Comparison of Sampson and extended Martin/Hopkins methods of low-density lipoprotein cholesterol calculations with direct measurement in pediatric patients with hypertriglyceridemia

OBJECTIVE

The Friedewald equation is the commonly used method of low-density lipoprotein cholesterol (LDL-C) calculation, requiring reflex to direct LDL-C measurement when triglycerides (TG) ≥ 400 mg/dL. Recently formulated Sampson and extended Martin/Hopkins methods have been validated with TG up to 800 mg/dL and thus have the potential to replace direct LDL-C measurement. Given the growing prevalence of childhood dyslipidemia, the objective of this study was to compare Sampson and extended Martin/Hopkins methods of LDL-C calculation with the direct measurement in a pediatric cohort with 400 ≤ TG ≤ 799 mg/dL.

METHODS

This study retrieved standard lipid panels and corresponding direct LDL-C measurements of 131 patients with 400 ≤ TG ≤ 799 mg/dL from a pediatric population. Following the application of Sampson and extended Martin/Hopkins calculations, calculated values were compared with direct LDL-C measurements using ordinary least squares linear regression analysis and bias plotting.

RESULTS

Both Sampson and extended Martin/Hopkins LDL-C calculations exhibited a strong correlation with the direct measurements (Pearson r = 0.89) in patients with 400 ≤ TG ≤ 800 mg/dL. Average percentages of bias of 45% and 21% were found between the direct LDL-C measurements and Sampson or extended Martin/Hopkins calculations, respectively.

CONCLUSION

Both Sampson and extended Martin/Hopkins calculations are applicable as clinical alternatives of direct LDL-C measurement in pediatric patients given 400 ≤ TG ≤ 799 mg/dL.

Post-acute sequelae of COVID-19 and longitudinal antibody levels in a community-based cohort

BACKGROUND

Coronavirus disease 2019 (COVID-19) infection invokes variable immune responses and poses a risk of post-acute sequelae SARS-CoV-2 infection (PASC) symptoms; however, most data on natural history are derived from patients with severe infection. Further data are needed among patients with mild infection, who comprise most cases.

METHODS

The Dallas Fort-Worth (DFW) COVID-19 Prevalence Study included 21,597 community-dwelling adults (ages 18-89) who underwent COVID-19 PCR and anti-nucleocapsid antibody testing between July 2020 and March 2021. We invited participants with positive COVID-19 results (cases) and a subset with negative results (controls), matched on age, sex, race/ethnicity, and ZIP code, to complete a follow-up questionnaire for PASC symptoms and repeat anti-nucleocapsid testing, and anti-spike antibody testing between July and December 2021.

RESULTS

Of 3,917 adults invited to participate, 2260 (57.7%) completed the questionnaire- 1150 cases and 1110 controls. Persistent symptoms were reported in 21.1% of cases, with the most common being shortness of breath, fatigue, and loss of taste or smell. Among 292 cases with asymptomatic infection, >15% reported new fatigue and 8-10% reported new loss of taste/smell, myalgias, or headache. Median anti-nucleocapsid levels in cases decreased from 3.5U to 0.7U over a median follow-up of 8.6 months. Anti-spike antibody levels at 6-7 months post-vaccination in cases were similar to that of controls.

CONCLUSIONS

More than 1 in 5 patients with COVID-19 infection, including those with mild infection, reported persistent symptoms during follow-up. Both nucleocapsid and spike protein antibody levels decreased within six months following a COVID-19 infection and vaccination.

Methods of Low-Density Lipoprotein-Cholesterol Measurement: Analytical and Clinical Applications

Among the five major classes of lipoprotein particles, low-density lipoprotein-cholesterol (LDL-C) is the primary lipoprotein risk factor for the development of cardiovascular diseases (CVD) through the promotion of atherosclerotic pathogenesis. Therefore, it is of paramount importance to accurately measure the plasma concentration of LDL-C using an appropriate method to examine the risk of CVD and determine the efficacy of therapeutic interventions to reduce the cholesterol level and examine the risk assessment strategy. At present, there is a wide variety of methods available for LDL-C measurement. In this review, we have outlined the commonly used methods of LDL-C measurement. These methods have been classified into non-automated analytical methods, calculation methods, and automated direct measurement of LDL-C. We have also described some recently proposed promising calculation methods which are being considered for clinical adoption. This current review could assist the clinicians to have a better understanding regarding the measurement techniques and comparative utilities of different methods of LDL-C measurement and guide them to select an appropriate method based on accuracy, turnaround time, and cost of test.

Population-based correlates of COVID-19 infection: An analysis from the DFW COVID-19 prevalence study

BACKGROUND

COVID-19 has resulted in over 1 million deaths in the U.S. as of June 2022, with continued surges after vaccine availability. Information on related attitudes and behaviors are needed to inform public health strategies. We aimed to estimate the prevalence of COVID-19, risk factors of infection, and related attitudes and behaviors in a racially, ethnically, and socioeconomically diverse urban population.

METHODS

The DFW COVID-19 Prevalence Study Protocol 1 was conducted from July 2020 to March 2021 on a randomly selected sample of adults aged 18-89 years, living in Dallas or Tarrant Counties, Texas. Participants were asked to complete a 15-minute questionnaire and COVID-19 PCR and antibody testing. COVID-19 prevalence estimates were calculated with survey-weighted data.

RESULTS

Of 2969 adults who completed the questionnaire (7.4% weighted response), 1772 (53.9% weighted) completed COVID-19 testing. Overall, 11.5% of adults had evidence of COVID-19 infection, with a higher prevalence among Hispanic and non-Hispanic Black persons, essential workers, those in low-income neighborhoods, and those with lower education attainment compared to their counterparts. We observed differences in attitudes and behaviors by race and ethnicity, with non-Hispanic White persons being less likely to believe in the importance of mask wearing, and racial and ethnic minorities more likely to attend social gatherings.

CONCLUSION

Over 10% of an urban population was infected with COVID-19 early during the pandemic. Differences in attitudes and behaviors likely contribute to sociodemographic disparities in COVID-19 prevalence.

SARS-CoV-2 infection enhances mitochondrial PTP complex activity to perturb cardiac energetics

SARS-CoV-2 is a newly identified coronavirus that causes the respiratory disease called coronavirus disease 2019 (COVID-19). With an urgent need for therapeutics, we lack a full understanding of the molecular basis of SARS-CoV-2-induced cellular damage and disease progression. Here, we conducted transcriptomic analysis of human PBMCs, identified significant changes in mitochondrial, ion channel, and protein quality-control gene products. SARS-CoV-2 proteins selectively target cellular organelle compartments, including the endoplasmic reticulum and mitochondria. M-protein, NSP6, ORF3A, ORF9C, and ORF10 bind to mitochondrial PTP complex components cyclophilin D, SPG-7, ANT, ATP synthase, and a previously undescribed CCDC58 (coiled-coil domain containing protein 58). Knockdown of CCDC58 or mPTP blocker cyclosporin A pretreatment enhances mitochondrial Ca2+ retention capacity and bioenergetics. SARS-CoV-2 infection exacerbates cardiomyocyte autophagy and promotes cell death that was suppressed by cyclosporin A treatment. Our findings reveal that SARS-CoV-2 viral proteins suppress cardiomyocyte mitochondrial function that disrupts cardiomyocyte Ca2+ cycling and cell viability.

Inhibitory effects of voluntary wheel exercise on apoptosis in splenic lymphocyte subsets of C57BL/6 mice

Two-month-old mice were placed in cages with (Ex) or without exercise running wheels with free access to the wheel 24 h/day for 10 mo. An equal amount of food for both groups was provided daily. Ex mice ran an average of 33.67 km/wk initially, and exercise decreased gradually with age. Ex mice had gained an average of 43.5% less body weight at the end of the experiment. Although serum lipid peroxides were not altered by exercise, superoxide dismutase and glutathione peroxidase activities in serum were significantly increased. Flow cytometric analysis of spleen cells revealed an increased percentage of CD8+ T cells and a decreased percentage of CD19+ B cells in Ex mice (P < 0.05). Exercise decreased apoptosis in total splenocytes and CD4+ cells incubated with medium alone or with H(2)O(2), dexamethasone, tumor necrosis factor-alpha (TNF-alpha), or anti-CD3 monoclonal antibody (P < 0.05) and CD8+ cells with medium alone or with TNF-alpha (P < 0.05). Even though exercise did not alter the intracellular cytokines (TNF-alpha and interleukin-2) or Fas ligand, it did significantly lower interferon-gamma in CD4+ and CD8+ cells (P < 0.05). In summary, voluntary wheel exercise appears to decrease H(2)O(2)-induced apoptosis in immune cells as well as decrease interferon-gamma production.

Effects of calorie restriction on polymicrobial peritonitis induced by cecum ligation and puncture in young C57BL/6 mice

Calorie restriction (CR) is known to prolong the life span and maintain an active immune function in aged mice, but it is still not known if rodents under CR can respond optimally to bacterial infection. We report here on the influence of CR on the response of peritoneal macrophages to lipopolysaccharide, splenic NF-kappaB and NF-interleukin-6 (IL-6) activities, and mortality in polymicrobial sepsis induced by cecal ligation and puncture (CLP). Macrophages from 6-month-old C57BL/6 mice on a calorie-restricted diet were less responsive to lipopolysaccharide, as evidenced by lower levels of IL-12 and IL-6 protein and mRNA expression. Furthermore, in vitro lipopolysaccharide-stimulated macrophages from mice under CR also expressed decreased lipopolysaccharide receptor CD14 levels as well as Toll-like receptor 2 (TLR2) and TLR4 mRNA levels. In addition, the phagocytic capacity and class II (I-A(b)) expression of macrophages were also found to be significantly lower in mice under CR. Mice under CR died earlier (P < 0.005) after sepsis induced by CLP, which appeared to be a result of increased levels in serum of the proinflammatory cytokines tumor necrosis factor alpha and IL-6 and splenic NF-kappaB and NF-IL-6 activation 4 h after CLP. However, mice under CR survived significantly (P < 0.005) longer than mice fed ad libitum when injected with paraquat, a free radical-inducing agent. These data suggest that young mice under CR may be protected against oxidative stress but may have delayed maturation of macrophage function and increased susceptibility to bacterial infection.

Calorie restriction decreases proinflammatory cytokines and polymeric Ig receptor expression in the submandibular glands of autoimmune prone (NZB x NZW)F1 mice

Calorie restriction or fish oil (enriched in n-3 fatty acids) supplementation ameliorates glomerulonephritis and Sjögren's syndrome lesions in (NZB x NZW)F1(B/W) mice. Enhanced proinflammatory cytokine expression and deposition of immune complexes are the important pathological events in the development of Sjögren's syndrome. In the present study, we have examined the effect of calorie restriction and fish oil supplementation on the expression of key inflammatory cytokines [gamma interferon (INF-gamma), interleukin-10 (IL-10), and IL-12] and polymeric immunoglobulin (Ig) receptor (pIgR) (receptor for IgA and IgM) and the secretion of Ig in the submandibular glands (SMG) of B/W mice. Weanling B/W mice were fed either ad libitum (AL) or calorie restricted (CR) (40% less calories than AL) diet supplemented with 5% corn oil (CO) or 5% fish oil (FO) until 4 or 9 months of age. The SMGs were removed and a portion of the tissue used for semiquantitive determinations of IFN-gamma, IL-10, IL-12 (p40), and pIgR mRNA. The remaining SMG tissue was fragmented and cultured for 7 days and the culture supernatants assayed for IgA, IgM, and IgG2a levels by enzyme-linked immunosorbent assay. Results revealed a significant increase in the expression of IFN-gamma, IL-10, and IL-12 mRNA with age in AL fed mice, whereas CR fed mice maintained their levels to near those seen in young animals regardless of the dietary fat. PIgR mRNA expression also remained unaltered in CR animals irrespective of age and dietary fat, while it was found significantly increased in AL fed mice. CR significantly inhibited the elevated levels of IgA and IgG2a seen in aged mice. Interestingly, CR also influenced the Ig level in young animals. In summary, these results indicate that amelioration of autoimmune disease by CR in B/W mice is possibly mediated by the lowered mRNA expression of IFN-gamma, IL-10, IL-12, and pIgR and the reduced Ig secretion.

Calorie restriction modulates Th-1 and Th-2 cytokine-induced immunoglobulin secretion in young and old C57BL/6 cultured submandibular glands

Immunoglobulin production by the salivary gland plays an important role in oral and upper respiratory tract immunity. Age and/or disease may compromise salivary gland function. In order to gain insight into the role of calorie restriction (CR) on immunoglobulin (Ig) production, we determined the effect of ad libitum (AL) feeding and CR in young (3 months) and old (18-24 months) C57BL/6 mouse submandibular glands (SM). The SM tissues were fragmented and cultured in the absence (control) or presence of either Th-1 cytokines, such as interleukin-2 (IL-2) and interferon-gamma (IFN-gamma), or Th-2 cytokines, e.g. IL-4 and IL-5, for seven days. Culture supernatants were then analyzed for immunoglobulin A (IgA), IgM, and IgG2a levels by ELISA. Aging increased basal (control) IgA and IgM production by 3.1-and 3.7-fold, respectively, in AL mice. CR prevented the age-dependent rise of both IgA and IgM, maintaining levels equal to those of young AL mice. Interestingly, age resulted in a decrease of Th-1 cytokine-induced IgA and IgM, and increased IgG2a secretion in AL mice, while Th-2 cytokines did not appear to have an age effect. In general, CR suppressed Ig production induced by both Th-1 and Th-2 cytokines in young mice. In contrast, CR in old mice resulted in enhanced IgA and IgM production to levels similar to those in their young counterparts, while IgG2a was predominantly suppressed by Th-1 and not Th-2 cytokines. The data presented herein show, for the first time, the ability of CR to offset age-induced changes in submandibular gland Ig production, which may play a role in maintaining mucosal immune function, including proper oral health.