Effects of ethanol on aggregation, serotonin release, and amyloid precursor protein processing in rat and human platelets

Enlarged perivascular spaces in alcohol-related brain damage induced by dyslipidemia

Perivascular spaces (PVSs) as the anatomical basis of the glymphatic system, are increasingly recognized as potential imaging biomarkers of neurological conditions. However, it is not clear whether enlarged PVSs are associated with alcohol-related brain damage (ARBD). We aimed to investigate the effect of long-term alcohol exposure on dyslipidemia and the glymphatic system in ARBD. We found that patients with ARBD exhibited significantly enlargement of PVSs in the frontal cortex and basal ganglia, as well as a notable increased levels of total cholesterol (TC) and triglycerides (TG). The anatomical changes of the glymphatic drainage system mentioned above were positively associated with TC and TG. To further explore whether enlarged PVSs affects the function of the glymphatic system in ARBD, we constructed long alcohol exposure and high fat diet mice models. The mouse model of long alcohol exposure exhibited increased levels of TC and TG, enlarged PVSs, the loss of aquaporin-4 polarity caused by reactive astrocytes and impaired glymphatic drainage function which ultimately caused cognitive deficits, in a similar way as high fat diet leading to impairment in glymphatic drainage. Our study highlights the contribution of dyslipidemia due to long-term alcohol abuse in the impairment of the glymphatic drainage system.

Alcohol intake including wine drinking is associated with decreased platelet reactivity in a large population sample

BACKGROUND

Alcohol consumption is linked to decreased platelet function. Whether this link is dependent on sex or type of beverage remains unclear.

METHODS

Cross-sectional data were obtained from the Framingham Heart Study (N = 3427). Alcohol consumption was assessed by using standardized medical history and Harvard semi-quantitative food frequency questionnaires. Five bioassays measured 120 platelet reactivity traits across agonists in whole-blood and platelet-rich plasma samples. Linear mixed-effects models adjusted for age, sex and aspirin use, hypertension, body mass index, cholesterol, high-density lipoprotein, triglycerides, smoking and diabetes evaluated associations between platelet reactivity and alcohol consumption. Beta effects, the regression coefficients that estimate the amount of change in each unit of the predictor variable whereas all other predictor variables remain fixed, for heavy alcohol consumption were compared with effects of aspirin use.

RESULTS

Alcohol consumption was associated with decreased platelet reactivity, with more associations among wine and liquor compared with beer. Many platelet-alcohol associations in the full sample (86%, P < 0.01) had larger effect sizes in females. Lower light transmission aggregometry adenosine diphosphate (1.82 µM) maximum aggregation (P = 2.6E-3, 95% CI = -0.07, -0.02, β = -0.042) and area under the curve (P = 7.7E-3, 95% CI = -0.07, -0.01, β = -0.039) were associated with white wine consumption; however, red wine had no associations with platelet reactivity. The effect of aspirin use was on average 11.3 (±4.0) times greater than that of heavy drinking in our full sample.

CONCLUSIONS

We confirm associations between alcohol consumption and decreased platelet reactivity. Effects appeared larger for liquor and wine intake and in our female cohort. Red wine consumption is not associated with lower platelet function, contrasting with prior population studies. Although we report an inhibitory relationship between alcohol intake and platelet function, these effects appear much smaller than that of aspirin use.

Alcohol-induced thrombocytopenia: Current review

Thrombocytopenia is a decrease in the platelet count below 150,000 in a microliter of blood, i.e., below the lower limit of the reference range, which is 150,000-400,000/μL. The phenomenon of thrombocytopenia related to heavy drinking began to arouse interest in the 1960s and 1970s. It was initially described in case reports and clinical studies on small groups. In the following years, the phenomenon itself and the significance of alcohol-induced thrombocytopenia was studied. Many methodological difficulties inhibiting objective conclusions from research were encountered. Model pathological mechanisms of alcohol thrombocytopenia and the effects of alcohol on the structure and function of platelets were described. Furthermore, the phenomenon of rapid normalization of the number of platelets in people who stopped drinking was described. Relationships between alcohol use, its intensity and occurrence, and intensity of thrombocytopenia have been demonstrated. Predictive platelet counts for alcohol withdrawal syndrome complications have been proven and calculated. The risk of occurrence of withdrawal seizures or delirium tremens in alcohol withdrawal syndrome increases significantly when the platelet count is less than 119,000/μL. The knowledge of the nature of the phenomenon of alcohol-induced thrombocytopenia in a clinical environment allows decisions that are more rational. The attention of clinicians should be drawn to the importance of results of blood tests routinely collected on admission.

Can mouse models mimic sporadic Alzheimer's disease?

Alzheimer's disease (AD) is a progressive neurodegenerative disorder and the most common form of dementia worldwide. As age is the main risk factor, > 97% of all AD cases are of sporadic origin, potentiated by various risk factors associated with life style and starting at an age > 60 years. Only < 3% of AD cases are of genetic origin caused by mutations in the amyloid precursor protein or Presenilins 1 or 2, and symptoms already start at an age < 30 years. In order to study progression of AD, as well as therapeutic strategies, mouse models are state-of-the-art. So far many transgenic mouse models have been developed and used, with mutations in the APP or presenilin or combinations (3×Tg, 5×Tg). However, such transgenic mouse models more likely mimic the genetic form of AD and no information can be given how sporadic forms develop. Several risk genes, such as Apolipoprotein E4 and TREM-2 enhance the risk of sporadic AD, but also many risk factors associated with life style (e.g., diabetes, hypercholesterolemia, stress) may play a role. In this review we discuss the current situation regarding AD mouse models, and the problems to develop a sporadic mouse model of AD.

Experimental alcoholism primes structural and functional impairment of the glymphatic pathway

Alcoholism is a risk factor for the development of cognitive decline and dementia. Here we demonstrated that the glymphatic function in the brain was impaired by alcohol administration. Acute moderate alcohol administration substantially retarded and reduced the entry of subarachnoid cerebrospinal fluid (CSF) via the paravascular space into the cerebral parenchyma, thus impaired CSF-interstitial fluid (ISF) exchange and parenchymal amyloid β (Aβ) peptide clearance. The elevated release of β-endorphin and reduced cerebrovascular pulsatility after acute alcohol administration may account for the impairment of the glymphatic function. Chronic moderate alcohol consumption led to pronounced activation of astrocytes and a widespread loss of perivascular AQP4 polarization in the brain, which results in an irreversible impairment of the glymphatic function. The results of the study suggest that impaired glymphatic functions and reduced parenchymal Aβ clearance found in both acute and chronic alcohol treatment may contribute to the development of cognitive decline and dementia in alcoholism.

Blossoming contusions: identifying factors contributing to the expansion of traumatic intracerebral hemorrhage

Here, the authors examined the factors involved in the volumetric progression of traumatic brain contusions. The variables significant in this progression are identified, and the expansion rate of a brain bleed can now effectively be predicted given the presenting characteristics of the patient.

Wine and beer within a moderate alcohol intake is associated with higher levels of HDL-c and adiponectin

The scientific evidence available on the association between moderate alcohol intake and levels of blood cardiometabolic markers is still inconsistent and difficult to interpret for future disease prevention. However, we hypothesize that moderate consumption of alcohol is associated with lower levels of inflammation markers and higher levels of protective cardiometabolic markers. Thus, this work aimed to examine the associations of moderate alcohol intake and the type of alcoholic beverage with metabolic and inflammatory biomarkers. An observational, cross-sectional study including 143 apparently healthy adults 55 years of age and older was performed. Interviewer-administered questionnaires were used to collect information on alcoholic beverage intake frequency, food frequency, physical activity, socioeconomic status, diseases and medications, and other health-related habits. Three groups were established prior to recruitment: (1) abstainers and occasional consumers (ABS, n = 54); (2) beer consumers (BEER ≥80% of total alcohol intake; n = 40), and (3) mixed beverage consumers (MIXED; n = 49). Univariate analysis of variance models, adjusted for confounding factors and covariables, were performed. High-density lipoprotein cholesterol (HDL-c) and sP-selectin were significantly higher in the MIXED group than in the ABS group, and adiponectin was higher in the MIXED group compared to the BEER group. All alcohol consumers also had higher mean platelet volume values compared to ABS. In linear regression analyses, HDL-c, sP-selectin, and adiponectin were positively associated with wine intake (g/d) (P < .001, P = .014, and P = .017, respectively); and mean platelet volume, with beer intake (P = .017). In conclusion, this cross-sectional study showed that moderate alcohol intake is associated with higher levels of HDL-c and adiponectin compared to those in abstainers, which are mainly explained by wine intake.

Factors associated with the progression of conservatively managed acute traumatic subdural hemorrhage

PURPOSE

Traumatic subdural hemorrhage (SDH) is associated with high mortality, yet many patients are not managed surgically. We sought to understand what factors might be associated with SDH enlargement to contribute to the triage of these conservatively managed patients.

MATERIALS AND METHODS

A consecutive series of 117 patients admitted to our institution's level 1 trauma center for SDH between January 1, 2010 and December 31, 2010 were evaluated. Volumetric measurement of SDHs was performed on initial and follow-up head computed tomography (CT) scans with recording of initial midline shift and classification by location. Multimodel analysis quantified associations with change in SDH volume.

RESULTS

Systolic blood pressure, presence of subarachnoid hemorrhage, and initial SDH volume demonstrated positive associations with change in SDH volume, while initial midline shift and transfusion of platelets demonstrated negative associations. Initial convexity SDH volume demonstrated positive association with change in convexity SDH volume, while initial midline shift and transfusion of platelets demonstrated negative associations. Anticoagulant/antiplatelet use demonstrated positive association with change in tentorial SDH volume, while time between CT scans demonstrated negative association.

CONCLUSIONS

Platelet transfusion, anticoagulation, and hypertension have significant associations with expansion in non-surgical cases of SDH. Monitoring these factors may assist triaging these patients.

Anticoagulant properties of enoxaparin 400 IU/mL-40 % ethanol catheter lock solution

Unfractionated heparin (UFH) is the most widely used interdialytic lock solution but has no anti-infectious properties. Ethanol at a content ≥40 %v/v eradicates experimental biofilm but has no anticoagulant properties. In contrast to UFH, enoxaparin (Enox) can be combined with 40 % ethanol without precipitation. Enoxaparin 400 UI/mL–40 % ethanol (Enox/Eth) has antibiofilm properties and therefore has promise as an alternative lock solution. This study assessed the anticoagulant properties of Enox/Eth. Enox and Enox/Eth were diluted in whole blood at a final Enox concentration of 0.5, 1 (N = 6 samples), 1.5 (N = 4) and 2 (N = 6) IU/mL. Anti-Xa activity was determined by chromogenic assay and the inhibition of endogenous thrombin potential (ETP) by thrombinography. Quantitative data were compared by the Mann-Withney U test. For Enox concentrations of 0.5, 1, 1.5 and 2 UI/mL in whole blood samples, the mean ± SD values of the anti-Xa activity were 0.68 ± 0.09, 1.26 ± 0.14, 1.73 ± 0.30, 2.35 ± 0.32 UI/mL for Enox/Eth and 0.94 ± 0.15, 1.80 ± 0.22, 2.74 ± 0.23, 3.54 ± 0.44 UI/mL for Enox (P = 0.03, P = 0.03, P = 0.13, P = 0.03); and of the percentage of ETP inhibition was 17.36 ± 9.65, 30.27 ± 17.06, 36.5 ± 17.06, 57.82 ± 15.42 for Enox/Eth, and 42.96 ± 15.68, 68.93 ± 10.01, 83.5 ± 8.81, 91.19 ± 4.67 for Enox (P = 0.03, P = 0.03, P = 0.13, P = 0.03), respectively. The median and IQR values of Enox concentration inhibiting 50 % of ETP (IC50 ETP) were 1.8 [1.1–2.4] IU/mL for Enox/Eth and 0.7 [0.3–0.9] IU/mL for Enox, P = 0.03. Enox/Eth has strong anticoagulant activity, albeit lower than that of Enox, but with an extremely low IC50 ETP compared to the Enox concentration of non-diluted Enox/Eth.

Differential changes in platelet reactivity induced by acute physical compared to persistent mental stress

Platelets are important in hemostasis, but also contain adhesion molecules, pro-inflammatory and immune-modulatory compounds, as well as most of the serotonin outside the central nervous system. Dysbalance in the serotonin pathways is involved in the pathogenesis of depressive symptoms. Thus, changes in platelet aggregation and content of bioactive compounds are of interest when investigating physiological stress-related mental processes as well as stress-related psychiatric diseases such as depression. In the present study, a characterization of platelet reactivity in acute physical and persistent mental stress was performed (aggregation, serotonin and serotonin 2A-receptor, P-selectin, CD40 ligand, matrix metalloproteinase-2 and -9 (MMP-2 and -9), platelet/endothelial adhesion molecule-1 (PECAM-1), intercellular adhesion molecule-1 (ICAM-1), β-thromboglobulin (β-TG) and platelet factor 4 (PF-4). Acute physical stress increased platelet aggregability while leaving platelet content of bioactive compounds unchanged. Persistent mental stress led to changes in platelet content of bioactive compounds and serotonin 2A-receptor only. The values of most bioactive compounds correlated with each other. Acute physical and persistent mental stress influences platelets through distinct pathways, leading to differential changes in aggregability and content of bioactive compounds.

Sleep Deprivation-Induced Blood-Brain Barrier Breakdown and Brain Dysfunction are Exacerbated by Size-Related Exposure to Ag and Cu Nanoparticles. Neuroprotective Effects of a 5-HT3 Receptor Antagonist Ondansetron

Military personnel are often subjected to sleep deprivation (SD) during combat operations. Since SD is a severe stress and alters neurochemical metabolism in the brain, a possibility exists that acute or long-term SD will influence blood-brain barrier (BBB) function and brain pathology. This hypothesis was examined in young adult rats (age 12 to 14 weeks) using an inverted flowerpot model. Rats were placed over an inverted flowerpot platform (6.5 cm diameter) in a water pool where the water levels are just 3 cm below the surface. In this model, animals can go to sleep for brief periods but cannot achieve deep sleep as they would fall into water and thus experience sleep interruption. These animals showed leakage of Evans blue in the cerebellum, hippocampus, caudate nucleus, parietal, temporal, occipital, cingulate cerebral cortices, and brain stem. The ventricular walls of the lateral and fourth ventricles were also stained blue, indicating disruption of the BBB and the blood-cerebrospinal fluid barrier (BCSFB). Breakdown of the BBB or the BCSFB fluid barrier was progressive in nature from 12 to 48 h but no apparent differences in BBB leakage were seen between 48 and 72 h of SD. Interestingly, rats treated with metal nanoparticles, e.g., Cu or Ag, showed profound exacerbation of BBB disruption by 1.5- to 4-fold, depending on the duration of SD. Measurement of plasma and brain serotonin showed a close correlation between BBB disruption and the amine level. Repeated treatment with the serotonin 5-HT3 receptor antagonist ondansetron (1 mg/kg, s.c.) 4 and 8 h after SD markedly reduced BBB disruption and brain pathology after 12 to 24 h SD but not following 48 or 72 h after SD. However, TiO2-nanowired ondansetron (1 mg/kg, s.c) in an identical manner induced neuroprotection in rats following 48 or 72 h SD. However, plasma and serotonin levels were not affected by ondansetron treatment. Taken together, our observations are the first to show that (i) SD could induce BBB disruption and brain pathology, (ii) nanoparticles exacerbate SD-induced brain damage, and (iii) serotonin 5-HT3 receptor antagonist ondansetron is neuroprotective in SD that is further potentiated byTiO2-nanowired delivery, not reported earlier.

Bioprofiling of platelets in medicated patients with depression

BACKGROUND

Changes in platelet bioactivity and aggregation are of interest when studying patients with depression as this could help to explain the statistically observed association of depression and chronic somatic, especially cardiovascular disease. This link could potentially be mediated through serotonergic signaling or immunological changes.

METHODS

38 medicated patients with major depressive disorder (MDD) and 30 mentally healthy controls, both without a diagnosis of cardiovascular disease, were included in this naturalistic study. Demographic and psychometric data were obtained. Platelet aggregability was measured by PFA-100 and bioactive compounds and serotonin levels were quantified in platelet sonicate.

RESULTS

The comparison of patients with controls revealed no changes in platelet aggregability, but significant differences in platelet content of several bioactive compounds. In a second analysis, patients were grouped according to the receptors and transporters influenced by their medication and again compared to controls. A significant effect of MDD was found for platelet content of serotonin, CD40L, interleukin-1β, and platelet factor-4, independent of medication. These markers can thus be classified as sensitive to MDD. The effect of medication on platelet parameters was also evaluated. Platelet content of matrix metalloproteinase-2 and β-thromboglobulin was normalized in MDD patients by medication acting on the serotonin transporter.

LIMITATIONS

Owing to the naturalistic study design, patients were on a variety of different medications and combination therapies. This was accounted for by a novel analysis method.

CONCLUSION

Platelet serotonin levels and content of immunomodulatory compounds are significantly altered in patients with MDD, even if treatment effects are taken into account.

CD36- and GPR120-mediated Ca²⁺ signaling in human taste bud cells mediates differential responses to fatty acids and is altered in obese mice

BACKGROUND & AIMS

It is important to increase our understanding of gustatory detection of dietary fat and its contribution to fat preference. We studied the roles of the fat taste receptors CD36 and GPR120 and their interactions via Ca(2+) signaling in fungiform taste bud cells (TBC).

METHODS

We measured Ca(2+) signaling in human TBC, transfected with small interfering RNAs against messenger RNAs encoding CD36 and GPR120 (or control small interfering RNAs). We also studied Ca(2+) signaling in TBC from CD36(-/-) mice and from wild-type lean and obese mice. Additional studies were conducted with mouse enteroendocrine cell line STC-1 that express GPR120 and stably transfected with human CD36. We measured release of serotonin and glucagon-like peptide-1 from human and mice TBC in response to CD36 and GPR120 activation.

RESULTS

High concentrations of linoleic acid induced Ca(2+) signaling via CD36 and GPR120 in human and mice TBC, as well as in STC-1 cells, and low concentrations induced Ca(2+) signaling via only CD36. Incubation of human and mice fungiform TBC with lineoleic acid down-regulated CD36 and up-regulated GPR120 in membrane lipid rafts. Obese mice had decreased spontaneous preference for fat. Fungiform TBC from obese mice had reduced Ca(2+) and serotonin responses, but increased release of glucagon-like peptide-1, along with reduced levels of CD36 and increased levels of GPR120 in lipid rafts.

CONCLUSIONS

CD36 and GPR120 have nonoverlapping roles in TBC signaling during orogustatory perception of dietary lipids; these are differentially regulated by obesity.