Platelet count and aging

Resolution of Deep Venous Thrombosis: Proposed Immune Paradigms

Venous thromboembolism (VTE) is a pathology encompassing deep vein thrombosis (DVT) and pulmonary embolism (PE) associated with high morbidity and mortality. Because patients often present after a thrombus has already formed, the mechanisms that drive DVT resolution are being investigated in search of treatment. Herein, we review the current literature, including the molecular mechanisms of fibrinolysis and collagenolysis, as well as the critical cellular roles of macrophages, neutrophils, and endothelial cells. We propose two general models for the operation of the immune system in the context of venous thrombosis. In early thrombus resolution, neutrophil influx stabilizes the tissue through NETosis. Meanwhile, macrophages and intact neutrophils recognize the extracellular DNA by the TLR9 receptor and induce fibrosis, a complimentary stabilization method. At later stages of resolution, pro-inflammatory macrophages police the thrombus for pathogens, a role supported by both T-cells and mast cells. Once they verify sterility, these macrophages transform into their pro-resolving phenotype. Endothelial cells both coat the stabilized thrombus, a necessary early step, and can undergo an endothelial-mesenchymal transition, which impedes DVT resolution. Several of these interactions hold promise for future therapy.

Comparison of Age (<75 Years Vs ≥75 Years) and Platelet Reactivity to the Risk of Thrombotic and Bleeding Events After Successful Percutaneous Coronary Intervention With Drug-Eluting Stents (from the ADAPT-DES Study)

Elderly patients may have increased platelet reactivity and adverse events after percutaneous coronary intervention. Whether age is an independent predictor of worse outcomes after accounting for platelet reactivity is unknown. We sought to determine the relation between age and platelet reactivity on 2-year outcomes after percutaneous coronary intervention with drug-eluting stents (DES). ADAPT-DES was a prospective observational registry comprising 8,582 DES-treated patients. Patients were categorized with an age cutoff of 75 years. On-clopidogrel platelet reactivity was evaluated with VerifyNow P2Y12 testing. Multivariable Cox proportional hazards regression models were used to describe the relation between increasing age and 2-year clinical outcomes. Patients ≥75 old were more likely to be women and had more cardiovascular risk factors and more extensive coronary artery disease than younger patients. Residual platelet reactivity on-clopidogrel increased slightly with age (adjusted r = 0.05, p <0.0001). Age ≥75 years was associated with greater all-cause mortality (adjusted HR 1.64, 95% CI 1.25 to 2.15, p <0.001), myocardial infarction (adjusted HR 1.33, 95% CI 1.01 to 1.74, p = 0.04) and clinically relevant bleeding (adjusted HR 1.33, 95% CI 1.10 to 1.61 p = 0.003). In contrast, the risk of stent thrombosis was independent of age (adjusted HR 0.83, 95% CI 0.46 to 1.52, and p = 0.55). Considered as a continuous variable, age was directly related to clinically relevant bleeding, cardiac and all-cause mortality, was inversely related to stent thrombosis, and was not related to myocardial infarction. There was no significant interaction between age and on-treatment platelet reactivity for the risk of 2-year clinical outcomes. In conclusion, increasing age had a stronger association with the risk of death and bleeding than of thrombotic events. Despite being associated with older age, higher residual platelet reactivity did not modify the adjusted relative risks of ischemic and bleeding events associated with age.

Personalized Indicator Thrombocytosis Shows Connection to Staging and Indicates Shorter Survival in Colorectal Cancer Patients with or without Type 2 Diabetes

BACKGROUND

Pre- and postoperative thrombocytosis was reported to have significant effect on patient survival. However, the definition of thrombocytosis throughout the literature is not unified.

METHODS

A retrospective longitudinal observational study has been conducted with the inclusion of 150 colorectal cancer (CRC) patients and 100 control subjects. A new measure of platelet changes at an individual level, named personalized indicator thrombocytosis (PIT) was defined, including 4 anemia adjusted variants.

RESULTS

In concordance with the literature, PIT values of control subjects showed a slow decrease in platelet counts, while PIT values of CRC patients were significantly higher (p < 0.0001). More advanced staging (p < 0.0001) and both local (p ≤ 0.0094) and distant (p ≤ 0.0440) metastasis are associated with higher PIT values. Higher PIT values suggested shorter survival times (p < 0.0001). Compared to conventional, a PIT-based definition resulted in approximately 3-times more patients with thrombocytosis. 28% and 77% of the deceased patients had conventional- and PIT-based thrombocytosis, respectively.

CONCLUSIONS

Compared to conventional thrombocytosis, as an individual metric, PIT values may indicate the condition of patients more precisely. Possible future applications of PIT may include its usage in therapy decision and early cancer detection; therefore, further investigations are recommended.

White Matter Hyperintensities and Blood Pressure Lowering in Acute Intracerebral Hemorrhage: A Secondary Analysis of the ATACH-2 Trial

BACKGROUND

It is not clear whether subsets of patients with intracerebral hemorrhage (ICH) benefit from intensive blood pressure (BP) lowering. We evaluated whether white matter hyperintensities (WMH) burden influences response to this therapy.

METHODS

Retrospective secondary analysis of the Antihypertensive Treatment of Acute Cerebral Hemorrhage 2 trial. Patients were randomized to intensive (systolic BP target: 110-139 mmHg) versus standard (systolic BP target: 140-179 mmHg) BP treatment with intravenous nicardipine within 4.5 h from onset between May 2011 and September 2015. WMH were rated on magnetic resonance images (fluid-attenuated inversion recovery sequences), defining moderate-severe WMH as total Fazekas scale score ≥ 3 (range 0-6). The main outcome was death or major disability at 90 days (modified Rankin scale ≥ 3). The secondary outcome was ICH expansion, defined as hematoma growth > 33% from baseline to follow-up CT scan. Predictors of the outcomes of interest were explored with multivariable logistic regression.

RESULTS

A total of 195/1000 patients had MRI images available for analysis, of whom 161 (82.6%) had moderate-severe WMH. When compared to patients with none-mild WMH, those with moderate-severe WMH did not have an increased risk of death or major disability (adjusted relative risk: 1.83, 95% CI 0.71-4.69) or ICH expansion (adjusted relative risk: 1.14, 95% CI 0.38-3.37). WMH burden did not modify the effect of intensive BP treatment on outcome (all p for interaction ≥ 0.2).

CONCLUSION

The majority of acute ICH patients have moderate-severe WMH, but advanced small vessel disease burden marked by WMH does not influence ICH-related outcomes or response to intensive BP reduction.

The association between platelet indices, cognitive screening tests and functional dependence screening questionnaires in hospitalized older people

PURPOSE

Activated platelets have been suggested to play an important role in the pathogenesis of dementia. Recent studies have shown contradictory results concerning the relationship between blood platelet indices and cognitive performance.

METHODS

This cross-sectional study evaluates the relationship between basic platelet indices and cognitive and functional performance of 754 men and women, aged 60-105 years old, admitted to the geriatric hospital unit. Assessment of global cognitive function and functional ability were performed using Mini-Mental State Examination, the seven-point Clock Drawing Test, the Katz Activities of Daily Living, the Lawton Instrumental Activities of Daily Living Scale and the Vulnerable Elders Survey Questionnaire. As platelet indices, platelet count, mean platelet volume, plateletcrit and platelet distribution width were measured.

RESULTS

There was no significant correlation between cognitive performance and platelet indices. Out of the functional dependence questionnaires, only the Katz Activities of Daily Living and the Vulnerable Elders Survey Questionnaire were weakly correlated with platelet count (r = - 0.080 and r = 0.096) and plateletcrit (r = - 0.075 and 0.082, respectively), but these associations diminished in sex-specific analyses.

CONCLUSIONS

Cognitive and functional status are not systematically related to platelet indices in multimorbid hospitalized older adults.

In-Hospital Outcomes After Transcatheter Aortic Valve Implantation in Patients With Versus Without Chronic Thrombocytopenia

Patients with chronic thrombocytopenia (cTCP) were excluded from the pivotal transcatheter aortic valve implantation (TAVI) trials. The National Inpatient Sample was queried and propensity score matching was performed to evaluate the prevalence and impact of cTCP on in-hospital clinical outcomes after TAVI. The main outcome was in-hospital mortality in patients with versus without cTCP. Among 38,855 TAVI hospitalizations, 7,105 had a diagnosis of cTCP (18.3%). In-hospital mortality was similar in both groups (ORadjusted 0.79; 95% confidence interval [CI] 0.57 to 1.09); however, cTCP was associated with higher risk of acute kidney injury (ORadjusted 1.29; 95% CI 1.08 to 1.54), vascular complications (ORadjusted 1.99; 95% CI 1.22 to 3.25), perioperative blood product transfusion (ORadjusted 1.69; 95% CI 1.42 to 2.01), cardiac tamponade (ORadjusted 4.04; 95% CI 1.51 to 10.82), cardiogenic shock (ORadjusted 1.52; 95% CI 1.07 to 2.15), and use of extracorporeal membrane oxygenation (ORadjusted 2.32; 95% CI 1.1 to 4.9). In conclusion, cTCP is common in patients who underwent TAVI and is associated with worse postprocedure clinical outcomes, however, with similar in-hospital mortality.

Platelet-generated amyloid beta peptides in Alzheimer's disease and glaucoma

Amyloid beta (Aβ) peptides have been implicated in both Alzheimer's disease (AD) and glaucoma and have been shown to be the key etiological factor in these dangerous health complications. On the other hand, it is well known that Aβ peptide can be generated from its precursor protein and massively released from the blood to nearby tissue upon the activation of platelets due to their involvement in innate immunity and inflammation processes. Here we review evidence about the development of AD and glaucoma neuronal damage showing their dependence on platelet count and activation. The correlation between the effect on platelet count and the effectiveness of anti-AD and anti-glaucoma therapies suggest that platelets may be an important player in these diseases.

A new indirect estimation of reference intervals: truncated minimum chi-square (TMC) approach

All known direct and indirect approaches for the estimation of reference intervals (RIs) have difficulties in processing very skewed data with a high percentage of values at or below the detection limit. A new model for the indirect estimation of RIs is proposed, which can be applied even to extremely skewed data distributions with a relatively high percentage of data at or below the detection limit. Furthermore, it fits better to some simulated data files than other indirect methods. The approach starts with a quantile-quantile plot providing preliminary estimates for the parameters (λ, μ, σ) of the assumed power normal distribution. These are iteratively refined by a truncated minimum chi-square (TMC) estimation. The finally estimated parameters are used to calculate the 95% reference interval. Confidence intervals for the interval limits are calculated by the asymptotic formula for quantiles, and tolerance limits are determined via bootstrapping. If age intervals are given, the procedure is applied per age interval and a spline function describes the age dependency of the reference limits by a continuous function. The approach can be performed in the statistical package R and on the Excel platform.

Haematologic toxicity in dogs with mast cell tumours treated with vinblastine/prednisolone chemotherapy with/without radiotherapy

OBJECTIVES

To determine whether dogs with surgically excised mast cell tumours receiving a vinblastine/prednisolone chemotherapy protocol in combination with radiation therapy are at greater risk of myelosuppression than patients receiving the chemotherapy protocol alone.

MATERIALS AND METHODS

Retrospective study of clinical records of dogs with mast cell tumours that, subsequent to surgical excision, had received combination vinblasine/prednisolone chemotherapy. Dogs were assigned to two groups: those treated with adjunctive radiotherapy and vinblastine/prednisolone (RT group) and those treated with surgery followed by vinblastine/prednisolone alone (control group). Haematology results were compared between groups.

RESULTS

Forty-three cases and 43 controls of similar breed, age and bodyweight were included. Concurrent radiation and vinblastine chemotherapy did not appear to increase the risk of neutropenia, which was observed in 18.6 and 23.2% of cases in the RT and control groups, respectively.

CLINICAL SIGNIFICANCE

Radiation and vinblastine chemotherapy can be safely combined in dogs with mast cell tumours without increasing the risk of clinically important myelosuppression.

Age associated non-linear regulation of redox homeostasis in the anucleate platelet: Implications for CVD risk patients

Background

Aging is a complex physiological phenomenon, intricately associated with cardiovascular pathologies, where platelets play a central pathophysiological role. Although antiplatelets are commonly employed to prevent and treat major adverse cardiovascular events, aging associated intraplatelet changes remain largely unexplored.

Methods

Platelets were studied in high cardiovascular risk patients (aged 40–100 years) comparing them to younger healthy subjects. This was followed by cross sectional and longitudinal mice studies. Flow cytometry, biochemical and molecular assays were used to study platelets comprehensively.

Findings

CVD Patients were categorized in the age groups 40–59, 60–79, and 80–100 years. Progressive decline in platelet health was observed in the 40–79 years age cohort, marked by increase in oxidative stress, hyperactivation and apoptotic markers. Paradoxically, this was reversed in patients aged above 79 years and the improved platelet phenotype was associated with lower oxidative damage. The platelets from the very old (80–100 year) group were found to be preloaded with increased antioxidants, which also contributed to higher resistance against induced redox insults. Cross sectional mouse studies excluded the effect of comorbidities and medications. Longitudinal mouse studies implicate an adaptive increase in antioxidant levels as the mechanism.

Interpretation

We report a novel age associated, non-linear redox regulation in platelets in both humans and mice. In advanced age, there occurs an adaptive increase in platelet antioxidants, reducing the intracellular ROS and leading to a healthier platelet phenotype. Clinically, our results advocate the use of less aggressive antiplatelet therapies for CVD in the elderly population.

Fund

Study funded by NIH-NHLBI, RO1-HL122815 and RO1-HL115247.

Deficiency of Bmal1 disrupts the diurnal rhythm of haemostasis

BACKGROUND

Mice deficient in the circadian clock gene BMAL1 (Brain and Muscle ARNT-like protein-1) exhibit a hypercoagulable state and an enhanced arterial and venous thrombogenicity, which aggravates with age. We investigated the effect of BMAL1 deficiency in mice at a different age on the diurnal rhythm of factors involved in coagulation and fibrinolysis.

MATERIALS AND METHODS

Hepatic, cardiac and brain tissues were isolated from 10- and 25-weeks-old Bmal1-deficient (BMAL1-/-) and wild-type (BMAL1+/+) mice at ZT2 and at ZT14 to analyze the mRNA expression level of genes involved in coagulation and fibrinolysis.

RESULTS

Body weight and brain weight were significantly lower in all BMAL1-/- versus BMAL1+/+ mice. Bmal1 deficiency disturbed the diurnal rhythm of plasminogen activator inhibitor-1 (PAI-1) in liver and plasma, but not in cardiac or brain tissues. BMAL1+/+ livers showed diurnal fluctuations in factor (F)VII, FVII, protein S and anti-thrombin gene expression, which were not observed in BMAL1-/- tissues. Interestingly, tissue plasminogen activator (t-PA) expression was significantly upregulated in all BMAL1-/- versus BMAL1+/+ brains at both time points. Plasma t-PA-PAI-1 complex levels were however similar for all groups.

CONCLUSION

Bmal1 deficiency affected the biphasic rhythm of coagulation and fibrinolysis factors predominantly in the liver. In the brain, Bmal1-dependent control of t-PA gene expression was documented for the first time.

Mean platelet volume is more important than age for defining reference intervals of platelet counts

Background

Platelet count is known to be associated with sex, age and mean platelet volume (MPV). Sex and age were proposed for adjustment of platelet count reference intervals, but MPV is currently not used for further adjustment. We investigated the association of MPV, age and sex with platelet counts and established individualized reference ranges respecting MPV.

Methods

The association of platelet count with age, sex and MPV was assessed in healthy participants (n = 3,033 individuals; 1,542 women) in the cross-sectional population-based cohort Study of Health in Pomerania. Reference intervals respecting age, sex, and MPV were estimated using quantile regressions for the 2.5^th and 97.5^th percentile.

Results

Women had higher platelet counts than men (239 vs. 207 x10⁹/L, p<0.001). Platelet counts correlated with age (p<0.001) and MPV (p<0.001). Quantile regression of lower and upper platelet count limits correlated less with age in female (p = 0.047 for 2.5^th percentile; p = 0.906 for 97.5^th percentile) and male subjects (p = 0.029 for 2.5^th percentile; p = 0.195 for 97.5^th percentile) compared to MPV (p<0.001 for upper and lower limit for both sexes). After adjustment for MPV, age did no longer correlate with the 2.5^th (p = 0.165) or 97.5^th percentile (p = 0.999) of platelet count. In contrast, after adjustment for age, MPV levels still significantly correlated with 2.5^th, 50^th and 97.5^th percentile (p<0.001).

Conclusion

MPV and sex have a stronger association with platelet count than age. MPV should be considered to adjust platelet count reference intervals and needs to be respected as confounder for platelet counts in epidemiological studies and clinical practice.

Incremental Prognostic Value of Platelet Count in Patients With Acute Heart Failure - A Retrospective Observational Study

BACKGROUND

Acute heart failure (AHF) triggers platelet aggregation and platelet markers are associated with the severity of AHF. The present study aimed to investigate the prognostic value of platelet count (PLT) in patients with AHF.

METHODS AND RESULTS

This single-center retrospective observational study analyzed 425 consecutive patients with AHF. The patients were divided into groups based on tertiles of PLT: low (PLT1 <170,000/μL), intermediate (170,000/μL≤PLT<230,000/μL), and high (PLT3 ≥230,000/μL). The endpoint was all-cause death with a composite endpoint of all-cause death and HF rehospitalization. Survival analysis was performed, and Cox proportional hazard models adjusted by an established risk score (Get With The Guidelines score) were generated. The PLT1 group had the worst survival for all-cause death (log-rank, P=0.003) and the composite endpoint (P=0.009). A significant trend of increasing survival was observed for all-cause death (log-rank trend, P<0.001) and the composite endpoint (P=0.002) in the following order: PLT1, PLT2, and PLT3. Adjusted Cox proportional hazard models demonstrated that low PLT was a risk factor of all-cause death and the composite endpoint.

CONCLUSIONS

Low PLT was associated with risk for all-cause death and HF rehospitalization in patients with AHF.

Prevalence of Low Platelet Count and Identification of Associating Determinants and Genetic Polymorphism in Healthy Individuals of Upper Assam, India

The purpose of the study was to assess the prevalence of low platelet count among the healthy population of upper Assam, India. The impact of socio-demographic features was moreover pointed to evaluate. Additionally, Mean platelet volume (MPV) and Interleukin-6 gene polymorphism (-174 G > C) were also determined to speculate their effect on the basal platelet count. For determination of hematological indices, CBC was done and genetic polymorphism was identified by ARMS-PCR technique. Out of 510 study subjects, 25.3% (n = 129) had low platelet count, and females were recorded with significantly higher mean platelet count as compared to their male counterpart (p < 0.001). A progressive decline in platelet count was observed with ageing and more significantly noticed in females across the various age groups (p < 0.001). The mean MPV was significantly higher in low platelet count group as compared to the normal group (p < 0.001). Both platelet count and MPV differed significantly among the individuals with varied ethnicity. An inverse correlation between platelet count and its volume was reported, and such observation was continued to persist in every age-group under the study. However, no significant differences were observed for other hematological indices between the studied groups except for platelet indices and RBC count. Moreover, the peripheral blood smear examined for cellular morphology and in vitro platelet clumping did not report any significant aberrancy. No significant penetrance of the risk allele was revealed in the studied groups. However, ARMS-PCR confirmed 6% (n = 8/129) of the low platelet count subjects with heterozygous for G allele. This happens to be the first description of low platelet count among the healthy population of upper Assam, where age, gender, ethnicity, and MPV are significantly associated with platelet count variation. Heterozygosity of the risk allele does not contribute to the low platelet count condition.

The regulatory role of curcumin on platelet functions

Curcumin, the main ingredient of Curcuma longa L., has been used as a spice and as a herbal medicine with different therapeutic characteristics for centuries in Asian countries. This phytochemical has been shown to possess beneficial antiplatelet activity that has introduced it as a promising candidate for the treatment of thromboembolism, atherothrombosis, and inflammatory diseases. Platelet dysfunction under different circumstances may lead to cardiovascular disease, and curcumin has been shown to have beneficial effects on platelet dysfunction in several studies. Therefore, this narrative review is aimed to summarize available evidence on the antiplatelet activity of curcumin and related molecular mechanisms for this activity.

Laboratory blood test results beyond normal ranges could not be attributed to healthy aging

Aging is related to a decline in the function of many organs. The results of blood tests are essential for clinical management and could change over a lifespan reflecting aging. The aim of this study was to examine serum levels of liver, kidney, and bone marrow function and to study their dynamics as a function of age and sex.The cross-sectional study conducted in Poland included 180 healthy individuals (20-90 years) divided into subgroups by sex and decade. These included subgroups of ≥65 or <65 years (men and women). We investigated serum levels of creatinine, estimated glomerular filtration rate, estimated effective renal blood/plasma flow, urine pH, urine neutrophil gelatinase-associated lipocalin (NGAL) as well as serum levels of transaminases, bilirubin, total cholesterol (TC), international normalized ratio (INR), and blood morphology.All parameters were within normal range in all groups. Urine NGAL was higher in men aged ≥65 years than women (25.67 ± 53.65 vs 16.49 ± 34.66, P = .001); serum levels of TC and platelet (PLT) count were higher in women than men aged ≥65 years (221.0 ± 41.7 vs 188.4 ± 48.2 and 250.3 ± 47.8 vs 202.5 ± 57.9, P = .003 and P = .038, respectively). The INR was lower in women (0.97 ± .06 vs 1.19 ± 0.48, P = .03).These blood tests were normal in healthy people aged ≥65 years. Higher PLT and TC and lower INR in women might indicate a higher risk of cardiovascular diseases. These changes in blood tests were not attributed to aging itself.

Biological variables influencing the estimation of reference limits

Reference limits (RLs) are required to evaluate laboratory results for medical decisions. The establishment of RL depends on the pre-analytical and the analytical conditions. Furthermore, biological characteristics of the sub-population chosen to provide the reference samples may influence the RL. The most important biological preconditions are gender, age, chronobiological influences, posture, regional and ethnic effects. The influence of these components varies and is often neglected. Therefore, a list of biological variables is collected from the literature and their influence on the estimation of RL is discussed. Biological preconditions must be specified if RL are reported as well for directly as for indirectly estimated RL. The influence of biological variables is especially important if RL established by direct methods are compared with those derived from indirect techniques. Even if these factors are not incorporated into the estimation of RL, their understanding can assist the interpretation of laboratory results of an individual.

High Sensitivity of T-Ray for Thrombus Sensing

Atherosclerotic plaque rupture or erosion and subsequent development of platelet-containing thrombus formation is the fundamental cause of cardiovascular disease, which is the most common cause of death and disability worldwide. Here we show the high sensitivity of 200-270 GHz T-ray to distinguish thrombus formation at its early stage from uncoagulated blood. A clinical observational study was conducted to longitudinally monitor the T-ray absorption constant of ex-vivo human blood during the thrombus formation from 29 subjects. Compared with the control group (28 subjects) with uncoagulated blood samples, our analysis indicates the high sensitivity of 200-270 GHz T-Ray to detect thrombus with a low p-value < 10-5. Further analysis supports the significant role of platelet-activated thrombotic cascade, which modified the solvation dynamics of blood and occurred during the early coagulation stage, on the measured T-Ray absorption change. The ability to sense the thrombus formation at its early stage would hold promise for timely identification of patients at risk of various atherothrombotic disorders and save billions of lives.

Appropriateness of antiplatelet therapy for primary and secondary cardio- and cerebrovascular prevention in acutely hospitalized older people

AIMS

Antiplatelet therapy is recommended for the secondary prevention of cardio- and cerebrovascular disease, but for primary prevention it is advised only in patients at very high risk. With this background, this study aims to assess the appropriateness of antiplatelet therapy in acutely hospitalized older people according to their risk profile.

METHODS

Data were obtained from the REPOSI register held in Italian and Spanish internal medicine and geriatric wards in 2012 and 2014. Hospitalized patients aged ≥65 assessable at discharge were selected. Appropriateness of the antiplatelet therapy was evaluated according to their primary or secondary cardiovascular prevention profiles.

RESULTS

Of 2535 enrolled patients, 2199 were assessable at discharge. Overall 959 (43.6%, 95% CI 41.5-45.7) were prescribed an antiplatelet drug, aspirin being the most frequently chosen. Among patients prescribed for primary prevention, just over half were inappropriately prescribed (52.1%), being mainly overprescribed (155/209 patients, 74.2%). On the other hand, there was also a high rate of inappropriate underprescription in the context of secondary prevention (222/726 patients, 30.6%, 95% CI 27.3-34.0%).

CONCLUSIONS

This study carried out in acutely hospitalized older people shows a high degree of inappropriate prescription among patients prescribed with antiplatelets for primary prevention, mainly due to overprescription. Further, a large proportion of patients who had had overt cardio- or cerebrovascular disease were underprescribed, in spite of the established benefits of antiplatelet drugs in the context of secondary prevention.

Age as a Confounding Factor for the Accurate Non-Invasive Diagnosis of Advanced NAFLD Fibrosis

OBJECTIVES

Non-invasive fibrosis scores are widely used to identify/exclude advanced fibrosis in patients with non-alcoholic fatty liver disease (NAFLD). However, these scores were principally developed and validated in patients aged between 35 and 65 years of age. The objective of this study was to assess the effect of age on the performance of non-invasive fibrosis tests in NAFLD.

METHODS

Patients were recruited from European specialist hepatology clinics. The cohort was divided into five age-based groups: ≤35 (n=74), 36-45 (n=96), 46-55 (n=197), 56-64 (n=191), and ≥65 years (n=76), and the performance of the aspartate aminotransferase (AST)/alanine transaminase (ALT) ratio, fibrosis 4 (FIB-4), and NAFLD fibrosis score (NFS) for advanced fibrosis (stage F3-F4) for each group was assessed using liver biopsy as the standard.

RESULTS

Six hundred and thirty-four patients were included. The diagnostic accuracy of the AST/ALT ratio was lower than NFS and FIB-4 in all the age groups. The AST/ALT ratio, NFS, and FIB-4 score performed poorly for a diagnosis of advanced fibrosis in those aged ≤35 years (area under the receiver operating characteristic curves (AUROCs 0.52, 0.52, and 0.60, respectively). For all groups >35 years, AUROCs for advanced fibrosis were similar for the NFS and FIB-4 score (range 0.77-0.84). However, the specificity for advanced fibrosis using the FIB-4 and NFS declined with age, becoming unacceptably low in those aged ≥65 years (35% for FIB-4 and 20% for NFS). New cutoffs were derived (and validated) for those aged ≥65 years, which improved specificity to 70% without adversely affecting sensitivity (FIB-4 2.0, sensitivity 77%; NFS 0.12, sensitivity 80%).

CONCLUSIONS

The NFS and FIB-4 scores have similar accuracy for advanced fibrosis in patients aged >35 years. However, the specificity for advanced fibrosis is unacceptably low in patients aged ≥65 years, resulting in a high false positive rate. New thresholds for use in patients aged ≥65 years are proposed to address this issue.

A new path to platelet production through matrix sensing

Megakaryocytes (MK) in the bone marrow (BM) are immersed in a network of extracellular matrix components that regulates platelet release into the circulation. Combining biological and bioengineering approaches, we found that the activation of transient receptor potential cation channel subfamily V member 4 (TRPV4), a mechano-sensitive ion channel, is induced upon MK adhesion on softer matrices. This response promoted platelet production by triggering a cascade of events that lead to calcium influx, β1 integrin activation and internalization, and Akt phosphorylation, responses not found on stiffer matrices. Lysyl oxidase (LOX) is a physiological modulator of BM matrix stiffness via collagen crosslinking. In vivo inhibition of LOX and consequent matrix softening lead to TRPV4 activation cascade and increased platelet levels. At the same time, in vitro proplatelet formation was reduced on a recombinant enzyme-mediated stiffer collagen. These results suggest a novel mechanism by which MKs, through TRPV4, sense extracellular matrix environmental rigidity and release platelets accordingly.

Critical comments to a recent EFLM recommendation for the review of reference intervals

In a recent EFLM recommendation on reference intervals by Henny et al., the direct approach for determining reference intervals was proposed as the only presently accepted “gold” standard. Some essential drawbacks of the direct approach were not sufficiently emphasized, such as unacceptably wide confidence limits due to the limited number of observations claimed and the practical usability for only a limited age range. Indirect procedures avoid these disadvantages of the direct approach. Furthermore, indirect approaches are well suited for reference limits with large variations during lifetime and for common reference limits.

Individuals with obesity and type 2 diabetes have additional immune dysfunction compared with obese individuals who are metabolically healthy

OBJECTIVE

The objective of the current study was to compare the responses to different ex vivo immunogenic challenges between immune cells derived from metabolically healthy subjects with obesity and subjects with obesity and type 2 diabetes.

RESEARCH DESIGN AND METHODS

We recruited 10 metabolically healthy subjects with obesity (Edmonton Obesity Staging System (EOSS) stage 0) and 9 subjects with obesity and type 2 diabetes (EOSS stage 2) aged between 21 years and 70 years and matched for body mass index. Peripheral blood mononuclear cells (PBMCs) were isolated and immune cell phenotypes and ex vivo cytokine production after phytohaemagglutinin (PHA, a T cell mitogen) stimulation were determined. Neutrophil oxidative burst activity was assessed in whole blood.

RESULTS

PBMCs from subjects with stage 2 obesity produced significantly less interleukin (IL)-2, IL-6 and tumour necrosis factor α after PHA stimulation than PBMCs from subjects with stage 0 obesity (all, p<0.05). Subjects with stage 2 obesity also had higher proportions of cytotoxic T cells, activated helper T cells (CD4+CD278+) and inflammatory monocytes (CD14+CRTh2+, all p<0.05). Poststimulation, neutrophils from subjects with stage 2 obesity produced significantly more free radicals, were larger and more granular and had a lower stimulation index (all p<0.05).

CONCLUSIONS

Our results suggest that compared with obese individuals metabolically healthy individuals with obesity and type 2 diabetes have an impaired neutrophil function and T cell response on challenge despite having a T cell population expressing more activation markers which may be partly responsible for the increased prevalence of infection reported in this population.

Safety of Antithrombotic Agents in Elderly Patients with Acute Coronary Syndromes

There are unique challenges in the treatment and prevention of acute coronary syndromes (ACS) with antithrombotics in elderly patients: elderly patients usually require multiple drugs due to comorbidities, are highly susceptible to adverse drug reactions and drug-drug interactions, may have cognitive problems affecting compliance and complications, are especially exposed to the risk of falls and, most importantly, ageing is an independent risk factor for bleeding. Antithrombotic drugs, alone or in association, further and variously amplify age-related bleeding risk. Moreover, age-related changes in primary haemostasis may potentially affect the pharmacodynamics of some antiplatelet drugs. Thus, elderly subjects might be more or less sensitive to standard antiplatelet regimens depending on individual characteristics affecting antiplatelet drug response. Importantly, elderly patients are a rapidly growing population worldwide, have the highest incidence of ACS, but are poorly represented in clinical trials. As a consequence, evidence on antithrombotic drug benefits and risks is limited. Thus, in the real-world setting, older people are often denied antithrombotic drugs because of unjustified concerns, or might be over-treated and exposed to excessive bleeding risk. Personalized antithrombotic therapy in elderly patients is particularly critical, to minimize risks without affecting efficacy.

Human and Murine Hematopoietic Stem Cell Aging Is Associated with Functional Impairments and Intrinsic Megakaryocytic/Erythroid Bias

Aging within the human hematopoietic system associates with various deficiencies and disease states, including anemia, myeloid neoplasms and reduced adaptive immune responses. Similar phenotypes are observed in mice and have been linked to alterations arising at the hematopoietic stem cell (HSC) level. Such an association is, however, less established in human hematopoiesis and prompted us here to detail characteristics of the most primitive human hematopoietic compartments throughout ontogeny. In addition, we also attempted to interrogate similarities between aging human and murine hematopoiesis. Coupled to the transition from human cord blood (CB) to young and aged bone marrow (BM), we observed a gradual increase in frequency of candidate HSCs. This was accompanied by functional impairments, including decreased lymphoid output and reduced proliferative potential. Downstream of human HSCs, we observed decreasing levels of common lymphoid progenitors (CLPs), and increasing frequencies of megakaryocyte/erythrocyte progenitors (MEPs) with age, which could be linked to changes in lineage-affiliated gene expression patterns in aged human HSCs. These findings were paralleled in mice. Therefore, our data support the notion that age-related changes also in human hematopoiesis involve the HSC pool, with a prominent skewing towards the megakaryocytic/erythroid lineages, and suggests conserved mechanisms underlying aging of the blood cell system.

Platelet parameters (PLT, MPV, P-LCR) in patients with schizophrenia, unipolar depression and bipolar disorder

There are no studies comparing platelet parameters platelet parameters (platelet count (PLT), mean platelet volume (MPV) and platelet large cell ratio (P-LCR)) between patients with schizophrenia, bipolar disorder and unipolar depression. Therefore, the aim of this study was to determine and compare differences in PLT, MPV and P-LCR in patients with schizophrenia, unipolar depression and bipolar disorder. This was a retrospective, cross-sectional, naturalistic study of 2377 patients (schizophrenia n=1243; unipolar depression n=791; bipolar disorder n=343, including bipolar depression n=259 and mania n=84). There were significant differences for PLT, MPV and P-LCR values between study groups. A significant percentage of patients with bipolar disorder had abnormal (too low or too high) number of platelets. Negative correlation between PLT and age was found in all study groups and positive correlation between age and MPV and P-LCR was found in patients with schizophrenia.

Age and gender effects on 15 platelet phenotypes in a Spanish population

INTRODUCTION

Several studies have analysed the platelet parameters in human blood, nevertheless there are no extensive analyses on the less common platelet phenotypes. The main objective of our study is to evaluate the age and gender effects on 15 platelet phenotypes.

METHODS

We studied 804 individuals, ranging in age from 2 to 93 years, included in the Genetic Analysis of Idiopathic Thrombophilia 2 (GAIT 2) Project. The 15 platelet phenotypes analysed were the platelets counts, platelet volumes, plateletcrits, immature platelet fraction (IPF) and platelet function assay (PFA). A regression-based method was used to evaluate the age and gender effects on these phenotypes.

RESULTS

Our results were consistent with the previously reported results regarding platelet counts and plateletcrit (PCT). They showed a decrease with increasing age. The mean platelet volume (MPV), platelet distribution width (PDW) and platelet-large cell ratio (P-LCR) increased with age, but did not present any gender effect. All the IPF phenotypes increased with age, whereas the PFA phenotypes did not show any relation to age or gender.

DISCUSSION

To sum up, our study provides a comprehensive analysis of the age and gender effects on the platelet phenotypes in a family-base sample. Our results suggest more reasonable age stratification into two distinct groups: childhood, ranging from 2 to 12 years, and the mature group, from 13 to 93 years. Moreover, the PFA phenotypes were maintained constant while the platelet counts, the MPV and IPF levels vary with age.

Sex-specific differences in genetic and nongenetic determinants of mean platelet volume: results from the Gutenberg Health Study

Mean platelet volume (MPV), a measure of platelet size, is a potential biological marker of platelet function. To date, a comprehensive analysis including known genetic and nongenetic factors that determine MPV is still lacking. MPV has been evaluated in 15 010 individuals from the population-based Gutenberg Health Study. Genetic information was available for 4175 individuals. Our results showed that age (β, 0.0346; 95% confidence interval [CI], 0.0255 to 0.0436), cardiovascular risk factors (CVRFs) such as smoking (β, 0.178; 95% CI, 0.128 to 0.229), hypertension (β, 0.05; 95% CI, 0.00289 to .0981), and high glucose level (β, 0.00179; 95% CI, 0.0006 to 0.00299) were linked with higher MPV in males only. Intake of oral contraceptives (β, 0.150; 95% CI, 0.0649 to 0.236) and menstruation (β, 0.123; 95% CI, 0.0231 to 0.224) were strongly associated with higher MPV in females. Seven single nucleotide polymorphisms (SNPs) for females and 4 SNPs for males were associated with higher MPV. The full model, including age, CVRFs, laboratory parameters, medications, and genetic variation, explained 20.4% of the MPV variance in females and 18.6% in males. The curves of cumulative mortality, stratified for sex, showed worse survival for males only with MPV > 9.96 fL vs MPV ≤ 9.96 fL (P < .0001). This study provides evidence for heterogeneity in the profile of determinants for MPV between sexes. The observed interactions between genetic variability, CVRFs, and MPV and its association with the development of cardiovascular disease or thrombotic risk need to be further investigated.