Table 1.
Fatty acid concentrations in CSF and plasma.
Table 2.
Group characteristics.
Figure 1.
Plasma and CSF fatty acid fractions by race.
Percentual abundance of saturated (SAFA), monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids in plasma (a.) and CSF (b.) are shown for Caucasian (C) and American Indian (AI) individuals in plasma and CSF. Diamonds (♦) represent least squared means adjusted for age, sex, and body fat and error bars indicate 95% confidence interval. *P = 0.01.
Figure 2.
Correlation heatmap of fatty acid species with metabolic traits.
Spearman Correlation Coefficients are represented by color codes as illustrated in the side panel. CSF: cerebrospinal fluid; 24EE: 24 hour energy expenditure measured in a metabolic chamber; SLEEP: energy expenditure measured during the sleep phase; RQ: respiratory quotient; GAUC: glucose area under the curve during the oral glucose tolerance test; *p<0.05, †p<0.01, ‡p<0.001, #significant after Bonferroni correction.
Figure 3.
Scatter plots of fatty acids in CSF and metabolic factors.
Erucic acid (C26∶0, panel a.) and Lignoceric acid (C24∶0, panel b.) are negatively associated with residuals of energy expenditure during sleep (SLEEP). SLEEP was adjusted for known confounders as described in the Statistical analyses section of the Materials and methods. Panel c. shows the association of palmitoleic acid (C16∶1) with residuals of glucose area under the curve (GAUC). GAUC was adjusted for age, sex and percent body fat. Bonferroni-corrected p-values were a) 0.004, b) 0.004 and c) 0.02.
Figure 4.
Glucose and insulin levels during the OGTT.
Glucose (a.) and insulin (b.) levels are shown over the time course of the OGTT. Dashed lines and open bars represent individuals with high palmitoleic acid (PA) in the CSF, full lines and closed bars represent low PA in the CSF. Groups were defined as PA>0.63 (high) and PA<0.63 (low), where 0.63 is the median of central PA representation. Error bars depict standard deviation. AUC: area under the curve; *p<0.05; †p<0.01.