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Clinical hemorheology and microcirculation [journal]
- Protective effect of quercetin against in vitro erythrocyte rheology alterations produced by arsenic. [JOURNAL ARTICLE]
- Clin Hemorheol Microcirc 2014 Jul 11.
Humans are exposed to heavy metals such as arsenic (As), through contaminated food and drinking water. The effect of As on RBC membrane is one of the most important biological effects. In a previous work, we have studied the AsV in vitro effect on erythrocytes biophysical properties discovering alterations regarding aggregability deformability, cell morphology, membrane fluidity and osmotic response. We have also observed that the presence of the metal produces an oxidative stress in RBCs that might be the origin of rheological impairment. In the present work we analyzed RBCs rheological properties associated with membrane fluidity and lipid peroxidation in presence of As and quercetin (Qc). From our results we can conclude that RBCs treatment with Qc is efficient to prevent the impairment of the mechanical properties of the cell membrane produced by the As, through oxygen reactive agents in the membrane structure, mainly on the lipids. This protective effect is observed in the preservation of the erythrocytes rheological properties and consequently in the maintenance of an appropriate blood flow, specially in the small vessels in the peripheral circulation.
- Heterogeneous responses of personalised high intensity interval training on type 2 diabetes mellitus and cardiovascular disease risk in young healthy adults. [JOURNAL ARTICLE]
- Clin Hemorheol Microcirc 2014 Jul 7.
Hypertension, decreased glucose tolerance, adverse lipid profiles and low physical activity levels are associated with increased type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD) risk. High intensity interval training (HIIT), a low volume, reduced time, high intensity programme, may be a useful alternative to current government guidelines which specify a minimum of 150 minutes of physical activity per week. We describe a personalised programme of high intensity exercise which provides significant improvements in CVD risk markers. Healthy volunteers undertook 6 weeks of HIIT. T2DM and CVD risk predictors including glucose tolerance, VO2max, blood pressure (BP), and lipids were measured before and after HIIT. HIIT training was associated with beneficial changes in a range of predictors of blood flow and cardiovascular risk. There was a heterogeneous response to HIIT, with some subjects responding with favourable changes and others being non-responders to HIIT. In responders, HIIT was associated with a statistically significant (p = 0.023) increase in VO2max, from 45.4 (38.4,52.5) to 56.9 (51.2,65.7) (median (interquartile range)(ml/min/kg)). In responders HIIT resulted in a decrease in systolic BP from 127 (126,129) to 116 (106,122) (mmHg) with p = 0.026 and a decrease is diastolic blood pressure from 72 (69,74) to 57 (56,66) with p = 0.026. There was also some evidence of a beneficial change in blood lipid and glucose concentrations with HIIT. In conclusion, personalised HIIT has potential as an intervention to improve blood flow and cardiovascular health.
- Blood viscosity is lower in trained than in sedentary sickle cell trait carriers. [JOURNAL ARTICLE]
- Clin Hemorheol Microcirc 2014 Jun 24.
The aim of this study was to compare blood and plasma viscosities, as well as the hematocrit/blood viscosity ratio (HVR), between trained and sedentary SCT carriers. Thirty African male SCT carriers from the city of Dakar (Senegal) participated in the study: one group composed of 15 trained SCT carriers (TSCTc) and one group composed of 15 sedentary individuals (SSCTc). Blood was sampled in resting condition and blood and plasma viscosities were measured using a cone-plate viscometer. After the determination of hematocrit by microcentrifugation, HVR was determined for each subject. Blood and plasma viscosities, as well as hematocrit, were significantly reduced in TSCTc compared to SSCTc. As a consequence, HRV was greater in TSCTc. These findings provide evidence that SCT carriers should be encouraged to practice regular physical activity to limit the cardiovascular strain usually caused by their blood hyperviscosity.
- S-nitrosoglutathione efflux in the erythrocyte. [JOURNAL ARTICLE]
- Clin Hemorheol Microcirc 2014 Jun 23.
Glutathione is an abundant molecule inside erythrocyte, originating S-nitrosoglutathione (GSNO) by reacting with nitric oxide (NO). GSNO has been regarded as a store and transporter of NO, with significant interest as a potential therapeutic agent, acting as an NO donor. NO metabolism inside the erythrocyte generates several derivatives, which can be altered by external and internal stimuli such as acetylcholine (ACh), a natural substrate of acetylcholinesterase (AChE). In spite of the knowledge gained in the last decades concerning NO efflux in erythrocytes little is known regarding erythrocyte GSNO efflux, which has also an significant role in microcirculation. Hence, the objective of this research was to evaluate the efflux of GSNO, concomitant with the efflux of NO, after stimulation with AChE effectors. To achieve these goals, the in vitro effect of AChE modulators - ACh and timolol - in erythrocyte NO and GSNO were studied. Timolol is an erythrocyte AChE inhibitor. Venous blood samples were collected from 18 healthy Caucasian men. For each blood sample, erythrocyte suspensions were obtained and incubated in the absence (controls) and presence of ACh and timolol maleate (10 μM final concentration of each modulator). Both timolol and ACh induced significant GSNO efflux in the erythrocyte when compared to the control; however the efflux was lower in the presence of timolol compared to ACh. Although erythrocyte NO efflux in presence of timolol is similar to the control, the efflux decreased when compared to the ACh treatment. The presence of timolol induces significant decrease of intra-erythrocyte GSNO levels, relative to control and ACh treatment. In conclusion, when erythrocytes were stimulated with ACh or timolol, GSNO efflux occurs associated with NO efflux. These new results brings new insight into the metabolism of erythrocyte NO and new possible therapeutic applications for GSNO.
- Rheological red blood cell properties in morbidly obese and super obese patients. [JOURNAL ARTICLE]
- Clin Hemorheol Microcirc 2014 Jun 23.
- The distinct abilities of tube-formation and migration between brain and spinal cord microvascular pericytes in rats. [JOURNAL ARTICLE]
- Clin Hemorheol Microcirc 2014 Jun 19.
Pericytes are contractile cells that wrap around the endothelial cells of capillaries throughout the body. They play an important role in regulating the blood brain barrier (BBB) and blood spinal cord barrier (BSCB). The differences between brain and spinal cord microvascular endothelial cells have been investigated. However, no report has elucidated the similarities and differences between brain microvasular pericytes (BMPs) and spinal cord microvascular pericytes (SCMPs) in vitro. The similarities were found between the two types of pericytes not only in the proliferation ability but also in the expression of toll like receptor 4. On the other hand, BMPs showed more than 2 fold in tubular length formation compared with SCMPs. The number of migratory SCMPs was larger than that of migratory BMPs. The expressions of connexin 43 and vascular endothelial growth factor (VEGF) in BMPs were increased compared with those in SCMPs, while SCMPs expressed more desmin and N-cadherin than BMPs. The abilities of tube-formation and migration between BMPs and SCMPs were markedly different, which might be mediated by VEGF, connexin 43, N-cadherin and desmin. These distinguishing features may reflect the more widespread differences between the BBB and BSCB which directly impact pathophysiological processes in various major diseases.
- Maternal microcirculation and sidestream dark field imaging: A prospective assessment of the association between labour pain and analgesia on the microcirculation of pregnant women. [JOURNAL ARTICLE]
- Clin Hemorheol Microcirc 2014 Jun 16.
Pregnancy places significant demands on the cardiovascular system leading to measurable changes in the macrocirculation and potentially the microcirculation. During labour, both uterine contractions and labour pain can further impact cardiovascular status. The objective of this observational study was to compare sublingual microcirculation in labouring parturients before and after epidural analgesia.Healthy pregnant, labouring women requesting epidural analgesia were approached to participate. Participants with cardiovascular disease, diabetes, obesity, smoking or caffeine intake were excluded. The sidestream dark field device was applied to the sublingual mucosa obtaining images of at least 20 seconds in 5 visual fields before and after epidural analgesia. Video clips were analyzed randomly and blindly. The primary outcome was mean microvascular flow index (MFI).Twelve participants completed this study. The results demonstrate no statistically significant difference in the MFI during labour pain (2.9 ± 0.1) compared to after epidural analgesia (3.0 ± 0.04, p = 0.31). Furthermore, there were no statistically significant differences in any secondary outcomes.Our findings indicate that epidural analgesia may not impact sublingual microcirculation in labouring women. This agrees with literature supporting epidural analgesia as a safe, appropriate method of pain relief during labour with limited impact on peripheral macro or microcirculation.
- Decrease in red blood cell deformability is associated with a reduction in RBC-NOS activation during storage. [JOURNAL ARTICLE]
- Clin Hemorheol Microcirc 2014 Jun 13.
During storage, red blood cells (RBC) become more susceptible to hemolysis and it has also been shown that RBC deformability, which is influenced by RBC nitric oxide synthase (RBC-NOS) activity, decreases during blood storage while a correlation between these two parameters under storage conditions has not been investigated so far. Therefore, blood from 15 male volunteers was anticoagulated, leuko-reduced and stored as either concentrated RBC or RBC diluted in saline-adenine-glucose-mannitol (SAGM) for eight weeks at 4°C and results were compared to data obtained from freshly drawn blood. During storage, decrease of RBC deformability was related to increased mean cellular volume and increased cell lysis but also to a decrease in RBC-NOS activation. The changes were more pronounced in concentrated RBC than in RBC diluted in SAGM suggesting that the storage method affects the quality of blood. These data shed new light on mechanisms underlying the phenomenon of storage lesion and reveal that RBC-NOS activation and possibly nitric oxide production in RBC are key elements that are influenced by storage and in turn alter deformability. Further studies should therefore also focus on improving these parameters during storage to improve the quality of stored blood with respect to blood transfusion.
- Preoperative differentiation of thyroid adenomas and thyroid carcinomas using high resolution contrast-enhanced ultrasound (CEUS). [JOURNAL ARTICLE]
- Clin Hemorheol Microcirc 2014 Jun 4.
Background: To evaluate the impact of high-resolution contrast-enhanced ultrasound (CEUS) in combination with Color Coded and Power Doppler Sonography (CCDS/PD) in the preoperative differentiation of thyroid adenomas and thyroid carcinomas. Methods: A total of 101 patients (55 female, median age 54 years) underwent surgery for thyroid adenoma and thyroid carcinoma. CCDS/PD and CEUS were performed in all patients by an experienced examiner using a multifrequency linear transducer (6-9 or 6-15 MHz) and were digitally stored. Reading of the ultrasound images was performed by two experienced radiologists in consensus. A histopathological evaluation was obtained as standard of reference in all patients. Results: Altogether, 75 thyroid adenomas and 26 thyroid carcinomas were detected. Mean diameter of thyroid adenomas and thyroid carcinomas was 27 mm and 32 mm, respectively. The differences in microcirculation of thyroid adenomas and thyroid carcinomas were statistically highly significant (p < 0.01). Representative features for thyroid adenomas were either no wash-out or wash-out with persisting edge in late phase, for thyroid carcinomas a complete wash-out in late phase. Thus, a calculation of sensitivity, specificity, positive and negative predictive value of 81%, 92%, 97% and 63%, respectively, for the differentiation of benignity and malignancy was possible. Conclusions: Dynamic evaluation of microcirculation using CEUS and CCDS/PD enables a more reliable preoperative discrimination between thyroid adenomas and thyroid carcinomas.