Association of ß-cell function and insulin resistance with pediatric type 2 diabetes among Chinese children.

BACKGROUND: In addition to insulin resistance, impaired insulin secretion has recently been identified as a crucial factor in the pathogenesis of type 2 diabetes mellitus (T2DM). Scarce clinical data exist for pediatric T2DM. AIM: To investigate the association of ß-cell function and insulin resistance with pediatric T2DM in the first Chinese multicenter study. METHODS: This multicenter cross-sectional study included 161 newly diagnosed T2DM children and adolescents between January 2017 and October 2019. Children with normal glycemic levels (n = 1935) were included as healthy control subjects. The homeostasis models (HOMAs) were used to assess the ß-cell function (HOMA2-%B) and insulin resistance (HOMA2-IR) levels. The HOMA index was standardized by sex and age. We performed logistic regression analysis to obtain odds ratios (ORs) for T2DM risk using the standardized HOMA index, adjusted for confounding factors including sex, Tanner stage, T2DM family history, body mass index z-score, and lipid profile. RESULTS: The male-female ratio of newly diagnosed T2DM patients was 1.37:1 (OR = 2.20, P = 0.011), and the mean ages of onset for boys and girls were 12.5 ± 1.9 years and 12.3 ± 1.7 years, respectively. The prevalence of related comorbidities including obesity, elevated blood pressure, and dyslipidemia was 58.2%, 53.2%, and 80.0%, respectively. The T2DM group had lower HOMA2-%B levels (P < 0.001) and higher HOMA2-IR levels (P < 0.001) than the control group. Both the decrease in HOMA2-%B z-score (OR = 8.40, 95%CI: 6.40-11.02, P < 0.001) and the increase in HOMA2-IR z-score (OR = 1.79, 95%CI: 1.60-2.02, P < 0.001) were associated with a higher risk of T2DM, and the decrease in HOMA2-%B z-score always had higher ORs than the increase in HOMA2-IR z-score after adjusting for confounding factors. CONCLUSION: Besides insulin resistance, ß-cell function impairment is also strongly associated with Chinese pediatric T2DM. Gender difference in susceptibility and high comorbidities warrant specific T2DM screening and prevention strategies in Chinese children.

Status and trends of diabetes in Chinese children: analysis of data from 14 medical centers.

BACKGROUND: Childhood diabetes has become a growing concern. We conducted a study to evaluate the status and trend of diabetes from 14 medical centers in China. Pre-diabetic status among obese children was also noted. METHODS: Hospital medical records were reviewed, and data of diabetes were collected from 1995 through 2010. We took every five years as a calculation unit to analyze the trend of new-onset diabetes. Data on obesity were collected in the recent five years. RESULTS: A total of 4 337 836 patients aged 0-18 years were discharged from the 14 centers. The prevalence (per 100 000 persons) of new-onset type 1 diabetes, type 2 diabetes and other types of diabetes were 96.8, 8.0, and 3.3, respectively. The prevalence of type 1 diabetes increased from 90.9 to 92.9 and 101.4, while type 2 diabetes increased from 4.1 to 7.1 and 10.0 in every five years (P<0.0001). The increasing trend was significant from Southwest to East and North China (type 1 diabetes from 59.76 to 80.02 and 120.45, type 2 diabetes from 2.52 to 3.77 and 15.64 (per 100 000 persons) (all P<0.0001). Well developed areas in China had a higher prevalence compared to less developed areas [type 1 diabetes: 151.51 vs. 32.2 (per 100 000 persons); type 2 diabetes: 15.16 vs. 1.64 and others: 7.54 vs. 0.42 (per 100 000 persons)]. Of the 3153 obese children, 18.24% had impaired fasting glucose (IFG), 5.99% had impaired gulose tolerance (IGT), and 4% had combined IFG and IGT. CONCLUSIONS: The prevalence of childhood diabetes in China has increased dramatically, with type 2 diabetes exceeding type 1 diabetes. The incidence rate of abnormal glucose metabolism in obese children has reached 28.26%.

[Inhibition of ACh on the delayed rectifier-like potassium current in acutely isolated cerebral cortical neurons of rats].

The modulation of ACh on delayed rectifier-like potassium currents (I(K)) was studied in freshly dissociated cerebral cortical neurons using the whole-cell patch-clamp technique. Wistar rats between 10- and 14-day old of both sexes were used. After rats were decapitated, their brains were quickly removed, iced, and then manually cut into 400 mum slices. Slices were then incubated for 0.5 h at 32 degrees C in a buffered artificial cerebrospinal fluid (ACSF) bubbled with 95% O2, 5% CO2. Slices were then removed into buffered ACSF containing protease (0.5 mg/ml) at 32 degrees C. After 30 min of enzyme digestion, tissue was rinsed three times in the buffered saline. Then the enzyme-treated slices were mechanically dissociated with a graded series of fire-polished Pasteur pipettes. The cell suspension was then plated into a 35 mm dish and placed on the stage of a Olympus inverted microscope. For whole-cell recordings of currents, standard voltage-clamp techniques were used. Neurons were held at -80 mV, and the I(K) was evoked by 2 000 ms depolarizing voltage commands to potential between -40 mV and +60 mV in 10 mV steps applied at a frequency of 0.5 Hz. It was found that the inhibitory effect of ACh (0.1, 1, 10, 100 mumol/L) on I(K) was dose-dependent. It was also found that ACh affected the activation process of I(K) significantly, i.e., the activation curve of I(K) was characterized by half-activation potential of (-41.8+/-9.7) mV and a slope factor of (30.7+/-7.2) mV in the cortical neurons and they were changed to (-122.4+/-38.6) mV and (42.4+/-7.0) mV, respectively, after giving ACh (10 mumol/L). Tubocurarine (100 mumol/L) antagonized the inhibitory effect of ACh on I(K), and the drop of currents varied from the control value of (36.5+/-7..8)% to (16.9+/-13.8)% (n=8, P<0.01). 4-DAMP (10 mumol/L) blocked the inhibitory effect of ACh on I(K), and the currents reduced from the control value of (36.5+/-7.8)% to (26.8+/-4.7) % (n=6, P<0.05). Pirenzepin did not antagonize the inhibition of ACh on I(K) (n=7, P>0.05). Chelerythrine (20 mumol/L) blocked the inhibitory effect of ACh on I(K) and the currents reduced from the control value of (36.5+/-7.8)% to (11.7+/-17.3)% (n=6, P<0.05). On the contrary, PDBu (10 mumol/L) strengthened the inhibition of ACh on I(K) and the drop of currents changed from the control value of (36.5+/-7.8)% to (59.2+/-14.0)% (n=5, P<0.05). PDBu abolished the antagonism of chelerythrine on ACh in cortical neurons. It is suggested that the ACh-induced depolarization of neurons in the cortex is attributed to the inhibition of I(K) that is most likely evoked by the activation of nicotinic ACh receptors and muscarinic M3 receptor via protein kinase C (PKC) signal transduction pathway.

In vivo patch clamp recording technique in the study of neurophysiology.

The patch clamp recording technique in vivo is a blind patch clamp recording methods to record the current of the spinal or cereral neurons of anaesthesia ( or awake) animals. This technique can be used to study the synaptic function and plasticity in central nervous system in vivo in order to understand the physiological properties of the ion channels from an integrated point of view. The advantage of this technique has already presented itself in the study of the synaptic transmission and nervous network. Nowadays, in vivo patch whole-cell recording technique in combination with other techniques is becoming a common method in the research fields.