Platelets Promote Liver Regeneration Following Surgery

A new study finds that platelet-derived growth factors can encourage the liver regeneration process in patients undergoing partial hepatectomy.

Researchers at MedUni Vienna (Austria) conducted a study to investigate the pattern of liver regeneration in 157 patients who had a part of their liver removed. Plasma levels of circulating platelet α-granule-derived factors in the liver vein were measured at the end of liver resection, as well as on the first postoperative day. The granules contain both growth-promoting and growth-inhibiting factors, including vascular endothelial growth factor (VEGF) and thrombospondin-1 (TSP-1). The researchers found that a rapid accumulation of platelets occurred within the liver after induction of liver regeneration.

The results showed that even though platelet count was not associated with postoperative liver dysfunction, patients with an unfavorable postoperative plasma α-granule profile (high TSP-1/low VEGF) showed substantially worse postoperative clinical outcomes. The unfavorable postoperative α-granule release profile was also associated with increased postoperative portal venous pressure and von Willebrand factor antigen levels, which serve as a marker for intrahepatic endothelial dysfunction. The study was published on November 3, 2015, in Hepatology.

“The postoperative profile of circulating platelet-derived factors correlates with the ability of the remnant liver to regenerate; portal venous pressure and intrahepatic endothelial dysfunction might account for the selective granule release profile,” concluded lead author Patrick Starlinger, MD, PhD, of the department of surgery, and colleagues. “Selective modulation of platelet α-granule release in patients may represent an attractive target for therapeutic interventions to improve liver regeneration and clinical outcomes after partial hepatectomy.”

Liver regeneration following partial hepatectomy is a complex and well-orchestrated phenomenon involving all mature liver cell types, and is associated with signaling cascades involving growth factors, cytokines, matrix remodeling, and several feedback circuits of stimulation and inhibition of growth related signals. The liver manages to restore any lost mass and adjust its size to that of the organism, while at the same time providing full support for body homeostasis during the entire regenerative process.

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