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Background: Arterial stiffness and wall shear stress are powerful determinants of cardiovascular health, and arterial stiffness is associated with increased cardiovascular mortality. Low and oscillatory wall shear stress, termed disturbed flow (d-flow), promotes atherosclerotic arterial remodeling, but the relationship between d-flow and arterial stiffness is not well understood. The objective of this study was to define the role of d-flow on arterial stiffening and discover the relevant signaling pathways by which d-flow stiffens arteries. Methods: D-flow was induced in the carotid arteries of young and old mice of both sexes. Arterial stiffness was quantified ex vivo with cylindrical biaxial mechanical testing and in vivo from duplex ultrasound and compared with unmanipulated carotid arteries from 80-week-old mice. Gene expression and pathway analysis was performed on endothelial cell–enriched RNA and validated by immunohistochemistry. In vitro testing of signaling pathways was performed under oscillatory and laminar wall shear stress conditions. Human arteries from regions of d-flow and stable flow were tested ex vivo to validate critical results from the animal model. Results: D-flow induced arterial stiffening through collagen deposition after partial carotid ligation, and the degree of stiffening was similar to that of unmanipulated carotid arteries from 80-week-old mice. Intimal gene pathway analyses identified transforming growth factor-β pathways as having a prominent role in this stiffened arterial response, but this was attributable to thrombospondin-1 (TSP-1) stimulation of profibrotic genes and not changes to transforming growth factor-β. In vitro and in vivo testing under d-flow conditions identified a possible role for TSP-1 activation of transforming growth factor-β in the upregulation of these genes. TSP-1 knockout animals had significantly less arterial stiffening in response to d-flow than wild-type carotid arteries. Human arteries exposed to d-flow had similar increases TSP-1 and collagen gene expression as seen in our model. Conclusions: TSP-1 has a critical role in shear-mediated arterial stiffening that is mediated in part through TSP-1’s activation of the profibrotic signaling pathways of transforming growth factor-β. Molecular targets in this pathway may lead to novel therapies to limit arterial stiffening and the progression of disease in arteries exposed to d-flow.

Mesenchymal stem cells (MSC) hold promise in promoting vascular regeneration of ischemic tissue in conditions like critical limb ischemia of the leg. However, this approach has been limited in part by poor cell retention and survival after delivery. New biomaterials offer an opportunity to localize cells to the desired tissue after delivery, but also to improve cell survival after delivery. Here we characterize the mechanical and microstructural properties of a novel hydrogel composed of pooled human platelet lysate (PL) and test its ability to promote MSC angiogenic activity using clinically relevant in vitro and in vivo models. This PL hydrogel had comparable storage and loss modulus and behaved as a viscoelastic solid similar to fibrin hydrogels despite having 1/4–1/10th the fibrin content of standard fibrin gels. Additionally, PL hydrogels enabled sustained release of endogenous PDGF-BB for up to 20 days and were resistant to protease degradation. PL hydrogel stimulated pro-angiogenic activity by promoting human MSC growth and invasion in a 3D environment, and enhancing endothelial cell sprouting alone and in co-culture with MSCs. When delivered in vivo , the combination of PL and human MSCs improved local tissue perfusion after 8 days compared to controls when assessed with laser Doppler perfusion imaging in a murine model of hind limb ischemia. These results support the use of a PL hydrogel as a scaffold for MSC delivery to promote vascular regeneration. Statement of Significance Innovative strategies for improved retention and viability of mesenchymal stem cells (MSCs) are needed for cellular therapies. Human platelet lysate is a potent serum supplement that improves the expansion of MSCs. Here we characterize our novel PL hydrogel’s desirable structural and biologic properties for human MSCs and endothelial cells. PL hydrogel can localize cells for retention in the desired tissue, improves cell viability, and augments MSCs’ angiogenic activity. As a result of these unique traits, PL hydrogel is ideally suited to serve as a cell delivery vehicle for MSCs injected into ischemic tissues to promote vascular regeneration, as demonstrated here in a murine model of hindlimb ischemia.

The ability to deliver cells in appropriate doses to their targeted site of action is a well-known obstacle to optimising stem cell therapy. Systemic administration of cells results in pulmonary "trapping," which significantly decreases the number of available circulating cells to impact underlying disorders. Directed delivery of stem cells in interventional radiology may provide an additional option for bypassing the lungs, as well as introduce novel potential avenues for decreasing doses required to effect cellular therapy, efficiently obtain local paracrine effects, and/or to simplify targeting strategies.

Objective Regenerative medicine seeks to stall or to reverse the pathologic consequences of chronic diseases. Many people with diabetes have peripheral arterial disease (PAD), which increases their already high risk of major amputation. Cellular therapies are a promising regenerative medicine approach to PAD that can be used to focally inject regenerative cells to endangered tissue beds. Mesenchymal stem cells (MSCs) are known to promote tissue regeneration through stromal support and paracrine stimulation of new blood vessels (angiogenesis). Whereas little is known about human diabetic MSCs (dMSCs), particularly those from patients with PAD, dMSCs have a limited expansion capacity but can be improved with human platelet lysate (PL) supplementation. PL is rich in many growth factors, including epidermal growth factor (EGF), which is known to be important to cell proliferation and survival signaling pathways. We hypothesize that dMSCs have a reversible defect in EGF receptor pathways. The objective of this work was to test this hypothesis using dMSCs from PAD patients. Methods The secretome expression of EGF and prominent angiogens was characterized from bone marrow (BM)-derived and adipose tissue-derived (ATD) dMSCs from five patients (six limbs) undergoing major amputation. Western blot was used to characterize the AKT and extracellular signal-regulated protein kinases 1 and 2 expression in dMSCs under standard culture (5% fetal bovine serum plus fibroblast growth factor 2 [FGF2]), 5% human PL, or 5% fetal bovine serum plus EGF. Healthy donor MSCs were control cells. The angiogenic activity of BM- and ATD-dMSCs was tested on human umbilical vein endothelial cells (ECs). Paired t-test, analysis of variance, and Kruskal-Wallis tests were used as appropriate. Results Both BM- and ATD-dMSCs had typical MSC surface marker expression and similar expansion profiles, and they did not express EGF in their secretome. PL supplementation of dMSCs improved AKT signaling, but they were resistant to FGF2 activation of extracellular signal-regulated protein kinases 1 and 2. EGF supplementation led to similar AKT expression as with PL, but PL had greater phosphorylation of AKT at 30 and 60 minutes. The conditioned media from both BM- and ATD-dMSCs had robust levels of prominent angiogens (vascular endothelial growth factor, monocyte chemoattractant protein 1, hepatocyte growth factor), which stimulated EC proliferation and migration, and the co-culture of dMSCs with ECs led to significantly longer EC sprouts in three-dimensional gel than EC-alone pellets. Conclusions PL and EGF supplementation improves AKT expression in dMSCs over that of FGF2, but PL improved pAKT over that of EGF. Thus, PL supplementation strategies may improve AKT signaling, which could be important to MSC survival in cellular therapies. Furthermore, BM- and ATD-dMSCs have similar secretomes and robust in vitro angiogenic activity, which supports pursuing dMSCs from both reservoirs in regenerative medicine strategies.

Introduction: We have recently characterized the in vitro benefits of the fibrin-rich pooled human platelet lysate (PL) in gel form on mesenchymal stem cells’ angiogenic activity. This study aimed to investigate the potential angiogenic activity of PL gel compared to a fibrin hydrogel (FG) in a murine model of hind limb ischemia (HLI). Methods: S129 male and female mice aged 20-weeks (n = 30) underwent right femoral artery ligation to induce HLI and were randomized to five groups: G1) Sham (n=5); G2) HLI-no treatment (n=5); G3) Saline (n=5; G4) PL (N=5); and G5) FG (n=5). The treatment limbs received PL, FG or saline by injection of 200 μL in the adductor muscle at day 0. Perfusion was quantitated with Laser Doppler Perfusion Imaging (LDPI) at 1-day post-procedurally and weekly for 28 days, and reported as ratios of the values in the ischemic limb (IL) to those in the contralateral nonischemic limb (NIL) for the adductor (thigh) and gastrocnemius (calf) areas. We then compared the change in the IL/NIL ratios for each group over the 28 days. Non-parametric analysis of variance with Dunn’s correction test was used to compare results among groups. The level of significance was set at p Results: There were trends in the thigh and calf IL/NIL perfusion ratios at 28 days for mice injected with PL and FG compared to those with saline injections or HLI and no treatment (P>.05). Perfusion in both calf and thigh areas improved from day one to day 28 in all HLI groups. However, only PL and FG groups had significantly increased progression in thigh perfusion, and this was in comparison to sham animals. In the calf, only the FG group demonstrated a significant increase in the perfusion ratio, and this was in comparison to both HLI with no treatment and sham groups (P Conclusions: While both FG and PL gel have active angiogenic properties, FG gel alone, and not PL gel, demonstrated superior in vivo angiogenic response in this model of HLI.

Current literature lacks sufficient data on outcomes after extensive laparoscopic liver resections. We hypothesized that laparoscopic right hepatectomy (LRH) is associated with better clinical outcomes and less overall hospital costs than open right hepatectomy (ORH), supporting the notion that major laparoscopic hepatic resections carry increased value when compared with the open approach.We reviewed medical records of all patients at our institution who underwent elective LRH (n = 48) or ORH (n = 57) from May 16, 2008 to March 1, 2012. Patient demographics, preoperative comorbidities, operative details, and postoperative outcomes were compared between the 2 groups. Hospital billing data were collected for each case to determine the average hospital costs per case.Average operative duration, estimated blood loss, intravenous fluid resuscitation requirements, high-grade postoperative complications, the need for postoperative admission to the ICU, and hospital length of stay were significantly less within the LRH cohort. Thirty-day mortality and readmission rates were equivalent between the 2 groups. Despite higher operative costs for LRH ($16,605 vs $10,411, p0.001), total postoperative costs were significantly less ($9,075 for LRH vs $16,341 for ORH, p0.001), resulting in equivalent overall costs ($25,679 for LRH vs $26,751 for ORH, p = 0.65).Although overall costs between LRH and ORH are equivalent, clinical outcomes after LRH are comparable to those after ORH, supporting the value of laparoscopy in extensive right hepatic resections. Efforts to reduce operative costs of LRH, while maintaining optimal patient outcomes, should be the focus of surgeons and hospitals moving forward.

METHODS: Cardiac delayed gadolinium enhancement magnetic resonance imaging (DGE-MRI) was performed on 72 patients with CAD and IMR presenting for surgical consultation. The Otsu’s method was used to quantify total and segmental (coronary territory) scar. Severity of IMR and sub-leaflet mitral dynamics were quantified and correlated to scar volume. 81.9% (59/72) of these patients underwent surgery: 45.7% CABG, 40.6% CABG with MV surgery, and 13.5% MV surgery. Surgical patients were followed for a median period of 3.3 years. A Cox model of all-cause mortality, and survival curves based on differential levels of SB (mild 30%) were developed