CREB3L1 and chronic obstructive pulmonary disease: The heat map of Pearson correlation coefficients showed that the expression of heat generation related genes (RPS6KB2, CREB3L1, RPS6KB1, ATP5G1, NDUFV1, NDUFA10) in COLD SAT were positively associated with the contents of organic acids in COLD plasma (Figure 6D), but not COLD VAT (Figure 6E).