Blood viscosity and the expression of inflammatory and adhesion markers in homozygous sickle cell disease subjects with chronic leg ulcers.

OBJECTIVE: To determine differences in TNF-α, IL-1β, IL-10, sICAM-1 concentrations, leg hypoxia and whole blood viscosity (WBV) at shear rates of 46 sec(-1) and 230 sec(-1) in persons with homozygous S sickle cell disease (SCD) with and without chronic leg ulceration and in AA genotype controls. DESIGN: & METHODS: fifty-five age-matched participants were recruited into the study: 31 SS subjects without leg ulcers (SSn), 24 SS subjects with leg ulcers (SSu) and 18 AA controls. Haematological indices were measured using an AC.Tron Coulter Counter. Quantification of inflammatory, anti-inflammatory and adhesion molecules was performed by ELISA. Measurement of whole blood viscosity was done using a Wells Brookfield cone-plate viscometer. Quantification of microvascular tissue oxygenation was done by Visible Lightguide spectrophotometry. RESULTS: TNF-α and whole blood viscosity at 46 sec(-1) and 230 sec(-1) (1.75, 2.02 vs. 0.83, 1.26, p<0.05) were significantly greater in sickle cell disease subjects than in controls. There were no differences in plasma concentration of sICAM-1, IL-1β and IL-10 between SCD subjects and controls. IL-1β (median, IQR: 0.96, 1.7 vs. 0, 0.87; p<0.01) and sICAM-1 (226.5, 156.48 vs. 107.63, 121.5, p<0.005) were significantly greater in SSu group compared with SSn. However there were no differences in TNF-α (2, 3.98 vs. 0, 2.66) and IL-10 (13.34, 5.95 vs. 11.92, 2.99) concentrations between SSu and SSn. WBV in the SSu group at 46 sec(-1) and at 230 Sec 1 were 1.9 (95%CI; 1.2, 3.1) and 2.3 (1.2, 4.4) times greater than in the SSn group. There were no differences in the degree of tissue hypoxia as determined by lightguide spectrophotometry. CONCLUSION: Inflammatory, adhesion markers and WBV may be associated with leg ulceration in sickle cell disease by way of inflammation-mediated vasoocclusion/vasoconstriction. Impaired skin oxygenation does not appear to be associated with chronic ulcers in these subjects with sickle cell disease

Degree of tissue oxygen saturation distributions in SCD cases and controls.

<p>Figure shows percentage of observations with SO₂ values below 15%.</p

Erythrocyte transport effectiveness at low and high shear rates in SCD patients with ulcers and those without.

<p>HVR was lower in the group with ulcers at both low and high shear rates of WBV.</p

Plasma concentration distributions of interleukin-1beta, tumor necrosis factor-alpha, inter-cellular adhesion molecule-1 and interleukin-10 in SCD patients with ulcers and without ulcers.

<p>IL-1β concentration was greater in ulcer group ; TNF-α showed no difference between groups; ICAM-1 was greater in patients with ulcers; IL-10 was no different between groups.</p

Whole blood viscosity distribution at low and high shear rates in SCD patients with ulcers and those without.

<p>WBV was greater in the group with ulcers at both the low and high shear rates. Both groups had outliers above and below their respective WBV ranges.</p

Lightguide haemoglobin oxygen saturation observations in SCD subjects with active leg ulcers (cases) and controls.

<p>Pooled mean SO₂ results taken at different sites along the length of the lower leg. Data are median with interquartile range.</p

Converting the yeast arginine Can1 permease to a lysine permease.

Amino-acid uptake in yeast cells is mediated by about sixteen plasma membrane permeases, most of which belong to the APC (amino acid, polyamine, organocation) transporter family. These proteins display various substrate specificity ranges. For instance, the general amino-acid permease Gap1 transports all amino acids, whereas Can1 and Lyp1 catalyze specific uptake of arginine and lysine, respectively. Though Can1 and Lyp1 have different narrow substrate specificities, they are close homologs. Here we investigated the molecular rules determining the substrate specificity of the H+-driven arginine-specific permease Can1. Using a Can1-Lyp1 sequence alignment as a guideline and a 3D Can1 structural model based on the crystal structure of the bacterial APC-family arginine-agmatine antiporter, we introduced amino acid substitutions liable to alter Can1 substrate specificity. We show that the single substitution T456S results in a Can1 variant transporting lysine in addition to arginine, and that the combined substitutions T456S and S176N convert Can1 to a Lyp1-like permease. Replacement of a highly conserved glutamate in the Can1 binding site leads to variants (E184Q, E184A) incapable of any amino acid transport, pointing to a potential role for this glutamate in H+ coupling. Measurements of the kinetic parameters of arginine and lysine uptake by the wild-type and mutant Can1 permeases, together with docking calculations for each amino acid in their binding site, suggest a model in which residues at positions 176 and 456 confer substrate selectivity at the ligand-binding stage and/or in the course of conformational changes required for transport.JOURNAL ARTICLESCOPUS: ar.jinfo:eu-repo/semantics/publishe

Blood Viscosity and the Expression of Inflammatory and Adhesion Markers in Homozygous Sickle Cell Disease Subjects with Chronic Leg Ulcers

OBJECTIVE: To determine differences in TNF-α, IL-1β, IL-10, sICAM-1 concentrations, leg hypoxia and whole blood viscosity (WBV) at shear rates of 46 sec(-1) and 230 sec(-1) in persons with homozygous S sickle cell disease (SCD) with and without chronic leg ulceration and in AA genotype controls. DESIGN: & Methods: fifty-five age-matched participants were recruited into the study: 31 SS subjects without leg ulcers (SS(n)), 24 SS subjects with leg ulcers (SS(u)) and 18 AA controls. Haematological indices were measured using an AC.Tron Coulter Counter. Quantification of inflammatory, anti-inflammatory and adhesion molecules was performed by ELISA. Measurement of whole blood viscosity was done using a Wells Brookfield cone-plate viscometer. Quantification of microvascular tissue oxygenation was done by Visible Lightguide spectrophotometry. RESULTS: TNF-α and whole blood viscosity at 46 sec(-1) and 230 sec(-1) (1.75, 2.02 vs. 0.83, 1.26, p<0.05) were significantly greater in sickle cell disease subjects than in controls. There were no differences in plasma concentration of sICAM-1, IL-1β and IL-10 between SCD subjects and controls. IL-1β (median, IQR: 0.96, 1.7 vs. 0, 0.87; p<0.01) and sICAM-1 (226.5, 156.48 vs. 107.63, 121.5, p<0.005) were significantly greater in SS(u) group compared with SS(n). However there were no differences in TNF-α (2, 3.98 vs. 0, 2.66) and IL-10 (13.34, 5.95 vs. 11.92, 2.99) concentrations between SS(u) and SS(n). WBV in the SS(u) group at 46 sec(-1) and at 230 Sec 1 were 1.9 (95%CI; 1.2, 3.1) and 2.3 (1.2, 4.4) times greater than in the SS(n) group. There were no differences in the degree of tissue hypoxia as determined by lightguide spectrophotometry. CONCLUSION: Inflammatory, adhesion markers and WBV may be associated with leg ulceration in sickle cell disease by way of inflammation-mediated vasoocclusion/vasoconstriction. Impaired skin oxygenation does not appear to be associated with chronic ulcers in these subjects with sickle cell disease

Newborn Adiposity and Cord Blood C-Peptide as Mediators of the Maternal Metabolic Environment and Childhood Adiposity

OBJECTIVE Excessive childhood adiposity is a risk factor for adverse metabolic health. The objective was to investigate associations of newborn body composition and cord C-peptide with childhood anthropometrics and explore whether these newborn measures mediate associations of maternal midpregnancy glucose and BMI with childhood adiposity. RESEARCH DESIGN AND METHODS Data on mother/offspring pairs (N = 4,832) from the epidemiological Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Study and HAPO Follow-up Study (HAPO FUS) were analyzed. Linear regression was used to study associations between newborn and childhood anthropometrics. Structural equation modeling was used to explore newborn anthropometric measures as potential mediators of the associations of maternal BMI and glucose during pregnancy with childhood anthropometric outcomes. RESULTS In models including maternal glucose and BMI adjustments, newborn adiposity as measured by the sum of skinfolds was associated with child outcomes (adjusted mean difference, 95% CI, P value) BMI (0.26, 0.12–0.39, &amp;lt;0.001), BMI z-score (0.072, 0.033–0.11, &amp;lt;0.001), fat mass (kg) (0.51, 0.26–0.76, &amp;lt;0.001), percentage of body fat (0.61, 0.27–0.95, &amp;lt;0.001), and sum of skinfolds (mm) (1.14, 0.43–1.86, 0.0017). Structural equation models demonstrated significant mediation by newborn sum of skinfolds and cord C-peptide of maternal BMI effects on childhood BMI (proportion of total effect 2.5% and 1%, respectively), fat mass (3.1%, 1.2%), percentage of body fat (3.6%, 1.8%), and sum of skinfolds (2.9%, 1.8%), and significant mediation by newborn sum of skinfolds and cord C-peptide of maternal glucose effects on child fat mass (proportion of total association 22.0% and 21.0%, respectively), percentage of body fat (15.0%, 18.0%), and sum of skinfolds (15.0%, 20.0%). CONCLUSIONS Newborn adiposity is independently associated with childhood adiposity and, along with fetal hyperinsulinemia, mediates, in part, associations of maternal glucose and BMI with childhood adiposity. </jats:sec