Chronic Limb-Threatening Ischemia

Participation in a Chronic Limb Threatening Ischemia Randomized Trial Is Inversely Correlated With Regional Amputation Rate in Limb Threatening Ischemia Patients

OBJECTIVE

The National Health Service demonstrated that regions of the United Kingdom with the highest number of patients enrolled in research studies had the lowest risk-adjusted mortality when patients were admitted to the hospital. Our goal was to investigate if this correlation was evident for patients with chronic limb threatening ischemia (CLI) treated in the United States (US). Accordingly, we examined correlations among sites participating in the Best Endovascular versus best Surgical Therapy in patients with Critical (BEST-CLI) trial, a multicenter, National Institute of Health-sponsored, international randomized controlled trial (RCT) comparing revascularization strategies in patients with CLI, and regional rates of major amputation from CLI.

METHODS

We measured regional participation in the BEST-CLI trial by evaluating trial participation and enrollment rosters. To determine regional rates of lower limb amputation, we queried the Medicare database (2007-2016) for patients with concurrent peripheral arterial disease (PAD) and diabetes, then assessed how many had lower extremity amputations. Correlation of regional amputation rates with distribution of BEST-CLI sites in four US geographical regions was calculated using Pearson's correlation coefficients. Simple regression equations were used to calculate the significance of these correlation coefficients.

RESULTS

Of 9,231,909 CLI patients, 342,406 underwent amputation in the Medicare dataset. Amputation rates per 1000 CLI patients differed by region (South 40.42, Midwest 40.12, West 34.81, Northeast 31.14). There were 116 US vascular centers, selected by volume and expertise that participated in BEST-CLI with the following distribution: South (n = 30, 26%), Midwest (n = 26, 22%), West (n = 29, 25%), and Northeast (n = 31, 27%). There was a negative correlation between the number of amputations per 1000 for Medicare CLI patients with diabetes and PAD and the number of BEST-CLI sites in the region which trended toward significance (Pearson R= -0.61, P = 0.39).

CONCLUSIONS

Amputation rate among Medicare CLI patients is inversely correlated with US BEST-CLI site distribution. Higher participation in clinical research, especially within large RCTs, may be a marker of optimal PAD management.

Low-intensity pulsed ultrasound decreases major amputation in patients with critical limb ischemia: 5-year follow-up study

Various therapeutic strategies for angiogenesis are performed to improve symptoms in patients with critical limb ischemia (CLI). Pre-clinical studies have shown that low-intensity pulsed ultrasound (LIPUS) exposure induces angiogenesis. LIPUS may be a new stratergy for treatment of CLI. The purpose of this pilot trial was to evaluate outcomes in patients with CLI who were treated with LIPUS. Fourteen patients with CLI, who were not candidates for angioplasty or surgical revascularization, were enrolled in this study. Historical control data were obtained from the Hiroshima University PAD database. The primary endpoints were major amputation and death. The outcomes were compared in 16 lower limbs of the 14 patients with CLI who were treated with LIPUS and in 14 lower limbs of 14 patients with CLI as historical controls. All patients were followed for after 5 years after treatment with LIPUS. The mean duration of LIPUS exposure in the LIPUS group was 381± 283 days. During the 5-year follow-up periods, there were 3 major amputations and 7 deaths in the LIPUS group and there were 14 major amputations and 7 deaths in the historical control group. The overall amputation-free survival rate was significantly higher in patients who were treated with LIPUS than in historical controls. There was no significant difference between overall mortality-free survival rates in the LIPUS group and historical control group. LIPUS is a noninvasive option for therapeutic angiogenesis with the potential to reduce the incidence of major amputations in patients with CLI.

The Impact of Chronic Kidney Disease on Peripheral Artery Disease and Peripheral Revascularization

Chronic kidney disease (CKD) is a clinical condition characterized by high morbidity and mortality. Globally, CKD is also increasing in prevalence and incidence. The two principal kidney measures namely estimated glomerular filtration rate (eGFR) and albuminuria have been found to be predictors of renal and cardiovascular (CV) endpoints including peripheral artery disease (PAD). The prevalence of PAD was increased in CKD patients and, particularly, in patients with more severe CKD stages. Despite the fact that revascularization strategies are suitable in CKD patients in similar fashion to non-CKD patients, few CKD patients underwent these procedures. In fact, if it is true that revascularization improves prognosis in PAD patients irrespective of baseline eGFR, it was also demonstrated that CKD patients, who underwent revascularization, were at higher risk for amputations, mortality, re-intervention and perioperative complications. With the present review article, we have examined the association between CKD, PAD and peripheral revascularization highlighting data about epidemiology, pathophysiologic mechanisms, and results from previous observational and intervention studies. We have also examined the future perspectives and challenges of research around the association between CKD and PAD.

Drug-Coated Balloon versus Bare Nitinol Stent in Femoropopliteal Artery: 12 Months Outcome from a Single Center in China

OBJECT

The study sought to compare the safety and effectiveness of drug-coated balloon (DCB) with bare nitinol stent in patients with complex femoropopliteal(FP) lesions in real-world practice.

METHODS

Patients with symptomatic (Rutherford stage 2 to 5) femoropopliteal lesions who underwent DCB or bare nitinol stent implantation at the Department of Cardiovascular Surgery of China-Japan Friendship Hospital from June 2016 to September 2017 were included. Demographics, angiographic and procedural variables were included. Freedom from target lesion revascularization (TLR), primary patency and major adverse events were obtained from follow-up results at 3,6 and12 months. Descriptive analysis was performed on all variables.

RESULTS

A total of 90 eligible patients were enrolled, which included 51 DCB subjects (mean age, 63.1 ± 13.2 years; 76.5% male) with 55 lesions and 39 nitinol stent subjects (mean age, 66.5 ± 10.5 years; 61.5% male) with 42 lesions. Significant higher primary patency was observed in the DCB group compared with the stent group (74.5% vs. 52.4%; log-rank test P = 0.018; HR 0.335, 95%CI 0.124-0.903, P = 0.031). The rates of freedom from TLR (f-TLR) were 78.2% and 59.5% (log-rank test P = 0.032) for the DCB group and the stent group, respectively, at 12 months. CD-TLR rates were 18.2% vs. 38.1% with a P-value of 0.023. Female sex (HR 6.122, 95%CI 1.880-19.934, P = 0.003), lesion length over 20 cm (HR 5.514, 95%CI 2.312-13.148, P < 0.001) and renal insufficiency (HR 2.609, 95%CI 1.087-6.260, P = 0.032) were suggested as independent risk factors of reducing primary patency. There were no significant differences in major adverse events between the 2 groups.

CONCLUSION

The result above demonstrates that DCB treatment has higher primary patency and lower TLR at 12 months than nitinol stent. These data confirm the safety and effectiveness of the DCB for patients with complex femoropopliteal lesions.

Cause of Death Among Patients With Peripheral Artery Disease

Background:

Peripheral artery disease is common and associated with high mortality. There are limited data detailing causes of death among patients with peripheral artery disease.

Methods:

EUCLID (Examining Use of Ticagrelor in Peripheral Artery Disease) was a randomized clinical trial that assigned patients with peripheral artery disease to clopidogrel or ticagrelor. We describe the causes of death in EUCLID using mortality end points adjudicated through a clinical events classification process. The association between baseline factors and cardiovascular death was evaluated by Cox proportional hazards modeling. The competing risk of noncardiovascular death was assessed by the cumulative incidence function for cardiovascular death and the Fine and Gray method to ascertain the association between baseline characteristics and cardiovascular mortality.

Results:

A total of 1263 out of 13 885 (9.1%) patients died (median follow-up: 30 months). There were 706 patients (55.9%) with a cardiovascular cause of death and 522 (41.3%) with a noncardiovascular cause of death. The most common cause of cardiovascular death was sudden cardiac death (20.1%); while myocardial infarction (5.2%) and ischemic stroke (3.2%) were uncommon. The most common causes of noncardiovascular death were malignancies (17.9%) and infections (11.9%). The factor most associated with a higher risk of cardiovascular death was age per 5 year increase (HR, 1.26 [95% CI, 1.20–1.32]). Female sex was associated with a lower risk of cardiovascular death (HR, 0.68 [95% CI, 0.56–0.82]). To evaluate the effect of noncardiovascular death as a competing risk, we superimposed the cumulative incidence function curve with the Kaplan-Meier curve. These curves closely approximated each other. After accounting for the competing risk of noncardiovascular death, the magnitude and direction of the factors associated with cardiovascular death were minimally changed.

Conclusions:

Among patients with symptomatic peripheral artery disease, noncardiovascular causes of death reflected a high proportion (40%) of deaths. Accounting for noncardiovascular deaths as a competing risk, there was not a significant change in the risk estimation for cardiovascular death.

Registration:

URL: https://www.clinicaltrials.gov ; Unique identifier: NCT01732822.

Comparison of Magnetic Resonance Angiography and Digital Subtraction Angiography for the Assessment of Infrapopliteal Arterial Occlusive Lesions, Based on the TASC II Classification Criteria

This paper aimed to study the agreement and repeatability, both intra- and interobserver, of infrapopliteal lesion assessment with magnetic resonance angiography (MRA), using the TransAtlantic Inter-Society Consensus (TASC) II criteria, with perioperative digital subtraction angiography (DSA) as a reference. Sixty-eight patients with an MRA preceding an endovascular infrapopliteal revascularization were included. Preoperative MRAs and perioperative DSAs were evaluated in random order by three independent observers using the TASC II classification. The results were analyzed using visual grading characteristics (VGC) analysis and Krippendorff’s α. No systematic difference was found between modalities: area under the VGC curve (AUC_VGC) = 0.48 (p = 0.58) or intraobserver; AUC_VGC for Observer 1 and 2 respectively, 0.49 (p = 0.85) and 0.53 (p = 0.52) for MRA compared with 0.54 (p = 0.30) and 0.49 (p = 0.81) for DSA. Interobserver differences were seen: AUC_VGC of 0.63 (p < 0.01) for DSA and 0.80 (p < 0.01) for MRA. These results were confirmed using Krippendorff’s α for the three observers showing 0.13 (95% confidence interval (CI) −0.07–0.31) for MRA and 0.39 (95% CI 0.23–0.53) for DSA. Poor interobserver agreement was also found in the choice of a target vessel on preoperative MRA: Krippendorff’s α = 0.19 (95% CI 0.01‒0.36). In conclusion, infrapopliteal lesions can be reliably determined on preoperative MRA, but interobserver variability regarding the choice of a target vessel is a major concern that appears to affect the overall TASC II grade.

The Monocyte/High Density Lipoprotein Cholesterol Ratio (MHR) as an Indicator of the Need for Amputation in Patients With Peripheral Artery Disease Developing Critical Limb Ischemia

The monocyte/high density lipoprotein cholesterol ratio (MHR) reflects the proatherogenic and antiatherogenic balance, and a high ratio is associated with the severity of atherosclerosis. We measured the MHR of patients with critical limb ischemia (CLI) due to peripheral artery disease (PAD) requiring amputation. Patients diagnosed with PAD were divided into 2 groups; those who underwent an amputation due to CLI without any sign of infection and those treated with surgical or percutaneous revascularization or followed up medically. A healthy control group was also included. In patients diagnosed with PAD (n = 563), the MHR value was higher for the control group (n = 200), (12.4 ± 0.42 vs 11.5 ± 0.28, P < .001). In the amputation group, the MHR was significantly higher for the group treated by other methods (15.7 ± 1.52 vs 12.8 ± 1.45, P < .001). Possible confounding factors affecting the MHR value were determined by the univariate regression analysis, and the multiple regression analysis revealed that MHR was an independent predictor of amputation in patients with PAD (P < .001). This study suggests that the MHR may be the predictor of amputation risk in patients with PAD and CLI.

Traditional Chinese medicine formulas, extracts, and compounds promote angiogenesis

Ischemic diseases, such as ischemic heart diseases and ischemic stroke, are the leading cause of death worldwide. Angiogenic therapy is a wide-ranging approach to fighting ischemic diseases. However, compared with anti-angiogenesis therapy for tumors, less attention has been paid to therapeutic angiogenesis. Recently, Traditional Chinese medicine (TCM) has garnered increasing interest for its definite curative effect and low toxicity. A growing number of studies have reported that TCM formulas, extracts, and compounds from herbal medicines exert pro-angiogenic activity, which has been confirmed in a few clinical trials. For comprehensive analysis of relevant literature, global and local databases including PubMed, Web of Science, and China National Knowledge Infrastructure were searched using keywords such as "angiogenesis," "neovascularization," "traditional Chinese medicine," "formula," "extract," and "compound." Articles were chosen that are closely and directly related to pro-angiogenesis. This review summarizes the pro-angiogenic activity and the mechanism of TCM formulas, extracts, and compounds; it delivers an in-depth understanding of the relationship between TCM and pro-angiogenesis and will provide new ideas for clinical practice.

Multifunctional Artificial Artery from Direct 3D Printing with Built-In Ferroelectricity and Tissue-Matching Modulus for Real-Time Sensing and Occlusion Monitoring

Treating vascular grafts failure requires complex surgery procedures and is associated with high risks. A real-time monitoring vascular system enables quick and reliable identification of complications and initiates safer treatments early. Here, an electric fieldassisted 3D printing technology is developed to fabricate in situ-poled ferroelectric artificial arteries that offer battery-free real-time blood pressure sensing and occlusion monitoring capability. The functional artery architecture is made possible by the development of a ferroelectric biocomposite which can be quickly polarized during printing and reshaped into devised objects. The synergistic effect from the potassium sodium niobite particles and the polyvinylidene fluoride polymer matrix yields a superb piezoelectric performance (bulk-scale d 33 > 12 pC N-1). The sinusoidal architecture brings the mechanical modulus close to the level of blood vessels. The desired piezoelectric and mechanical properties of the artificial artery provide an excellent sensitivity to pressure change (0.306 mV mmHg-1, R 2 > 0.99) within the range of human blood pressure (11.25-225.00 mmHg). The high pressure sensitivity and the ability to detect subtle vessel motion pattern change enable early detection of partial occlusion (e.g., thrombosis), allowing for preventing grafts failure. This work demonstrates a promising strategy of incorporating multifunctionality to artificial biological systems for smart healthcare systems.

Systematic Interrogation of Angiogenesis in the Ischemic Mouse Hind Limb: Vulnerabilities and Quality Assurance

Supplemental Digital Content is available in the text.

Objective:

There has been little success in translating preclinical studies of mouse hind limb ischemia into benefit for patients with peripheral artery disease. Using systematic strategies, we sought to define the injury and angiogenesis landscapes in mice subjected to hind limb ischemia and ascertain whether published studies to date have used an analysis strategy concordant with these data.

Approach and Results:

Maps of ischemic injury were generated from 22 different hind limb muscles and 33 muscle territories in 12-week-old C57BL/6 mice, based on loss or centralization of myofiber nuclei. Angiogenesis was similarly mapped based on CD (cluster of differentiation) 31–positive capillary content. Only 10 of 33 muscle territories displayed consistent muscle injury, with the distal anterior hind limb muscles most reliably injured. Angiogenesis was patchy and exclusively associated with zones of regenerated muscle (central nuclei). Angiogenesis was not observed in normal appearing muscle, necrotic muscle, or injury border zones. Systematic review of mouse hind limb angiogenesis studies identified 5147 unique publications, of which 509 met eligibility criteria for analysis. Only 7% of these analyzed manuscripts evaluated angiogenesis in distal anterior hind limb muscles and only 15% consistently examined for angiogenesis in zones of muscle regeneration.

Conclusions:

In 12-week C57BL/6 mice, angiogenesis postfemoral artery excision proceeds exclusively in zones of muscle regeneration. Only a minority of studies to date have analyzed angiogenesis in regions of demonstrably regenerating muscle or in high-likelihood territories. Quality assurance standards, informed by the atlas and mapping data herein, could augment data reliability and potentially help translate mouse hind limb ischemia studies to patient care.

Effect of Chitosan oligosaccharides on ischemic symptom and gut microbiota disbalance in mice with hindlimb ischemia

This study was designed to explore the effect of Chitosan oligosaccharides (COS) on mouse hindlimb ischemia by femoral artery ligation. Here, we demonstrated that COS treatment statistically promoted the blood perfusion and neovascularization in ischemic hindlimb of mice, accompanied by the suppression of inflammation and oxidative stress. By 16S rDNA gene sequencing, the disbalanced gut microbiota was observed in ischemic mice, while COS treatment, at least in part, restored the abundance changes of some intestinal bacteria at either phylum or genus levels. Based on metabolomics analysis on mouse plasma by UPLC-QTOF-MS, we screened 20 metabolites with the largest responses to ischemia, several of which were markedly reversed by COS. By Spearman's correlation analysis, the changed metabolites might act as a bridge between improved intestinal bacterial structure and alleviated hindlimb ischemia of mice treated by COS. Our studies point towards a potential role of COS in treatment of peripheral ischemia diseases.

Diagnostic and Therapeutic Approaches in the Management of Infrapopliteal Arterial Disease

Chronic limb-threatening ischemia represents end-stage peripheral artery disease. It is underdiagnosed; it relies on clinical symptoms and traditional noninvasive tests, which significantly underestimate the severity of disease. Innovative techniques, approaches, technologies, and risk-assessment tools have significantly improved our ability to treat these patients and to better understand their complex disease process. For patients with chronic limb-threatening ischemia considered without options, the reengineering of deep venous arterialization procedures has shown promising results. Finally, the creation of interactive and multidisciplinary teams in centers of excellence is of paramount importance to significantly improve the care and outcomes of these patients.

Microvascular Disease Increases Amputation in Patients With Peripheral Artery Disease

It is estimated that >2 million patients are living with an amputation in the United States. Peripheral artery disease (PAD) and diabetes mellitus account for the majority of nontraumatic amputations. The standard measurement to diagnose PAD is the ankle-brachial index, which integrates all occlusive disease in the limb to create a summary value of limb artery occlusive disease. Despite its accuracy, ankle-brachial index fails to well predict limb outcomes. There is an emerging body of literature that implicates microvascular disease (MVD; ie, retinopathy, nephropathy, neuropathy) as a systemic phenomenon where diagnosis of MVD in one capillary bed implicates microvascular dysfunction systemically. MVD independently associates with lower limb outcomes, regardless of diabetic or PAD status. The presence of PAD and concomitant MVD phenotype reveal a synergistic, rather than simply additive, effect. The higher risk of amputation in patients with MVD, PAD, and concomitant MVD and PAD should prompt aggressive foot surveillance and diagnosis of both conditions to maintain ambulation and prevent amputation in older patients.

A single-center experience in the eversion femoral endarterectomy

OBJECTIVES

Endarterectomy is the treatment of choice for arterial occlusive disease of the femoral bifurcation. Longitudinal arteriotomy and prosthetic patch angioplasty is the standard technique but, due to the increasing concerns with prosthetic-related infections and multidrug-resistant pathogens our group adopted an alternative approach. We present our experience with eversion femoral endarterectomy.

METHODS

All patients submitted to eversion femoral endarterectomy in a single institution during 2016-2019 were retrospectively analyzed. Patient demographics, surgical data, and complications were captured from medical records.

RESULTS

Nineteen patients, 84.2% male and a median age of 67 years (IQR 62-78) were submitted to eversion femoral endarterectomy with a median follow-up of 180 days (IQR 71-395). Seventeen (89.4%) patients were treated for chronic limb ischemia and the other two were submitted to femoral endarterectomy during endovascular aortic aneurysm repair. Most of the patients had smoking history (84.2%), followed by hypertension (68.4%), dyslipidemia (63.2%), coronary heart disease (29.4%), and diabetes (26.3%). Only 3 patients (15.8%) were submitted exclusively to endarterectomy, 13 (68.4%) were submitted to endarterectomy as an adjuvant for peripheral endovascular treatment, 2 (10.5%) as a concomitant procedure to endovascular repair of aortic aneurysm, and 1 (5.3%) was complemented with thrombectomy of the femoro-popliteal sector. Primary patency rates were 100% and 87.5% (CI (38.7-98.1)) at 6 and 12 months, respectively. Primary-assisted and secondary patency rates were 100%. The 30-day mortality rate was 5.3% (n = 1) and complication rate 10.5% (n = 2). One patient complicated with acute renal disease related to rhabdomyolysis. Another patient developed a wound-related hematoma treated with surgical drainage, but died three days after consequent to ischemia-reperfusion injury.

CONCLUSIONS

Eversion femoral endarterectomy is a safe and feasible technique, with good patency results and respecting the concept of leaving nothing behind. A careful control of the proximal and distal endpoints is essential for the success of the technique.

Predictors of Wound Healing Following Revascularization for Chronic Limb-Threatening Ischemia

OBJECTIVES

After surgical or endovascular revascularization, some ischemic lesions will not heal, while some others will heal at a variable period of time from the intervention, indicating a multifactorial interaction between local and systematic "wound healing-promoting" factors. Our objective was to identify predictors of wound healing following revascularization for chronic limb-threatening ischemia (CLTI).

METHODS

A literature review was performed to identify published research concerning clinical, biochemical, and noninvasive methods as predictors of wound healing time and wound-free period after surgical and endovascular revascularization for CLTI.

RESULTS

Our review indicated that potential predictors included local wound factors, wound depth, patient's comorbidities, medications, smoking and alcohol abuse, poor vessel runoff, and direct versus indirect revascularization. Among the clinical biomarkers, platelet-derived growth factor, transforming growth factor β, basic fibroblast growth factor, tumor necrosis factor α, interleukin (IL) 1, and IL-6 have been proposed as potential predictors. Furthermore, the potential of noninvasive microcirculation assessment to predict proper wound healing has been the topic of extensive investigation. Among the novel methods, transcutaneous measurement of oxygen partial pressure, skin perfusion pressure, oxygen-to-see method, indocyanine green fluorescence imaging, and multispectral optoacoustic tomography have shown promising results.

CONCLUSIONS

The risk factor profile of an ischemic lesion in the lower extremities with a delayed/failed healing response, following a successful revascularization, is not fully clarified. Although many predictors have been assessed so far, further research needs to be done to identify the optimal clinical and biochemical indices and the noninvasive technique assessing the microcirculation that is associated with complete wound healing.

Iloprost treatment on top of infrapopliteal angioplasty accelerates wound healing in critical leg ischemia

Objectives

This study aimed to examine the efficacy of the concomitant use of infrapopliteal drug-eluting balloon angioplasty and a medical treatment (iloprost) in the treatment of critical leg ischemia.

Methods

Eighty-seven patients that underwent infrapopliteal drug-eluting balloon angioplasty for critical leg ischemia were included in this retrospective study. For analyses, patients were allocated into one of the two groups: 55 patients that underwent drug-eluting balloon angioplasty alone (drug-eluting balloon Group), and 32 patients that received intravenous iloprost for one week after drug-eluting balloon (DEB-I Group). Demographic, perioperative and follow-up clinical data were extracted retrospectively and analyzed.

Results

Duration of hospitalization was significantly longer in the DEB-I group (9.7 vs. 3.1 days, p < 0.001); however, the two groups were similar in terms of other clinical outcomes including early postoperative mortality, and primary patency, wound healing, reintervention, mortality, and amputation rates at one year ( p > 0.05 for all). Primary patency was similar across groups. Wound healing occurred earlier in the DEB-I group when compared to drug-eluting balloon group, in the subgroup of patients with ischemic wound at baseline. Mean time to wound healing was 3.0 ± 0.6 and 4.4 ± 0.6 months in DEB-I and drug-eluting balloon groups, respectively ( p = 0.037).

Conclusions

Iloprost add-on treatment in patients undergoing drug-eluting balloon angioplasty for critical limb ischemia seems to have additional benefits, at least in terms of accelerated wound healing. Further large prospective studies are warranted.

Microvascular Disease, Peripheral Artery Disease, and Amputation

BACKGROUND

The mechanism of adverse limb events associated with peripheral artery disease remains incompletely understood. We investigated whether microvascular disease is associated with amputation in a large cohort of veterans to determine whether microvascular disease diagnosed in any location increases the risk of amputation alone and in concert with peripheral artery disease.

METHODS

Participants in the Veterans Aging Cohort Study were recruited from April 1, 2003 through December 31, 2014. We excluded participants with known prior lower limb amputation. Using time-updated Cox proportional hazards regression, we analyzed the effect of prevalent microvascular disease (retinopathy, neuropathy, and nephropathy) and peripheral artery disease status on the risk of incident amputation events after adjusting for demographics and cardiovascular risk factors.

RESULTS

Among 125 674 veterans without evidence of prior amputation at baseline, the rate of incident amputation over a median of 9.3 years of follow-up was 1.16 per 1000 person-years, yielding a total of 1185 amputations. In time-updated multivariable-adjusted analyses, compared with those without peripheral artery disease or microvascular disease, microvascular disease alone was associated with a 3.7-fold (95% CI, 3.0-4.6) increased risk of amputation; peripheral artery disease alone conferred a 13.9-fold (95% CI, 11.3-17.1) elevated risk of amputation; and the combination of peripheral artery disease and microvascular disease was associated with a 22.7-fold (95% CI, 18.3-28.1) increased risk of amputation.

CONCLUSIONS

Independent of traditional risk factors, the presence of microvascular disease increases the risk of amputation alone and synergistically increases risk in patients with peripheral artery disease. Further research is needed to understand the mechanisms by which this occurs.

JNKi- and DAC-programmed mesenchymal stem/stromal cells from hESCs facilitate hematopoiesis and alleviate hind limb ischemia

Background

Mesenchymal stem/stromal cells (MSCs) derived from human embryonic stem cells (hESCs) are attractive for their hematopoietic-supporting or potential therapeutic effects. However, procedures for high-effective and scalable generation of MSCs from hESCs within 2 weeks are still unestablished, which also hinder the development and mechanism study of mesengenesis.

Methods

In this study, we aimed to establish a strategy for programming hESC differentiation into MSCs by practicing small-scale chemical compound screening. Then, we used flow cytometry, multi-lineage differentiation, and karyotype analyses to investigate the biological phenotypes of the derived hESC-MSCs. Also, to explore whether the derived cells had hematopoietic-supporting ability in vitro, we carried out the cobblestone formation and megakaryocytic differentiation experiments. To further evaluate the function of hESC-MSCs in vivo, we transplanted the cells into a mouse model with hind limb ischemia.

Results

By simultaneous treatments with a JAK/STAT antagonist and a DNA methylation inhibitor, the efficiency of generating hESCs into CD73⁺ hESC-MPCs could reach 60% within 7 days. The derived cells further matured into hESC-MSCs, with comparable characteristics to those of adult MSCs in terms of surface markers, normal karyotype, and the potential for adipogenic, osteogenic, and chondrogenic differentiation. Functionally, hESC-MSCs had hematopoietic-supporting effects in vitro and could notably relieve symptoms of hind limb ischemia.

Conclusions

In the study, we established a high-efficient procedure for large-scale generation of MSCs from hESCs, which would be of great help for genesis and mechanism studies of MSCs. Meanwhile, the derived cells provide an alternative for translational clinical research.

Electronic supplementary material

The online version of this article (10.1186/s13287-019-1302-1) contains supplementary material, which is available to authorized users.

Fortifying Angiogenesis in Ischemic Muscle with FGF9-Loaded Electrospun Poly(Ester Amide) Fibers

Delivery of angiogenic growth factors lessens ischemia in preclinical models but has demonstrated little benefit in patients with peripheral vascular disease. Augmenting the wrapping of nascent microvessels by mural cells constitutes an alternative strategy to regenerating a functional microvasculature, particularly if integrated with a sustained delivery platform. Herein, electrospun poly(ester amide) (PEA) nanofiber mats are fabricated for delivering a mural cell-targeting factor, fibroblast growth factor 9 (FGF9). Proof-of-principle is established by placing FGF9/FGF2-loaded PEA fiber mats on the chick chorioallantoic membrane and identifying enhanced angiogenesis by 3D power Doppler micro-ultrasound imaging. To assess the delivery system in ischemic muscle, FGF9-loaded PEA fiber mats are implanted onto the surface of the tibialis anterior muscle of mice with hindlimb ischemia. The system supplies FGF9 into the tibialis anterior muscle and yields a neo-microvascular network with enhanced mural cell coverage up to 28 days after injury. The regenerating muscle that receives FGF9 display near-normal sized myofibers and reduced interstitial fibrosis. Moreover, the mice demonstrate improved locomotion. These findings of locally released FGF9 from PEA nanofibers raise prospects for a microvascular remodeling approach to improve muscle health in peripheral vascular disease.

Unique aspects of peripheral artery disease in patients with chronic kidney disease

Peripheral artery disease (PAD) represents a major health care burden. Despite the advent of screening and interventional procedures, the long-term clinical outcomes remain suboptimal, especially in patients with chronic kidney disease (CKD). While CKD and PAD share common predisposing factors, emerging studies indicate that their co-existence is not merely an association; instead, CKD represents a strong, independent risk factor for PAD. These findings implicate CKD-specific mediators of PAD that remain incompletely understood. Moreover, there is a need to understand the mechanisms underlying poor outcomes after interventions for PAD in CKD. This review discusses unique clinical aspects of PAD in patients with CKD, including high prevalence and worse outcomes after vascular interventions and the influence of renal allograft transplantation. In doing so, it also highlights underappreciated aspects of PAD in patients with CKD, such as disparities in revascularization and higher peri-procedural mortality. While previous reviews have discussed general mechanisms of PAD pathogenesis, focusing on PAD in CKD, this review underscores a need to probe for CKD-specific pathogenic pathways that may unravel novel biomarkers and therapeutic targets in PAD and ultimately improve the risk stratification and management of patients with CKD and PAD.