Vascular Complications and Diabetes: Current Therapies and Future Challenges

Table 1

Possible causes of pericyte dropout.

Factors	Evidence
BAX expression	(i) Proapoptotic member of the Bcl-2 family [12].
	(ii) Increased levels shown in retinal pericyte nuclei [13].
	(iii) Shift of the balance toward pericyte apoptosis.
TNF-α	(i) Cytokine involved in the regulation of immune cells during systematic inflammation including apoptosis [14].
	(ii) Elevated levels of TNF-α are associated with the early events of DR [14].
	(iii) Inhibition of TNF-α shown to cause a large reduction in the number of microvascular cells that expressed apoptotic indicators [15].
TGF-β	(i) Cytokine that regulates signaling pathways.
	(ii) High concentrations evidenced in response to hyperglycemia in pericytes and other vascular cells [16, 17].
	(iii) Increased TGF-β leads to βIG-H3 and RGD signaling that activates the capsase signaling pathway leading to apoptosis [18–23].
Ang/Tie	(i) Ang-2/Tie-2 binding shown to produce downstream pericyte apoptosis [24–26].
	(ii) Ang-2 is upregulated in retinal pericytes in response to hyperglycemia [27].