Table 1.
Characteristics of the Leipzig Adipose Tissue Childhood Cohort.
Table 2.
Characteristics of adult subjects with low or high UCP1 expression levels in AT.
Fig 1.
Immunohistochemical evidence of brown-like adipocytes in adipose tissue samples.
A: Immunohistochemical staining of AT samples showed multilocular adipocytes, which stained positive for UCP1 (black arrows), surrounded by UCP1-negative white unilocular fat cells (white arrows) in subcutaneous (top), perirenal (middle) and visceral (bottom) AT samples of children. B: Two perirenal unilocular samples also exhibited positive UCP1 staining (grey arrows). C: Representative images of UCP1-negative subcutaneous (top, left) and perirenal (top, right) AT samples of lean children and subcutaneous samples of lean adults (bottom). Nuclei were counterstained with Mayer’s hematoxylin. Scale bars represent 50 μm in each panel.
Fig 2.
Expression of brown, beige and white adipocyte markers in adipose tissue samples of children and adults.
A: UCP1 mRNA expression was significantly increased in UCP1histological+ samples compared to lean and obese children as well as adult UCP1histological- samples with the exception of a single outlier from an UCP1histological- subcutaneous sample (indicated as black box). B: PRDM16 was also increased in UCP1histological+ compared to all other UCP1histological- samples. C, D, E and F: mRNA expression of PAT2, P2RX5, ZIC1 and LHX8 were not different in UCP1histological+ samples, although, one UCP1histological+ and one UCP1histological- sample presented exceedingly high PAT2 expression values, marked with black squares. G,H and I: mRNA expression of the beige adipocyte markers TMEM26 and HOXC9 was not different in UCP1histological+ samples, although, two UCP1histological+ samples (from different donors) presented exceedingly high HOXC9 values, marked with black squares. These samples showed only islets of UCP1 positive adipocytes. TBX1 mRNA expression was slightly increased in UCP1histological- samples of lean children and obese adults compared to UCP1histological+ samples. J and K: The WAT marker LEP was significantly decreased in UCP1histological+ samples compared to UCP1histological- samples in contrast to ASC1, another white specific marker. L: ADIPOQ, a general marker for AT was not different between UCP1histological+ and UCP1histological- samples. Target gene expression was normalized to the mean of the three housekeeping genes: ACTB, TBP and HPRT1. Statistical significance was assessed by one-way ANOVA and post-hoc Dunnett’s test and was compared to UCP1histological+ samples and marked with *P<0.05; **P< 0.01; ***P<0.001.
Table 3.
Comparison of UCP1histological+ and UCP1 histological-samples.
Fig 3.
Expression analyses of brown and beige markers in adipose tissue samples of adults with low compared to high UCP1 mRNA expression.
We compared the upper 10% with the lowest 10% of UCP1 mRNA expression in paired subcutaneous and visceral AT samples of adults (n = 48) (A). Subcutaneous and visceral AT samples of adults with a high UCP1 expression showed significantly increased mRNA levels of PRDM16 (B) and PAT2 (C) in both subcutaneous and visceral depots. The classical brown specific marker ZIC1 was not altered between subcutaneous/visceral samples with a low or high UCP1 expression (D). Furthermore, samples with a high UCP1 expression appear to have slightly higher TMEM26 expression in subcutaneous and significantly increased mRNA levels in visceral AT samples (E). In contrast, TBX1 levels were significant increased in subcutaneous depots and slightly in visceral depots (F). Expression levels were normalized with the reference gene RPL27. Statistical significance was assessed by Student t-test and was marked with *P<0.05; **P< 0.01; ***P<0.001.
Fig 4.
Correlation analysis in UCP1histological+ samples.
In statistical analyses which were restricted UCP1histological+ samples, we observed a negative association between UCP1 mRNA and age (A) and a positive association between UCP1 mRNA and PRDM16 (B). Pearson correlation coefficient R and p-value are shown in each scatterplot. Significant p-values (p<0.05) are indicated in bold. Black circles, subcutaneous depots; white circles, perirenal depots; and black squares, visceral depots.
Table 4.
Correlation of UCP1 mRNA expression with anthropometric parameters and expression data in UCP1histological+ samples from children (n = 10).