On the preservation of vessel bifurcations during flow-mediated angiogenic remodelling

During developmental angiogenesis, endothelial cells respond to shear stress by migrating and remodelling the initially hyperbranched plexus, removing certain vessels whilst maintaining others. In this study, we argue that the key regulator of vessel preservation is cell decision behaviour at bifurcations. At flow-convergent bifurcations where migration paths diverge, cells must finely tune migration along both possible paths if the bifurcation is to persist. Experiments have demonstrated that disrupting the cells’ ability to sense shear or the junction forces transmitted between cells impacts the preservation of bifurcations during the remodelling process. However, how these migratory cues integrate during cell decision making remains poorly understood. Therefore, we present the first agent-based model of endothelial cell flow-mediated migration suitable for interrogating the mechanisms behind bifurcation stability. The model simulates flow in a bifurcated vessel network composed of agents representing endothelial cells arranged into a lumen which migrate against flow. Upon approaching a bifurcation where more than one migration path exists, agents refer to a stochastic bifurcation rule which models the decision cells make as a combination of flow-based and collective-based migratory cues. With this rule, cells favour branches with relatively larger shear stress or cell number. We found that cells must integrate both cues nearly equally to maximise bifurcation stability. In simulations with stable bifurcations, we found competitive oscillations between flow and collective cues, and simulations that lost the bifurcation were unable to maintain these oscillations. The competition between these two cues is haemodynamic in origin, and demonstrates that a natural defence against bifurcation loss during remodelling exists: as vessel lumens narrow due to cell efflux, resistance to flow and shear stress increases, attracting new cells to enter and rescue the vessel from regression. Our work provides theoretical insight into the role of junction force transmission has in stabilising vasculature during remodelling and as an emergent mechanism to avoid functional shunting.

Dynamic hematological changes in patients undergoing distal pancreatectomy with or without splenectomy: a population-based cohort study

Background The clinical outcomes of patients who received distal pancreatectomy with splenectomy (DPS) and spleen-preserving distal pancreatectomy (SPDP) have been generally investigated. However, postoperative hematological changes after distal pancreatectomy with or without splenectomy are poorly understood. Methods Information from patients undergoing distal pancreatectomy (DP) between January 2014 and June 2019 at a single institution was reviewed. A linear mixed-effects model was used to compare dynamic hematological changes between different groups. Results A total of 302 patients who underwent DP were enrolled. In the long term, most postoperative hematological parameters remained significantly higher than preoperative levels in the DPS group, while postoperative lymphocyte, monocyte, basophil, and platelet levels returned to preoperative levels in the SPDP group. All postoperative hematological parameters except for red blood cell count and serum hemoglobulin level were significantly higher in the DPS group than in the SPDP group. There were no significant differences in hematological changes between the splenic vessel preservation (SVP) and Warshaw technique (WT) groups. Conclusions Postoperative hematological changes were significantly different between the DPS and SPDP groups. Compared to DPS, SPDP reduced abnormal hematological changes caused by splenectomy. SVP and WT were comparable in terms of postoperative hematological changes.

Dynamic hematological changes in patients undergoing distal pancreatectomy with or without splenectomy: a population-based cohort study

Background: The clinical outcomes of patients who received distal pancreatectomy with splenectomy (DPS) and spleen-preserving distal pancreatectomy (SPDP) have been generally investigated. However, postoperative hematological changes after distal pancreatectomy with or without splenectomy are poorly understood.Methods: Information from patients undergoing distal pancreatectomy (DP) between January 2014 and June 2019 at a single institution was reviewed. A linear mixed-effects model was used to compare dynamic hematological changes between different groups.Results: A total of 302 patients who underwent DP were enrolled. In the long term, most postoperative hematological parameters remained significantly higher than preoperative levels in the DPS group, while postoperative lymphocyte, monocyte, basophil, and platelet levels returned to preoperative levels in the SPDP group. All postoperative hematological parameters except for red blood cell count and serum hemoglobulin level were significantly higher in the DPS group than in the SPDP group. There were no significant differences in hematological changes between the splenic vessel preservation (SVP) and Warshaw technique (WT) groups.Conclusions: Postoperative hematological changes were significantly different between the DPS and SPDP groups. Compared to DPS, SPDP reduced abnormal hematological changes caused by splenectomy. SVP and WT were comparable in terms of postoperative hematological changes.

Dynamic hematological changes in patients undergoing distal pancreatectomy with or without splenectomy: a population-based cohort study

Background: The clinical outcomes of distal pancreatectomy with splenectomy (DPS) and spleen-preserving distal pancreatectomy (SPDP) patients have been generally investigated. However, postoperative hematological changes after distal pancreatectomy with or without splenectomy are poorly understood. Methods: Information from patients undergoing distal pancreatectomy (DP) between January 2014 and June 2019 at a single institution was reviewed. A linear mixed-effect model was used to compare dynamic hematological changes between different groups. Results: In total, 302 patients who underwent DP were enrolled. In the long term, most postoperative hematological parameters remained significantly higher than preoperative levels in the DPS group, while postoperative lymphocyte, monocyte, basophil, and platelet levels returned to preoperative levels in the SPDP group. All postoperative hematological parameters except for red blood cell count and serum hemoglobulin level were significantly higher in the DPS group than in the SPDP group. There were no significant differences in hematological changes between the splenic vessel preservation (SVP) and Warshaw technique (WT) groups. Conclusions: Postoperative hematological changes were significantly different between the DPS and SPDP groups. Compared to DPS, SPDP reduced abnormal hematological changes caused by splenectomy. SVP and WT were comparable in terms of postoperative hematological changes.