Inflammation induces stunting by lowering bone mass via GH/IGF-1 inhibition in very preterm infants.

BACKGROUND

Sustained systemic inflammatory response (SIR) was associated with poor postnatal growth in very preterm infants (VPI). We hypothesize that VPI with sustained SIR will exhibit linear growth retardation related to lower bone mass accrual mediated by GH/IGF-1 axis inhibition at term corrected age (CA).

METHODS

C-reactive protein (CRP), procalcitonin (PCT), growth hormone (GH), insulin-like growth factor 1 (IGF-1), calcium, phosphorus, alkaline phosphatase, anthropometric, nutritional, neonatal and maternal data were collected prospectively in 23 infants <32 weeks gestational age. Body composition using dual-energy X-ray absorptiometry was performed at term CA. Analysis was undertaken with multiple linear regression models.

RESULTS

At term CA 11 infants with sustained SIR compared with 12 infants without sustained SIR present significantly lower IGF-1, length z-score (LZS), bone mineral content (BMC) and lean mass (LM), and higher GH and fat mass (FM). LZS was associated significantly with PCT, BMC with IGF-1, FM and LM with CRP, GH with bronchopulmonary dysplasia and CRP, and IGF-1 with invasive mechanical ventilation, CRP and PCT.

CONCLUSIONS

In addition to the known effect on linear growth failure, sustained SIR induces lower bone mass accrual related to higher GH and lower IGF-1 levels in VPI.

IMPACT: Very preterm infants (VPI) with sustained systemic inflammatory response (SIR) compared with VPI without SIR present stunting, lower bone mass, higher GH and lower IGF-1 levels at term corrected age. SIR may help to explain the influence of non-nutritional factors on growth and body composition in VPI. SIR induces postnatal stunting related to lower bone mass accrual via GH/IGF-1 axis inhibition in VPI. VPI with SIR need special attention to minimize inflammatory stress, which could result in improved postnatal growth. Research on inflammatory-endocrine interactions involved in the pathophysiology of postnatal stunting is needed as a basis for new interventional approaches.