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Impaired microvascular vasodilatory function in 3-month-old infants of low birth weight
1Diabetes and Vascular Medicine, School of Postgraduate Medicine and Health Sciences, University of Exeter, Barrack Rd., Exeter, Devon EX2 5AX, U.K.
Insights
Infants with lowest quartile birth weight (LQBW) showed impaired skin microvascular function, specifically a lower maximal hyperemic response. This finding supports the idea that poor vascular function in early life may precede type 2 diabetes and cardiovascular disease.
Area of Science:
- Cardiovascular Physiology
- Neonatal Health
- Metabolic Disease Research
Background:
- Low birth weight (LBW) is associated with increased risks of type 2 diabetes and cardiovascular disease later in life.
- The fetal insulin hypothesis suggests impaired vascular development may be linked to genetic predispositions for insulin resistance.
- Microvascular dysfunction could be an early, intrinsic abnormality in LBW infants, predating clinical signs of insulin resistance syndrome.
Purpose of the Study:
- To investigate skin microvascular function in 3-month-old infants based on birth weight quartiles.
- To determine if impaired vascular function is an early characteristic of infants born with low birth weight.
Main Methods:
- Comparison of two groups: lowest quartile birth weight (LQBW) and highest quartile birth weight (HQBW) infants.
- Assessment of three aspects of skin microvascular function: response to local heating, acetylcholine iontophoresis, and capillary density.
Main Results:
- LQBW infants exhibited a significantly lower maximal hyperemic response to local heating compared to HQBW infants (P = 0.020).
- No significant differences were found in endothelium-dependent vasodilatory response (P = 0.297) or capillary density (P = 0.736) between the groups.
- Median birth weights differed significantly between the LQBW (3,140 g) and HQBW (3,920 g) groups.
Conclusions:
- Lower maximal hyperemic response in LQBW infants suggests impaired microvascular function.
- This early microvascular alteration supports the hypothesis that it is a precursor to type 2 diabetes and cardiovascular disease.
- Capillary density and endothelium-dependent vasodilation were not found to be different in early infancy based on birth weight.
Objective:
Low birth weight has been linked to an increased risk of type 2 diabetes and cardiovascular disease in adult life. The fetal insulin hypothesis proposed that a genetic predisposition to insulin resistance may also influence vascular development. Therefore, impaired vascular function may be an intrinsic abnormality in low-birth weight infants that antedates clinical features of the insulin resistance syndrome.
Research Design And Methods:
Two groups of 3-month-old term infants were included in the study: 17 infants of lowest quartile birth weight (LQBW) and 21 infants of highest quartile birth weight (HQBW). Three aspects of skin microvascular function were examined; response to local heating, response to acetylcholine iontophoresis, and capillary density.
Results:
Median (interquartile ranges) birth weights of the LQBW and HQBW infants were 3,140 g (2,738-3,254) and 3,920 g (3,750-4,020), respectively. Skin maximal hyperemic response to local heating was 2.14 V (1.68-2.30) in the LQBW group vs. 2.44 V (1.96-2.90) in the HQBW group (P = 0.020), and the endothelium-dependent vasodilatory response was 1.03 V (0.62-1.32) in the LQBW group vs. 0.78 V (0.45-1.32) in the HQBW group (P = 0.297). Capillary density in the LQBW and HQBW groups were 46.3 mm(-2) (40.1-53.7) and 44.1 mm(-2) (41.7-56.0), respectively (P = 0.736).
Conclusions:
Skin maximal hyperemic response was lower in LQBW infants, although no reduction in capillary density or defect in endothelium-dependent vasodilatation was observed. Such a lower maximal hyperemic response in early life in LQBW subjects who are at risk for type 2 diabetes and cardiovascular disease supports the hypothesis that impaired microvascular function is an early antecedent to diabetes in later life.