Analysis of possible factors relating to prognosis in autologous peripheral blood mononuclear cell transplantation for critical limb ischemia

Acupoint transplantation versus non-acupoint transplantation using autologous peripheral blood mononuclear cells in treating peripheral arterial disease

Numerous studies have discussed the therapeutic outcomes of using cell therapy or acupuncture to treat peripheral artery disease (PAD). However, there are no long-term studies on the safety and efficacy of transplanting peripheral blood mononuclear cells (PBMNCs) via acupoints to treat PAD. We first reviewed the short-term and long-term clinical results of PAD patients treated with PBMNCs through intramuscular non-acupoint transplantation (control group; n = 45) or intramuscular acupoint transplantation (acupoint group; n = 45) at a single university hospital general medical center between December 2002 and September 2022. Pain intensity (assessed with the verbal rating scale [VRS] score) in the acupoint group was considerably lower than that in the control group at month 1 (mean ± standard deviation [SD]: 1.29 ± 0.96 vs 1.76 ± 0.82; P = 0.016) and month 3 (mean ± SD: 1.27 ± 0.90 vs 1.61 ± 0.86; P = 0.042). We observed significant improvement of VRS score (P < .001 for all) and ankle-brachial index (ABI; P < .001 for all) from baseline in both groups at months 1, 3, 6, 12, 36, and 60. The 10-year cumulative rate of major amputation-free survival (MAFS) was higher in the acupoint group as compared to the control group (81.9%, 95% confidence interval [CI]: 71.3%-94.1% vs 78.5%, 95% CI: 66.7%-92.3%; P = 0.768). Compared with the routine injection method, intramuscular transplantation of PBMNCs via selected acupoints could significantly decrease the short-term pain intensity in patients with PAD, which remains an option for consideration.

Peripheral blood mononuclear cell transplantation to treat no-option critical limb ischaemia: effectiveness and safety

OBJECTIVE

Local intramuscular transplantation of granulocyte colony-stimulating factor (G-CSF)-mobilised peripheral blood mononuclear cells (PB-MNC) has been shown to be effective for treating patients with no-option critical limb ischaemia (CLI) who are not considered suitable to undergo surgical bypass or percutaneous transluminal angioplasty. The aim of this study was to investigate the effectiveness and safety of PB-MNCs as a treatment for no-option CLI patients.

METHOD

This prospective cohort study was conducted between April 2013 and December 2017. Patients with no-option CLI were treated with G-CSF 5-10 µg/kg/day for 3 days. PB-MNCs (7.1±2.2×10¹⁰) with CD34+ cells (2.1±1.2×10⁸) were collected by blood cell separator and then injected into the calf or thigh of ischaemic limbs. Ankle-brachial index, toe-brachial index and transcutaneous oxygen tension were recorded at 1 and 3 months after injection. The amputation rate and the wound healing rate were also recorded.

RESULTS

Eight patients took part in the study. Two patients experienced rest pain relief 1 month after PB-MNC therapy. Five patients had healed ulcer at 6 months after PB-MNC therapy. Limb ischaemia did not improve after PB-MNC therapy in one patient. Below-knee amputation was performed in that patient due to extension of gangrene. Two patients required reinjection of PB-MNCs because of recurrence of ischaemic ulcer. The limb salvage rate after 1 year was 87.5%.

CONCLUSION

Local intramuscular transplantation of G-CSF-mobilised PB-MNCs might be a safe and effective treatment for no-option CLI patients.

Predictors of responders to mononuclear stem cell-based therapeutic angiogenesis for no-option critical limb ischemia

Background

Although the mononuclear cell (MNC) transplantation could theoretically induce therapeutic angiogenesis in the patients with no-option critical limb ischemia (NO-CLI), the clinical responses to this approach are inconsistent among different clinical trials. The purpose of this study was to identify the prognostic factors of responders and develop a predictive nomogram to guide patient selection.

Methods

We retrospectively reviewed a consecutive NO-CLI cohort who received peripheral blood-derived transplantation in our center. The patients who survived and achieved complete remission of CLI at 6 months post-transplantation were defined as responders. Logistic regression models were used to screen and identify the prognostic factors based on which predictive nomogram was developed. A receiver operating characteristic (ROC) curve and a calibration curve were drawn to determine the discrimination level and predictive accuracy.

Results

The study ultimately enrolled 103 patients, including 58 responders and 45 non-responders. Based on the multivariate regression analysis, age ≥ 50 years (odds ratio [OR] 0.201, P = 0.004), blood fibrinogen > 4 g/L (OR 0.176, P = 0.003), arterial occlusion above the knee/elbow (OR 0.232, P = 0.010), the transcutaneous pressure of oxygen (TcPO₂) (OR 1.062, P = 0.006), and the Log total transplanted CD34⁺ cell count (OR 3.506, P = 0.046) were identified as independent prognostic factors of the responders in the nomogram. An area under the ROC curve of 0.851 indicated good discrimination, and the calibration curve of the predicted probability showed optimal agreement with that of the observed probability.

Conclusions

Age, blood fibrinogen, arterial occlusion level, TcPO₂, and the total transplanted CD34⁺ cell count were independent prognostic factors of the responders. A nomogram with high discrimination and accuracy was developed to provide individualized predictions.

Trail registration

ChiCTR, ChiCTR1800019401. Registered 9 November 2018—Retrospectively registered

Electronic supplementary material

The online version of this article (10.1186/s13287-018-1117-5) contains supplementary material, which is available to authorized users.

Autologous Cell Therapy for Peripheral Arterial Disease

Rationale:

Critical limb ischemia is a life-threatening complication of peripheral arterial disease. In patients who are ineligible for revascularization procedures, there are few therapeutic alternatives, leading to amputations and death.

Objective:

To provide a systematic review of the literature and a meta-analysis of studies evaluating safety and efficacy of autologous cell therapy for intractable peripheral arterial disease/critical limb ischemia.

Methods and Results:

We retrieved 19 randomized controlled trials (837 patients), 7 nonrandomized trials (338 patients), and 41 noncontrolled studies (1177 patients). The primary outcome was major amputation. Heterogeneity was high, and publication bias could not be excluded. Despite these limitations, the primary analysis (all randomized controlled trials) showed that cell therapy reduced the risk of amputation by 37%, improved amputation-free survival by 18%, and improved wound healing by 59%, without affecting mortality. Cell therapy significantly increased ankle brachial index, increased transcutaneous oxygen tension, and reduced rest pain. The secondary analysis (all controlled trials; n=1175 patients) shows that there may be potential to avoid ≈1 amputation/year for every 2 patients successfully treated. The tertiary analysis (all studies; n=2332 patients) precisely estimated the changes in ankle brachial index, transcutaneous oxygen tension, rest pain, and walking capacity after cell therapy. Intramuscular implantation appeared more effective than intra-arterial infusion, and mobilized peripheral blood mononuclear cells may outperform bone marrow–mononuclear cells and mesenchymal stem cells. Amputation rate was improved more in trials wherein the prevalence of diabetes mellitus was high. Cell therapy was not associated with severe adverse events. Remarkably, efficacy of cell therapy on all end points was no longer significant in placebo-controlled randomized controlled trials and disappeared in randomized controlled trials with a low risk of bias.

Conclusions:

Although this meta-analysis highlights the need for more high-quality placebo-controlled trials, equipoise may no longer be guaranteed because autologous cell therapy has the potential to modify the natural history of intractable critical limb ischemia.

Therapeutic strategies for cell-based neovascularization in critical limb ischemia

Critical limb ischemia (CLI) causes severe ischemic rest pain, ulcer, and gangrene in the lower limbs. In spite of angioplasty and surgery, CLI patients without suitable artery inflow or enough vascular bed in the lesions are often forced to undergo amputation of a major limb. Cell-based therapeutic angiogenesis has the potential to treat ischemic lesions by promoting the formation of collateral vessel networks and the vascular bed. Peripheral blood mononuclear cells and bone marrow-derived mononuclear cells are the most frequently employed cell types in CLI clinical trials. However, the clinical outcomes of cell-based therapeutic angiogenesis using these cells have not provided the promised benefits for CLI patients, reinforcing the need for novel cell-based therapeutic angiogenesis strategies to cure untreatable CLI patients. Recent studies have demonstrated the possible enhancement of therapeutic efficacy in ischemic diseases by preconditioned graft cells. Moreover, judging from past clinical trials, the identification of adequate transplant timing and responders to cell-based therapy is important for improving therapeutic outcomes in CLI patients in clinical settings. Thus, to establish cell-based therapeutic angiogenesis as one of the most promising therapeutic strategies for CLI patients, its advantages and limitations should be taken into account.