Calculated whole blood viscosity in non-diabetic subjects with asymptomatic carotid atherosclerosis: How insulin resistance may affect blood viscosity

BACKGROUND AND OBJECTIVE

Asymptomatic atherosclerosis is an important early marker of vascular damage and, among its risk factors, hemorheological alterations play an important role.

PATIENTS AND METHODS

In a cohort of 85 non-diabetic subjects with asymptomatic carotid atherosclerosis (ACA), we have measured whole blood viscosity (cWBV) according to the haematocrit and plasma fibrinogen level. The cWBV distinguish the subgroup of ACA subjects with 3-5 cardiovascular risk factors (CRFs) from that with 1-2 CRFs and the same behavior is present for haematocrit and plasma fibrinogen level. Therefore, we divided the whole group of ACA subjects according to the medians of the four surrogate indexes with an insulin resistance degree of TG/HDL-C, TyG, VAI and LAP.

RESULTS

The analysis of the correlation between cWBV and each index of insulin resistance has shown that no correlation is present in the whole group and in the group of ACA subjects with 1-2 CRFs, while in the subgroup with 3-5 CRFs there is a positive correlation between cWBV with TG/HDL-C and TyG at a low degree of statistical significance.

CONCLUSIONS

The date underline that subjects with this clinical condition have an unaltered evaluation of the cWBV compared to the other indices.

Mendelian randomization study of whole blood viscosity and cardiovascular diseases

AIMS

Association between whole blood viscosity (WBV) and an increased risk of cardiovascular disease (CVD) has been reported. However, the causal relationship between WBV and CVD remains not thoroughly investigated. The aim of this study was to investigate the causal relation between WBV and CVD.

METHODS

Two-sample Mendelian randomization (MR) was employed, with inverse variance weighting (IVW) as the primary method, to investigate the casual relationship between WBV and CVD. The calculated WBV and medical records of 378,210 individuals participating in the UK Biobank study were divided into halves and analyzed.

RESULTS

The means of calculated WBVs were 16.9 (standard deviation: 0.8) and 55.1 (standard deviation: 17.2) for high shear rate (HSR) and low shear rate (LSR), respectively. 37,859 (10.0%) major cardiovascular events (MACE) consisted of 23,894 (6.3%) cases of myocardial infarction (MI), 9,245 (2.4%) cases of ischemic stroke, 10,377 (2.7%) cases of revascularization, and 5,703 (1.5%) cases of coronary heart disease-related death. In the MR analysis, no evidence was found indicating a causal effect of WBV on MACE (IVW p-value for HSR = 0.81, IVW p-value for LSR = 0.47), MI (0.92, 0.83), ischemic stroke (0.52, 0.74), revascularization (0.71, 0.54), and coronary heart disease-related death (0.83, 0.70). The lack of sufficient evidence for causality persisted in other MR methods, including weighted median and MR-egger.

CONCLUSIONS

The Mendelian randomization analysis conducted in this study does not support a causal relationship between calculated WBV and CVD.

Forces of interaction of red blood cells and endothelial cells at different concentrations of fibrinogen: Measurements with laser tweezers in vitro

Blood microrheology depends on the constituents of blood plasma, the interaction between blood cells resulting in red blood cell (RBC) and platelets aggregation, and adhesion of RBC, platelets and leukocytes to vascular endothelium. The main plasma protein molecule -actuator of RBC aggregation is fibrinogen. In this paper the effect of interaction between the endothelium and RBC at different fibrinogen concentrations on the RBC microrheological properties was investigated in vitro. Laser tweezers were used to measure the RBC-endothelium interaction forces. It was shown for the first time that the interaction forces between RBC and endothelium are comparable with the RBC aggregation forces, they increase with fibrinogen concentration and reach the saturation level of about 4 pN at the concentration of 4 mg/ml. These results are important for better understanding the mechanisms of RBC and endothelium interaction and developing the novel therapeutic protocols of the microrheology correction in different pathologies.

HIIT serves as an efficient training strategy for basketball players by improving blood fluidity and decreasing oxidative stress

BACKGROUND

A challenge for coaches and athletes is to find the best combination of exercises during training. Considering its favorable effects, HIIT has been very popular recently.

OBJECTIVE

The goal of this study was to investigate anthropometric features, performance, erythrocyte deformability, plasma viscosity (PV) and oxidative stress in response to acute and long-term (6 weeks) HIIT in adolescent basketball players.

METHODS

22 sportsmen between the ages of 14-16 were included. Tabata protocol was applied to the HIIT group in addition to their routine training program 3 days/week, for 6 weeks. Erythrocyte deformability was determined using an ectacytometer (LORCA), PV with a rotational viscometer. Total oxidant status (TOS), total antioxidant status (TAS) were measured by kits.

RESULTS

HIIT for 6 weeks induced an improvement in performance tests and waist circumference. 6 weeks of HIIT resulted in a decrement, while the last exercise session yielded an increment in RBC deformability. PV and TOS of HIIT groups were decreased on the 6th week.

CONCLUSIONS

Our results demonstrate that, HIIT in addition to the routine exercise program is beneficial for improving performance and blood fluidity as well as decreasing oxidative stress in basketball players. Therefore, HIIT seems as an efficient training strategy for highly-trained individuals.

Relationship between blood viscosity and thrombus burden in ST-segment elevation myocardial infarction

BACKGROUND

İncreased whole blood viscosity (WBV) is associated with increased infarct area, impaired microvascular circulation and mortality in patients with ST-elevation myocardial infarction (STEMI).

OBJECTIVES

We aimed to analyze the association between the WBV and thrombus burden (TB) in STEMI patients.

METHODS

This cross-sectional study included 167 STEMI patients who received primary percutaneous coronary intervention. WBV values were assessed using hematocrit and total protein values, and low shear rate(LSR) and high shear rate(HSR) were calculated. Angiographic TB was assessed according to the definition of the Thrombolysis in Myocardial Infarction (TIMI) study group. The cases were dichotomized into low TB (grade 1-3) (n = 87) and high TB (grade 4-5) (n = 80) groups.

RESULTS

The mean HSR and LSR values of the high TB group were significantly increased compared to the low TB group (p < 0.001, for each). In ROC analysis,for prediction of TB, a cut-off value of 3.83 WBV for HSR had a 71% sensitivity and a 60.7% specificity, and a cut-off value of 21 WBV for LSR had a 70% sensitivity and 59.9% specificity (p < 0.001,for each). Multivariate regression analysis showed that both HSR (OR = 2.408;p=0.020) and LSR (OR = 1.055;p=0.021) were independent predictors for high TB.

CONCLUSION

İncreased WBV was an independent predictor for the presence of high TB in patients with STEMI.

Higher systolic blood pressure is specifically associated with better islet beta-cell function in T2DM patients with high glycemic level

BACKGROUND

Patients with type 2 diabetes mellitus (T2DM) usually have higher blood viscosity attributed to high blood glucose that can decrease blood supply to the pancreas. A mild increase in blood pressure (BP) has been reported as a potential compensatory response that can maintain blood perfusion in the islet. However, how BP influences beta-cell function in T2DM subjects remains inconsistent. This study aimed to examine the relationship between BP and beta-cell function in patients with T2DM under different HbA1c levels.

METHODS

This is a cross-sectional study of 615 T2DM patients, whose clinical data were extracted from hospital medical records. Beta-cell function was assessed by insulin secretion-sensitivity index-2 (ISSI2). Multivariable linear regression analysis and restricted cubic splines (RCS) analysis were performed to identify the association between systolic BP (SBP) and ISSI2. Mediation analysis was performed to determine whether higher SBP could reduce blood glucose by enhancing beta-cell function.

RESULTS

After adjustment of potential confounders, in participants with HbA1c ≥ 10%, the SBP between 140 to150 mmHg had the highest log ISSI2 (b = 0.227, 95% CI 0.053-0.402), an association specific to participants with < 1 year duration of diabetes. RCS analyses demonstrated an inverted U-shaped association between SBP and ISSI2 with the SBP at 144 mmHg corresponding to the best beta-cell function. This higher SBP was "paradoxically" associated with lower 2 h postprandial blood glucose (PBG) when SBP < 150 mmHg that was almost exclusively mediated by ISSI2 (mediating effect = - 0.043, 95%CI - 0.067 to - 0.018; mediating effect percentage = 94.7%, P < 0.01). SBP was however not associated with improvement in ISSI2 or 2 h PBG in participants with HbA1c < 10%.

CONCLUSIONS

In early stage of diabetes, a slightly elevated SBP (140-150 mmHg) was transiently associated with better beta-cell function in T2DM patients with HbA1c ≥ 10% but not in those with HbA1c < 10%.

Comparison between whole blood viscosity measured and calculated in subjects with monoclonal gammopathy of undetermined significance and in patients with multiple myeloma: Re-evaluation of our survey

BACKGROUND

in this study, with a re-evaluation of the hemorheological determinants previously described in MGUS subjects and in MM patients, we have detected the calculated whole blood viscosity, according whether to the hematocrit and total plasma protein concentration (de Simone formula) or to the haematocrit and plasma fibrinogen level (Merrill formula), and a marker of the erythrocyte aggregation (albumin/fibrinogen level).

METHODS

data were expressed as means±standard deviation. Student's t test for unpaired data was used to compare MGUS subjects and MM patients. The correlation coefficient between mean erythrocyte aggregation (MEA) and hematocrit (Ht) was evaluated in MGUS, MM and MGUS + MM groups using the Spearman test.

RESULTS

the comparison between MGUS and MM shows that the measured blood viscosity and calculated blood viscosity based on hematocrit and total plasma protein, but not which estimated in relation to the hematocrit and plasma fibrinogen, differentiate the two groups. A difference between the two groups also regards the measured erythrocyte aggregation and its surrogate marker. In addition, the measured plasma viscosity at low shear rate (0.51 s-1) and, in particular, the ratio between plasma viscosity at low (0.51 s-1) and high (450 s-1) shear rates distinguish MGUS and MM.

CONCLUSIONS

calculated blood viscosity (de Simone formula and other formulas) and the surrogate marker of erythrocyte aggregation disclose an alike trend with the corresponding hemorheological determinants obtained by using their direct measurement.

An assessment of the hemorheological profile in patients with subclinical carotid atherosclerosis divided in relation to the number of cardiovascular risk factors and different degrees of insulin resistance

We present a cohort of 100 subjects [43 men and 57 women; median age 66.00(25)] who were tested using carotid ultrasound to identify subclinical carotid atherosclerosis (SCA). We have evaluated the behaviour of whole blood viscosity (WBV) at high (450 s-1) and low (0.51 s-1) shear rates, plasma viscosity (450-1), hematocrit and mean erythrocyte aggregation. When compared to normal control subjects, using the Mann-Whitney test, we observed in SCA patients a significant increase in WBV only. The results were substantial after having divided the SCA subjects according to the cardiovascular risk factors (CRFs) and the degree of insulin resistance; the research was performed using two surrogate indexes such as TG/HDL-C and TyG. With the division carried out according to CRFs, employing the Kruskal-Wallis test, results show a significant increase in WBV (at high and low shear rates), in plasma viscosity, in erythrocyte aggregation and plasma fibrinogen level. Whereas by dividing them into the median of TG/HDL-C and TyG, we noticed a significant increase in WBV (at high and low shear rates) and in erythrocyte aggregation in the two groups with high TG/HDL-C ratio and with high TyG; having found an increased level of plasma fibrinogen in the latter. The data underlines the role of the main hemorheologic aspects in subclinical carotid atherosclerosis being closely correlated to the CRFs and different degrees of insulin resistance.

Erythrocyte deformability and aggregation in morbidly obese women undergoing laparoscopic gastric bypass surgery and effects of oral omega-3 fatty acid supplementation

BACKGROUND: An adequate erythrocyte function is vital for tissue oxygenation and wound healing. The erythrocyte membrane phospholipid composition plays an important role in erythrocyte function and administration of omega-3 fatty acids may provide a means to improve it. OBJECTIVE: To investigate peri-operative erythrocyte function and effects of oral omega-3 fatty acids in morbidly obese women undergoing gastric bypass surgery METHODS: Fifty-six morbidly obese women undergoing laparoscopic Roux-en-Y gastric bypass (LRYGB) surgery were randomized between a low calorie diet (LCD) during 2 weeks or oral omega-3 poly-unsaturated fatty acids (n-3 PUFAs) and a normal diet during 4 weeks. Peri-operative blood samples were analyzed with the Lorrca MaxSIS Ektacytometer for erythrocyte deformability and aggregability. RESULTS: There were no significant differences in erythrocyte function between the groups at any time point. Only erythrocyte aggregability parameters were affected by surgery. At six month follow-up, aggregation index (AI) and cholesterol, glucose and insulin were significantly improved. CONCLUSIONS: In this study, oral Omega-3 supplementation did not affect erythrocyte function compared to a LCD. Six months after surgery a significant improvement in AI and metabolic parameters was observed in both groups, contributing to a reduction in the risk at thromboembolic and cardiovascular complications.

Patient and haemodynamic factors affecting intraoperative graft flow during coronary artery bypass grafting: an observational pilot study

Transit-time flow measurement (TTFM) is frequently used to evaluate intraoperative quality control during coronary artery bypass grafting (CABG) and has the ability to assess graft failure intraoperatively. However, perioperative factors affecting TTFM during CABG remain poorly understood. Patients who underwent CABG at a single institution between July 2016 and May 2018 were prospectively evaluated. TTFM and blood viscosity were measured haemodynamically, while mean flow (mL/min), pulsatility index, and diastolic filling were recorded. Arterial blood gas was analysed immediately after left internal mammary artery to left descending artery anastomosis and before sternal closure. Factors associated with TTFM were assessed using multiple linear regression analysis. We evaluated 57 of the 62 patients who underwent CABG during the study period, including 49 who underwent off-pump and 8 who underwent on-pump surgeries. Blood viscosity was not significantly associated with TTFM (p > 0.05). However, TTFM was significantly associated with body mass index, systolic blood pressure, and cardiac index (p < 0.05 each). In conclusion, maintaining the SBP in the perioperative period and maintaining the CI with inotropic support or fluid resuscitation can be important in improving blood flow of graft vessels after surgery.

High-intensity interval training irrespective of its intensity improves markers of blood fluidity in hypertensive patients

Aim: The present study examined and compared the effects of two different HIIT (High-intensity interval training) protocols on markers of blood fluidity in hypertensive patients.Methods: Thirty hypertensive (stage 1, systolic BP >140 and diastolic BP>90 mmHg) patients (age, 47.96 ± 3.20 yrs), were randomly allocated to short-duration HIIT (SDHIIT, n = 10), long-duration HIIT (LDHIIT, n = 10), and control (n = 10) groups. After 2 weeks of continuous mild training, patients in SDHIIT group performed 8 weeks of HIIT included 27 min HIIT that encompassed 27 repetitions of 30 s activity at 80%-100% of VO₂peak interspersed by 30 s passive/active (10%-20% of VO₂peak) recovery, while, patients in LDHIIT group performed 8 weeks of HIIT (32 min per session) included 4 repetitions of 4 min activity at 75%-90% of VO₂peak interspersed by 4 min passive/active (15%-30% of VO₂peak) recovery. Two blood samples were taken before and after training and were analyzed for hemorheological variables.Results: Significant (P < .05) reductions in systolic blood pressure (SBP), blood and plasma viscosity, fibrinogen concentration and red blood cell (RBC) aggregation (8-12%) were found following two training protocols (P < .05), though, the differences between adaptations were not statistically significant (P > .05). In addition, HIIT protocols increased RBC deformability significantly (P < .05), with no significant differences being observed between two protocols.Conclusion: It is concluded that HIIT training reduces SBP and markers of blood fluidity in patients with stage 1 hypertension irrespective of the HIIT intensity and duration. Therefore, this type of exercise training could be prescribed for improving the blood fluidity markers in hypertensive patients.

Altered erythrocyte morphology in Mexican adults with prediabetes and type 2 diabetes mellitus evaluated by scanning electron microscope

AIM

To evaluate the erythrocyte morphology in people with prediabetes, T2DM and healthy subjects in a Mexican population and its association with biochemical parameters.

METHODS

Cross-sectional study consisted of three groups: healthy (HG), people with prediabetes (PG) and with T2DM (DMG). A blood sample was obtained from all participants to assess the erythrocyte morphology, and levels of HbA1c, glucose and lipid profile. Anthropometrical parameters were also evaluated.

RESULTS

It was observed that compared with healthy individuals, people with prediabetes presented a significant decrease in the diameter (-0.08 μm, P = 0.014) and height (-0.07 μm, P = 0.004), as well as people with T2DM (-0.33 μm, P < 0.001 in diameter; and -0.36 μm, P < 0.001 in height). Besides, it was found a significant difference in diameter (-0.25 μm, P < 0.001) and height (-0.29 μm, P < 0.001) between the PG and DMG. No significant differences in the axial ratio between groups. Also, HbA1c, glucose, triglycerides, cholesterol, LDL cholesterol, systolic blood pressure, weight, BMI, waist and hip circumference were significantly associated with diameter and height.

CONCLUSIONS

Erythrocyte morphological alterations can serve as an indicator of early diagnosis of T2DM and a factor implicated in the course of the clinical condition, so the correction of these alterations could serve as a treatment for prediabetes and T2DM. It is essential to promote constantly checkups of biochemical and anthropometrical parameters, as well as erythrocyte morphological alterations to prevent the onset of prediabetes and T2DM and possible clinical complications.

Plasmapheresis for hypertriglyceridemia: The association between blood viscosity and triglyceride clearance rate

OBJECTIVES

Several factors in double filtration plasmapheresis (DFPP) were associated with triglyceride (TG) clearance rate. This study examines whether baseline whole blood viscosity was a predictor for efficient TG removal.

METHODS

Adult subjects who receiving DFPP for hyperlipidemia in Taoyuan General Hospital from January 2015 to March 2018 were classified into efficient and inefficient TG removal according to TG removal rate ≥50% vs <50%. TG removal rate was defined as following formula: (pre-apheresis TG- post-apheresis TG)/pre-apheresis TG. Whole blood viscosity (WBV) was estimated by following equation: WBV = 0.12 × hematocrit +0.17 × (total protein -2.07). Univariate linear regression was used to assess the association between TG removal rate and WBV. Odds ratios (ORs) and 95% confidence interval (95%CI) for associations between variables and efficient TG removal were evaluated by logistic regression model to including univariate and multivariate adjustment.

RESULTS

From a total of 66 subjects receiving DFPP, 37 subjects reached efficient TG removal. The difference in pre-apheresis TG levels, hematocrit, and WBV between efficient vs. inefficient TG removal groups was 4.1 vs 6.7 mmol/L; 43.1% vs 39.5%; and 6.0cP vs 5.cP (Ps <0.05). After multivariate adjustment, WBC was a significant predictor for efficient TG removal (ORs and 95% CI were 3.192 (1.300-7.838), P < 0.05). The correlation between WBV and extraction of TG was significant (r = -0.255, P = 0.039).

CONCLUSION

Hyperviscosity reduced the efficiency of TG removal in those receiving DFPP.

Blood Pressure and Haematological Indices in Twelve Communities in Ashanti, Ghana

Hypertension is the most important risk factor for cardiovascular mortality and morbidity in Sub-Saharan Africa. In western populations, high haemoglobin levels are associated with raised BP unlike in Sub-Saharan Africa where there is a paucity of data. Our study examines the association between haematological indices with BP variables. Weight, height, BP, and whole blood indices of viscosity (Hb, haematocrit, RBC count, and MCV) were measured in 921 adults (340 men, 581 women; aged 40-75) in 12 communities in Ghana. Mean values for Hb (12.3 g/dl ± 1.7 SD), haematocrit (36.7% ± 5.2), RBC (4.10 million/μL ± 0.64), and MCV were lower than reference values used in Sub-Saharan Africa. Mean BMI was 21.1 ± 4.1 indicating a lean population. Systolic BP increased by 1.0 mmHg (95% CI 0.5-1.5), p < 0.001, for women and 0.5 (0.1-1.0), p = 0.027, for men per unit increase in haematocrit. Similar relationships were found for Hb and RBC but not for MCV or platelets. The relationships were weaker when adjusted for BMI, 0.7 mmHg (0.2-1.2) in women and 0.5 (0.0-1.0) in men. Findings for diastolic BP were similar. Overall haematological indices were low. We have found a significant, positive relationship between BP, Hb, Haematocrit, and RBC count in our population.

Body fat and blood rheology: Evaluation of the association between different adiposity indices and blood viscosity

BACKGROUND

In recent years, new measures of body adiposity have been introduced: lipid accumulation product (LAP), body adiposity index (BAI) and body shape index (ABSI). These indices have been demonstrated to better associate with cardiovascular disease than other measures of adiposity.

OBJECTIVES

The aim of the present study was to evaluate if LAP or BAI better associate with blood viscosity than other measures of adiposity (body mass index, BMI; waist circumference, WC; waist-to-hip ratio, W/HR; waist-to-height ratio, W/HtR).

METHODS

344 subjects were recruited for the present investigation. Exclusion criteria were: diabetes, elevated triglycerides, smoking and drug use. Blood lipids and glucose were measured by routine methods. Blood and plasma viscosity were measured by a cone-plate viscometer. Adiposity measures were computed as previously described.

RESULTS

In simple correlation analyses, blood viscosity (BV) correlated with BMI, BAI, and LAP in males and with LAP in females. Correlations between plasma viscosity and adiposity indices were weak and not statistically significant. Other variables significantly related with BV were: gender, HDL- and LDL-Cholesterol, and triglycerides (p < 0.05). In multiple regression analysis only LAP was associated with BV.

CONCLUSIONS

Our data suggest that LAP index is strongly associated to blood viscosity. This result, along with previous evidence, identifies LAP index as a potential cardiovascular risk marker.