Haptoglobin-related protein in human plasma correlates to haptoglobin concentrations and phenotypes.

Haptoglobin-related protein (Hpr) is a plasma protein with high sequence similarity to haptoglobin (Hp). Like Hp, Hpr also binds hemoglobin (Hb) with high affinity, but it does not bind to the Hb-Hp receptor CD163 on macrophages. The Hpr concentration is markedly lower than Hp in plasma and its regulation is not understood. In the present study, we have developed non-crossreactive antibodies to Hpr to analyze the Hpr concentration in 112 plasma samples from anonymized individuals and compared it to Hp. The results show that plasma Hpr correlated with Hp concentrations (rho = 0.46, p = .0001). Hpr accounts for on average 0.35% of the Hp/Hpr pool but up to 29% at low Hp levels. Furthermore, the Hpr concentrations were significantly lower in individuals with the Hp2-2 phenotype compared to those with the Hp2-1 or Hp1-1 phenotypes. Experimental binding analysis did not provide evidence that Hpr associates with Hp and in this way is removed via CD163. In conclusion, the Hpr concentration correlates to Hp concentrations and Hp-phenotypes by yet unknown mechanisms independent of CD163-mediated removal of Hb-Hp complexes.

Re-evalution of the measurement of haptoglobin in human plasma samples.

Haptoglobin (Hp) is an abundant plasma protein scavenging hemoglobin (Hb) via CD163 on macrophages. This process consumes Hp, which therefore negatively correlates to hemolysis. However, exact measurements of Hp plasma levels are complicated by different phenotypes (Hp1-1, Hp2-1, and Hp2-2) forming different oligomeric states with differences in immunoreactivity. In addition, humans have an immune-cross-reactive Hp-related protein. In the present study, we developed Hp-specific monoclonal antibodies for an accurate Hp analysis of the different Hp phenotypes in a panel of 112 anonymous samples from hospitalized individuals subjected to routine Hp immunoturbidimetric measurements. The data revealed immunoturbidimetry as a reliable method in most cases but also that the use of non-phenotype-specific calibrators leads to substantial bias in the measurement of the Hp-concentration, non at least in Hp1-1 individuals. Furthermore, analysis of the Hb-dependence of the CD163 interaction with Hp1-1 and Hp2-2 showed that a higher 'cost-effectiveness' in the consumption of dimeric Hp1-1 versus multimeric Hp phenotypes is a likely contribution to the observed differences in the plasma levels of the Hp phenotypes. In conclusion, the determination of Hp phenotype and the use of phenotype-specific calibrators are essential to obtain a precise estimate of the Hp level in healthy and diseased individuals.

Platelet parameters and leukocyte morphology is altered in COVID-19 patients compared to non-COVID-19 patients with similar symptomatology.

In this nested case-control study, we evaluated haematological and morphological parameters of hospitalised patients with real-time polymerase chain reaction verified COVID-19 infection compared to patients with similar symptomatology but without COVID-19 infection. Seventy-four COVID-19 positive and 228 COVID-19 negative patients were evaluated with routine haematological parameters. Severe disease was defined as death and/or need of intensive care treatment. Twenty-seven COVID-19 positive and 18 COVID-19 negative patients were furthermore included for morphological evaluation using smear examination. Significant differences were found for platelet indices and white blood cell parameters. Thus, platelet count and plateletcrit was lower in COVID-19 patients, whilst mean platelet volume, platelet distribution width, and platelet large cell ratio was significantly higher than in non-COVID-19 patients. Leukocyte, neutrophil, immature granulocyte, lymphocyte, monocyte, eosinophil, and basophil count was lower in COVID-19 patients. No significant differences were found for red blood cell count, haemoglobin, haematocrit or mean corpuscular haemoglobin for COVID-19 versus non-COVID-19 patients. COVID-19 patients with a severe disease course had higher levels of immature granulocytes, but lower lymphocyte and platelet counts compared to patients with non-severe COVID-19. In terms of morphology, 14.8% of COVID-19 patients had a normal smear examination, compared to 83.3% of non-COVID-19 patients. Hypogranulated neutrophils were more frequent in COVID-19 patients (p < .001), but non-COVID-19 patients had higher levels of reactive lymphocytes, compared to COVID-19 patients. In conclusion, several haematological morphological abnormalities are more frequent in patients with COVID-19 disease, and several findings indicate that platelets play a fundamental role in the pathophysiology of the disease.

Verification of the hemolysis index measurement: imprecision, accuracy, measuring range, reference interval and impact of implementing analytically and clinically derived sample rejection criteria.

Automated spectrophotometric measurement of hemolysis index (HI) allows rapid and cost-effective assessment of hemolysis interference. We evaluated the analytical performance of HI on two different platforms. Further, the impact of implementing analytically and clinically derived sample rejection criteria was investigated. Precision profiles were established, and analytical error was assessed by comparison with the reference method for hemoglobin measurement on Architect c8000/c16000 (Abbott) and Cobas c702 (Roche Diagnostics) instruments. The impact of a more analyte-specific cut off based on analytical and biologival variation was examined for five hemolysis-sensitive plasma analyses according to European recommendations. Lastly, a reference interval was established for the HI on Cobas, using the CLSI C28A3c nonparametric method. Imprecision for HI of 0.6-3.0 % for Architect and 1.5-4.5 % for Cobas was considered acceptable, which also applied for trueness in the measuring tange > 2 g/L. If cutoffs based on analytical and biological variation were used to manage results from hemolyzed samples, more potassium, LDH, conjugated bilirubin and phosphate results would be suppressed. Considering RCV only LDS remained sensitive to hemolysis. The Cobas-based HI reference interval was established to 0.01-0.16 g/L. Thorough verification of the HI on two different clinical chemistry analyzers reveals acceptable analytical performance. HI cutoffs suggested by manufacturers may be optimized by clinical laboratories using analytical and/or biological variation. A reference interval for the HI analysis is relevant as the analysis has been suggested as a diagnostic tool in the assessment of in vivo hemolysis.

Prenatal Exposures to Perfluoroalkyl Acids and Associations with Markers of Adiposity and Plasma Lipids in Infancy: An Odense Child Cohort Study.

BACKGROUND: Perfluoroalkyl acids (PFAA) are repellants that cross the placental barrier, enabling interference with fetal programming. Maternal PFAA concentrations have been associated with offspring obesity and dyslipidemia in childhood and adulthood, but this association has not been studied in infancy. OBJECTIVES: We investigated associations between maternal PFAA concentrations and repeated markers of adiposity and lipid metabolism in infancy. METHODS: In the prospective Odense Child Cohort, maternal pregnancy serum concentrations of five PFAA: Perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA) were measured in 649 women. Offspring were examined at birth (n=613) and at 3 months (n=602) and 18 months (n=503) of age. Total cholesterol, LDL, HDL, and triglyceride were evaluated at 3 months (n=262) and 18 months (n=198) of age. Mixed effects linear regression models estimated associations between PFAA and standardized (SDS) body mass index (BMI), ponderal index, and waist circumference. Associations between PFAA and body fat% (BF%) and plasma lipids SDS at 3 months and 18 months of age were investigated with linear regression models. RESULTS: PFNA and PFDA were associated with higher BMI SDS [adjusted ß=0.26; 95% confidence interval (CI): 0.03, 0.49 and ß=0.58; 95% CI: -0.03, 1.19, respectively, for 1-ng/mL increases] and ponderal index SDS (ß=0.36; 95% CI: 0.13, 0.59 and ß=1.02; 95% CI: 0.40, 1.64, respectively) at 3 and 18 months of age (pooled) in girls. Corresponding estimates for boys were closer to the null but not significantly different from estimates for girls. In boys and girls (combined), PFNA and PFDA were associated with BF% at age 3 months (for 1-ng/mL PFDA, ß=0.40; 95% CI: 0.04, 0.75), and PFDA was associated with total cholesterol SDS at 18 months (ß=1.06; 95% CI: 0.08, 2.03) (n=83). DISCUSSION: Prenatal PFAA were positively associated with longitudinal markers of adiposity and higher total cholesterol in infancy. These findings deserve attention in light of rising rates of childhood overweight conditions and dyslipidemia. https://doi.org/10.1289/EHP5184.

Trans-10,cis-12 CLA increases adipocyte lipolysis and alters lipid droplet-associated proteins: role of mTOR and ERK signaling.

Lipid droplet-associated proteins play an important role in adipocyte triglyceride (TG) metabolism. Here, we show that trans-10,cis-12 conjugated linoleic acid (CLA), but not cis-9,trans-11 CLA, increased lipolysis and altered human adipocyte lipid droplet morphology. Before this change in morphology, there was a rapid trans-10,cis-12 CLA-induced increase in the accumulation of perilipin A in the cytosol, followed by the disappearance of perilipin A protein. In contrast, protein levels of adipose differentiation-related protein (ADRP) were increased in cultures treated with trans-10,cis-12 CLA. Immunostaining revealed that ADRP localized to the surface of small lipid droplets, displacing perilipin. Intriguingly, trans-10,cis-12 CLA increased ADRP protein expression to a much greater extent than ADRP mRNA without affecting stability, suggesting translational control of ADRP. To this end, we found that trans-10,cis-12 CLA increased activation of the mammalian target of rapamycin/p70 S6 ribosomal protein kinase/S6 ribosomal protein (mTOR/p70S6K/S6) pathway. Collectively, these data demonstrate that the trans-10,cis-12 CLA-mediated reduction of human adipocyte TG content is associated with the differential localization and expression of lipid droplet-associated proteins. This process involves both the translational control of ADRP through the activation of mTOR/p70S6K/S6 signaling and transcriptional control of perilipin A.