Serum Ascorbic Acid and Thiamine Concentrations in Sepsis: Secondary Analysis of the Swiss Pediatric Sepsis Study

Thiamine status and genes encoding intestinal thiamine transporters and transcription factors in obese subjects

BACKGROUND AND AIMS

The inconsistent data on thiamine status in obese subjects necessitates an examination of genes associated with intestinal absorption of thiamine. We aimed to reveal thiamine status in obese subjects and examine the expression of SLC19A2/3 genes encoding thiamine transporters and Sp1 transcription factor.

METHODS AND RESULTS

Thirty-five adult obese subjects and 11 healthy controls were included in this cross-sectional study. Small intestine epithelial cells were used for quantitative RT-PCR analysis of the gene expression. The daily thiamine and energy intake were assessed with a food frequency questionnaire. Thiamine phosphate esters were hydrolyzed to free thiamine, and liquid chromatography with a tandem mass spectrometry-based method was used to measure total thiamine in whole blood. Daily energy intake according to body weight and daily carbohydrate intake were not significantly different between groups after adjustment for sex. Although daily thiamine intake was significantly lower in the obesity group (p = 0.015), obese subjects had significantly higher whole blood thiamine levels than controls (44.96 ± 14.6 ng/mL and 33.05 ± 8.6 ng/mL, p = 0.002). There was a significant positive correlation between whole blood thiamine and BMI (r = 0.342, p = 0.020). SLC19A2 gene expression was lower in those with BMI ≥35 kg/m2 (p = 0.036). A significant positive correlation was found between SLC19A2 expression and whole blood thiamine level (r = 0.310, p = 0.038).

CONCLUSION

A possible association between intestinal thiamine intake and total thiamine in whole blood was determined. The transcriptional changes of genes encoding the high-affinity membrane thiamine transporters, especially SLC19A2, probably play a role in this relationship.

Serum Levels of Vitamin C and Thiamin in Children With Suspected Sepsis: A Prospective Observational Cohort Study

OBJECTIVES

Vitamin C and thiamin have been trialed as adjunctive therapies in adults with septic shock but their role in critically ill children is unclear. We assessed serum levels of vitamin C and thiamin in children evaluated for sepsis.

DESIGN

Single-center prospective observational study. Serum levels of vitamin C and thiamin were measured on admission and association with multiple organ dysfunction syndrome (MODS) was explored using logistic regression.

SETTING

Emergency department and PICU in a tertiary children's hospital, Queensland, Australia.

PATIENTS

Children greater than 1 month and less than 17 years evaluated for sepsis.

INTERVENTIONS

Not applicable.

MEASUREMENTS AND MAIN RESULTS

Vitamin levels were determined in 221 children with a median age of 3.5 (interquartile range [IQR] 1.6, 8.3) years. Vitamin C levels were inversely correlated with severity as measured by pediatric Sequential Organ Failure Assessment (Spearman's rho = -0.16, p = 0.018). Median (IQR) vitamin C levels on admission were 35.7 (17.9, 54.1) µmol/L, 36.1 (21.4, 53.7) µmol/L, and 17.9 (6.6, 43.0) µmol/L in children without organ dysfunction, single organ dysfunction, and MODS, respectively (p = 0.017). In multivariable analyses, low levels of vitamin C at the time of sampling were associated with greater odds of MODS (adjusted odds ratio [aOR] 3.04; 95% CI, 1.51-6.12), and vitamin C deficiency was associated with greater odds of MODS at 24 hours after sampling (aOR 3.38; 95% CI, 1.53-7.47). Median (IQR) thiamin levels were 162 (138, 192) nmol/L, 185 (143, 200) nmol/L, and 136 (110, 179) nmol/L in children without organ dysfunction, single organ dysfunction, and MODS, respectively (p = 0.061). We failed to identify an association between thiamin deficiency and either MODS at sampling (OR 2.52; 95% CI, 0.15-40.86) or MODS at 24 hours (OR 2.96; 95% CI, 0.18-48.18).

CONCLUSIONS

Critically ill children evaluated for sepsis frequently manifest decreased levels of vitamin C, with lower levels associated with higher severity.

Thiamine deficiency disorders in women and children

Thiamine (vitamin B1) is available in common foods such as the outer husk of rice and is necessary for normal cardiovascular, neurological and metabolic processes. Thiamine deficiency is common in many parts of Asia and Africa, affecting up to a third or more of children and women of child-bearing age. The diagnosis is based on clinical suspicion, especially when noting heart failure in infants, encephalopathy in patients of any age, and peripheral neuropathy in older children and adults. Blood tests for whole-blood thiamine diphosphate (the quantity of biologically active thiamine present) and erythrocyte transketolase activity (the functional impact of thiamine) are not always readily available in areas where thiamine deficiency is common. Treatment is safe and effective, although dosing guidelines vary widely; 50 mg daily for 5 days is probably effective for treating acute thiamine deficiency disorders, and ongoing adequate thiamine intake is also needed. Prevention efforts depend on local and regional circumstances, including dietary diversification, food fortification, and/or supplementation of children and women at risk.Abbreviations: HIC: high-income countries; LMIC: low- and middle-income countries; MRI: magnetic resonance imaging; TDD: thiamine deficiency disorders.