CSF2 and obesity due to melanocortin 4 receptor deficiency: The severity of the underlyingcoronary stenosis, proximal location of the lesion, symptom duration, and slow heartrates are described as clinical factors that influence the development ofcollaterals.18-20 Granulocyte-monocyte-colonystimulating factor (GM-CSF) and granulocyte-colony stimulating factor (G-CSF),physical exercise, and external counterpulsation have also been found to positivelyaffect the development of collaterals, whereas aging, obesity, and levels of uricacid and C-reactive protein have been found to have negative effects.21-28