Why some people are prone to high blood sugar in the morning? The Chinese joint team reveals a new unexpected mechanism

▎The content team editor of WuXi AppTec.
Recently, a research team led by Chinese scientists published research papers in the top academic journal Nature.
This is a common phenomenon among patients with type 2 diabetes-that blood sugar is prone to abnormally rise early in the morning.
A new interpretation mechanism has been introduced.

Researchers discovered that Rev-erb, a gene related to the biological clock in the brain, may be the basis of this phenomenon.

Based on this discovery, corresponding therapies can be developed in the future to help diabetic patients better control blood sugar.

Professor Sun Zheng from Baylor College of Medicine, one of the co-leaders of this research, said: "We are interested in this gene because it is a drug target in the molecular biological clock and has potential clinical application value.

" The expression of the gene shows a circadian rhythm, which is only expressed during the day and not at night.

And the researchers noticed that the expression of this gene is particularly abundant in a specific brain area of ​​mice-the suprachiasmatic nucleus, and this brain area is mainly composed of GABA neurons.

Therefore, in order to study the function of Rev-erb in the brain, the researchers first constructed a mouse model and knocked out the Rev-erb gene in its GABA neurons.

As a result, the researchers unexpectedly observed a phenomenon.

"These mice developed glucose intolerance, but only increased blood sugar in the evening.

As a nocturnal animal, the evening is the time when they start to be active, which is equivalent to the morning of humans.

" Further analysis of the mechanism found that the lack of Rev- Erb mice have abnormally increased blood sugar in the evening, due to the insufficient inhibitory effect of insulin on liver sugar production.

When these gene-deficient mice wake up, the GABA neurons in the suprachiasmatic nucleus have higher activity, and the excessively high neuronal activity changes the liver's ability to respond to insulin.

In contrast, these GABA neurons in normal mice reduce their activity at night, thereby reducing blood sugar levels.

Image source: 123RF mice have increased blood sugar at night, which reminds researchers that some patients with type 2 diabetes are prone to hyperglycemia at dawn and after breakfast.

In order to verify whether the Rev-erb gene is related, researchers at Qilu Hospital of Shandong University conducted continuous dynamic blood glucose monitoring on 27 patients with type 2 diabetes.

These patients are very similar in indicators such as basal blood glucose levels and obesity levels, but half of them have the dawn phenomenon and half of them do not.

The researchers measured the Rev-erb gene expression in these patients through blood sampling.

"We found that in the two groups of patients with and without dawn phenomenon, the expression of this gene follows a different time pattern.

" Professor Sun concluded, "We believe that this change in gene expression pattern can explain type 2 diabetes.
The dawn phenomenon of patients.
In the
future, it may be hopeful that drugs can regulate this gene to help patients improve their symptoms.

"References[1] Guolian Ding et al.
, (2021) REV-ERB in GABAergic neurons controls diurnal hepatic insulin sensitivity.
Nature Doi: https://doi.
org/10.
1038/s41586-021-03358-w[2] Study may provide an explanation for dawn phenomenon in patients with type 2 diabetes.
Retrieved Apr.
12, 2021 from dawn-phenomenon-in-patients-with-type-2-diabetes.
aspx