Consistent evidence links insulin-like growth factor (IGF)-1 deficiency to a range of cardiovascular and metabolic disorders including hypertension and stroke. A biomarker for IGF-1 function would be clinical useful for the prognosis of cardiovascular conditions. While plasma IGF-1 is largely inactive due to its high affinity binding of IGF binding protein (IGFBP), cyclic glycine-proline (cGP), an IGF-1 metabolite, can regulate the bioavailability of plasma IGF-1 and improve IGF-1 function by competing with IGF-1 to IGFBP-3 binding1. The relative value of cGP to IGF-1 (cGP/IGF-1 molar ratio) can represent the bioavailable IGF-11-4. Our recent clinical observations showed that plasma cGP is low in women with hypertension4 and treatment of cGP normalised the systolic blood pressure in a rat model of high fat diet (HFD)-induced metabolic disorders. Plasma cGP was also low in stroke patients at hospital admission (<3 days of stroke). The concentration of cGP was increased and neurological deficits and the disability were gradually improved in next 90 days. The changes of cGP at hospital admission (<3days) was correlated with the scores of NIHSS, mRS and FM-UL 90 days after stroke. Administration of cGP prevents ischemic brain injury though preventing IGF-1 associated vascular injury in rats1. The cGP/IGF-1 ratio at admission may be a potential biomarker for predicting functional recovery in stroke patients. In conclusion, low cGP concentrations and low cGP/IGF-1 ratio suggest an impairment of IGF-1 function in hypertension and stroke. The change of plasma cGP concentration and/or cGP/IGF-1 ratio may be a prognostic biomarker for stroke and hypertension and may also provide the guidance for individualizing cGP intervention.
Audience Take Away:
• The role for cGP in normalizing IGF-1 function is novel and provides additional insights to IGF-1 research, which aims the normalisation.
• cGP is also nature nutrient and presents in some foods.
• cGP research provides and develops the opportunities to the interventions with plant based supplementation, which has far more advantages in pharmaceutical developed drugs.