Adipose-derived stem cell/FGF19-loaded microfluidic hydrogel microspheres for synergistic restoration of critical ischemic limb

The efficacy of stem cell therapy is substantially compromised due to low cell survival rate and poor local retention post-delivery. These issues drastically limit the application of stem cells for ischemic limb therapy, which requires effective blood perfusion and skeletal muscle regeneration. Herein, based on microfluidic technology, an integrated stem cell and cytokine co-delivery system designed for functional ischemic limb salvage was constructed by first incorporating the myogenic cytokine, fibroblast growth factor 19 (FGF19), into microspheres composed of methacrylate gelatin (GelMA). Then adipose-derived stem cells (ADSCs) were highly absorbed into the porous structure of the microspheres, overcoming the insufficient loading efficiency and activities by conventional encapsulation strategy. The fabricated ADSCs/FGF19@μsphere system demonstrated a uniform size of about 180 μm and a highly porous structure with pore sizes between 20 and 40 μm. The resultant system allowed high doses of ADSCs to be precisely engrafted in the lesion and to survive, and achieved sustained FGF19 release in the ischemic region to facilitate myoblast recruitment and differentiation and myofibrils growth. Furthermore, the combination of ADSCs and FGF19 exhibited a positive synergistic effect which substantially improved the therapeutic benefit of angiogenesis and myogenesis, both in vitro and in vivo. In summary, a stem cell and cytokine co-delivery system with the properties of easy preparation and minimal invasiveness was designed to ensure highly efficient cell delivery, sustained cytokine release, and ultimately realizes effective treatment of ischemic limb regeneration.

Clinical Efficacy of Interventional Therapy on Lower Extremity Arteriosclerosis Obliterans and Prognostic Factors

Objective

This study was designed to analyse the clinical efficacy of interventional therapy on lower extremity arteriosclerosis obliterans (LEASO) and prognostic factors.

Methods

A total of 122 patients with LEASO diagnosed in our hospital from March 2017 to March 2019 were retrospectively analysed. Among them, 72 patients who received conservative therapy were assigned to a conservative group, and 50 patients who received interventional therapy additionally based on conservative therapy were assigned to an intervention group. The short-term (12 weeks after therapy) and long-term (3 years after therapy) clinical efficacies on the two groups were compared. Death, amputation, and vascular restenosis (vascular stenosis > 50% in computed tomography reexamination) were defined as unfavourable outcomes, and Cox regression was conducted to analyze the factors influencing the prognosis of patients. The incidence of adverse events in the two groups within 3 years was compared and statistically analyzed. Additionally, the hospital stay, therapy cost, claudication distance, and ankle brachial index were compared between the two groups.

Results

After therapy, the conservative group showed a notably lower total effective rate than the intervention group (P < 0.05), but the clinical efficacy after 3 years was similar between the two groups (P > 0.05). Additionally, the conservative group experienced notably longer hospital stay than the intervention group (P < 0.05), and cost less in treatment than the intervention group (P < 0.05). However, the conservative group experienced a notably shorter claudication distance and showed a notably lower ankle brachial index than the intervention group (P < 0.05). The two groups were not significantly different in mortality, amputation rate, and vascular restenosis rate (P > 0.05). Moreover, Cox regression analysis revealed that age and conservative therapy were independent risk factors for the prognosis of patients (P < 0.05).

Conclusion

Interventional therapy can substantially improve the short-term efficacy and prognosis of patients with LEASO, but the cost is high, so the therapeutic regimen should be selected according to the patient's economic condition.

Therapeutic Alternatives in Diabetic Foot Patients without an Option for Revascularization: A Narrative Review

Background: The healing of foot wounds in patients with diabetes mellitus is frequently complicated by critical limb threatening ischemia (neuro-ischemic diabetic foot syndrome, DFS). In this situation, imminent arterial revascularization is imperative in order to avoid amputation. However, in many patients this is no longer possible (“too late”, “too sick”, “no technical option”). Besides conservative treatment or major amputation, many alternative methods supposed to decrease pain, promote wound healing, and avoid amputations are employed. We performed a narrative review in order to stress their efficiency and evidence. Methods: The literature research for the 2014 revision of the German evidenced-based S3-PAD-guidelines was extended to 2020. Results: If revascularization is impossible, there is not enough evidence for gene- and stem-cell therapy, hyperbaric oxygen, sympathectomy, spinal cord stimulation, prostanoids etc. to be able to recommend them. Risk factor management is recommended for all CLTI patients. With appropriate wound care and strict offloading, conservative treatment may be an effective alternative. Timely amputation can accelerate mobilization and improve the quality of life. Conclusions: Alternative treatments said to decrease the amputation rate by improving arterial perfusion and wound healing in case revascularization is impossible and lack both efficiency and evidence. Conservative therapy can yield acceptable results, but early amputation may be a beneficial alternative. Patients unfit for revascularization or major amputation should receive palliative wound care and pain therapy. New treatment strategies for no-option CLTI are urgently needed.

Bmal1 Downregulation Worsens Critical Limb Ischemia by Promoting Inflammation and Impairing Angiogenesis

Critical limb ischemia (CLI) is the most advanced clinical stage of peripheral vascular disease with high mobility and mortality. CLI patients suffer from lower extremity rest pain, ulceration, and gangrene caused by insufficient blood and oxygen supply. Seeking for effective biomarkers and therapeutic targets is of great significance for improving the life quality of CLI patients. The circadian clock has been reported to be involved in the progression of kinds of cardiovascular diseases. Whether and how circadian genes play a role in CLI remains unknown. In this study, by collecting femoral artery and muscle specimens of CLI patients who underwent amputation, we confirmed that the circadian gene Bmal1 is downregulated in the CLI femoral artery and ischemic distal lower limb muscle. Furthermore, we verified that Bmal1 affects CLI by regulating lipid metabolism, inflammation, and angiogenesis. A hindlimb ischemia model performed in wild-type and Bmal1^−/− mice confirmed that Bmal1 disruption would lead to impaired angiogenesis. In vitro experiments indicated that the decreased expression of Bmal1 would increase ox-LDL uptake and impair endothelial cell functions, including proliferation, migration, and tube formation. As for mechanisms, Bmal1 represses inflammation by inhibiting lipid uptake and by activating IL-10 transcription and promotes angiogenesis by transcriptionally regulating VEGF expression. In conclusion, we provide evidence that the circadian gene Bmal1 plays an important role in CLI by inhibiting inflammation and promoting angiogenesis. Thus, Bmal1 may be an effective biomarker and a potential therapeutic target in CLI.

TurboHawk plaque rotation system for treatment of arteriosclerosis occlusion in lower extremities: A pilot retrospective study

This pilot study retrospectively assessed the feasible efficacy of TurboHawk plaque rotation system (THPRS) for treatment of arteriosclerosis occlusion in lower extremities (AOLE).A total of 36 eligible patients with AOLE were included in this pilot retrospective study. We divided all those patients into a treatment group and a control group, each group 18 patients. All patients in both groups administered conventional therapy. Additionally, all patients in the treatment group received THPRS, while all patients in the control group received percutaneous transluminal angioplasty (PTA) and percutaneous transluminal stenting (PTS). All outcomes were evaluated and analyzed at 3-month after surgery.At 3-month postsurgery, there were not significant statistical differences in clinical manifestations (intermittent claudication, P = .49; resting pain, P = .28), ankle brachial index change (P = .07), 6-minute walk distance (P = .43), and complications between 2 groups.This pilot study did not show better outcome improvement of THPRS for patients with AOLE. We cautiously draw the present conclusion, because it suffers from several major restrictions. Thus, further studies with larger sample size and longer term follow-up are still needed to warrant the current conclusion.

Wound outcomes and factors associated with wound healing after first-time femoropopliteal artery intervention in patients with ischemic tissue loss

BACKGROUND/OBJECTIVE

This study's goal is to describe wound outcomes at 2 years following intervention for atherosclerotic femoropopliteal lesions in patients with ischemic tissue loss.

METHODS

A retrospective review of 135 first-time endovascular procedures for chronic femoropopliteal atherosclerotic lesions related to ischemic tissue loss was performed. The final wound outcomes were categorized according to the initial wound healing, recurrence and the need of major/minor amputation.

RESULTS

At 2-years of follow up, 76 limbs (56.3%) showed complete wound healing without recurrence, however, wound development occurred at other sites on the same foot following complete primary healing in 11 limbs (8.1%). Tolerable wounds persisted or wounds recurred at the same site in 30 limbs (22.2%), and 18 limbs (13.3%) needed major amputations. Independent factors that prevented wound healing without recurrence at 2 years were renal insufficiency (HR = 0.225, 95% C.I. = 0.091-0.556, p = 0.001), ankle pressure < 50 mmHg or flat forefoot PVR (HR = 0.328, 95% C.I. = 0.124-0.867, p = 0.025) and functional performance < 4 metabolic equivalents (MET) (HR = 0.150, 95% C.I. = 0.063-0.360, p < 0.001).

CONCLUSION

Wound outcome classifications showed detailed information regarding clinical outcomes in patients with ischemic tissue loss. Renal insufficiency, ischemia grade 3 and poor functional performance were independent risk factors that prevented wound healing.

Ameliorative effects of the traditional Chinese medicine formula Qing-Mai-Yin on arteriosclerosis obliterans in a rabbit model

CONTEXT

Qing-Mai-Yin (QMY) is a clinically used herbal formula for treating arteriosclerosis obliterans (ASO).

OBJECTIVE

To evaluate the chemical constituents and effects of QMY on ASO rabbit model.

MATERIALS AND METHODS

Forty-eight New Zealand rabbits were divided into six groups (n = 8): normal (normal rabbits treated with 0.5% CMC-Na), vehicle (ASO rabbits treated with 0.5% CMC-Na), positive (simvastatin, 1.53 mg/kg), and QMY treatment (300, 600, and 1200 mg/kg). ASO rabbit model was prepared by high fatty feeding, roundly shortening artery, and bovine serum albumin immune injury. QMY (300, 600 and 1200 mg/kg) was orally administered for 8 weeks. The effects and possible mechanisms of QMY on ASO rabbits were evaluated by pathological examination, biochemical assays, and immunohistochemical assays. The compositions of QMY were analysed using HPLC-Q-TOF-MS/MS analysis.

RESULTS

Compared to the vehicle rabbit, QMY treatment suppressed plaque formation and intima thickness in aorta, and decreased intima thickness, whereas increased lumen area of femoral artery. Additionally, QMY treatment decreased TC, TG and LDL, decreased CRP and ET, and increased NO and 6-K-PGF1α in serum. Furthermore, the potential mechanisms studied revealed that QMY treatment could suppress expression of TNF-α, IL-6, ICAM-1 and NF-κB in endothelial tissues, and increase IκB. In addition, HPLC analysis showed QMY had abundant anthraquinones, stilbenes, and flavonoids.

CONCLUSION

QMY has ameliorative effects on ASO rabbit, and the potential mechanisms are correlated to reducing inflammation and down-regulating NF-κB. Our study provides a scientific basis for the future application and investigation of QMY.

Endovascular Therapy in an "All-Comers" Risk Group for Chronic Limb-Threatening Ischemia Demonstrates Safety and Efficacy When Compared with the Established Performance Criteria Proposed by the Society for Vascular Surgery

BACKGROUND

The aim of this study was to describe the applicability of the Society for Vascular Surgery (SVS) objective performance goals (OPGs) as a tool to evaluate results in the context of endovascular management of noncomplex and complex patients (i.e., end stage renal disease/history of prosthetic conduit) with chronic limb-threatening ischemia (CLTI).

METHODS

Patients diagnosed with CLTI undergoing endovascular procedures from March 2016 to April 2017 were included, and medical records were examined. Patients were categorized as OPG risk (OPGR) and non-OPG risk (nOPGR) groups in accordance with the SVS performance criteria. We compared clinical events between the two groups and then further to the SVS OPGs. Thirty-day outcomes (safety) were major amputation (AMP), major adverse limb events (MALEs), and major adverse cardiovascular events (MACEs), and 1-year outcomes (efficacy) were limb salvage, MALE + 30-day perioperative death (MALE + POD), and survival. Mortality was demonstrated using Kaplan-Meier analysis.

RESULTS

A total of 72 patients were included (OPGR = 58.3% vs. nOPGR = 41.7%). Mean follow-up was 20 months (range, 1-40 months). Retrograde pedal access was used in 65.2% of patients. The overall AMP rate was 2.7% (OPGR = 4.7%, nOPGR = 0%, P = 0.225, vs. SVS OPG<3%), MALE was 4.1% (OPGR = 7.1%, nOPGR = 0%, P = 0.135, vs. SVS OPG<8%), and MACE was 6.9% (OPGR = 2.3%, nOPGR = 13.3%, P = 0.071, vs. SVS OPG<8%). The limb salvage was 90.3% (OPGR = 88%, nOPGR = 93.3%, P = 0.46, vs. SVS OPG>84%), MALE + POD was 76.4% (OPGR = 78.6%, nOPGR = 73.4%, P = 0.606, vs. SVS OPG>71%), and survival was 77.7% (OPGR = 83.3%, nOPGR = 70%, P = 0.18, vs. SVS OPG>80%).

CONCLUSIONS

The SVS OPGs set appropriate safety and efficacy standards as a bar for new technologies. In this series, endovascular therapy in all-comers exceeded the safety and efficacy endpoints proposed by the limited risk OPG panel.

Protective effect of rivaroxaban on arteriosclerosis obliterans in rats through modulation of the toll-like receptor 4/NF-κB signaling pathway

The aim of the present study was to explore the pharmacological role of rivaroxaban in rats with arteriosclerosis obliterans (ASO) and the potential mechanism of its action. A total of 60 adult male Sprague Dawley (weighing 210–250 g) were randomly assigned into either the sham group, model group or Riv group. Rats in the sham group were fed a normal diet, whereas those in model group and Riv group were fed a high-fat diet for 8 weeks. After establishment of the ASO model, rats in the Riv group were intragastrically administered 10 mg/kg rivaroxaban, whereas those in the sham group and the model group were administrated with the same volume of 0.9% saline for 4 weeks. At the end of animal procedures, a blood sample and the femoral artery of the rats were harvested. The results of the present study revealed that rats in the model group presented with an irregularly narrowed femoral artery lumen, disordered endothelial cells, internal elastic plates and smooth muscle cells. By comparison, the arterial wall structure and stenosis of the femoral artery of rats in Riv group recovered and all the pathological changes were alleviated after rivaroxaban treatment. Levels of total cholesterol, triglycerides and low-density lipoproteins decreased, whereas the level of high-density lipoproteins increased in the Riv group compared with the model group. Rivaroxaban treatment significantly reduced serum levels of interleukin-1, tumor necrosis factor-α and monocyte chemoattractant protein-1 (MCP-1), and increased the serum level of transforming growth factor-β (TGF-β). Rats in the Riv group had reduced expression of toll-like receptor 4 (TLR4), NF-κB and MCP-1, and increased expression of TGF-β in femoral artery tissues compared with the model group. Therefore rivaroxaban may have exerted its anti-atherosclerotic effects by regulating the expression of genes in the TLR4/NF-κB signaling pathway and the activation of the downstream molecules.

Multidisciplinary Treatment for Critical Limb Ischemia in Peripheral Arterial Disease

Critical limb ischemia (CLI) is a severe blockage of the arteries to the lower limbs characterized by poor prognoses for both salvage of the lower limb and patient survival. Accordingly, CLI must be diagnosed and treated appropriately from the earliest possible stage. To do so, multidisciplinary treatment not only by vascular surgeons but also by many other doctors and medical staff is necessary. Accurate diagnosis is indispensable to appropriate treatment of CLI; thus, the definitions in the recently issued new guidelines for CLI treatment are reviewed. The multidisciplinary treatment of CLI should be recognized as three elements: namely, multidisciplinary treatment to salvage the lower limb, to improve of survival prognosis, and to prevent CLI occurrence. In all of these events, team medicine administered by expert staff is indispensable. The specialist must have not only profound knowledge of his/her field of specialty but also professional skills and the ability to cooperate with other departments. A multidisciplinary treatment approach that combines the abilities of many specialists for treating severely ischemic limbs in patients with peripheral arterial disease is expected to improve both limb salvage and patient survival and should be promoted in daily clinical settings. (This is a translation of Jpn J Vasc Surg 2018; 27: 507–512.)

Telomerase Plays a Pivotal Role in Collateral Growth Under Ischemia by Suppressing Age-Induced Oxidative Stress, Expression of p53, and Pro-Apoptotic Proteins

Aging is not only a major risk factor for impaired collateral growth under ischemia but also shortens the telomere length, which is regulated by telomerase. We examined the role of telomerase activity during impaired collateral growth during aging in ischemic skeletal muscle. Unilateral hind limb ischemia was generated in old, young, and old mice chronically administered a telomerase activator. In old mice, blood flow recovery and capillary density development in ischemic hind limbs were reduced compared to those in young mice, and these changes were restored to equal levels by administration of TA-65, a telomerase activator. During the early phase of ischemic muscle changes in old mice, telomerase reverse transcriptase expression and telomerase activity were both low compared to those in young mice and old mice treated with TA-65. Levels of reactive oxygen species (ROS), DNA double-strand breaks, and expression of p53, p16, and Bax/Bcl-2 were all elevated in ischemic muscles of old mice compared to those in the muscles of young mice and old mice treated with TA-65 treatment; these factors were maintained at low levels equivalent to those seen in young mice during the experiment. Expression of HIF1α/vascular endothelial growth factor (VEGF) and PGC1α were decreased in old mice compared to those in young mice and old mice treated with TA-65. Collateral growth under ischemic conditions is impaired in aged animals due to low telomerase activity, increased ROS, resultant DNA damage, and expression of tumor suppressor and pro-apoptotic proteins. These data suggest that telomerase activation enhances collateral growth and rescues ischemic tissue in old individuals.