Associations Between Insulin Resistance And Adverse Regnancy Outcomes In Women With Gestational Diabetes Mellitus And Mechanism Of NK Cells In Gestational Diabetes Mellitus

BACKGROUND:Gestational diabetes mellitus(GDM)is a common disease in obstetrics,often associated with other complications,and has adverse effects on maternal and child health.However,GDM with insulin resistance presents more adverse metabolic characteristics and has a greater risk of adverse pregnancy outcomes.This study aimed to explore the relationship between insulin resistance(IR)and adverse pregnancy outcomes in women with gestational diabetes mellitus(GDM),and to determine the risk factors for IR in women with GDM.METHOD:This study reviewed 100 women diagnosed with GDM and 100 normal pregnant women during this same period,and IR was evaluated using the homeostasis model assessment(HOMA-IR)method.ROC curve was drawn to calculate the best HOMA-IR cut-off value of GDM.Then,we employed a retrospective survey of 710 women diagnosed with GDM.Serum lipids,fasting plasma glucose(FPG),glycosylated hemoglobin(HbA1c),and serum protein were measured in the first trimester(6-12 weeks),and OGTT and fasting insulin tests were performed in the second trimester(24-28 weeks).These results were then used to evaluate IR by homeostasis model assessment(HOMA).The relationship between HOMA-IR and adverse pregnancy outcomes was analyzed by a logistic regression model,and multiple stepwise regression was used to analyze the risk factors of IR.RESULT:HOMA-IR predicted that the AUC of women with GDM was 0.694(95%CI:0.622～0.766),and the Youden index was 2.0.When HOMA-IR≥2.0,IR was diagnosed.IR significantly increasd the risk of the hypertensive disorders of pregnancy and large for gestational age(OR=5.31,95%CI:1.87,15.10;OR=1.65,95%CI:1.10,2.48,respectively)in women with GDM,but not for cesarean section,premature delivery,premature rupture of membranes,postpartum hemorrhage,macrosomia and small for gestational age.Compared to normal weight groups,greater body mass index(BMI)before pregnancy category(overweight or obesity group)were associated with higher risk of IR in the second trimester,the OR(95%CI)were 4.09(2.65,6.30)and 6.52(2.99,14.20).And higher level of FPG(OR=1.63,95%CI:1.11,2.40),TG(OR=1.32,95%CI:1.08,1.63)and weight gain before diagnosis of GDM(OR=1.08,95%CI:1.02,1.15)were also associated with higher risk of IR in the second trimester in women with GDM,while age(OR=0.94,95%CI:0.90,0.98)was the weak protective factor for IR.CONCLUSION:GDM with IR in the second trimester increased adverse pregnancy outcomes,especially the risk of hypertensive disorders of pregnancy and large for gestational age.In addition,FPG,HbAlc,and TG in early pregnancy,pre-pregnant BMI and weight gain before diagnosis of GDM were all independent risk factors for IR.BACKGROUND:The pathogenesis of GDM has not been fully clarified.It is generally believed that it is multifactorial,including insulin resistance,β-cell dysfunction,low-grade inflammation and immune dysfunction.NK cells are important components of the innate immune system.Abnormal activation of NK cells may also cause immune disorders and metabolic diseases.The further study of NK cells in vivo and in vitro is important for understanding the pathogenesis and development mechanism of GDM and provides a new idea for the development of prevention and treatment.METHOD:35 women with GDM from-December 2020 to August 2021 and 40 normal pregnant women during this same period were recruited as the control group.75g oral glucose tolerance test(OGTT)was performed at 24-28 weeks.NKG2A,NKG2D,NKp30,NKp46,Tim3,GLUT1,GLUT2,SGLT2,IL-10,TNF-α,IFN-γ,GM-CSF,perforin and granzyme B were analyzed by flow cytometry.NK92-MI cell lines were cultured with 5mM,10mM and 20mM glucose in vitro.Cytotoxicity against NK-92MI cells sensitive K562 cells was detected by CCK8;Flow cytometry was used to analyze the surface receptors;Flow cytometry was used to analyze the expression of cytokines after intervention with different concentrations of glucose and rapamycin;The expressions of mTOR,p-mTOR,p70S6K,p-p70S6K,Akt and p-Akt in NK92-MI cells after intervention with different concentrations of glucose and rapamycin were detected by Western-Blot.RESULT:The proportion of NK cells and CD3-CD56dimNK cells in peripheral blood of women with GDM were significantly increased;The expression of inhibitory receptor NKG2A decreased,while the expression of activated receptor NKG2D and NKp46 increased;SGLT2 expression decreased;Serum IFN-y and perforin levels increased.NKG2A was negatively correlated with HOMA-IR,while NKp46,Tim3 and perforin were positively correlated with HOMA-IR.In vitro,high concentrations of glucose(l0mM and 20mM)decreased the expression of NKG2A,GLUT1 and SGLT2,but increased cytolytic activity and expression of IFN-y,IL-10,TNF-α and perforin in NK92-MI cells.High concentration glucose up-regulated the levels of mTOR,p-mTOR and p-p70S6K,while up-regulated the secretion of IFN-y and perforin,which was inhibited by rapamycin.CONCLUSION:The activity and toxicity of NK cells in peripheral blood of women with GDM were significantly increased,and proinflammatory cytokine was increased.The function of NK cells is closely related to insulin resistance.High concentration glucose can improve the activity and toxicity of NK-92MI cells and increase the secretion of cytokines.High concentration glucose stimulated the increase of secretionn of IFN-γ and perforin in NK-92MI cells,which is mediated by mTOR/p70S6K signaling pathway.In conclusion,the change of NK cells in peripheral blood of women with GDM showed the same trend as that of NK cells cultured with high concentration of glucose.The study showed that hyperglycemia in pregnant women changes the function of NK cells,and the activation of this phenomenon further exacerbates inflammation and insulin resistance,and finally the GDM was developed.