Lower Hct Levels Research Articles

Effects of hematocrit levels on flow structures and stress levels in the healthy and diseased carotid arteries

Flow structures and wall shear stress (WSS) distribution in human arteries depend strongly on blood rheology. Blood viscosity undergoes significant alterations due to varying hematocrit (Hct) levels. Hematocrit levels can change from the normal level (45%) due to numerous disorders such as leukemia, lymphoma, and congenital heart disease. However, the effects of Hct levels on the flow features and WSS levels in large stenotic arteries are not well reported in literature. The present study computationally assesses the variation in flow features in healthy and stenosed carotid arteries due to changes in blood Hct levels. We have reported variations in axial and secondary flow characteristics, vortex structures, and WSS-based parameters for different Hct levels. Specifically, we consider high (65%) and low (25%) Hct levels in addition to a normal Hct level. Our results reveal that both high and low Hct levels have adverse effects on the hemodynamic features inside a healthy carotid artery model. The low Hct level displays a much more widespread low time-averaged WSS (TAWSS) area, while the high Hct shows an increased oscillatory shear index (OSI) zone at the carotid sinus wall. In stenotic arteries, low Hct enhances the spread of the low TAWSS zone in the post-stenotic carotid sinus, whereas high Hct increases the risk of plaque rupture. The high Hct level also increases the spread of high OSI zone at the inner wall of internal carotid artery for the moderately stenosed artery.

Prognostic analysis of inflammatory response-related genes and biomarkers in patients with urothelial carcinoma of ureter.

Ureteral urothelial carcinoma is a common urinary system tumor, accounting for 40% to 60% of all ureteral diseases. This study attempted to analyze the prognosis of patients with urothelial carcinoma, judging ureteral urothelial carcinoma by genes and biomarkers of inflammatory response. In this paper, co-expression network analysis and gene-based image fusion evaluation methods were proposed to obtain the prognosis results of patients with ureteral urothelial carcinoma. The experimental results showed that the levels of PLR and NLR increased, and the levels of HGB and HCT decreased; high PLR and high NLR levels, low HGB and low HCT levels were all risk factors affecting bladder urothelial carcinoma, and their ratios (OR) were 1.023, 1.611, 0.961, 0.859, 1.015, 1.072, 0.979, and 0.951, respectively. However, high PLR and high NLR levels were independent risk factors for bladder urothelial carcinoma, and their OR values were 1.497 and 1.071, respectively. Through biomarker diagnosis, the area under the curve, sensitivity, specificity and Youden index of hsa-mir-17, hsa-mir-93, hsa-mir-429 and hsa-mir-20a all exceeded 0.9, indicating that this is a potential diagnostic indicators. All in all, during the treatment of ureteral cancer, in order to reduce tumor recurrence, systemic therapy should be combined with ureteral cancer. In addition, this study also analyzed the prognosis of chemotherapy patients, and the results showed that immunotherapy may increase the risk of tumor cell reperfusion during chemotherapy.

Hematocrit, hemoglobin and red blood cells are associated with vascular function and vascular structure in men

High and low hematocrit (Hct) and hemoglobin (Hb) levels are associated with the risk of cardiovascular disease. The purpose of this study was to determine the relationships of Hct, Hb and red blood cells (RBCs) with vascular function and structure. We measured flow-mediated vasodilation (FMD), nitroglycerin-induced vasodilation (NID), brachial intima media thickness (IMT), and brachial-ankle pulse wave velocity (baPWV) in 807 men. The subjects were divided into six groups according to the levels of Hct, Hb and RBCs. NID was highest in the 46.0–48.9% Hct group among the six groups according to Hct levels. Brachial IMT was lowest in the 46.0–48.9% Hct group among the six groups. There were no significant differences in FMD and baPWV among the six groups. We used 46.0–48.9% Hct as a reference to define the lower tertile. The adjusted odds ratio of being in the low tertile of NID was significantly higher in the < 42.9% and ≥ 49.0% Hct groups. Adjusted odds ratio of being in the low tertile of brachial IMT was significantly lower in the < 39.9% Hct groups. Similar results were obtained for Hb and RBCs. Low and high levels of Hct, Hb and RBCs were associated with vascular smooth muscle dysfunction, and low Hct levels were associated with abnormal vascular structure. Increases in the levels of Hct, Hb and RBCs within normal ranges may have beneficial effects on the vasculature.

Fetal Hemoglobin Improves Cerebral Blood Flow and Decreases Brain Inflammation in Transgenic- Sickle Mice

Introduction: Fetal hemoglobin (HbF) inhibits the deoxygenation-induced polymerization of sickle hemoglobin (HbS), the underlying pathophysiology of sickle cell disease (SCD). Higher HbF levels are associated with reduced sickle related pathology (Lettre G, Bauer DE. The Lancet 2016; 387(10037): 2554-64.). A major therapeutic approach to SCD has been to try to increase HbF levels, primarily by hydroxyurea administration. While hydroxyurea improves HbF and reduces sickling, its mechanism of action remains controversial, and even less is known regarding its effects on sickle-related cerebral pathology. We studied transgenic Berkeley sickle mice (BERK) (Paszty C et. al., Science 1997; 278(5339): 876-8.) with different HbF levels using in vivo MRI in an effort to estimate the ameliorative effects of HbF on cerebral blood flow and brain inflammation.Methods: BERK mice, expressing exclusively human a- and bS-globins with low (LF, n=7), medium (MF, n=8) and high (HF, n=6) HbF levels were studied at 9.4 T MRI system under isoflurane anesthesia. C57BL/6J mice were used as controls (n=9). We measured whole-brain cerebral blood flow (CBF-WB) using MRI. Diffusion tensor imaging was used to measure whole-brain mean diffusivity (MD-WB), a measure of brain edema and inflammation, and white matter fractional anisotropy (FA-WM) a biomarker of neuropathology. Tail vein blood was employed to obtain hematological parameters prior to MRI.Results: Select MRI and related data are shown in Table 1. BERK-LF mice (~3% HbF) exhibited lower mean cell hemoglobin concentration (MCHC) and hematocrit (Hct) compared with C57BL mice. BERK-MF mice (~20% HbF) showed increased MCHC compared with BERK-LF mice. BERK-HF mice (~30% HbF) had the highest MCHC and Hct of all BERK mice, but MCHC was still lower than levels seen in C57BL mice. The low MCHC and Hct levels in BERK-LF mice were associated with high CBF and MD . CBF was significantly elevated in BERK-LF and BERK-MF mice by 130% and 120%, respectively, compared to C57BL mice. BERK-HF mice, on the other hand, exhibited normalized CBF (187.0±27.5 vs. 180.0±30.5 ml/100g/min, BERK-HF vs. C57BL respectively), despite lower MCHC and Hct levels compared to C57BL mice. Brain inflammation (elevated MD levels) were also observed in BERK-LF mice compared to controls. In contrast, BERK-MF and BERK-HF mice showed reduced MD; both were significantly lower than BERK-LF mice and not different from control. Only the BERK-LF demonstrated significantly lower FA values (reduced microstructuraly complexity) compared to controls.CBF in all mice (BERK and C57BL) was inversely related to Hct (r=-0.433, p=0.019) and MCHC (r=-0.527, p=0.003). However, when controls were excluded from this analysis, only HbF level significantly predicted CBF (r=-0.485, p=0.030) and MD (r=-0.636, p=0.003), shown in Figure 1. HbF level also positively predicted MCHC (r=0.832, p<0.0001) and Hct (r=0.448, p=0.042) in BERK mice.Conclusions: Cerebral perfusion is markedly elevated in BERK mice compared to C57BL control mice and is inversely correlated with Hct, MCHC and total fetal Hb level. These data suggest that increased HbF can significantly reduce CBF, and in our study CBF levels in high-gamma BERK (~30%) were indistinguishable from control CBF, despite the lower Hct levels. We also demonstrate that brain edema, as reflected in lower MD, is improved when HbF levels reach ~20%.The improved CBF and reduced edema with higher HbF may be due to several factors: an antisickling effect on HbS, reduced oxidative stress, improved NO activity, and improved blood oxygen carrying capacity. HbF levels approaching 30% improved CBF, improved FA and reduced MD, suggesting that increased HbF levels may reduce cerebral insults stemming from cerebral hyperemia.These data suggest that new therapeutic approaches to further increase HbF to even higher levels than that achieved with hydroxyurea may provide greater hematologic and neuropathologic improvements in patients with SCD. If hydroxyuyrea induced HbF increases cannot be further improved, additional or combined therapeutic approaches (such as Pegylated Hb) may be combined with HbF therapies to improve oxygen delivery, reduce oxidative stress and reduce CBF toward normal levels. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Predictors of low haematocrit among repeat donors in São Paulo, Brazil: Eleven year longitudinal analysis

Few longitudinal studies have examined the long-term effect on deferral for low haematocrit (Hct) or haemoglobin, indicators of presence of anaemia. This study retrospectively analysed 11 years of donation history to examine predictors related to such deferrals among repeat blood donors. We included 385,357 donors with at least two visits to the blood centre between January 1996 and December 2006 who were not deferred due to haematocrit at their first visit. We evaluated variables related to the development of low Hct (LHct-below 38% for females and 39% for males) after whole blood donations. Over the 11-year period, 3,850 (1.5%) of the 252,301 males and 18,104 (13.6%) of the 133,056 females were deferred due to LHct at some point after their first donation. Genders, age, baseline Hct, Hct at the visit immediately before deferral due to LHct, and interval between donations, were associated with higher rates of development of LHct in repeat donors. Our analysis showed that deferral due to low Hct levels in repeat blood donors is highly prevalent in Brazil. Assigning longer donations intervals based on the Hct levels at the qualifying donation or supplementing iron to donors at risk may decrease deferral rate of donors with low Hct.

Assessment of risk factors for cardiovasuclar disease in pediatric renal transplant patients

Pediatric renal TP recipients are at risk for CVD. We performed a cross-sectional study of the prevalence of RF for CVD in 45 long-term pediatric renal TP patients. The time since TP was 42 months. The GFR was 87.8 +/- 3.4 mL/min/1.73 m(2); 25/45 (56%) had Stage 2-4 CKD. A total of 33% had elevated SBP and 24% had high DBP; 57% had elevated SBP or DBP. A total of 20% had elevated serum CHOL levels, while 45% had high serum TG levels. A total of 42% had high HCY levels and 50% had low HCT levels. The vast majority (66.7%) had at least two RF for CVD. A total of 18.2% had abnormal post-TP echocardiography results. There was a negative correlation between GFR and SBP, DBP, serum CHOL, HCY, and BMI. There was a positive correlation between GFR and HCT. Serum CHOL was significantly lower and SBP and DBP trended lower in patients on a SF immunosuppression regimen. Similarly, SBP and DBP trended higher and CHOL was significantly higher in patients receiving SRL vs. mycophenolate mofetil. We conclude that the majority of pediatric renal TP patients exhibit multiple CVD RF.

Un niveau réduit d’hématocrite aggrave les lésions cérébrales après un arrêt circulatoire hypothermique prolongé chez le rat

This study tests the hypothesis that low hematocrit (Hct) worsens cerebral injury after prolonged hypothermic circulatory arrest (HCA) in rats, and the mechanism involves variable expression of the genes C-Fos, Bcl-2 and Bax. A rat HCA model was developed, and 40 animals were randomly assigned to four groups: Sham (sham) group, or Hct groups of Hct 10%, Hct 20% and Hct 30%. After 90 min of HCA at 18 degrees C, physiologic variables were recorded and brain morphological changes were evaluated with light and electron microscopy. Expressions of C-Fos, Bcl-2, Bax in various brain areas were measured by the reverse transcriptase polymerase chain reaction and standard immunohistochemistry techniques. The number of injured neurons in the hippocampus CA1 and parietal cortex in the Hct 10% group (CA1: 11.44 +/- 2.52; cortex: 13.65 +/- 2.31) exceeded the mean number of injured neurons in the Hct 20% group (CA1: 8.29 +/- 1.31; cortex: 10.68 +/- 1.24; P < 0.05) and the Hct 30% group. Mean mitochondrial injury scores were greatest at lower Hct levels, while the expression of C-Fos and Bax were highest in the Hct 10% group and lowest in the Hct30% group (P < 0.05). In contrast, the expression of the Bcl-2 mRNA was greatest in the Hct 30% group (P < 0.05). Low Hct worsens cerebral injury after prolonged HCA and CPB in rats, which may relate in part to the variable expression of the genes C-Fos, Bcl-2 and Bax.

Does Hepcidin Affect Erythropoiesis in Hemodialysis Patients?

Introduction: Prohepcidin is the precursor of hepcidin, a liver-derived peptide involved in iron metabolism by blocking its intestinal absorption and its release by the reticuloendothelial system. Iron overload and inflammation increase hepcidin expression, whereas anemia and hypoxia suppress it. In the present study prohepcidin levels were determined in the serum of hemodialysis (HD) patients and its correlations with iron metabolism markers, C-reactive protein (CRP) and hematocrit (Hct) were assessed. Patients and Methods: Forty-sixHD patients and 22 healthy volunteers were enrolled in the study. Hct, serum prohepcidin, CRP, iron, ferritin, transferrin saturation and transferrin receptors were measured. The weekly erythropoietin dose, last-month intravenous iron dose and the patients’ demographics were recorded. Results: In comparison to the healthy volunteers, the HD patients had higher serum ferritin, transferrin receptors and CRP, lower serum iron and similar transferrin saturation and prohepcidin levels. In the patient group prohepcidin levels were negatively correlated with Hct but not with any other of the examined parameters. Multiple linear regression analysis considering age, inflammation, iron adequacy, erythropoietin dose and prohepcidin levels revealed that prohepcidin was the predominant determinant of Hct. Conclusions: Taking into account the low Hct levels in the HD patients of our study, it seems plausible that the prohepcidin levels assessed in this group are inappropriately high. These functionally high prohepcidin levels may be associated with the factors that inhibit erythropoiesis in HD patients. On the other hand, the absence of other expected correlations indicates that further studies are needed in order to definitely clarify this aspect.

The potential role of oxygen-carrying products in autologous blood transfusion protocols.

For surgical patients transfusion of autologous blood (AB) is the most useful of measures to reduce patient's exposure to homologous blood (HB). In our Institute an autotransfusion program was started in 1982 utilizing all the autotransfusion techniques currently available. The integrated use of the techniques offered to the majority of the patients the possibility of receiving AB (98% of the elective surgery patients) and a consistent conservation of HB has been achieved (60-70%). However 42% are still exposed to some HB. Critical parameters that render the patients unable to fulfill the anticipated transfusion needs with the current AB transfusion techniques are: the patient's ability to predonate sufficient AB prior to surgery and the amount of blood transfused intraoperatively that in turn depends on different "transfusion trigger". In our Institute over 50% of all the blood units are transfused the day of operation (60% being AB, 40% HB) and 50% postoperatively (only 33% being AB). For this reason, a clinical application for the oxygen-carrying products can be the replacement of the blood lost during, or immediately after the operation permitting the surgeon to operate safely at a lower Hct levels, thereby delaying the transfusion of blood and saving the AB obtained.