Hybrid spheroids containing mesenchymal stem cells promote therapeutic angiogenesis by increasing engraftment of co-transplanted endothelial colony-forming cells in vivo

BACKGROUND

Peripheral artery disease is an ischemic vascular disease caused by the blockage of blood vessels supplying blood to the lower extremities. Mesenchymal stem cells (MSCs) and endothelial colony-forming cells (ECFCs) have been reported to alleviate peripheral artery disease by forming new blood vessels. However, the clinical application of MSCs and ECFCs has been impeded by their poor in vivo engraftment after cell transplantation. To augment in vivo engraftment of transplanted MSCs and ECFCs, we investigated the effects of hybrid cell spheroids, which mimic a tissue-like environment, on the therapeutic efficacy and survival of transplanted cells.

METHODS

The in vivo survival and angiogenic activities of the spheroids or cell suspension composed of MSCs and ECFCs were measured in a murine hindlimb ischemia model and Matrigel plug assay. In the hindlimb ischemia model, the hybrid spheroids showed enhanced therapeutic effects compared with the control groups, such as adherent cultured cells or spheroids containing either MSCs or ECFCs.

RESULTS

Spheroids from MSCs, but not from ECFCs, exhibited prolonged in vivo survival compared with adherent cultured cells, whereas hybrid spheroids composed of MSCs and ECFCs substantially increased the survival of ECFCs. Moreover, single spheroids of either MSCs or ECFCs secreted greater levels of pro-angiogenic factors than adherent cultured cells, and the hybrid spheroids of MSCs and ECFCs promoted the secretion of several pro-angiogenic factors, such as angiopoietin-2 and platelet-derived growth factor.

CONCLUSION

These results suggest that hybrid spheroids containing MSCs can serve as carriers for cell transplantation of ECFCs which have poor in vivo engraftment efficiency.

Transplantation of adipose tissue-derived microvascular fragments promotes therapy of critical limb ischemia

BACKGROUND

Adipose tissue-derived microvascular fragments are functional vessel segments derived from arterioles, capillaries, and veins. Microvascular fragments can be used as vascularization units in regenerative medicine and tissue engineering containing microvascular networks. However, the in vivo therapeutic and vascularization properties of human microvascular fragments have not been investigated.

METHODS

In this study, we isolated microvascular fragments, stromal vascular fractions, and mesenchymal stem cells from human lipoaspirate and studied their therapeutic efficacy and in vivo vasculogenic activity in a murine model of hindlimb ischemia. In addition, in vivo angiogenic activity and engraftment of microvascular fragments into blood vessels were measured using Matrigel plug assay.

RESULTS

Both microvascular fragments and stromal vascular fractions contain not only mesenchymal stem cells but also endothelial progenitor cells. In a Matrigel plug assay, microvascular fragments increased the number of blood vessels containing red blood cells more than mesenchymal stem cells and stromal vascular fractions did. The engraftment of the microvascular fragments transplanted in blood vessels within the Matrigel plug significantly increased compared to the engraftment of mesenchymal stem cells and stromal vascular fractions. Moreover, intramuscular injection of microvascular fragments markedly increased blood flow in the ischemic hindlimbs and alleviated tissue necrosis compared to that of mesenchymal stem cells or stromal vascular fractions. Furthermore, transplanted microvascular fragments formed new blood vessels in ischemic limbs.

CONCLUSIONS

These results suggest that microvascular fragments show improved engraftment efficiency and vasculogenic activity in vivo and are highly useful for treating ischemic diseases and in tissue engineering. Adipose tissue-derived microvascular fragments are vascularization units in regenerative medicine and tissue engineering containing microvascular networks. Intramuscular injection of microvascular fragments markedly increased blood flow in the ischemic hindlimbs and alleviated tissue necrosis. The present study suggests that microvascular fragments show improved engraftment efficiency and vasculogenic activity in vivo and are highly useful for treating ischemic diseases and in tissue engineering.

Angio-Seal Used as a Bailout for Incomplete Hemostasis After Dual Perclose ProGlide Deployment in Transcatheter Aortic Valve Implantation

BACKGROUND

The failure rate of vascular closure devices remains a significant cause of major vascular complications in contemporary transcatheter aortic valve implantation practice.

METHODS

This research aimed to evaluate use of the Angio-Seal device in a bailout context in the setting of incomplete hemostasis following use of dual Perclose ProGlide devices in patients undergoing transfemoral transcatheter aortic valve implantation. A total of 185 patients undergoing transfemoral transcatheter aortic valve implantation with either dual Per-close ProGlide (n = 139) or a combination of dual Perclose ProGlide and Angio-Seal (n = 46) were retrospectively analyzed. The baseline, procedural characteristics, and all outcomes (defined according to Valve Academic Research Consortium-2 criteria) were compared.

RESULTS

No significant differences were seen between the dual Perclose ProGlide vs dual Perclose ProGlide+Angio-Seal groups with regard to the in-hospital Valve Academic Research Consortium-2 primary end points of major vascular complications (n = 13 [9.4%] vs n = 2 [4.3%]; P = .36), minor vascular complications (n = 13 [9.4%] vs n = 8 [14.7%]; P = .14), major bleeding (n = 16 [11.5%] vs n = 2 [4.3%]; P = .25), and minor bleeding (n = 9 [6.5%] vs n = 5 [10.9%]; P = .34), with higher rates of hematoma in the dual Perclose ProGlide+Angio-Seal group (n = 4 [2.9%] vs n = 5 [10.9%]; P = .044).

CONCLUSION

Finding from the current study suggest that adjunctive Angio-Seal deployment may be feasible and safe, especially in patients with incomplete hemostasis following dual Perclose ProGlide use, and can be an optimal "bailout" procedure.

Use of Mendelian randomization to evaluate the effect of atrial fibrillation on cardiovascular diseases and cardiac death

AIMS

Several observational studies indicated that atrial fibrillation might aggravate other cardiovascular diseases apart from ischaemic stroke. However, it remains to be determined whether these associations reveal independent causation. Using Mendelian randomization (MR), we systematically investigated how genetically predicted atrial fibrillation affected other cardiovascular diseases and cardiac death.

METHODS AND RESULTS

Summary-level data for atrial fibrillation and other cardiovascular diseases were obtained from public genome-wide association study data. The random inverse-variance weighted method was treated as the primary analysis. Sensitivity analyses (including weighted median, MR-Egger, and multivariable MR methods) were also performed. Atrial fibrillation was significantly associated with higher risks of heart failure [odds ratio (OR): 1.24; 95% confidence interval (CI): 1.19-1.28; P < 0.001], ischaemic stroke (OR: 1.21; 95% CI: 1.17-1.25; P < 0.001), transient ischaemic attack (OR: 1.10; 95% CI: 1.05-1.15; P < 0.001), peripheral artery diseases (OR: 1.09; 95% CI: 1.03-1.15; P = 0.002), cardiac death (OR: 1.08; 95% CI: 1.02-1.15; P = 0.008), and hypertension (OR: 1.06; 95% CI: 1.01-1.11; P = 0.010), without effects on coronary heart disease or pulmonary embolism. Associations for heart failure and ischaemic stroke remained robust to the sensitivity analyses. MR-Egger method (P > 0.05) and funnel plot yielded no indication of directional pleiotropy. The leave-one-out analysis suggested that the causal associations were not driven by individual single nucleotide polymorphism.

CONCLUSIONS

This comprehensive MR analysis verified the causal associations between atrial fibrillation and high risks of heart failure, ischaemic stroke, transient ischaemic attack, peripheral artery diseases, cardiac death, and hypertension. Interventions to reduce cardiovascular diseases beyond ischaemic stroke are warranted in patients with atrial fibrillation.

Thrombotic Lesions are Associated with Poor Outcomes after Endovascular Treatment in Patients with Non-Acute Aortoiliac Total Occlusions

Aim: The post-endovascular treatment outcomes of thrombotic lesions remain unclear. This study aimed to investigate the effects of thrombotic lesions on post-endovascular treatment outcomes in patients with non-acute aortoiliac total occlusions.

Methods: This subanalysis of a multicenter prospective observational registry study included patients from 64 institutions in Japan between April 2014 and April 2016. A total of 346 patients (394 limbs; median age, 72 years), including 186 men, underwent endovascular treatment for non-acute aortoiliac total occlusions and were included. The patients were classified as having thrombotic or non-thrombotic lesions. The primary (1-year primary patency rate) and secondary (1-year overall survival rate) endpoints were evaluated.

Results: Thrombotic lesions were identified in 18.5% (64/346) of the patients. The 1-year primary patency (85.9% versus 95.4%, log-rank p ＜.001) and overall survival (90.6% versus 97.9%, log-rank p =.003) rates were significantly lower in the thrombotic group than in the non-thrombotic group. Thrombotic lesions had significant effects on the post-endovascular treatment outcomes, with adjusted hazard ratios of 3.91 (95% confidence interval, 1.64–9.34, p =.002) for primary patency and 4.93 (95% confidence interval, 1.59–15.3, p =.006) for all-cause mortality.

Conclusions: Thrombotic lesions were associated with 1-year restenosis and all-cause mortality after endovascular treatment for non-acute aortoiliac total occlusions. Endovascular treatment strategies should be carefully planned for patients with thrombotic lesions.

A systematic review investigating the identification, causes, and outcomes of delays in the management of chronic limb-threatening ischemia and diabetic foot ulceration

OBJECTIVE

Patients presenting with chronic limb-threatening ischemia and diabetic foot ulceration (DFU) are at high risk of major lower limb amputation. Long-standing concern exists regarding late presentation and delayed management contributing to increased amputation rates. Despite multiple guidelines existing on the management of both conditions, there is currently no accepted time frame in which to enact specialist care and treatment. This systematic review aimed to investigate potential time delays in the identification, referral, and management of both chronic limb-threatening ischemia and DFU.

METHODS

A systematic review conforming to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement standards was performed searching MEDLINE, Embase, The Cochrane Library, and Cumulative Index to Nursing and Allied Health Literature from inception to November 14, 2018. All English-language qualitative and quantitative articles investigating or reporting the identification, causes, and outcomes of time delays within "high-income" countries (annual gross domestic product per person >$15,000) were included. Data were extracted independently by the investigators. Given the clinical crossover, both conditions were investigated together. A study protocol was designed and registered at the International Prospective Register of Systematic Reviews.

RESULTS

A total of 4780 articles were screened, of which 32 articles, involving 71,310 patients and 1388 health care professionals, were included. Twenty-three articles focused predominantly on DFU. Considerable heterogeneity was noted, and only 12 articles were deemed of high quality. Only four articles defined a delay, but this was not consistent between studies. Median times from symptom onset to specialist health care assessment ranged from 15 to 126 days, with subsequent median times from assessment to treatment ranging from 1 to 91 days. A number of patient and health care factors were consistently reported as potentially causative, including poor symptom recognition by the patient, inaccurate health care assessment, and difficulties in accessing specialist services. Twenty articles reported outcomes of delays, namely, rates of major amputation, ulcer healing, and all-cause mortality. Although results were heterogeneous, they allude to delays being associated with detrimental outcomes for patients.

CONCLUSIONS

Time delays exist in all aspects of the management pathway, which are in some cases considerable in length. The causes of these are complex but reflect poor patient health-seeking behaviors, inaccurate health care assessment, and barriers to referral and treatment within the care pathway. The adoption of standardized limits for referral and treatment times, exploration of missed opportunities for diagnosis, and investigation of novel strategies for providing specialist care are required to help reduce delays.