Diferencia en las distintas funciones de las lipoproteínas de alta densidad en respuesta a la infección por SARS-CoV-2 / Differential Functions of High-density Lipoproteins in Response to SARS-CoV-2 Infection

RESUMEN Introducción. El síndrome post COVID (SPC), que se caracteriza por síntomas que se extienden superando las 4 semanas post-infección, podría desencadenar aumento en el riesgo cardiovascular. Las lipoproteínas de alta densidad (HDL) presentan funciones antiaterogénicas, como su capacidad para promover el transporte inverso del colesterol (TIC) y su actividad antioxidante, en la que es clave la enzima paraoxonasa 1 (PON 1). Objetivo. Evaluar funcionalidad de HDL en pacientes con SPC comparados con pacientes asintomáticos (PA) y controles. Material y métodos. Se incluyeron 9 individuos con SPC, 18 PA y 10 controles. Se midieron el hemograma, el perfil lipoproteico básico, las apolipoproteínas A-I y B, y marcadores inflamatorios por métodos automatizados. La actividad de PON 1 se evaluó empleando un método espectrofotométrico y los 3 pasos del TIC, eflujo de colesterol (ECC), y actividades de lecitina:colesterol aciltransferasa (LCAT) y proteína transportadora de colesterol esterificado (CETP), por métodos radiométricos. Resultados. No se observaron diferencias en sexo, edad, ni parámetros generales. El grupo PA presentó mayor actividad PON que los controles (94±76 vs. 183±111 vs. 148±58 nmol/mL.min, en controles, PA y SPC, respectivamente; p=0,049). No se observaron diferencias en el TIC. El ECC (r=-0,45; p=0,049) y CETP (r=-0,38; p=0,028) correlacionaron negativamente con el índice neutrófilos/linfocitos. LCAT correlacionó inversamente con la ferritina (r=-0,34; p=0,046). Conclusiones. El incremento de PON 1 en el grupo PA representaría un mecanismo de defensa frente al estrés oxidativo post-infección. Todos los pasos del TIC mostraron una correlación negativa con marcadores inflamatorios. Nuestros resultados podrían explicar, en parte, el vínculo entre COVID y ateroesclerosis.

ABSTRACT Background. Post-COVID syndrome (PCS), characterized by symptoms that persist for more than 4 weeks after initial infection, could increase cardiovascular risk. High-density lipoproteins (HDL) have antiatherogenic functions, such as the ability to promote reverse cholesterol transport (RCT) and antioxidant activity. In this regard, paraoxonase 1 (PON 1) plays a key role. Objective. The aim of this study was to evaluate HDL functions in patients with PCS and compare them with asymptomatic patients (AP) and controls. Methods. The study included 9 patients with PCS, 18 AP and 10 controls. Complete blood count, basic lipoprotein profile, apolipoproteins A-I and B, and inflammatory markers were measured using automated methods. PON 1 activity was evaluated by a spectrophotometric assay, and the 3 steps of RCT, cellular cholesterol (efflux CCE), lecithin-cholesterol acyltransferase (LCAT) activity and cholesteryl ester transfer protein (CETP) activity were evaluated by radiometric assays. Results. There were no differences in sex, age, or general parameters. The AP group had higher PON activity than the control group (94±76 vs. 183±111 vs. 148±58 nmol/mL.min, in controls, AP and PCS, respectively; p=0.049). There were no differences in RCT. Cellular cholesterol efflux (r=-0.45; p=0.049) and CETP (r=- 0.38; p=0.028) had a negative correlation with neutrophil-to-lymphocyte ratio. LCAT had an inverse correlation with ferritin (r=-0.34; p=0.046). Conclusions . Increased antioxidant activity of PON 1 would represent a defensive mechanism against oxidative stress after infection. All the RCT steps had a negative correlation with inflammatory markers. Our findings may explain, at least in part, the link between COVID-19 and atherosclerosis.

Increased Cholesteryl Ester Transfer Protein and Lipoprotein-Associated Phospholipase A2 Activities in Children and Adolescents Presenting High Triglyceride/High-Density Lipoprotein Cholesterol (TG/HDL-C) Ratio.

OBJECTIVE: To explore the association between Triglyceride/High-density lipoprotein cholesterol (TG/HDL-C) index and these enzymes and proteins in a pediatric population. METHODS: Children and adolescents (7-14 y old) were recruited (n = 150) and anthropometric data were registered. Glucose, TG, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), HDL-C plus cholesteryl ester transfer protein (CETP), lipoprotein-associated phospholipase A2 (Lp-PLA2) and paraoxonase 1 (PON1) activities were determined. RESULTS: Twenty-five individuals presented TG/HDL-C ratio ≥ 3.0. These individuals exhibited higher TG [164 (126-186) vs. 65 (48-72) mg/dL; p < 0.01] CETP [250 (232-263) vs. 223 (193-237)% mL/min; p < 0.01] and Lp-PLA2 (4.5 ± 1.9 vs. 3.5 ± 1.3; p < 0.05) plus lower HDL-C [41 (37-49) vs. 52 (48-62) mg/dL; p < 0.01] compared to an age-matched group with TG/HDL-C < 3.0. TG/HDL-C ratio was associated to CETP (p < 0.01) and Lp-PLA2 (p < 0.05). Multiple lineal regression analyses showed TG/HDL-C index as an independent predictor of CETP (r2 = 0.29; beta = 0.49; p < 0.01) and Lp-PLA2 (r2 = 0.21; beta = 0.32; p < 0.05) activities. CONCLUSION: Children and adolescents with TG/HDL-C ≥ 3.0 presented a more atherogenic lipid profile and higher CETP and Lp-PLA2 activities, which would indicate alterations in lipoprotein metabolism and quality.

Effect of Tocilizumab on LDL and HDL Characteristics in Patients with Rheumatoid Arthritis. An Observational Study.

BACKGROUND: In patients with rheumatoid arthritis (RA), qualitative alterations of low and high-density lipoproteins (LDL and HDL, respectively) might partially explain their increased cardiovascular risk. Tocilizumab has been associated with an increase in lipids, including triglyceride (TG) and cholesterol levels. The aim of this study is to evaluate the effect of tocilizumab on certain LDL and HDL characteristics (oxidized LDL levels, HDL-associated enzymes, chemical composition of both total HDL and HDL3c subpopulation, and their capacity to promote cellular cholesterol efflux) at baseline and 3 months after the start of treatment in patients with RA. METHODS: Twenty-eight RA patients (ACR/EULAR 2010 criteria) with indication of treatment with tocilizumab were included in the present study. Clinical assessment [Health assessment questionnaire (HAQ)], disease activity score 28 (DAS28), high-sensitivity C reactive protein (hsCRP) concentration, lipid profile, and lipoprotein (a) [Lp(a)] levels were evaluated in all patients at baseline and after 3 months of treatment with tocilizumab. Lipoprotein characteristics were evaluated through the levels of oxidized LDL (OxLDL), the activity of paraoxonase (PON) 1, the composition of total HDL and small, dense HDL3c subpopulation, and their ability to promote cellular cholesterol efflux. RESULTS: After 3 months of treatment with tocilizumab, HAQ (- 23%, p < 0.05), DAS28 (- 49%, p < 0.001), and hsCRP (- 94%, p < 0.01) levels decreased significantly. Total cholesterol (TC), LDL-C, non-HDL-C, and apo B levels showed a significant increase after treatment (TC: + 7.0%, p < 0.01; LDL-C: + 10%, p < 0.01; non-HDL-C: + 9.9%, p < 0.01; and apo B: + 9.6%, p < 0.05). Decreases in Lp(a) and OxLDL levels were also observed after treatment [Lp(a): - 50%, p < 0.01; and oxLDL: - 5.4%, p < 0.05]. The latter was in accordance with the increment detected in PON activity. No changes were observed in HDL capacity to promote cholesterol efflux (p > 0.05) in the whole group. CONCLUSIONS: Treatment with tocilizumab reduced hsCRP levels and displayed positive effects on certain lipoprotein-related parameters, such as a potent decrease inLp(a) and a reduction in OxLDL levels. Moreover, HDL capacity to promote cellular cholesterol efflux was maintained after 3 months of treatment.

Effects of Pubertal Status and Inflammation on the Use of Ferritin to Define Iron Deficiency in Children With Overweight or Obesity.

BACKGROUND AND AIMS: A worldwide increase in childhood overweight (OW) and obesity (OB) has been reported. OB is an inflammatory state which affects iron metabolism and the sensibility of the tests to detect iron deficiency (ID). Our aim was to evaluate the adequacy of current ferritin cut-offs to define ID in children with OW/OB. METHODS: This cross-sectional study included 152 children (54% girls) aged (median [Q1-Q3]) 11 (8-13) years with OW/OB. Complete blood count and iron metabolism were evaluated. Low ferritin, transferrin saturation (TSat), and anemia were defined by age- and sex-specific cut-offs recommended by National Guidelines. Iron intake was assessed in a subgroup (n = 80) by a 24-hour dietary recall. Analyses were made according to pubertal development and ferritin tertiles. RESULTS: The overall prevalence of low ferritin, TSat, and anemia was 2.6%, 23.8%, and 5.2%, respectively. Among pre-pubertal children (n = 87), the frequency of low TSat rose across ferritin tertiles (P < .05), whereas it decreased among pubertal children (n = 65; P < .005). Cases of anemia among pre-pubertal children were found in the highest ferritin tertile, whereas 4/6 anemia cases in pubertal children were found in the lowest ferritin tertile (<39 µg/L). Pubertal children within the lowest ferritin tertile + low TSat (n = 11) showed lower hemoglobin (-9%; P < .005) and hematocrit (-8%, P < .01) than those in the same tertile + normal TSat (n = 16). The overall prevalence of children with ferritin < 39 µg/L + low TSat was 9.2%. CONCLUSIONS: Higher ferritin cut-off values are required to define ID in children with OW/OB. Such cut-off remains to be validated in larger, multi-ethnic cohorts of children with OW/OB.