CD49d is important for neutrophil recruitment to and revascularization of avascular islets. (A) Ly6G⁺CD49d⁺VEGFR1^highCXCR4^high neutrophils are enriched in muscles transplanted with avascular pancreatic islets. (B) Numbers of neutrophils (Ly6G⁺) in the peritoneal cavity of mice 5 hours post i.p. injection with saline (n = 2) or VEGF-A (n = 4) and (C) the proportion of the proangiogenic Ly6G⁺CD49d⁺VEGFR1^highCXCR4^high subpopulation. (D-E) Representative confocal Z-projection images of transplanted pancreatic islets (blue, dashed lines) in the cremaster muscle of mice treated with isotype control or anti-CD49d antibodies during islet engraftment, and (F-G) corresponding surface renderings. Images acquired by in vivo confocal microscopy 4 days after transplantation (n = 6 mice per treatment group; 18 islets were analyzed for the isotype control and 21 islets were analyzed for the anti-CD49d-treated group). Scale bars = 50 μm. (H) In mice in which CD49d was inhibited, less than half the amounts of recruited neutrophils (green) were found surrounding the graft compared with isotype-treated animals. (I) Blood vessels (red) surrounding the islets were quantified and (J) islet capillary diameter was measured. (L) The capillary diameters in anti-CD49d treated animals were more heterogeneous than (K) those in animals treated with isotype control antibodies. *P < .05.