Hemostatic changes in patients undergoing hemodialysis: Differences between central venous catheters and arterio-venous fistulas.

BACKGROUND: Failure to mature the fistula in patients undergoing hemodialysis leads to prolonged use of the central venous catheter (CVC) and can compromise the patency of the catheter and the arteriovenous fistula (AVF) due to thrombus development. OBJECTIVE: To evaluate hemostatic changes in patients undergoing hemodialysis with prolonged use of CVC or AVF. METHOD: Cross-sectional study with a total of 200 adult participants who were divided into the following groups: I:control; II: patients who had 5-8 months of CVC insertion; III: patients who had 9-36 months of insertion; IV patients who had 5-8 months of AVF; and V: patients who had 9-36 months of AVF. Platelet activation was investigated by expressions of GPIIb/IIIa and p-selectin using flow cytometry. The Elisa-thrombomodulin (TM) test was used to compare groups III and V. RESULTS: The p-selectin percentage expression of group I was 15.30 (12.30-16.80), II 23.25 (20.75-30.55); and III 54.00 (44.75-59.29) were significant (p < 0.001). Groups I, IV, and V were also significant (p < 0.001). The median fluorescence for GPIIb/IIIa for groups I, II, and III were significant (p < 0.0001). As for the Elisa test, an increased absorbance of TM was verified in patients who used the CVC 4372 (3951-4733) compared with those patients who used the AVF 2162 (1932-2485) (p < 0.0001). CONCLUSION: It can be concluded that CVC patients had a larger platelet expression of GPIIb/IIIa and p-selectin than AVF patients. The high concentration of TM in CVC patients may suggest a greater stimulation of the intrinsic than extrinsic coagulation pathways.

Effect of the expression of CD62P and thrombin generation on patients using central venous catheters for hemodialysis.

The formation of thrombi in medical devices that come into contact with blood is a common cause of increased morbidity and mortality. Prolonged use of central venous catheters (CVCs) may cause high infection rates or compromise CVC patency due to thrombus development. In this study, we sought insights into possible changes in the hemostatic system during prolonged use of inserted CVCs for hemodialysis by assessing platelets by CD62P and CD41a expression and the potential for thrombin generation (TG). This study included patients with chronic renal failure who were undergoing hemodialysis three times a week using a CVC, and healthy subjects as controls. The participants were distributed into three groups: Group 1: clinically and laboratorially healthy individuals matched by sex and age to the patients (controls); Group II: patients who had completed 1 month of CVC insertion; and Group III: the same patients after they had completed 4 months of CVC insertion. Platelet activation analysis and TG evaluation were performed using blood samples obtained through two different accesses, that is, through a peripheral vein and directly from the CVC lumen. The data showed platelet activation and an increase in the generation of thrombin, particularly after 4 months of CVC use. The results also indicated that insertion of the catheter into the blood stream stimulated the intrinsic rather than the extrinsic pathway. Taken together, the data showed a direct relationship between the use of CVCs in hemodialysis patients and a state of hypercoagulability, most likely associated with endothelial damage and the contact of the medical device with blood components such as platelets and coagulation factors.

Anti-inflammatory and cytotoxic activities of the extracts, fractions, and chemical constituents isolated from Luehea ochrophylla Mart.

BACKGROUND: Stem bark of Luehea ochrophylla (L. ochrophylla) is used by the traditional Brazilian medicine for treatment of rheumatic diseases and tumors. This study aimed to investigate inhibition of acute and chronic inflammations and cytotoxic activity of extracts, fractions, and isolated compounds from L. ochrophylla. METHODS: Hexane (HE) and ethanol (EE) extracts obtained from stem bark of L. ochrophylla were submitted to chromatographic fractionation. In order to test acute inflammation, experimental model of impact injury was used, followed by transdermal application of gels using phonophoresis. Histological analysis was based on scores assigned by the capacity of decreasing the lesion. To evaluate the effect EE and fractions on cell proliferation, human lymphocytes were stimulated with phytohemagglutinin and analyzed using flow cytometry. Proliferation was measured using VPD 450 staining and the calculated proliferative index (PI). The cytotoxic activity was evaluated using MTT colorimetric method against MDA-MB-231, MCF-7, HCT-116, and Vero cells. GraphPad Prism Version 5 was used for statistical analysis. RESULTS: HE and EE provided friedelin, ß-friedelinol, lupeol, mixture of lupeol and pseudotaraxasterol, ß-sitosterol, betulinic acid, mixture of lupeol and taraxasterol, (-)-epicatechin, ß-sitosterol-3-O-ß-D-glucopyranoside, and (+)-epicatechin-(4ß-8)-epicatechin. HE, ethyl acetate fraction (AF), betulinic acid, and ß-sitosterol promoted regeneration of muscle fibers caused by muscle injury. AF significantly (p < 0.05) reduced the lymphocyte proliferation index (1.36 for cultures stimulated with PHA, 0.7 for untreated cultures and 0.12 for cultures stimulated with PHA and treated with AF 25 µg/mL and AF 50 µg/mL, respectively). ß-Sitosterol-3-O-ß-D-glucopyranoside exhibited high cytotoxic activity (IC50 = 1.279 µg/mL) against HCT-116 cell line. CONCLUSION: These results suggest that extracts, fractions, and chemical constituents from L. ochrophylla decreases inflammatory processes generated by muscle injury. The anti-inflammatory activity may be justified by high inhibition of T cell proliferation. These extracts, fractions, and chemical constituents from L. ochrophylla may be useful as a therapeutic agent against rheumatic diseases. Moreover, chemical constituents from L. ochrophylla show potent cytotoxic activity against colon and rectal carcinomas.

Association between Anti-DENV IgM Serum Prevalence and CD11b Expression by Classical Monocytes in Obesity.

Dengue and obesity are currently highly prevalent conditions worldwide and the association between these two conditions may result in greater risk for DENV infection and disease severity. In this study the association between obesity and recent, inapparent dengue was investigated. Serum DENV IgM and NS1 were evaluated in 49 adult volunteers (15 lean and 34 individuals with obesity, according to body mass index), between September 2017 and June 2018. Adiposity, endocrine, metabolic, and immune data of the participants were also obtained. None of the study participants tested positive for the DENV NS1 antigen. DENV IgM was detected in 33.3% of the lean individuals, and in 44.1% of those with obesity; the presence of DENV IgM was not associated with body mass index (OR = 1.32, 95% CI = 0.59-2.98, p = 0.48). However, body fat index was higher in obese individuals who had recent inapparent dengue (14.7 ± 3.1 versus 12.7 ± 2.1 kg/m2, p = 0.04), as was the expression of CD11b by classical (CD14++CD16-) monocytes (1103.0 ± 311.3 versus 720.3 ± 281.1 mean fluoresce intensity). Our findings suggest an association between adiposity and recent inapparent dengue and the involvement of classical monocytes in this association.

Background autofluorescence induced by plant extracts in human lymphocytes: A flow cytometric analysis of a critical bias.

The presence of background autofluorescence sources is considered as an important problem when performing fluorometric methods, due to the possible spectral overlap between it and the fluorescence emission of probes. Regarding that, we evaluated the presence of background autofluorescence in human lymphocytes after the treatment with extracts from three medicinal plants, including ethanolic extract from aerial parts of Ageratum fastigiatum, ethanolic extract from aerial parts of Eriosema campestre and the ethanolic extract from stem of Pseudobrickellia brasiliensis. Human peripheral blood mononuclear cells were treated with each extract in vitro during 24 h, followed by flow cytometric analysis. Additionally, the fluorescence emission of plant extracts was evaluated by fluorometry, using the same concentrations used in cell cultures. We identified that plant extracts treatment on lymphocytes induced background autofluorescence detectable in several wavelength ranges. Isolated extracts showed no expressive fluorescence emission in fluorometric analyses, suggesting that background autofluorescence was induced in lymphocytes by interactions between cellular components and extracts compounds. Here we discuss the importance to perform previous tests to evaluate a possible background autofluorescence induction after cell treatments with plant extracts or any other substance. In spite of being mandatory, background autofluorescence analysis of cells after treatments and stimulations is still underestimated on literature. In summary, following the precautions herein established should help to reduce the incidence of false positive results.

Activated platelets in central venous catheters: a flow cytometry and numerical simulation approach

The central venous catheter that is inserted in patients undergoing hemodialysis can cause hemodynamic instability and trigger complications such as thrombus formation. The objective of this study was to investigate hemostatic and numerical influences on thrombus formation in patients undergoing hemodialysis with a central venous catheter. Participants were assigned to three groups: I: clinical and laboratorial healthy individuals matched by sex and age (controls); II: participants after one month of insertion of the catheter and III: participants after 4 months of insertion of the catheter. Platelet activation was investigated by GPIIb/IIIa and p-selectin expressions using flow cytometry. A three-dimensional model of the catheter was constructed in the numerical simulation for the calculation of partial differential equation of a platelet activation model. A significant difference was detected by the expression of p-selectin comparing the group I (33.42 ± 4.74), group II (40.79 ± 5.54) and group III(51.00 ± 7.21) (p < 0.0001). The median values for GPIIb/IIIa were 10426 (10029-10721), 13921 (13412-15652) and 19946 (18714-21815) after catheter insertion (p < 0.0001), for groups I, II and III, respectively. Excluding the first arterial orifice, venous orifices tend to have greater platelet activation when compared to the other arterial orifices. The results of this study showed the influence of arterial and venous lateral orifices in stimulating the development of thrombi associated with the activation of platelet markers the longer the catheter was used.