Platelets as an indicator of vascular repair in elderly Japanese men

Role of Platelets in Rheumatic Chronic Autoimmune Inflammatory Diseases

Platelets are essential in maintaining blood homeostasis and regulating several inflammatory processes. They constantly interact with immune cells, have immunoregulatory functions, and can affect, through immunologically active substances, endothelium, leukocytes, and other immune response components. In reverse, inflammatory and immune processes can activate platelets, which might be significant in autoimmune disease progression and arising complications. Thus, considering this interplay, targeting platelet activity may represent a new approach to treatment of autoimmune diseases. This review aims to highlight the role of platelets in the pathogenic mechanisms of the most frequent chronic autoimmune inflammatory diseases to identify gaps in current knowledge and to provide potential new targets for medical interventions.

Association between underweight, serum albumin levels, and height loss in the Japanese male population: a retrospective study

BACKGROUND

Previous study has shown that height loss (defined as the highest quartile of height loss per year) was inversely associated with serum albumin levels. Furthermore, comparatively healthy hyponutrition has been linked with being underweight; as such, underweight might be inversely associated with serum albumin levels and positively associated with height loss.

METHODS

To clarify the associations between serum albumin level, underweight status, and height loss, we conducted a retrospective study of 8,096 men over 4.0 years (median).

RESULTS

Serum albumin level at baseline was inversely associated with being underweight (body mass index [BMI]: < 18.5 kg/m2) at baseline and height loss. The known cardiovascular risk factor adjusted odds ratio (OR) and 95% confidence interval (CI) of underweight at baseline and of height loss for 1 standard deviation increment of serum albumin (0.28 g/dL) was 0.79 (0.70, 0.90) and 0.84 (0.80, 0.88). Underweight was also shown to be positively associated with height loss: with the reference of normal-low weight (BMI: 18.5-22.9 kg/m2), the adjusted OR (95% CI) was 1.60 (1.21, 2.10).

CONCLUSION

Comparative healthy hyponutrition, which is related to low serum albumin levels and being underweight, is a significant risk factor for height loss among Japanese men. These results help to clarify the mechanisms underlying height loss.

Grip strength affects the association between platelet count and disability-free survival: Evidence from the China Health and Retirement Longitudinal Study

BACKGROUND AND AIMS

Previous studies found elevated platelet count (PLT), especially long-term persist high or increased PLT was associated with less likelihood disability-free survival (DFS). However, whether grip strength affects the relationship between them is still not elucidated.

METHODS

A total of 6252 participants were recruited in the analysis based on the China Health and Retirement Longitudinal Study. The primary outcome was DFS, evaluated by a composite endpoint based on the first occurrence of either disability (having difficulty in at least one of the 6 activities of daily living: namely, dressing, bathing, continence, eating, getting into or out of bed, and toileting) or all-cause mortality.

RESULTS

The association of PLT with primary outcome was significantly modified by grip strength (pinteraction = 0.022). The rates of primary outcome were significantly lower among participants with lower baseline PLT in participants with normal grip strength (multivariable odds ratio [OR], 0.67; 95% confidence interval [CI], 0.54-0.84; ptrend < 0.001), but not in those with low grip strength (multivariable OR, 1.70; 95% CI, 0.88-3.15; ptrend = 0.135), for the lowest quartile vs the highest quartile. Adding baseline PLT (quartiles or continuous) to a model containing conventional risk factors significantly improved risk reclassification for primary outcome among those with normal grip strength (most of p < 0.05).

CONCLUSION

An inverse dose-response association of PLT with DFS was found among participants with normal grip strength, but not among those with low grip strength. Low grip strength might weaken the benefit of low PLT on DFS among middle-aged and older Chinese.

Progression of Carotid Intima-Media Thickness Partly Indicates the Prevention of Hypertension among Older Individuals in the General Population

Structural atherosclerosis, as evaluated by carotid intima-media thickness (CIMT), is reported to be positively associated with hypertension. However, angiogenesis, which plays an important role in the progression of structural atherosclerosis, prevents hypertension by reducing peripheral vascular resistance. These associations evoke a contradiction: characteristics associated with the progression of structural atherosclerosis, which is related to hypertension, might prevent hypertension. To clarify novel mechanisms underlying the association between structural atherosclerosis and hypertension, multifaceted analyses are necessary. We performed several epidemiological studies based on this concept. This study summarizes those epidemiological studies and adds some discussion. Studies focusing on circulating CD34-positive cells, single-nucleotide polymorphisms (SNPs) of vascular endothelial growth factor (VEGF), SNPs in BRACA1-associated protein (BRAP), platelets, human T-cell leukemia virus type 1 (HTLV-1), and SNPs in aldehyde dehydrogenase 2 (ALDH2) have shown that active endothelial repair, which leads to the progression of structural atherosclerosis, helps prevent hypertension. These associations indicate that the progression of structural atherosclerosis could act as a marker of angiogenesis, which reduces peripheral vascular resistance. In general, a positive association between structural atherosclerosis and hypertension has been reported. However, the progression of structural atherosclerosis could act as a marker of activity that prevents hypertension via reductions in peripheral vascular resistance.

Mechanism underlying vascular remodeling in relation to circulating CD34-positive cells among older Japanese men

Development of structural atherosclerosis, an established cardiovascular risk factor, requires hematopoietic stem cells known as CD34-positive cells. However, an inverse association between circulating CD34-positive cell count and cardiovascular disease has been reported. These studies evoke a contradiction: characteristics associated with a low risk of developing structural atherosclerosis are also associated with a high risk of cardiovascular disease. To clarify the mechanisms underlying vascular remodeling, we conducted several epidemiological studies of Japanese men aged 60 to 69 years who participated in annual health check-ups. The present study summarizes those epidemiological studies and adds some discussion. From the perspective of endothelial repair activity, there are significant differences between functional versus structural atherosclerosis. Aggressive endothelial repair increases both functional and structural atherosclerosis. Deficient endothelial repair related to a shortage of CD34-positive cells due to consumption furthers functional atherosclerosis but not structural atherosclerosis. Therefore, the lack of structural atherosclerosis does not always reflect a favorable condition for the endothelium. Although further investigation is necessary, the present study suggests that higher endothelial repair activity that leads to structural atherosclerosis might have a beneficial effect on vascular health among older men.

Vascular endothelial growth factor (VEGF) polymorphism rs3025039 and atherosclerosis among older with hypertension

Angiogenesis inhibition therapy causes hypertension by increasing peripheral vascular resistance. Vasa vasorum angiogenesis plays a crucial role in the development of atherosclerosis. Since vascular endothelial growth factor (VEGF), which contributes to the progress of angiogenesis, is reported to be inversely associated with the minor allele of polymorphism rs3025039, the minor allele of rs3025039 could be inversely associated with atherosclerosis among individuals with hypertension. A cross-sectional study of 1793 older Japanese adults aged 60–89 years with hypertension who participated in general health check-ups was conducted. Atherosclerosis was defined as carotid intima-media thickness (CIMT) ≥ 1.1 mm. The minor allele of polymorphism rs3025020 was positively associated with VEGF. Therefore, in addition to known cardiovascular risk factors, rs3025020 genotype acted as a confounding factor in the present study. Independent of known confounding factors, the minor allele of rs3025039 was inversely associated with atherosclerosis among older Japanese adults with hypertension. The fully adjusted odds ratio (OR) and 95% confidence interval (CI) for atherosclerosis with the minor allele of rs3025039 was 0.78 (0.64, 0.96). The angiogenesis-related polymorphism rs3025039 was associated with the development of atherosclerosis among older Japanese individuals. This study indicates that the development of atherosclerosis among older individuals might partly indicate a capacity for angiogenesis.

Influence of height on endothelial maintenance activity: a narrative review

Recent studies have revealed an inverse association between height and cardiovascular disease. However, the background mechanism of this association has not yet been clarified. Height has also been reported to be positively associated with cancer. Therefore, well-known cardiovascular risk factors, such as increased oxidative stress and chronic inflammation, are not the best explanations for this inverse association because these risk factors are also related to cancer. However, impaired blood flow is the main pathological problem in cardiovascular disease, while glowing feeding vessels (angiogenesis) are the main characteristic of cancer pathologies. Therefore, endothelial maintenance activity, especially for the productivity of hematopoietic stem cells such as CD34-positive cells, could be associated with the height of an individual because this cell contributes not only to the progression of atherosclerosis but also to the development of angiogenesis. In addition, recent studies have also revealed a close connection between bone marrow activity and endothelial maintenance; bone marrow-derived hematopoietic stem cells contribute towards endothelial maintenance. Since the absolute volume of bone marrow is positively associated with height, height could influence endothelial maintenance activity. Based on these hypotheses, we performed several studies. The aim of this review is not only to discuss the association between height and bone marrow activity, but also to describe the potential mechanism underlying endothelial maintenance. In addition, this review also aims to explain some of the reasons that implicate hypertension as a major risk factor for stroke among the Japanese population. The review also aims to clarify the anthropological reasons behind the high risk of atherosclerosis progression in Japanese individuals with acquired genetic characteristics.

Possible mechanisms underlying the association between human T-cell leukemia virus type 1 (HTLV-1) and hypertension in elderly Japanese population

Background

Human T-cell leukemia virus type 1 (HTLV-1) activates inflammatory cascades by activating the NF-κB pathway. The minor allele of single nucleotide polymorphism (SNP) in breast cancer suppressor BRCA1-associated protein (BRAP), which has a common etiology with HTLV-1 infection, has been reported to be positively associated with carotid atherosclerosis, but inversely associated with hypertension. Therefore, HTLV-1 infection may be inversely associated with hypertension by activating endothelial maintenance, including atherosclerosis. To clarify these associations, a cross-sectional study was conducted using 2989 Japanese individuals aged 60–99 years participating in a general health check-up.

Methods

Logistic regression models were used to clarify the association between HTLV-1 and hypertension. Platelet levels stratified analyses were also performed since platelet production, which plays a crucial role in endothelium maintenance, can be stimulated by activating the NF-κB pathway.

Results

HTLV-1 infection was found to be significantly inversely associated with hypertension, particularly in subjects with high platelet levels (≥ second tertiles of platelet levels); the fully adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were 0.75 (0.62, 0.92) for total and 0.64 (0.50, 0.82) for high platelet levels, respectively. Further analysis of the non-hypertensive subjects demonstrated that HTLV-1 infection was significantly positively associated with atherosclerosis in subjects with the highest tertile of platelet levels (2.11 [1.15, 3.86]) but not in subjects with low platelet levels (first and second tertiles of platelet level) (0.89 [0.57, 1.39]).

Conclusion

Asymptomatic HTLV-1 infection is inversely associated with hypertension, possibly by activating endothelial maintenance, including atherosclerosis progression.

Association between serum sodium level within normal range and handgrip strength in relation to hypertension status: a cross-sectional study

Serum sodium concentration within the normal range could act as an indicator of age-related changes such as decrease in muscle strength and impairment of capillary function. Since endothelial injury stimulates endothelial repair by enhancing CD34-positive cell production, the level of serum sodium may be inversely associated with that of circulating CD34-positive cells, thus indicating the degree of age-related endothelial injury. We conducted a cross-sectional study of 246 elderly Japanese men aged 60–69 years. Subjects were stratified by hypertension status because hypertension should act as a strong confounding factor for the analyses performed in this study. Serum sodium concentration was positively associated with handgrip strength in non-hypertensive subjects [standardized parameter estimate (β) = 0.29; p = 0.003], but not for hypertensive subjects (β = 0.01; p = 0.878), while it was inversely associated with circulating CD34-positive cell levels in non-hypertensive subjects [simple correlation coefficient (r) = − 0.28; p = 0.002] but not for hypertensive subjects (r = − 0.07; p = 0.454). For non-hypertensive elderly subjects, serum sodium concentration within the normal range is positively associated with handgrip strength and inversely associated with CD34-positive cells, thus partly indicating the degree of age-related endothelium injury. These associations could prove to be an efficient tool for clarifying the background mechanism governing the decrease in age-related muscle strength.

Platelet indices in patients with chronic inflammatory arthritis: a systematic review and meta-analysis

Correlation between platelet indices and chronic inflammatory arthritis (CIA) remains a moot point today. This meta-analysis aimed to evaluate whether platelet (PLT) count, mean platelet volume (MPV) and platelet distribution width (PDW) associated with rheumatoid arthritis (RA), ankylosing spondylitis (AS) and psoriatic arthritis (PsA). A systematic literature search was performed in PubMed, EMBASE, and Web of Science up to August 2019. Pooled standardized mean differences (SMD) and 95% confidence interval (CI) were calculated using a random-effect model. As a result, 34 studies were included, encompassing 17 on RA, 12 on AS, 3 on PsA and 2 on both RA and AS. In these studies, PLT count was significantly higher in RA (SMD = 0.55, 95% CI = 0.36-0.73, P < .001), AS (SMD = 0.53, 95% CI = 0.36-0.70, P < .001) and PsA patients (SMD = 1.29, 95% CI = 0.82-1.77, P < .001) than that in healthy subjects, while MPV and PDW presented nonsignificant differences in these intergroup comparisons (P > .05), and similar results were observed in subgroup analyses. The meta-regression analysis demonstrated that there were strong positive correlations between erythrocyte sedimentation rate and PLT count, and weak correlation trend between the disease activity score and PLT count in both RA and AS subjects without statistically significant difference. The sensitivity analysis indicated that these results were not unduly influenced by any single study. In conclusion, this meta-analysis demonstrated that PLT count was elevated in CIA patients and could be suitable for evaluating the disease activity, whereas MPV and PDW were independent of CIA.

Potential mechanisms underlying the association between single nucleotide polymorphism (BRAP and ALDH2) and hypertension among elderly Japanese population

Minor allele frequency (MAF) of rs3782886 (BRAP) and rs671 (ALDH2) are reported to be inversely associated with blood pressure. Another study revealed that hematopoietic activity which is evaluated by reticulocytes could influenced on hypertension status partly by indicating activity of endothelial maintenance. Therefore, to evaluate the association between genetic factor and hypertension, influence of hematopoietic activity should be considered. A multi-faced analysis was performed in a simple general elderly population model (1,313 older Japanese aged 60–98 years). Participants were stratified by median values of reticulocytes (5.21 × 10⁴ cells/μL for men and 4.65 × 10⁴ cells/μL for women). Independent of known cardiovascular risk factors, MAF of rs3782886 and rs671 are significantly inversely associated with hypertension for participants with high hematopoietic activity (high reticulocytes level) (fully adjusted odds ratio (ORs) were 0.72 (0.55, 0.96) for rs3782886 and 0.72 (0.54, 0.96) for rs671) but not for low reticulocytes count (the corresponding values were 1.05 (0.79, 1.39) and 1.08 (0.81, 1.45), respectively). Hematopoietic activity evaluated by reticulocytes levels could influence on the association between single nucleotide polymorphism (rs3782886 and rs671) and hypertension. Those results were efficient tool to clarify the part of the mechanism that underlying the association between genetic factor and hypertension.

Relationships of handgrip strength with the presence of cerebral microbleeds and platelet count in older Japanese adults

Introduction: Lower handgrip strength is a manifestation of sarcopenia and frailty, and has been reported to be associated with cerebral microbleeds (CMBs), which appear on T2^*-weighted magnetic resonance scans as low-intensity spots. However, the underlying mechanism is unknown. We hypothesized that vascular endothelial injury could be the common factor in loss of handgrip strength and CMBs. We aimed to clarify the relationship between handgrip strength and CMBs, with reference to a marker of vascular repair capability.

Materials and Methods: We conducted a cross-sectional study of 95 60- to 87-year-old Japanese people who underwent brain magnetic resonance imaging in 2016–2017. Baseline information was obtained by trained interviewers regarding the age, sex, smoking status, nutrient intake, cognition, medical history, education, and household income of the participants. Physical activity was assessed using a tri-axial accelerometer. We used the Fried frailty phenotype definition. Multivariable linear regression analysis was performed.

Results: Handgrip strength was independently associated with the presence of CMB after adjustment for age, sex, body mass index, classical cardiovascular risk factors, protein intake, and daily activity (B = −3.43, p = 0.027). This association was shown in participants with a low (B = −4.05, p = 0.045) but not high platelet count (B=−2.23, p = 0.479). Frailty was also independently associated with the presence of CMB after adjustment for confounders (B = 0.57, p = 0.014). Although this association was not present in participants a high platelet count, there was a positive trend in those with a low platelet count (B = 0.50, p = 0.135).

Conclusions: Platelet count, a marker of vascular repair capability, appears to modify the relationship between handgrip strength and CMBs.

Association between height and circulating CD34-positive cells taken into account for the influence of enhanced production among elderly Japanese men: a cross-sectional study

Recent studies have revealed an inverse association between height and cardiovascular disease and that endothelial progenitor cells (CD34-positive cells) contribute to vascular maintenance, which is associated with cardiovascular disease. However, evidence of the association between height and CD34-positive positive cells among elderly participants is limited. To assess this association, we conducted a cross-sectional study of 231 elderly Japanese men aged 65–69. Since enhanced production of circulating CD34-positive cells in response to endothelial injury might act have a strong confounding effect on the association between height and circulating CD34-positive cells, the median value for the levels of these cells (0.93 cells/μL) was used to stratify the participants. Multivariable linear regression analysis demonstrated that height was significantly positively associated with circulating CD34-positive cells for those participants with low levels of circulating CD34-positive cells (n=114) but not for those with higher levels (n=117), with a multi-adjusted standardized parameter estimate (β) of 0.27 (p=0.008) for low and 0.11 (0.275) for higher circulating CD34-positive cell levels. The positive association is limited to participants with relatively low circulating CD34-positive cell levels, whose productivity of these cells is not activated. Our findings indicate that height is an indicator of vascular maintenance capability in elderly Japanese men.

Circulating CD34+ cells and active arterial wall thickening among elderly men: A prospective study

Age-related physical changes, such as low-grade inflammation and increased oxidative stress, induce endothelial repair and cause active arterial wall thickening by stimulating the production of CD34+ cells (the principal mediators of atherosclerosis). Despite this, aggressive endothelial repair (progressing atherosclerosis) might cause a wasting reduction in CD34+ cells, which could result in a lower capacity of endothelial repair and hypertension. As yet, no prospective study has clarified the association of circulating CD34+ cells with active arterial wall thickening. We conducted a prospective study of 363 men aged 60-69 years who participated in a general health check-up at least twice from 2014-2017. The circulating CD34+ cell count was significantly positively associated with active arterial wall thickening among subjects without hypertension (n = 236), but not among subjects with hypertension (n = 127). The fully adjusted odds ratios (ORs) of active arterial wall thickening for the logarithmic circulating CD34+ cell count were 1.83 (1.19, 2.84) and 0.69 (0.36, 1.32) for subjects without and with hypertension, respectively. Circulating CD34+ cells are positively associated with active arterial wall thickening in subjects without hypertension. This study demonstrates a means to clarify the mechanisms of endothelial repair in elderly subjects.

Insulin-Like Growth Factor-1 (IGF-1) and Reduced Tongue Pressure in Relation to Atherosclerosis Among Community-Dwelling Elderly Japanese Men: A Cross-Sectional Study

Even though higher serum insulin-like growth factor-1 (IGF-1) levels have a positive effect on preventing reduction in muscle strength, a U-shaped association between IGF-1 and mortality has been reported. Since a recent experimental study revealed that IGF-1 is associated with atherosclerotic lesion formation, the inflammatory status of atherosclerosis could act as a confounding factor on the association between IGF-1 levels and reduced muscle strength. This study aimed to clarify the atherosclerosis-specific association between IGF-1 levels and reduced muscle strength. We conducted a cross-sectional study of 410 elderly men aged 60-89 years. Since a reduction in maximum voluntary tongue pressure against the palate (MTP) is reportedly associated with sarcopenia, we evaluated muscle strength by using MTP and defined reduced MTP as the lowest tertiles of the study population. Among study population, 295 showed no atherosclerosis (carotid intima-media thickness < 1.1 mm). Even though a significant inverse association between IGF-1 and reduced MTP was observed for subjects without atherosclerosis, no such association was detected for subjects with atherosclerosis. The known cardiovascular risk-factor adjusted odds ratio (OR) of a one-standard deviation (SD) increment (28.1 ng/mL) of IGF-1 for reduced MTP was 0.69 (0.51, 0.95) for subjects without atherosclerosis and 1.93 (1.05, 3.52) for subjects with atherosclerosis. IGF-1 was found to be inversely associated with a reduced MTP among elderly men without atherosclerosis but not among those with atherosclerosis. Atherosclerosis can thus act as a powerful confounding factor on the association between IGF-1 levels and a reduced MTP.

Reticulocyte levels have an ambivalent association with hypertension and atherosclerosis in the elderly: a cross-sectional study

Purpose: Age-related reduction in bone marrow activity has been shown to cause anemia, and hypertension and endothelial dysfunction (atherosclerosis) are age-related diseases. However, recent studies have revealed a close association between bone marrow activity and endothelial maintenance. This study aimed to determine the association between elevated reticulocyte levels in conjunction with vigorous bone marrow activity and hypertension and atherosclerosis among the elderly.

Study population and Methods: To determine the associations between reticulocyte levels and hypertension and atherosclerosis, we conducted a cross-sectional study of 2,098 elderly Japanese individuals, aged between 60 and 89 years, who had participated in an annual health check-up in 2014.

Results: Of the total study population, 1,348 individuals were diagnosed with hypertension (systolic blood pressure ≥140 mmHg and/or diastolic blood pressure ≥90 mmHg and/or having used antihypertensive medication), and 393 were diagnosed with atherosclerosis (carotid intima-media thickness ≥1.1 mm). Reticulocyte levels were found to be significantly positively associated with hypertension and inversely associated with atherosclerosis. Cardiovascular risk factor-adjusted odds ratios and 95% confidence intervals for hypertension and atherosclerosis, when raised incrementally by 1 standard deviation to determine reticulocyte levels (5.5×10⁴ cells/μL for men and 5.0×10⁴ cells/μL for women), were 1.12 (1.01, 1.25) and 0.83 (0.72, 0.94), respectively.

Conclusion: Along with established cardiovascular risk factors, reticulocyte levels in elderly Japanese individuals were found to be positively associated with hypertension and inversely associated with atherosclerosis. This finding may help clarify the background mechanisms concerning the association between bone marrow activity and vascular remodeling.

Short stature-related single-nucleotide polymorphism (SNP) activates endothelial repair activity in elderly Japanese

Background

Hypertension and atherosclerosis are bidirectionally related, while platelet count could serve as an indicator of endothelial repair. Therefore, high platelet counts could be associated with hypertension by indicating more intense endothelial repair activity. Furthermore, short stature has been shown to constitute a risk of atherosclerosis. Since inflammation-related single-nucleotide polymorphism (SNP (rs3782886)) is reportedly associated with myocardial infarction and short stature, rs3782886 could be associated with a high platelet count and thus more intense endothelial repair activity.

Methods

We conducted a cross-sectional study of 988 elderly Japanese who participated in a general health check-up. Short stature was defined as a height of at or under the 25th percentile of the study population, and high platelet count as the highest tertiles of the platelet levels.

Results

High platelet counts were found to be independently and positively associated with hypertension while rs3782886 was independently associated with high platelet levels and short stature. The classical cardiovascular risk factor-adjusted odds ratio (OR) and 95% confidence interval (CI) of high platelet count for hypertension was 1.34 (1.02, 1.77). With non-minor homo of the rs3782886 as the reference group, the adjusted OR and 95% CI for high platelet count and short stature of minor home were 2.40 (1.30, 4.42) and 2.21 (1.16, 4.21), respectively.

Conclusion

SNP (rs3782886) was shown to be associated with high platelet count and short stature. This result partly explains how a genetic factor can influence the impact of height on endothelial repair.

Cardio-ankle vascular index and circulating CD34-positive cell levels as indicators of endothelial repair activity in older Japanese men

AIM

The cardio-ankle vascular index (CAVI) reflects functional arterial stiffness, which is related to endothelial dysfunction. CD34-positive cells carry out an important function in endothelial repair. However, there have been no reports assessing the association between CAVI and the number of circulating CD34-positive cells.

METHODS

We carried out a cross-sectional study of 249 Japanese men, aged 60-69 years, who underwent annual health checkups between 2013 and 2015. As individuals with high levels of circulating CD34-positive cells might indicate the influence of consumptive reduction of circulating CD34-positive cells as a result of aggressive endothelial repair, participants were stratified by circulating CD34-positive cell levels, using the median value in this population (0.95 cells/μL) as the cut-off.

RESULTS

For participants with low circulating CD34-positive cell levels, logarithmic values of circulating CD34-positive cells were inversely associated with CAVI (multivariable standardized parameter estimate [β] = -0.22, P = 0.014), but not for participants with high levels (β = -0.04, P = 0.638). In addition, even when no significant associations between CAVI and carotid intima-media thickness were detected for participants with low circulating CD34-positive cell levels (β = -0.02, P = 0.865), significant positive associations were identified for participants with high levels (β = 0.22, P = 0.028).

CONCLUSIONS

As circulating CD34-positive cell count might indicate endothelial repair activity, the present results show that CAVI is affected by insufficient endothelial repair in individuals with low circulating CD34-positive cell counts. Our results also show that a positive association between CAVI and carotid intima-media thickness exists only in individuals with aggressive endothelial repair, which indicates the presence of organic arterial disease, such as atherosclerosis. Geriatr Gerontol Int 2019; 19: 557-562.

Association between chronic kidney disease and carotid intima-media thickness in relation to circulating CD34-positive cell count among community-dwelling elderly Japanese men

BACKGROUND AND AIMS

Endothelial injury is well-known as a process that can lead to chronic kidney disease (CKD) and atherosclerosis. Hematopoietic activity is known to be associated inversely with CKD and positively with atherosclerosis. Since bone-derived progenitor cells (CD34-positive cells) contribute to endothelial repair (including the progression of atherosclerosis), understanding the association between CKD and carotid intima-media thickness (CIMT), in relation to circulating CD34-positive cell count, may be an efficient means of clarifying the mechanisms underlying endothelial activity.

METHODS

We conducted a cross-sectional study of 570 elderly Japanese men aged 60-69 years, who underwent a general health check-up. Participants were stratified as per a median circulating CD34-positive cell count (1.01 cells/μL).

RESULTS

Independent of the known cardiovascular risk factors, CIMT was found to be positively associated with CKD in the participants with high circulating CD34-positive cell counts but not in participants with low counts. Odds ratios were 1.40 (1.04, 1.89) for participants with high and 1.01 (0.72, 1.43) for participants with low circulating CD34-positive cell counts after adjustment for known cardiovascular risk factors at 95% confidence intervals for CKD with one standard deviation increment of CIMT.

CONCLUSIONS

A positive association between CIMT and CKD was observed among participants with high circulating CD34-positive cell counts but not among participants with low counts. Endothelial repair activity might determine the association between CKD and CIMT.

Common Injuries and Repair Mechanisms in the Endothelial Lining

Objective:

Endothelial cells (ECs) are important metabolic and endocrinal organs which play a significant role in regulating vascular function. Vascular ECs, located between the blood and vascular tissues, can not only complete the metabolism of blood and interstitial fluid but also synthesize and secrete a variety of biologically active substances to maintain vascular tension and keep a normal flow of blood and long-term patency. Therefore, this article presents a systematic review of common injuries and healing mechanisms for the vascular endothelium.

Data Sources:

An extensive search in the PubMed database was undertaken, focusing on research published after 2003 with keywords including endothelium, vascular, wounds and injuries, and wound healing.

Study Selection:

Several types of articles, including original studies and literature reviews, were identified and reviewed to summarize common injury and repair processes of the endothelial lining.

Results:

Endothelial injury is closely related to the development of multiple cardiovascular and cerebrovascular diseases. However, the mechanism of vascular endothelial injury is not fully understood. Numerous studies have shown that the mechanisms of EC injury mainly involve inflammatory reactions, physical stimulation, chemical poisons, concurrency of related diseases, and molecular changes. Endothelial progenitor cells play an important role during the process of endothelial repair after such injuries. What's more, a variety of restorative cells, changes in cytokines and molecules, chemical drugs, certain RNAs, regulation of blood pressure, and physical fitness training protect the endothelial lining by reducing the inducing factors, inhibiting inflammation and oxidative stress reactions, and delaying endothelial caducity.

Conclusions:

ECs are always in the process of being damaged. Several therapeutic targets and drugs were seeked to protect the endothelium and promote repair.

Platelet number is negatively and independently associated with carotid intima-media thickness in apparently healthy overweight/obese subjects

BACKGROUND AND AIM

A significant change of platelet number may be a risk factor for atherosclerotic cardiovascular disease. The aim of this study was to investigate the association between platelet number and early signs of atherosclerosis, evaluated by carotid intima-media thickness (c-IMT), in a apparently healthy population mainly represented by obese subjects.

METHODS AND RESULTS

As many as 961 subjects, 686 women and 275 men, aged between 18 and 74 years, were enrolled in the study. Of these, 54 individuals (5.6% of all subjects) were normal weight, 259 individuals (27.0% of all subjects) were overweight, and 648 individuals (67.4% of all subjects) were obese. Waist circumference (WC) and blood glucose, insulin, total cholesterol, high and low density lipoprotein cholesterol, triglycerides and platelet count were also detected in all subjects, who underwent carotid echo color doppler ultrasound to measure c-IMT. c-IMT was significantly and positively associated to age (r = 0.204, P < 0.0001), fasting glucose (r = 0.073, P < 0.0240), total cholesterol (r = 0.096, P = 0.0031), and systolic and diastolic blood pressure (r = 0.140, P < 0.0001 and r = 0.119, P < 0.0003 respectively); c-IMT was significantly and negatively correlated with platelet count (r = -0.165, P < 0.0001). Only age (P < 0.0001) and systolic blood pressure (P = 0.0393), positively, and platelet number (P < 0.0001), negatively, were significantly and independently associated to c-IMT in a final multiple regression analysis.

CONCLUSION

Lower platelet number represented an independent determinant of c-IMT in a population, mainly represented by obese patients. These results suggest that a decrease of platelet number may well be an early defensive mechanism in subjects developing the thickening of carotid artery.

Association between tongue pressure and subclinical carotid atherosclerosis in relation to platelet levels in hypertensive elderly men: a cross-sectional study

Background

Age-related low-grade inflammation causing endothelial disruption influences sarcopenia, hypertension, and atherosclerosis. We reported previously that maintenance of muscle strength in elderly hypertensive men with high platelet levels is positively associated with subclinical atherosclerosis but not in those with low platelet levels. Since reduced tongue pressure is related to sarcopenia, tongue pressure may be associated with subclinical carotid atherosclerosis in hypertensive elderly subjects, and platelet levels may function as an indicator of the association between tongue pressure and subclinical carotid atherosclerosis.

Methods

We conducted a cross-sectional study of 342 hypertensive elderly Japanese men aged 60–89 who participated in an annual health check-up in 2015 and 2016. Subclinical carotid atherosclerosis was defined as a common carotid intima-media thickness (CIMT) of 1.1 mm or more.

Results

In the overall study population, 171 subjects demonstrated low platelets (< 21.4 × 10⁴/μL). Tongue pressure was significantly inversely associated with subclinical carotid atherosclerosis in these subjects, but not in subjects with high platelets. The known cardiovascular risk factor adjusted odds ratios (ORs) and 95% confidence intervals (CIs) of subclinical carotid atherosclerosis for a 1 standard deviation (SD) increment in tongue pressure (10.4 kPa) were 0.54 (0.35, 0.85) and 1.31 (0.87, 1.96), respectively.

Conclusion

Tongue pressure is inversely associated with subclinical carotid atherosclerosis in hypertensive elderly men with low platelet levels, but not in those with high levels. This finding may thus constitute an efficient tool for clarifying the background mechanism of age-related diseases such as sarcopenia, hypertension, and atherosclerosis.

Possible mechanism underlying the association between height and vascular remodeling in elderly Japanese men

Height is reported to be inversely associated with cardiovascular disease. And platelets play an important role in vascular remodeling by supporting CD34-positive cells. To clarify the association between height and platelet, we conducted a cross-sectional study of 219 elderly Japanese men. Since hemoglobin concentration is influenced by vascular remodeling activity, an analysis stratified by hemoglobin level was performed. An inverse association was seen between height and platelet count in subjects with a high hemoglobin concentration (≥ 14.5 g/dL), but not in subjects with a low hemoglobin concentration (< 14.5 g/dL). The standardized parameter estimates (β) were β = -0.22, p = 0.019 for subjects with high hemoglobin, and β = -0.01, p = 0.931 for subjects with low hemoglobin. We also found a positive association between platelets and carotid intima media thickness (CIMT) and circulating CD34-positive cells in subjects with high hemoglobin (partial correlation coefficient (r) = 0.21, p = 0.037 and r = 0.40, p =< 0.001), but not in subjects with low hemoglobin (r = 0.04, p = 0.710 and r = 0.06, p = 0.544). In subjects with a high hemoglobin concentration, platelets were inversely associated with height, and positively associated with CIMT and circulating CD34-positive cells. These results indicate that subjects with a short stature activate vascular remodeling to a much greater extent than subjects with a tall stature.

Handgrip strength and subclinical carotid atherosclerosis in relation to platelet levels among hypertensive elderly Japanese

Age-related disruption of microvascular endothelium exacerbates hypertension and sarcopenia; and atherosclerosis is a well-known biological response to vascular endothelial injury. Therefore, prevalence of atherosclerosis among hypertensive elderly subjects may partly indicate the presence of an appropriate response to endothelial injury. We conducted a cross-sectional study of 795 elderly hypertensive Japanese subjects aged 60-89 years. Since platelet level is an indicator of vascular repair activity, subjects were stratified by platelet counts. No significant association between handgrip strength and subclinical carotid atherosclerosis (carotid intima-media thickness (CIMT) ≥1.1mm) was observed for subjects with lower platelet counts, while a significant positive association was observed for subjects with higher platelets. Adjusted odds and 95% confidence intervals of subclinical carotid atherosclerosis for 1 standard deviation increments in handgrip strength were 0.86 (0.61, 1.22) for subjects with lower platelets and 1.82 (1.26, 2.64) for subjects with higher platelets. A positive association between handgrip strength and subclinical carotid atherosclerosis exists in hypertensive elderly subjects with higher, but not lower, platelet counts. These results lead us to speculate that subjects with a beneficial influence on prevention of sarcopenia (maintenance of handgrip strength) may possess the capacity of active endothelial repair that causes atherosclerosis.

Association between high-density lipoprotein-cholesterol and hypertension in relation to circulating CD34-positive cell levels

Background

Although high-density lipoprotein-cholesterol (HDL) level is inversely correlated with cardiovascular events, HDL is also reported to be positively associated with hypertension, which is a known endothelial impairment factor. Since HDL mediates important protective actions on the vascular endothelium by increasing the number of circulating endothelial progenitor cells (CD34-positive cells), the level of circulating CD34-positive cells should influence the association between HDL and hypertension.

Methods

To investigate the association between HDL and hypertension in relation to the level of circulating CD34-positive cells, we conducted a cross-sectional study of 477 elderly men aged 60–69 years who participated in general health checkup.

Results

HDL was found to be significantly positively associated with hypertension in subjects with a high level of circulating CD34-positive cells, while no significant association was observed for subjects with low circulating CD34-positive cells. Known cardiovascular risk factors adjusted odds (ORs) and 95% confidence intervals (CIs) of hypertension for increments of one standard deviation (SD) in HDL (13.8 mg/dL) were 1.44 (1.06, 1.96) for subjects with a high level of circulating CD34-positive cells and 0.87 (0.63, 1.19) for subjects with low circulating CD34-positive cells. We also revealed a significant association between HDL level and CD34-positive cell level on hypertension, with fully adjusted p values for the effect of this interaction on hypertension at 0.022.

Conclusions

Independent of known cardiovascular risk factors, HDL was found to be positively associated with hypertension in subjects with a high level of circulating CD34-positive cells but not for subjects with low circulating CD34-positive cells.