Glucagon and insulin cord blood levels in very preterm, late preterm and full-term infants

Comparison of Homeostasis Model Assessment-Insulin Resistance (HOMA-IR) and the Level of Cortisol Between Preterm and Term Newborns

Introduction According to the thrifty (Barker's) phenotype hypothesis, poor nutrition in fetal and early infancy plays a role in the development and function of the beta cells of the islets of Langerhans, which leads to the development of type 2 diabetes mellitus. Insulin resistance is due to decreased suppressive effect of insulin on hepatic glucose production. Thus, elevated insulin levels during perinatal life may predispose the infant to the development of diabetes mellitus in future life. Intrauterine undernutrition plays an important role in causing adult insulin resistance and diabetes but the exact cause is still unknown. Preterm infants born small for gestational age (SGA) show lower adrenocortical response to stimulation due to an immature hypothalamic-pituitary axis. Methods The cross-sectional study conducted at Rajendra Institute of Medical Sciences, Ranchi from June 2020 to November 2021 included 216 newborns enrolled as per the inclusion and exclusion criteria. Maternal and neonatal details were collected at birth and recorded. Cord blood samples for measurement of serum insulin, glucose, and cortisol were collected from 84 preterm and 132 term neonates. Using this information, homeostasis model assessment-insulin resistance (HOMA-IR) was calculated using a mathematical formula. Insulin resistance was defined as HOMA-IR > 2.5. Based on birth weight and gestational age, they were further categorized into SGA, appropriate for gestational age (AGA), and large for gestational age (LGA). The parametric data were presented as means ± standard deviation (SD), and nonparametric data as medians (first quartile and third quartile). The Student's (independent samples) t-test and Mann-Whitney U test were used to compare mean differences between the two groups for parametric and nonparametric data, respectively. The Spearman correlation coefficient was used to determine the significant association between variables. Results Umbilical cord plasma glucose and serum insulin were high in preterm in comparison to term newborns. Serum cortisol levels were high in term than in preterm newborns. HOMA-IR showed a very strong positive correlation with serum insulin and a moderate positive correlation with serum glucose. HOMA-IR showed a strong negative correlation with gestational age and a moderate negative correlation with birth weight. Insulin resistance was seen in 34 preterm newborns and two term newborns. Insulin resistance was seen in 29.8% (n = 25) of SGA preterm babies, 7.1% (n = 6) of AGA preterm babies, and 1.5% (n = 2) of AGA term newborns. A total of 55.6% of newborns were below normal weight (48.1% had low birth weight, 4.6% had very low birth weight, and 2.8% had extremely low birth weight). Conclusion Our study suggests that preterm newborns are more insulin resistant at birth than term newborns. SGA preterm babies are having a higher incidence of insulin resistance compared to AGA preterm babies. It is clear that high insulin level is needed to overcome high insulin resistance in the very early gestational period. Serum cortisol increases as gestational age and birth weight increase. Thus, serum cortisol helps in the maturation of the fetus and neonatal adaptation at birth.

Type of feeding provided with dextrose gel impacts hypoglycemia outcomes: comparing donor milk, formula, and breastfeeding

OBJECTIVE

Examine neonatal hypoglycemia (NH) outcomes based on type of feeding provided with first dextrose gel.

STUDY DESIGN

Retrospective matched cohort study of 99 infants ≥35 weeks gestational age who received dextrose gel in combination with breastfeeding, formula feeding, or donor milk feeding for NH. The exposure was feeding type. The outcomes were: (1) median change in blood glucose (Δ BG) concentration after first gel, (2) odds of second gel, and (3) odds of recurrent NH.

RESULTS

Median Δ BG was greater in formula (17.0 mg/dL) and donor milk (19.0 mg/dL) fed vs. breastfed infants (7.0 mg/dL). Donor milk and formula feeding were both associated with lower odds of second gel and recurrent NH. Associations remained significant in late-preterm infants, but only formula feeding remained significant in full-term infants.

CONCLUSIONS

Formula and donor milk feedings both raised blood sugar concentrations, but the impact differed by gestational age.

Is Fat Mass Accretion of Late Preterm Infants Associated with Insulin Resistance?

BACKGROUND

Late preterm infants show a major fat mass accretion from birth to term. The contribution of preterm birth to the development of the metabolic syndrome is still under investigation.

OBJECTIVES

To evaluate body composition changes in late preterm infants during the first 3 months and to investigate their insulin sensitivity and resistance.

METHODS

We conducted an observational, longitudinal study. A total of 216 late preterm infants underwent body composition assessment using an air displacement plethysmograph at term and at 3 months of corrected age. In a subgroup of infants (n = 48) the blood glucose and insulin concentration were determined at term and insulin resistance (homeostasis model assessment for insulin resistance; HOMA-IR) and sensitivity (quantitative insulin sensitivity check index; QUICKI) were then calculated. The reference group comprised 71 healthy term infants.

RESULTS

The mean birth weight and gestational age were 2,390 ± 391 g and 35.2 ± 0.8 weeks, respectively. At term the fat mass index (kg/m2) of late preterm infants, born adequate for their gestational age and small for their gestational age, was higher than that of term infants (2.08 ± 0.82 vs. 1.62 ± 0.64 vs. 1.03 ± 0.36, p < 0.005, respectively), whereas at 3 months of corrected age no difference was found among the groups. The mean values of glucose, insulin, HOMA-IR, and QUICKI were within the 5th and 95th percentiles.

CONCLUSIONS

On the basis of these preliminary findings, fat mass accretion of late preterm infants appears not to be associated with perturbation of the glucose homeostasis.

Indices of Glucose Homeostasis in Cord Blood in Term and Preterm Newborns

OBJECTIVE

According to the thrifty phenotype hypothesis, intrauterine malnutrition has a role in the etiology of type 2 diabetes. This study was planned to determine the early alterations in indices of glucose homeostasis (glucose, insulin, and cortisol) in term and preterm newborns and the correlations of glucose, insulin, and cortisol levels with insulin resistance indices.

METHODS

A descriptive study comprising 35 term and 35 preterm newborns was carried out from December 2013 to June 2015. Venous cord blood was collected and plasma glucose was analyzed by the glucose oxidase-peroxidase method in an auto analyzer. Serum insulin and cortisol levels were assessed by the enzyme-linked immunosorbent assay. Homeostasis model assessment of insulin resistance (HOMA-IR), quantitative insulin sensitivity check index and glucose insulin ratio were calculated to assess insulin resistance. The data on physical and metabolic parameters were analyzed using standard tests for statistical significance.

RESULTS

In term newborns, mean glucose and cortisol levels (83.6±17.4 mg/dL and 11.88±5.78 µg/dL, respectively) were significantly higher than those in preterm infants (70.4±15.8 mg/dL and 8.9±4.6 µg/dL, respectively). Insulin and HOMA-IR levels were found higher in preterm newborns (10.8±4.8 µIU/mL and 1.52±0.66, respectively) than in term newborns (7.9±2.7 µIU/mL and 1.19±0.29, respectively). Insulin was found to positively correlate with HOMA-IR, whereas cortisol was negatively correlated with HOMA-IR in both term and preterm newborns.

CONCLUSION

Higher insulin levels and HOMA-IR values in the cord blood of preterm newborns support the theory of intrauterine origin of metabolic diseases.

Insulin and glucagon levels of umbilical cord blood in appropriate for gestational age - preterm infants with or without postnatal hypoglycemia

PURPOSE

To determine whether serum insulin and glucagon levels of umbilical cord blood correlate with subsequent postnatal hypoglycemia in appropriate for gestational age (AGA) - preterm infants at different gestational ages (GAs).

METHODS

The serum insulin and glucagon levels of umbilical cord blood were measured using magnetic bead based multiplex immunoassay in 69 AGA - premature infants, stratified according to GA: GA 23-30 weeks, early preterm (EP, n=31); GA 31-34 weeks, late preterm (LP, n=38). Postnatal hypoglycemia was defined as a capillary glucose level <40 mg/dL within the first 60 minutes of life, regardless of GA.

RESULTS

The capillary glucose concentration in EP infants (65.5±21.2 mg/dL) was significantly higher than that of LP infants (55.9±17.3 mg/dL) (P=0.043). The serum glucagon level in EP infants (44.3±28.7 pg/mL) was significantly higher than that in LP infants (28.1±13.6 pg/mL) (P=0.006). There was not a significant difference in serum insulin level between EP and LP infants (372.7±254.2 pg/mL vs. 372.4±209.1 pg/mL, P=0.996). There was a significant difference in the serum glucagon level between infants with and without hypoglycemia (27.7±8.9 mg/dL vs. 36.8±24.6 mg/dL, P=0.036), but not in the serum insulin level (451.9±256.9 pg/mL vs. 357.4±222.2 pg/mL, P=0.211). Postnatal glucose concentration within the first 60 minutes of life had a significant positive correlation with serum glucagon levels (r=0.256, P=0.034), but not with serum insulin levels (r=-0.020, P=0.867).

CONCLUSION

Lower glucagon levels of cord blood were seen in premature infants with higher GA, which might contribute to the occurrence of postnatal hypoglycemia.

Cord Blood Levels of Insulin, Cortisol and HOMA2-IR in Very Preterm, Late Preterm and Term Newborns

INTRODUCTION

Alteration in the glucose homeostasis is still the major cause of morbidity and mortality in the newborns. Intrauterine undernutrition plays an important role in causing adult insulin resistance and diabetes but the exact cause is still unknown.

AIM

To estimate the plasma glucose, serum insulin and cortisol levels at birth in newborns at different gestational age.

MATERIALS AND METHODS

The present cross-sectional study conducted from December 2014 to June 2015 included 58 newborns enrolled as per the inclusion criteria and further categorized into Group I (very preterm; n=19; gestational age < 32 weeks), Group II (late preterm; n=20; gestational age between 32-37 weeks) and Group III (full term; n=19; gestational age >37 weeks) newborns. Venous Cord Blood (VCB) was collected and plasma glucose was analysed by GOD-POD (Glucose Oxidase-Peroxidase) method in auto analyser whereas serum insulin and cortisol were analysed by ELISA (Enzyme Linked Immunosorbent Assay). HOMA2-IR (Homeostatic Model Assessment) calculator was used to assess insulin resistance. All parametric data was expressed as mean±SD and analysed using ANOVA with Tukey's as the Post-Hoc test. Correlation analysis was done using Pearson's correlation co-efficient with scatter plot as the graphical representation.

RESULTS

Significantly increased insulin and HOMA2-IR levels were found in group I (13.7±4.7μIU/mL and 1.6±0.58 respectively) when compared to group II (8.3±2.9μIU/mL and 0.93±0.2 respectively) and group III (8.3±2.1μIU/mL and 1.03±0.26 respectively). A positive correlation between cortisol levels and gestational age (r = 0.6, n = 58, p < 0.001) and a negative correlation between insulin and gestational age (r = -0.654, n = 58, p < 0.001) was observed in the study population.

CONCLUSION

Increased levels of insulin and HOMA2-IR as seen in the very preterm newborns signify the predisposition of these newborns to development of diabetes in later stages of life. The inverse association of cortisol and insulin with gestational age suggests that cortisol could also be responsible for impaired β cell function and insulin sensitivity.