Improved Erythrocyte Deformability Research Articles

Effects of Cardiotonic Pills<sup>®</sup> on Cerebrovascular CO<sub>2</sub> Reactivity and Erythrocyte Deformability in Normal Subjects: A Pilot Study

Backgrounds and objectives: Cardiotonic Pills<sup>®</sup> (CP) are used for vascular diseases such as coronary diseases, atherosclerosis, and cerebral infarction. This study aimed to determine the transient effects of CP on cerebrovascular CO<sub>2</sub> reactivity (CVR) and erythrocyte deformability in normal subjects.Methods: This study had a crossover design and included 10 participants who were randomly allocated to 2 groups. The experimental group was given CP with water, while the control group was given only water. CVR was measured by hyperventilation-induced CVR of the middle cerebral artery (MCA) using transcranial Doppler (TCD). Erythrocyte deformability was measured using a Rheoscan-D microfluidic ektacytometer. All measurements were performed prior to and 1, 2, and 3 hours after CP or water administration. Blood pressure and heart rate were also measured before and after administration.Results: CP significantly improved CVR 3 hours after administration in the experimental group compared to the control group (<i>p</i> = 0.042). The corrected blood flow velocity at partial pressure of end-tidal carbon dioxide (PETCO<sub>2</sub>) = 40mmHg (CV40) was also significantly improved 2 and 3 hours after administration in the CP group compared to the control group (<i>p</i> = 0.036 and <i>p</i> = 0.021, respectively). CP significantly improved erythrocyte deformability 3 hours after administration in the experimental group compared to the control group (<i>p</i> = 0.027). Mean heart rate and mean blood pressure showed no change.Conclusions: This study demonstrated that CP increases CVR and erythrocyte deformability. These results suggested that CP improves cerebral microcirculation which provide evidence for the future use of CP for prevention of ischemic stroke and neurodegenerative diseases.

The Effect of Voxelotor on Erythrocyte Deformability, Neutrophil Phenotype and Endothelial Activation

Introduction Sickle cell disease (SCD) is characterized by chronic intravascular hemolysis, caused by polymerization of abnormal sickle hemoglobin. The ongoing intravascular hemolysis leads to release of cell-free heme and iron, resulting in widespread oxidative damage, inflammation, neutrophil activation, endothelial activation and hypercoagulability, all contributing to vaso-occlusive events and end organ damage. Voxelotor, a small molecule reversibly binding to hemoglobin S (HbS) increases its oxygen affinity, thereby decreasing HbS polymerization and sickling, resulting in decreased hemolysis. The decrease in erythrocyte sickling might lead to improved erythrocyte deformability and decreased adhesion, while reductions in cell-free heme and labile plasma iron levels might result in decreased neutrophil activation, adhesion and aging and decreased endothelial activation. The aim of this study is to assess the effects of voxelotor on erythrocyte deformability, neutrophil activation, adhesion and aging and endothelial activation. Methods SCD patients (HbSS and HbSβ 0-thalassemia), with hemoglobin (Hb) ≤ 10.5 g/dL were treated with voxelotor 1500 mg in a single arm interventional study. Blood was collected at baseline and after 3 months of treatment. Erythrocyte deformability was assessed by ektacytometry (Lorrca, RR mechatronics), measuring elongation index (EI) and point of sickling (PoS). EI max and EI min indicate the highest and lowest erythrocyte deformability upon oxygenation and deoxygenation respectively. PoS is the oxygen tension at which 5% reduction of the EI max is observed. Antigen expression of neutrophil markers for activation, adhesion and aging were assessed with flow cytometry. Reactive oxygen species (ROS) production of neutrophils was measured by Amplex Red Assay (Molecular probes), measuring hydrogen peroxide (H 2O 2) production under unstimulated and stimulated (zymosan, streptozotocin (STZ), factor-n-formyl-MET-LEU-Phe (fMLP), Phorbol myristate acetate (PMA)) and platelet-activating factor-fMLP (PAF-fMLP)). Endothelial activation was assessed by measuring von Willebrand Factor antigen (vWF-Ag) using enzyme-linked immunosorbent assay (ELISA) (Glostrup). Prothrombin fragment 1+2 (F 1+2), thrombin-antithrombin complexes (TAT) and D-dimer were measured using ELISA. Data are presented as median with interquartile range (IQR), unless stated otherwise. A P value of <0.05 was considered significant. Results 15 SCD patients (11 HbSS, 4 HbSβ 0-thalassemia), 5 female, median age 35 years (IQR 27-46)) completed 3-month follow-up. Hb levels increased significantly after 3 months of treatment (from 7.4 (6.9 - 8.1) g/dL to 9.7 (7.9 - 11.0) g/dL, p=0.002), corresponding to significant decreases in LDH and bilirubin levels and reticulocyte counts as markers of hemolysis (p<0.05). PoS decreased significantly after 3 months (from 20.1 (17.5 - 26.1) mmHg to 16.1 (10.3 - 18.1) mmHg, p=0.006). Both EI max and EI min increased after 3 months of treatment (from 0.33 (0.24 - 0.42) to 0.38 (0.28 - 0.48), p=0.029 and from 0.13 (0.07 - 0.26) to 0.21 (0.16 - 0.41), p=0.007 respectively). Markers of neutrophil activation, adhesion and aging were generally lower after 3 months of treatment, though the differences were not statistically significant (Figure 1 A-C). Neutrophil ROS production in both unstimulated and stimulated condition remained unchanged (Figure 1D). After 3 months of treatment vWF-Ag significantly decreased (from 252 (187 - 284) % to 183 (153-205) %, p = 0.033). No changes were observed in markers of coagulation activation (F 1+2 and TAT, and D-dimer). Conclusion Voxelotor significantly improved erythrocyte deformability as suggested by decreased PoS and increased EI max and EI min, potentially leading to improved rheological properties. While markers of neutrophil activation seem to decrease, the differences are not statistically significant, possibly due to the relatively small sample size. A reduction in vWF-Ag was observed possibly reflecting diminished endothelial activation, due to a decrease in intravascular hemolysis.

Zinc improved erythrocyte deformability and aggregation in patients with beta-thalassemia: An in vitro study.

Thalassemia patients have reduced red cell deformability and decreased plasma zinc levels in their blood. This study aimed to evaluate the effects of zinc (Zn) on the hemorheological parameters and antioxidant enzyme activities in β-thalassemia major (TM) and healthy volunteers (HV). Hemorheological parameters were measured using LORCA (laser-assisted optical rotational cell analyzer) after adjusting the hematocrit to 40%. Zinc sulfate (ZnSO4.7H2O) was used for Zn incubation with a concentration of 0.5μg/dl. Oxidative stress and antioxidant status were determined using commercial kits. Data showed that after Zn incubation, EImax, the area under the EI-osmolarity curve (Area), and Omax decreased in TM. However, no significant difference was observed in the osmotic deformability parameters of HV. The increased elongation index was obtained at different shear stresses for TM and HV, and SS1/2 decreased in both groups. The AMP and aggregation index (AI) decreased in TM, and the required time for half of the maximum aggregation (t1/2) increased in HV. However, Zn did not affect oxidative parameters in both groups. This study showed that Zn incubation increased deformability and decreased aggregation in thalassemic erythrocytes. It means that Zn supplementation will contribute to microcirculation in thalassemia patients.

Comparative evaluation of clinical glycemic control markers treated with imeglimin and its effect on erythrocytes in patients with type 2 diabetes mellitus: study protocol of a single-arm, open-label, prospective, exploratory trial.

Background: Imeglimin is a novel type 2 diabetes (T2D) drug that is expected to improve mitochondrial function. In its phase 3 clinical trials in Japanese patients with T2D, the hemoglobin A1c (HbA1c) decrease following imeglimin administration was slow, reaching a plateau after 20-24weeks of treatment. In general, the erythrocyte lifespan may be a factor when HbA1c shows an abnormal value. Therefore, this study will comparatively evaluate HbA1c and other markers of glycemic control in patients with T2D after imeglimin administration and also examine the effects of imeglimin on erythrocytes. Methods: This single-arm, open-label, prospective, exploratory study is designed to evaluate the divergence between HbA1c and glycoalbumin (GA) or 1,5-anhydroglucitol (1,5-AG) and the glycemic reduction rate in 30 patients with T2D with inadequate glycemic control when imeglimin 2,000mg is administered for 6months. In addition, we will examine the effect on erythrocytes, the presumed cause of this divergence. We will measure sustained glycemic variability using flash glucose monitoring and examine the relationship between changes in these indices and HbA1c. Moreover, because prolonged erythrocyte lifespan is a possible cause of falsely high HbA1c levels, erythrocyte lifespan, erythrocyte deformability, and hemoglobin concentration will be evaluated as effects of imeglimin on erythrocytes. Furthermore, if imeglimin has an ameliorative effect on erythrocyte deformability, it may improve peripheral arterial disease; thus, we will also evaluate the toe-brachial pressure index, a measure of this effect. Discussion: In this study, if imeglimin administration results in diverging rates of hypoglycemic effect between HbA1c and GA or 1,5-AG and prolongs erythrocyte lifespan, GA and 1,5-AG, rather than HbA1c, will be considered appropriate measures of the hypoglycemic effect in the early stages of imeglimin administration. If imeglimin improves erythrocyte deformability, it may also be a new treatment strategy for peripheral arterial disease, a chronic complication of T2D. Ethics and dissemination: The study protocol was scientifically and ethically reviewed and approved by the Certified Clinical Research Review Board of Toho University (approval number: THU22002). The study protocol was registered in the Japan Registry of Clinical Trials (jRCT) in December 2022 (jRCTs031220489).

The effect of sulfur baths on hemorheological properties of blood in patients with osteoarthritis

Balneotherapy is an effective treatment method in various diseases and commonly used treatment modality among patients with musculoskeletal disorders. Sulfur baths are known for healing properties however effect on rheological properties is unstudied. Thus the aim of our study was to determine the effect of sulfur balneotherapy on hemorheological blood indices. A total of 48 patients with osteoarthritis were enrolled to the study. Blood samples were collected twice, before and after 3-week time period. We evaluated complete blood count, fibrinogen, hs-CRP and blood rheology parameters such as elongation index (EI), half-time of total aggregation (T1/2) and aggregation index (AI) analyzed with the Lorrca Maxis. Mean age of studied cohort was 67 ± 5 years. After sulfur baths WBC count was significantly decreased is studied group (p = 0.021) as well as neutrophile count (p = 0.036). Red blood cell EIs were statistically higher after sulfur baths in shear stress ranging from 8.24 to 60.30 Pa. T1/2 was significantly higher (p = 0.031) and AI lower (p = 0.003) compared to baseline. No significant changes in fibrinogen and hs-CRP were observed. It is the first study that evaluate effect of sulfur balneotherapy on rheologic properties of blood. Sulfur water baths may improve erythrocyte deformability and aggregation parameters.

Vitamin C supplementation attenuates oxidative stress and improves erythrocyte deformability in cardiac surgery with cardiopulmonary bypass.

Cardiopulmonary bypass (CPB) depletes endogenous Vitamin C and generates oxidative stress in cardiac surgery. This study aimed to clarify whether Vitamin C supplementation reduces oxidant production and improves erythrocyte deformability in cardiac surgery with CPB. In a randomized and controlled design, 30 eligible patients undergoing cardiac surgery with hypothermic CPB were equally assigned to the Vitamin C group and control group. Subjects of the Vitamin C group and control group received an intravenous infusion of Vitamin C 20 mg·kg-1 and a placebo during rewarming period of CPB, respectively. We measured the plasma level of reactive oxygen species (ROS) and phosphorylation levels of non-muscle myosin IIA (NMIIA) in erythrocyte membrane, as an index of erythrocyte deformability, before and after CPB. Vitamin C supplementation attenuated the surge in plasma ROS after CPB, mean 1.661 ± standard deviation 0.801 folds in the Vitamin C group and 2.743 ± 1.802 in the control group. The tyrosine phosphorylation level of NMIIA after CPB was upregulated in the Vitamin C group compared to the control group, 2.159 ± 0.887 folds and 1.384 ± 0.445 (P = 0.0237). In addition, the phosphorylation of vasodilator-stimulated phosphoprotein (VASP) and focal adhesion kinase (FAK) in erythrocytes was concurrently enhanced in the Vitamin C group after CPB. The phosphorylation level of endothelial nitric oxide synthase in erythrocytes was significantly increased in the Vitamin C group (1.734 ± 0.371 folds) compared to control group (1.102 ± 0.249; P = 0.0061). Patients receiving Vitamin C had lower intraoperative blood loss and higher systemic vascular resistance after CPB compared to controls. Vitamin C supplementation attenuates oxidative stress and improves erythrocyte deformability via VASP/FAK signaling pathway in erythrocytes during CPB.

Beneficial Effect of Quercetin on Erythrocyte Properties in Type 2 Diabetic Rats.

Diabetes mellitus is characterized by tissue oxidative damage and impaired microcirculation, as well as worsened erythrocyte properties. Measurements of erythrocyte deformability together with determination of nitric oxide (NO) production and osmotic resistance were used for the characterization of erythrocyte functionality in lean (control) and obese Zucker diabetic fatty (ZDF) rats of two age categories. Obese ZDF rats correspond to prediabetic (younger) and diabetic (older) animals. As antioxidants were suggested to protect erythrocytes, we also investigated the potential effect of quercetin (20 mg/kg/day for 6 weeks). Erythrocyte deformability was determined by the filtration method and NO production using DAF-2DA fluorescence. For erythrocyte osmotic resistance, we used hemolytic assay. Erythrocyte deformability and NO production deteriorated during aging—both were lower in older ZDF rats than in younger ones. Three-way ANOVA indicates improved erythrocyte deformability after quercetin treatment in older obese ZDF rats only, as it was not modified or deteriorated in both (lean and obese) younger and older lean animals. NO production by erythrocytes increased post treatment in all experimental groups. Our study indicates the potential benefit of quercetin treatment on erythrocyte properties in condition of diabetes mellitus. In addition, our results suggest potential age-dependency of quercetin effects in diabetes that deserve additional research.

Old cells die hard - sympatholysis and the ageing erythrocyte.

Old cells die hard - sympatholysis and the ageing erythrocyte.

High-dose nitroglycerin administered during rewarming preserves erythrocyte deformability in cardiac surgery with cardiopulmonary bypass.

We aimed to determine whether high-dose nitroglycerin, a nitric oxide donor, preserves erythrocyte deformability during cardiopulmonary bypass and examines the signaling pathway of nitric oxide in erythrocytes. In a randomized and controlled fashion, forty-two patients undergoing cardiac surgery with hypothermic cardiopulmonary bypass were allocated to high-dose (N=21) and low-dose groups (N=21). During rewarming period, patients were given intravenous nitroglycerin with an infusion rate 5 and 1µg·kg-1 ·min-1 in high-dose and low-dose groups, respectively. Tyrosine phosphorylation level of non-muscle myosin IIA in erythrocyte membrane was used as an index of erythrocyte deformability and analyzed using immunoblotting. Tyrosine phosphorylation of non-muscle myosin IIA was significantly enhanced after bypass in high-dose group (3.729±1.700 folds, P=.011) but not low-dose group (1.545±0.595 folds, P=.076). Phosphorylation of aquaporin 1, vasodilator-stimulated phosphoprotein, and focal adhesion kinase in erythrocyte membrane was also upregulated in high-dose group after bypass. Besides, plasma nitric oxide level was highly correlated with fold change of non-muscle myosin IIA phosphorylation (Pearson's correlation coefficient .871). High-dose nitroglycerin administered during cardiopulmonary bypass improves erythrocyte deformability through activating phosphorylation of aquaporin 1, vasodilator-stimulated phosphoprotein, and focal adhesion kinase in erythrocytes.

Effect of curcumin extract against oxidative stress on both structure and deformation capability of red blood cell

The normal deformability of erythrocytes plays an important role in ensuring blood mobility, erythrocyte longevity, and microcirculation, which is the ability of erythrocytes to change shapes in response to external forces. However, the effects of curcumin extracts on the deformability of erythrocytes have not yet been evaluated. Accordingly, in this study, we explored the effects of pre-treatment with curcumin extract on erythrocyte deformation and erythrocyte band 3 (SLC4A1; EB3) expression. We also evaluated the associations between EB3 expression and erythrocyte deformability induced by hydrogen peroxide. Blood samples were divided into the control group, pre-treatment group (treated with curcumin extract or vitamin C), and negative control group, and oxidant stress parameters, antioxidant status, erythrocyte deformability and elasticity, and EB3 modifications were evaluated using immunoblotting and immunofluorescence staining. Hydrogen peroxide significantly increased oxidative stress parameters, modulus elasticity values and clustered EB3 levels and induced conjugation of membrane proteins to form high-molecular-weight complexes (p < 0.05). Erythrocyte deformability and elasticity were significantly decreased in the treated groups compared with those in the control group. Overall, our findings suggested that pre-treatment with curcumin extracts increased antioxidant status, reduced EB3 cross-linking, and improved erythrocyte deformability, to an even better extent than vitamin C. These results provide important insights into the effects of treatment with curcumin extracts on erythrocyte damage and suggest that curcumin may have applications in antioxidant therapy.

Effect of the herbal medicine Danggui Sini plus Wuzhuyu Shengjiang Tang on erythrocyte deformability in normal subjects: a cross-over trial

OBJECTIVETo show whether Danggui Sini plus Wuzhuyu Shengjiang Tang (DSWST) has any transient effect on erythrocyte deformability in normal subjects. METHODSA total of 25 subjects [mean age (27.8 ± 1.8) years] was enrolled in this study. The study was designed as a cross-over trial in which the subjects took part for 2 d. On the first day, blood samples were collected at baseline and 1-2 h after administration of water, whereas, on the second day, instead of water, the subjects were administered DSWST after the baseline blood sampling. The blood samples collected at baseline and after the administration water or DSWST, were examined for erythrocyte deformability. RESULTSThe elongation index increased significantly after 2 h (P = 0.009) compared to the baseline after DSWST intake. However, after water intake, there was no significant difference observed. When comparing the percent change of erythrocyte deformability between DSWST and water, we found that after 2 h of administration, DSWST improved erythrocyte deformability significantly compared to water (P < 0.001). CONCLUSIONDSWST has a transient effect on erythrocyte deformability in normal subjects.

Acute dark chocolate ingestion is beneficial for hemodynamics via enhancement of erythrocyte deformability in healthy humans

Erythrocyte deformability is an important property of erythrocytes that considerably affects blood flow and hemodynamics. The high content of polyphenols present in dark chocolate has been reported to play a protective role in functionality of erythrocytes. We hypothesized that chocolate might influence erythrocytes not only after repeated chronic intake, but also immediately after its ingestion. Thus, we determined the acute effect of dark chocolate and milk (with lower content of biologically active substances) chocolate intake on erythrocyte deformability. We also focused on selected factors that may affect erythrocyte deformability, specifically nitric oxide production in erythrocytes and total antioxidant capacity of plasma. We determined posttreatment changes in the mentioned parameters 2hours after consumption of chocolate compared with their levels before consumption of chocolate. In contrast to milk chocolate intake, the dark chocolate led to a significantly higher increase in erythrocyte deformability. Nitric oxide production in erythrocytes was not changed after dark chocolate intake, but significantly decreased after milk chocolate. The plasma total antioxidant capacity remained unaffected after ingestion of both chocolates. We conclude that our hypothesis was confirmed. Single ingestion of dark chocolate improved erythrocyte deformability despite unchanged nitric oxide production and antioxidant capacity of plasma. Increased deformability of erythrocytes may considerably improve rheological properties of blood and thus hemodynamics in humans, resulting in better tissue oxygenation.

Effect of Cydonia oblonga Mill. fruit and leaf extracts on blood pressure and blood rheology in renal hypertensive rats

Ethnopharmacological relevanceQuince, Cydonia oblonga Mill. (COM), is used in traditional Uyghur medicine to treat or prevent cardiovascular diseases. Uyghur people have greater longevity and lower blood pressure than other central Asian populations. We therefore tested COM fruit and leaf extracts on blood pressure and rheology in renal hypertensive rats (RHR). Materials and methodsTwo-kidney, one-clip (2K1C) renal hypertensive rats were divided randomly into eleven groups: sham, model, and model treated with daily doses of 80 and 160mg/kg aqueous or ethanol extracts of COM fruit or leaves, or 25mg/kg captopril (n=10 per group), given orally once daily for 8 weeks. Blood pressure was measured before treatment and every 2 weeks thereafter. Blood rheology was tested after 8 weeks. ResultsModel rats had higher blood pressure than sham 8 weeks after the procedure (systolic blood pressure 193±7 vs. 138±8mmHg, p<0.05). Those treated with captopril had decreased blood pressure within 2 weeks but that did not return to the level found in the sham group at 8 weeks (167±7, p<0.05 vs. model). With the COM extracts, the effect on blood pressure was notable after 4 weeks. At 8 weeks blood pressure was similar with captopril and with 160mg ethanol leaf extract (166±4, p<0.05 vs. model), the most effective of the extracts. Model rats had higher blood viscosity and lower erythrocyte deformability than sham. Captopril had little effect on blood rheology; whereas COM extracts reduced whole blood viscosity and improved erythrocyte deformability to levels approaching those found in sham. ConclusionsCOM extracts have antihypertensive activity in renal hypertensive rats. The additional effect on rheology, compared to captopril, may convey added interest. Further studies of these effects in man appear warranted.

Effects of ethanol on red blood cell rheological behavior

Consumption of red wine is associated with a decreased risk of several cardiovascular diseases (e.g., coronary artery disease, stroke), but unfortunately literature reports regarding ethanol's effects on hemorheological parameters are not concordant. In the present study, red blood cell (RBC) deformability was tested via laser ektacytometry (LORCA, 0.3-30 Pa) using two approaches: 1) addition of ethanol to whole blood at 0.25%-2% followed by incubation and testing in ethanol-free LORCA medium; 2) addition of ethanol to the LORCA medium at 0.25%-6% then testing untreated native RBC in these media. The effects of ethanol on deformability for oxidatively stressed RBC were investigated as were changes of RBC aggregation (Myrenne Aggregometer) for cells in autologous plasma or 3% 70 kDa dextran. Significant dose-related increases of RBC deformability were observed at 0.25% (p < 0.05) and higher concentrations only if ethanol was in the LORCA medium; no changes occurred for cells previously incubated with ethanol then tested in ethanol-free medium. The impaired deformability of cells pre-exposed to oxidative stress was improved only if ethanol was in the LORCA medium. RBC aggregation decreased with concentration at 0.25% and higher for cells in both autologous plasma and dextran 70. Our results indicate that ethanol reversibly improves erythrocyte deformability and irreversibly decreases erythrocyte aggregation; the relevance of these results to the health benefits of moderate wine consumption require further investigation.

Calpain-1 knockout reveals broad effects on erythrocyte deformability and physiology

Pharmacological inhibitors of cysteine proteases have provided useful insights into the regulation of calpain activity in erythrocytes. However, the precise biological function of calpain activity in erythrocytes remains poorly understood. Erythrocytes express calpain-1, an isoform regulated by calpastatin, the endogenous inhibitor of calpains. In the present study, we investigated the function of calpain-1 in mature erythrocytes using our calpain-1-null [KO (knockout)] mouse model. The calpain-1 gene deletion results in improved erythrocyte deformability without any measurable effect on erythrocyte lifespan in vivo. The calcium-induced sphero-echinocyte shape transition is compromised in the KO erythrocytes. Erythrocyte membrane proteins ankyrin, band 3, protein 4.1R, adducin and dematin are degraded in the calcium-loaded normal erythrocytes but not in the KO erythrocytes. In contrast, the integrity of spectrin and its state of phosphorylation are not affected in the calcium-loaded erythrocytes of either genotype. To assess the functional consequences of attenuated cytoskeletal remodelling in the KO erythrocytes, the activity of major membrane transporters was measured. The activity of the K+-Cl- co-transporter and the Gardos channel was significantly reduced in the KO erythrocytes. Similarly, the basal activity of the calcium pump was reduced in the absence of calmodulin in the KO erythrocyte membrane. Interestingly, the calmodulin-stimulated calcium pump activity was significantly elevated in the KO erythrocytes, implying a wider range of pump regulation by calcium and calmodulin. Taken together, and with the atomic force microscopy of the skeletal network, the results of the present study provide the first evidence for the physiological function of calpain-1 in erythrocytes with therapeutic implications for calcium imbalance pathologies such as sickle cell disease.

Effects of Hyul-Bu-Chuke-Tang on Erythrocyte Deformability and Cerebrovascular CO2Reactivity in Normal Subjects

Aim. Hyul-bu-chuke-tang (HCEt) is a well-known traditional herbal medicine that is used for the treatment of ischemic cerebrovascular disorders. We investigated the acute effects of HCEt on erythrocyte deformability and cerebrovascular CO2 reactivity (CVR) in healthy male subjects. Materials and Methods. We examined erythrocyte deformability in an HCEt group (n = 14) and a control group (n = 10). CVR was measured using hyperventilation-induced CO2 reactivity of the middle cerebral artery and transcranial Doppler (TCD) in the HCEt group (n = 11). A historical control group (n = 10) of CVR measurements was also created from our previous study. All measurements were performed prior to and 1, 2, and 3 hours after HCEt administration. Results. HCEt significantly improved erythrocyte deformability 1 hour after administration compared to the control group (2.9 ± 1.1% versus −0.6 ± 1.0%, P = 0.034). HCEt significantly improved the CVR 2 hours after administration compared to the historical control group (9.1 ± 4.0% versus −8.1 ± 4.1%, P = 0.007). The mean blood pressure and pulse rate did not vary from baseline values in either group. Conclusions. We demonstrated that HCEt improved erythrocyte deformability and CVR. Our findings suggest that an improvement in erythrocyte deformability contributes to HCEt's effect on cerebral microcirculation.

Potential for Transcranial Laser or LED Therapy to Treat Stroke, Traumatic Brain Injury, and Neurodegenerative Disease

Near-infrared (NIR) light passes readily through the scalp and skull and a small percentage of incident power density can arrive at the cortical surface in humans.1 The primary photoreceptors for red and NIR light are mitochondria, and cortical neurons are exceptionally rich in mitochondria. It is likely that brain cells are ideally set up to respond to light therapy. The basic biochemical pathways activated by NIR light, e.g., increased adenosine-5′-triphosphate (ATP) production, and signaling pathways activated by reactive oxygen species, nitric oxide release, and increased cyclic adenosine monophosphate (AMP) all work together to produce beneficial effects in brains whose function has been compromised by ischemia, traumatic injury, or neurodegeneration. One of the main mechanisms of action of transcranial light therapy (TLT) is to prevent neurons from dying, when they have been subjected to some sort of hypoxic, traumatic, or toxic insult. This is probably because of light-mediated upregulation of cytoprotective gene products such as anti-oxidant enzymes, heat shock proteins, and anti-apoptotic proteins. Light therapy in vitro has been shown to protect neurons from death caused by methanol,2 cyanide or tetrodotoxin,3 and amyloid beta peptide.4 There is also probably a second mechanism operating in TLT; increased neurogenesis. Neurogenesis is the generation of neuronal precursors and birth of new neural cells.5 Two key sites for adult neurogenesis include the subventricular zone (SVZ) of the lateral ventricles, and the subgranular layer (SGL) of the dentate gyrus in the hippocampus.6 Neurogenesis can be stimulated by physiological factors, such as growth factors and environmental enrichment, and by pathological processes, including ischemia and neurodegeneration.7 Adult neurogenesis (in the hippocampus particularly) is now recognized as a major determinant of brain function both in experimental animals and in humans. Neural progenitor cells in their niche in the SGL of the dentate gyrus give birth to newly formed neurons that are thought to play a role in brain function, particularly in olfaction and in hippocampal-dependent learning and memory.8 In small animal models neurogenesis can be readily detected by incorporation of bromodeoxyuridine (BrdU), injected before euthanasia, into proliferating brain cells. Increased neurogenesis after TLT, has been demonstrated in a rat model of stroke,9 and in the Hamblin laboratory after TLT for acute traumatic brain injury (TBI) in mice (W. Xuan, T. Ando, et al., unpublished data). These two mechanisms of action of TLT in ameliorating brain damage (prevention of neuronal death and increased neurogenesis) have motivated studies in both animals and humans for diverse brain disorders and diseases. TLT for acute stroke is the most developed,10 but acute TBI has also been shown to benefit from TLT.11 These areas are reviewed further.

Effects of iloprost on blood rheology and tissue perfusion in patients with intermittent claudication: Results of a double-blind placebo-controlled study

The effects of an infusion of a single dose of Iloprost (from 0.5 up to a maximum of 2 ng/kg/min for six hours) in patients with stage II peripheral vascular disease (PVD) on blood rheology and tissue perfusion were determined in a double-blind placebo-controlled study using repeated treadmill exercise test to stress leg circulation. Blood viscosity (BV) at low shear, soluble P-selectin levels (expression of platelet activation), unfractioned leukocyte and erythrocyte filterability rates (using a constant-flow positive-pressure system), plasma fibrinogen concentration, haematocrit, leukocyte and platelet counts were measured in two matched groups of 8 PVD patients before and after treatment. Transcutaneous oxygen pressure (TcPO2) during controlled ischaemia was also measured. Controlled peripheral ischaemia generated an impaired haemorheological profile. Iloprost reduced the impairments in BV and the filterability rates of unfractioned leukocytes, inhibited platelet activation and improved erythrocyte deformability. These improvements were associated with significant shortening of the TcPO2 half recovery time, indicating that ischaemic damage had been contained.

Pioglitazone in addition to metformin improves erythrocyte deformability in patients with Type 2 diabetes mellitus

The aim of the present study was to compare the effect of PIO (pioglitazone) or GLIM (glimepiride) on erythrocyte deformability in T2DM (Type 2 diabetes mellitus). The study covered 23 metformin-treated T2DM patients with an HbA1c (glycated haemoglobin) >6.5%. Patients were randomized to receive either PIO (15 mg, twice a day) or GLIM (1 mg, twice a day) in combination with metformin (850 mg, twice a day) for 6 months. Blood samples were taken for the measurement of fasting glucose, HbA1c, fasting insulin, intact proinsulin, adiponectin and Hct (haematocrit). In addition, the erythrocyte EI (elongation index) was measured using laser diffractoscopy. Both treatments significantly improved HbA1c levels (PIO, -0.9+/-1.1%; GLIM, -0.6+/-0.4%; both P<0.05) and resulted in comparable HbA1c levels after 6 months (PIO, 6.5+/-1.2%; GLIM, 6.2+/-0.4%) Treatment with PIO reduced fasting insulin levels (-8.7+/-15.8 milli-units/l; P=0.098), intact proinsulin levels (-11.8+/-9.5 pmol/l; P<0.05) and Hct (-1.3+/-2.3%; P=0.09), whereas adiponectin levels increased (8.2+/-4.9 microg/ml; P<0.05). No significant change in these parameters was observed during GLIM treatment. PIO improved the EI, resulting in a significant increase in EI at all physiological shear stress ranges (0.6-6.0 Pa; P<0.05). The improvement in EI correlated with the increase in adiponectin levels (r=0.74; P<0.001), and inversely with intact proinsulin levels (r=-0.47; P<0.05). This is the first study showing an improvement in EI during treatment with PIO, which was associated with an increase in adiponectin and a decrease in intact proinsulin levels, but independent of glycaemic control.

C‐Peptide and Its C‐Terminal Fragments Improve Erythrocyte Deformability in Type 1 Diabetes Patients

Aims/hypothesis. Data now indicate that proinsulin C-peptide exerts important physiological effects and shows the characteristics of an endogenous peptide hormone. This study aimed to investigate the influence of C-peptide and fragments thereof on erythrocyte deformability and to elucidate the relevant signal transduction pathway. Methods. Blood samples from 23 patients with type 1 diabetes and 15 matched healthy controls were incubated with 6.6 nM of either human C-peptide, C-terminal hexapeptide, C-terminal pentapeptide, a middle fragment comprising residues 11–19 of C-peptide, or randomly scrambled C-peptide. Furthermore, red blood cells from 7 patients were incubated with C-peptide, penta- and hexapeptides with/without addition of ouabain, EDTA, or pertussis toxin. Erythrocyte deformability was measured using a laser diffractoscope in the shear stress range 0.3–60 Pa. Results. Erythrocyte deformability was impaired by 18–25% in type 1 diabetic patients compared to matched controls in the physiological shear stress range 0.6–12 Pa (P < .01–.001). C-peptide, penta- and hexapeptide all significantly improved the impaired erythrocyte deformability of type 1 diabetic patients, while the middle fragment and scrambled C-peptide had no detectable effect. Treatment of erythrocytes with ouabain or EDTA completely abolished the C-peptide, penta- and hexapeptide effects. Pertussis toxin in itself significantly increased erythrocyte deformability. Conclusion/interpretation. C-peptide and its C-terminal fragments are equally effective in improving erythrocyte deformability in type 1 diabetes. The C-terminal residues of C-peptide are causally involved in this effect. The signal transduction pathway is Ca2+-dependent and involves activation of red blood cell Na+, K+-ATPase.