Dried blood spot omega-3 and omega-6 long chain polyunsaturated fatty acid levels in 7-9 year old Zimbabwean children: a cross sectional study

Dried blood spots in clinical lipidomics: optimization and recent findings

Dried blood spots (DBS) are being considered as an alternative sampling method of blood collection that can be used in combination with lipidomic and other omic analysis. DBS are successfully used in the clinical context to collect samples for newborn screening for the measurement of specific fatty acid derivatives, such as acylcarnitines, and lipids from whole blood for diagnostic purposes. However, DBS are scarcely used for lipidomic analysis and investigations. Lipidomic studies using DBS are starting to emerge as a powerful method for sampling and storage in clinical lipidomic analysis, but the major research work is being done in the pre- and analytical steps and procedures, and few in clinical applications. This review presents a description of the impact factors and variables that can affect DBS lipidomic analysis, such as the type of DBS card, haematocrit, homogeneity of the blood drop, matrix/chromatographic effects, and the chemical and physical properties of the analyte. Additionally, a brief overview of lipidomic studies using DBS to unveil their application in clinical scenarios is also presented, considering the studies of method development and validation and, to a less extent, for clinical diagnosis using clinical lipidomics. DBS combined with lipidomic approaches proved to be as effective as whole blood samples, achieving high levels of sensitivity and specificity during MS and MS/MS analysis, which could be a useful tool for biomarker identification. Lipidomic profiling using MS/MS platforms enables significant insights into physiological changes, which could be useful in precision medicine.

Whole blood fatty acid profile of young subjects and adherence to the Mediterranean diet: an observational cohort study

Background

Relatively little is known about the physiological whole blood fatty acid composition in young people. Likewise, few studies have addressed the question of correlations between Mediterranean diet (MedDiet) adherence and blood fatty acids in childhood.

Methods

The fatty acid profile in whole blood from subjects, 46 days-19 years old (n = 152), without acute, chronic, or inflammatory diseases was analysed by gas chromatography. Dietary data was extracted from a 24-h recall in a subgroup of subjects (n = 60) into a modified Diet Quality Index for Children (KIDMED) questionnaire to evaluate MedDiet adherence. The cohort was divided into three age groups: < 2, 2- < 10, and 10–19 years. Kruskal-Wallis test and Bonferroni post hoc test were used to check for age group fatty acid differences. For correlations, Spearman’s correlation coefficient and partial Spearman’s correlation coefficient were used.

Results

Linoleic acid, EPA, DHA, palmitic acid, and total saturated fatty acids were stable over age groups. Dihomo-gamma-linolenic acid (DGLA), arachidonic acid (AA), total polyunsaturated FAs (PUFA), and total omega-6 PUFA increased from age group < 2 years; alpha-linolenic acid, total omega-3 PUFA, oleic acid, and total monounsaturated FAs decreased. Adherence to the MedDiet was at low-medium level in 91.7% of the subjects. In the age group 2- < 10 yrs., the degree of adherence correlated positively with total MUFA and PUFA balance, negatively with total PUFA, total n6-PUFA, AA/DHA, AA/EPA, and n6/n3. Age did not influence the correlations as to PUFA balance and AA/EPA.

Conclusions

Increased FA proportions with age were seen in the n6-series of PUFA. The n3-FA species decreased or were stable. The vast majority of the subjects with dietary data, 92%, obtained a KIDMED score indicative of low-medium adherence to the MedDiet. The score correlated negatively with various n6-species, i.e. the MedDiet suppressed circulating n6-PUFA. Whole blood may be used to investigate FAs and MedDiet adherence correlations which may be applied in the study of health issues in childhood.

Polyunsaturated Fatty Acid Composition in Breast Milk Plasma of HIV-infected and Uninfected Mothers in Relation to Infant Clinical Outcomes

Background:

The increased coverage of prevention of mother to child transmission (PMTCT) services has significantly reduced paediatric HIV infection incidence. The aim of the study was to compare breast milk omega-6 and omega-3 polyunsaturated fatty acid profiles of HIV infected and uninfected mothers and determine the association between fatty acid profiles and postnatal transmission of HIV, morbidity/mortality of HIV exposed and unexposed infants.

Methods:

A prospective cohort study of 57 HIV infected and 57 HIV uninfected lactating mothers was conducted in Gweru, Zimbabwe from July 2019 to March 2020. The women’s 114 babies (term and preterm) were also enrolled and stratified by HIV exposure and infection status. The mother-infant pairs were followed up at 6 weeks, 16 weeks and 6 months postpartum to determine, HIV transmission rate, breast milk polyunsaturated fatty acid profiles as well as infant clinical outcomes.

Results:

The mean breast milk docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) levels in HIV uninfected mothers (0.82 ± 0.92; 0.47 ± 0.75 μg/ml respectively) at 6 weeks postpartum were significantly higher compared to those of HIV infected mothers (0.33 ± 0.32; 0.08 ± 0.14 μg/ml) respectively. The same pattern was observed at 16 weeks postpartum in terms of DHA and EPA mean concentration. However, the arachidonic acid (AA) levels and AA/DHA ratio measured at 6 weeks postpartum were significantly higher in HIV infected mothers (2.31 ± 2.01; 17.18 ± 52.47 respectively) compared to HIV uninfected mothers (0.82 ± 0.54; 9.71 ± 21.80; P < .001). A higher morbidity rate was observed amongst HIV exposed infants than HIV unexposed infants (3.26 ± 0.13; 2.49 ± 0.09; P < .001) respectively. A significant positive correlation was observed between AA and infant morbidity (r = .388; P < .001).

Conclusion:

Deficiencies in breast milk omega-3 fatty acids were observed in HIV infected women. Maintaining a healthy balance between omega-6 and omega-3 fatty acid diets is critical for breast feeding mothers regardless of their HIV status. The adverse clinical outcomes observed amongst HIV exposed infants emphasise their vulnerability under conditions of maternal universal antiretroviral therapy.

Impact of Treatment with RUTF on Plasma Lipid Profiles of Severely Malnourished Pakistani Children

(1) Background: Little is known on impacts of ready-to-use therapeutic food (RUTF) treatment on lipid metabolism in children with severe acute malnutrition (SAM). (2) Methods: We analyzed glycerophospholipid fatty acids (FA) and polar lipids in plasma of 41 Pakistani children with SAM before and after 3 months of RUTF treatment using gas chromatography and flow-injection analysis tandem mass spectrometry, respectively. Statistical analysis was performed using univariate, multivariate tests and evaluated for the impact of age, sex, breastfeeding status, hemoglobin, and anthropometry. (3) Results: Essential fatty acid (EFA) depletion at baseline was corrected by RUTF treatment which increased EFA. In addition, long-chain polyunsaturated fatty acids (LC-PUFA) and the ratio of arachidonic acid (AA)/linoleic acid increased reflecting greater EFA conversion to LC-PUFA, whereas Mead acid/AA decreased. Among phospholipids, lysophosphatidylcholines (lyso.PC) were most impacted by treatment; in particular, saturated lyso.PC decreased. Higher child age and breastfeeding were associated with great decrease in total saturated FA (ΣSFA) and lesser decrease in monounsaturated FA and total phosphatidylcholines (ΣPC). Conclusions: RUTF treatment improves EFA deficiency in SAM, appears to enhance EFA conversion to biologically active LC-PUFA, and reduces lipolysis reflected in decreased ΣSFA and saturated lyso.PC. Child age and breastfeeding modify treatment-induced changes in ΣSFA and ΣPC.

Serum n-6 Fatty Acids are Positively Associated with Growth in 6-to-10-Year Old Ugandan Children Regardless of HIV Status-A Cross-Sectional Study

Fatty acids (FAs) are crucial in child growth and development. In Uganda, antiretroviral therapy (ART) has drastically reduced perinatal human immunodeficiency virus (HIV) infection of infants, however, the interplay of FAs, ART, and HIV in relation to child growth is not well understood. To investigate this, serum was collected from 240 children between 6–10 years old in Uganda and analyzed for FAs using gas-chromatography mass-spectrometry. HIV status and anthropometric measurements were taken, and relationships with FAs were assessed. No significant differences in growth parameters or serum FAs were found between HIV uninfected children with and without exposure to ART. HIV positive children had significantly lower height-for-age-z-scores (HAZ) than uninfected children (p < 0.001). HIV-positive children had higher arachidonic acid than uninfected children (p = 0.003). Total omega-6 FAs were significantly associated with HAZ regardless of HIV status (p = 0.035). Mean total omega-3 FAs (2.90%) were low in this population compared to other cohorts in Africa. These results provide reference serum FA values for 6–10-year-old children in Uganda and may be used to inform lipid supplementation programs to promote child growth. Future studies should investigate the relationships between child growth trajectories in relation to HIV status and serum FAs.

Quantitating fatty acids in dried blood spots on a common collection card versus a novel wicking sampling device

Blood biomarkers of n - 3 polyunsaturated fatty acids can serve as indicators of dietary intake and benefits and/or disease risk. The use of dried blood spots for fatty acid analyses is increasing but most of the reported data is qualitative (relative percentages of total fatty acids). The ability to quantitate concentrations of fatty acids on a common blood spot collection card and a novel wicking device designed to collect 10 µL of blood was compared with a wet blood sample in ten young adult participants. Prior to this comparison, the collection materials were screened for contaminants by gas chromatography with flame ionization and liquid chromatography/tandem mass spectrometry, and the blood volume and blood spot area relationship of the collection card was confirmed using technical replicates. Palmitate and stearate were detected as free fatty acids on both collection materials and as lysophosphatidylcholines on the wicking device. The low amounts (<1.0 µg) did not affect the quantitation of these fatty acids in either material. The relationship between blood volume and blood spot area was linear (r = 0.99, p < 0.001) and it was determined that a 6 mm hole punch contained 9.6 µL of blood. When compared with wet blood, the fatty acid determinations from the dried blood spots were largely similar although there were some minor differences in low abundant fatty acids. Quantitative fatty acid determinations of dried blood spots are possible and should be reported along with relative percentage data to improve interpretation in the future.