT. PD and PSP groups did not differ in the FERT, but PSP performed worse than PD in the mFP test. The mFP test distinguished PSP from PD with 89% accuracy. CONCLUSION: The assessment of ToM may contribute to the differentiation between PD and PSP.

Hyperphosphorylated Tau in Mesial Temporal Lobe Epilepsy: a Neuropathological and Cognitive Study.

Temporal lobe epilepsy (TLE) often courses with cognitive deficits, but its underlying neuronal basis remains unclear. Confluent data suggest that epilepsy share pathophysiological mechanisms with neurodegenerative diseases. However, as most studies analyze subjects 60 years old and older, it is challenging to rule out that neurodegenerative changes arise from age-related mechanisms rather than epilepsy in these individuals. To fill this gap, we conducted a neuropathological investigation of the hippocampal formation of 22 adults with mesial TLE and 20 age- and sex-matched controls (both younger than 60 years). Moreover, we interrogated the relationship between these neuropathological metrics and cognitive performance. Hippocampal formation extracted from patients with drug-resistant mesial TLE undergoing surgery and postmortem non-sclerotic hippocampal formation of clinically and neuropathologically controls underwent immunohistochemistry against amyloid ß (Aß), hyperphosphorylated tau (p-tau), and TAR DNA-binding protein-43 (TDP-43) proteins, followed by quantitative analysis. Patients underwent a comprehensive neuropsychological evaluation prior to surgery. TLE hippocampi showed a significantly higher burden of p-tau than controls, whereas Aß deposits and abnormal inclusions of TDP-43 were absent in both groups. Patients with hippocampal sclerosis (HS) type 2 had higher immunostaining for p-tau than patients with HS type 1. In addition, p-tau burden was associated with impairment in attention tasks and seizures frequency. In this series of adults younger than 60 years-old, the increase of p-tau burden associated with higher frequency of seizures and attention impairment suggests the involvement of tau pathology as a potential contributor to cognitive deficits in mesial TLE.

Cerebral blood flow is associated with markers of neurodegeneration in Huntington's disease.

INTRODUCTION: The ultimate cause of neuronal death in Huntington's disease (HD) is still uncertain. Apart from impairment in systems handling abnormal proteins, other mechanisms might contribute to neurodegeneration and progression of HD. Decreased cerebral blood flow (CBF) has been described in other neurodegenerative disorders and may play a role in HD. OBJECTIVES: To investigate CBF changes in HD gene carriers. METHODS: A group of 39 HD gene carriers (18 premanifest and 21 manifest HD) and 16 controls underwent a comprehensive clinical evaluation and a brain magnetic resonance imaging protocol that included pseudo-continuous arterial spin labeling to quantify CBF. Regions of interest (ROI) analyses were performed to compare CBF in controls vs premanifest HD vs manifest HD. Correlation analyses were performed to ascertain the relationship between CBF and clinical and biomarkers data. RESULTS: We found a decrease in CBF in bilateral caudate and putamen of patients with manifest HD in comparison with controls. CBF of premanifest HD carriers in the same ROIs was midway between controls and the HD patients, with differences not reaching statistical significance. Lower CBF in caudate and putamen was associated with worse motor symptoms, functionality, and cognitive performance. CBF was also associated with markers of neurodegeneration: higher CBF in caudate and putamen significantly correlated to higher volumes in the same ROI and to lower levels of neurofilament light chain. CONCLUSION: As CBF changes in caudate and putamen nuclei were associated with markers of neurodegeneration and with clinical outcomes, decreased CBF and oxygen supply could emerge as a relevant mechanism contributing to degeneration in HD.