Human adipose-derived mesenchymal stem cells-derived exosomes encapsulated in pluronic F127 hydrogel promote wound healing and regeneration.

BACKGROUND: Large area skin trauma has always been a great challenge for both patients and clinicians. Exosomes originating from human adipose-derived mesenchymal stem cells (hADSCs) have been a novel promising cell-free treatment in cutaneous damage repair. Nevertheless, the low retention rate of exosomes post-transplantation in vivo remains a significant challenge in clinical applications. Herein, we purposed to explore the potential clinical application roles of hADSCs-Exos encapsulated in functional PF-127 hydrogel in wound healing. METHODS: hADSCs-Exos were isolated from human hADSCs by ultracentrifugation. An injectable, biocompatible, and thermo-sensitive hydrogel Pluronic F-127 hydrogel was employed to encapsulate allogeneic hADSCs-Exos, and this complex was topically applied to a full-thickness cutaneous wound in mice. On different days post-transplantation, the mice were sacrificed, and the skin tissue was excised for histological and immunohistochemical analysis. RESULTS: Compared with hADSCs-Exos or PF-127 only, PF-127/hADSCs-Exos complexes enhanced skin wound healing, promoted re-epithelialization, increased expression of Ki67, α-SMA, and CD31, facilitated collagen synthesis (Collagen I, Collagen III), up-regulated expression of skin barrier proteins (KRT1, AQP3), and reduced inflammation (IL-6, TNF-α, CD68, CD206). By using PF-127/hADSCs-Exos complexes, hADSCs-Exos can be administrated at lower doses frequency while maintaining the same therapeutic effects. CONCLUSION: Administration of hADSCs-Exos in PF-127 improves the efficiency of exosome delivery, maintains the bioactivity of hADSCs-Exos, and optimizes the performance of hADSCs-Exos. Thus, this biomaterial-based exosome will be a promising treatment approach for the cutaneous rejuvenation of skin wounds.

Carbon Nanotube Polymer Scaffolds as a Conductive Alternative for the Construction of Retinal Sheet Tissue.

With the great success of graphene in the biomedical field, carbon nanotubes have attracted increasing attention for different applications in ophthalmology. Here, we report a novel retinal sheet composed of carbon nanotubes (CNTs) and poly(lactic-co-glycolic acid) (PLGA) that can enhance retinal cell therapy. By tuning our CNTs to regulate the mechanical characteristics of retina sheets, we were able to improve the in vitro viability of retinal ganglion cells derived from human-induced pluripotent stem cells incorporated into CNTs. Engrafted retinal ganglion cells displayed signs of regenerating processes along the optic nerve. Compared with PLGA scaffolds, CNT-PLGA retinal sheet tissue has excellent electrical conductivity, biocompatibility, and biodegradation. This new biomaterial offers new insight into retinal injury, repair, and regeneration.

Biodegradable scaffolds facilitate epiretinal transplantation of hiPSC-Derived retinal neurons in nonhuman primates.

Transplantation of stem cell-derived retinal neurons is a promising regenerative therapy for optic neuropathy. However, significant anatomic differences compromise its efficacy in large animal models. The present study describes the procedure and outcomes of human-induced pluripotent stem cell (hiPSC)-derived retinal sheet transplantation in primate models using biodegradable materials. Stem cell-derived retinal organoids were seeded on polylactic-coglycolic acid (PLGA) scaffolds and directed toward a retinal ganglion cell (RGC) fate. The seeded tissues showed active proliferation, typical neuronal morphology, and electrical excitability. The cellular scaffolds were then epiretinally transplanted onto the inner surface of rhesus monkey retinas. With sufficient graft-host contact provided by the scaffold, the transplanted tissues survived for up to 1 year without tumorigenesis. Histological examinations indicated survival, further maturation, and migration. Moreover, green fluorescent protein-labeled axonal projections toward the host optic nerve were observed. Cryopreserved organoids were also able to survive and migrate after transplantation. Our results suggest the potential efficacy of RGC replacement therapy in the repair of optic neuropathy for the restoration of visual function. STATEMENT OF SIGNIFICANCE: In the present study, we generated a human retinal sheet by seeding hiPSC-retinal organoid-derived RGCs on a biodegradable PLGA scaffold. We transplanted this retinal sheet onto the inner surface of the rhesus monkey retina. With scaffold support, donor cells survive, migrate and project their axons into the host optic nerve. Furthermore, an effective cryopreservation strategy for retinal organoids was developed, and the thawed organoids were also observed to survive and show cell migration after transplantation.

Human Exosomes Accelerate Cutaneous Wound Healing by Promoting Collagen Synthesis in a Diabetic Mouse Model.

Chronic wounds including diabetic foot ulcers are clinical emergencies that need careful management. Exosomes from human adipose-derived mesenchymal stem cells (hADSCs-Ex) are a new promising cell-free therapy for the regeneration of dermal wounds. We established a delayed wound healing model using diabetic female mice. A 1.5 cm2 full-thickness cutaneous wound was made ventrally in 6-week-old db/db mice. After treatment with phosphate-buffered saline, recombinant human epidermal growth factor, hADSCs-CM, or hADSCs-Ex three times a day for 2 weeks, we measured wound healing closure rates and performed histological analysis. Human dermal fibroblasts (WS1) were evaluated by PKH26-Exo co-localization test, CCK-8 test, cell scratch test, and the transwell test, while the expression of matrix metalloproteinase-1 (MMP1), MMP3, Collagen I, and Collagen III were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR) and western blot. Wound closure and re-epithelialization were accelerated by hADSCs-Ex. Besides, hADSCs-Ex enhanced skin collagen production, angiogenesis, cell proliferation, inhibited apoptosis, promoted skin barrier function repair, and reduced inflammation in skin lesions. Furthermore, negative regulation of MMP1 and MMP3 enhanced collagen synthesis wound healing-promoting effects of hADSCs-Ex. hADSCs-Ex treatment for diabetic wounds provided a novel cell-free therapeutic strategy.

Combined topical and systemic administration with human adipose-derived mesenchymal stem cells (hADSC) and hADSC-derived exosomes markedly promoted cutaneous wound healing and regeneration.

BACKGROUND: Cutaneous wound healing and regeneration have become a recognized health challenge in the world, which causes severe damage to the mental and physical health of patients. Human adipose-derived mesenchymal stem cells (hADSC) play an essential role in wound healing via their paracrine function. Exosomes secreted by hADSC may contribute to this progress. In this study, we investigated the potential clinical application roles of hADSC and hADSC-derived exosomes (hADSC-Exo) in cutaneous wound healing. METHODS: hADSC-Exo was isolated from human hADSC by ultracentrifugation. Mice were subjected to a full-thickness skin biopsy experiment and treated with either control vehicle or hADSC or hADSC-Exo by smearing administration (sm) or subcutaneous administration (sc) or intravenous administration (iv). The efficacy of hADSC and hADSC-Exo on wound healing was evaluated by measuring wound closure rates, histological analysis. RESULTS: Combined application of local hADSC-Exo smearing and hADSC/hADSC-Exo intravenous administration offered the additional benefit of promoting wound healing, accelerating re-epithelialization, reducing scar widths, and enhancing angiogenesis and collagen synthesis. Either topical application of hADSC-Exo or systemic administration with hADSC/hADSC-Exo appeared more effective in stimulating cell proliferation, inhibiting cell apoptosis and inflammation, and promoting skin elasticity and barrier integrity, with increased genes expression of PCNA, VEGF, collagen III, Filaggrin, Loricrin, and AQP3, with decreased genes expression of TNF-alpha. CONCLUSION: Our findings suggest that the combined administration of hADSC/hADSC-Exo can facilitate cutaneous wound healing and reduce scar formation. These data provide the first evidence for the feasibility of smearing of hADSC-Exo as a cell-free therapy in treating cutaneous wounds, and the potential clinical value of combined administration of hADSC/hADSC-Exo.

Systematic Review and Meta-Analysis of Antibiotic-Impregnated Shunt Catheters on Anti-Infective Effect of Hydrocephalus Shunt.

OBJECTIVE: Shunt infection is a common complication while treating hydrocephalus. The antibiotic-impregnated shunt catheter (AISC) was designed to reduce shunt infection rate. A meta-analysis was conducted to study the effectiveness of AISCs in reduction of shunt infection in terms of age, follow-up time and high-risk patient population. METHODS: This study reviewed literature from three databases including PubMed, EMBASE, and Cochrane Library (from 2000 to March 2019). Clinical studies from controlled trials for shunt operation were included in this analysis. A subgroup analysis was performed based on the patient's age, follow-up time and high-risk population. The fixed effect in RevMan 5.3 software (Cochrane Collaboration) was used for this meta-analysis. RESULTS: This study included 19 controlled clinical trials including 10105 operations. The analysis demonstrated that AISC could reduce the infection rate in shunt surgery compared to standard shunt catheter (non-AISC) from 8.13% to 4.09% (odds ratio [OR], 0.48; 95% confidence interval [CI], 0.40-0.58; p=0.01; I2=46%). Subgroup analysis of different age groups showed that AISC had significant antimicrobial effects in all three groups (adult, infant, and adolescent). Follow-up time analysis showed that AISC was effective in preventing early shunt infections (within 6 months after implant). AISC is more effective in high-risk population (OR, 0.24; 95% CI, 0.14-0.40; p=0.60; I2=0%) than in general patient population. CONCLUSION: The results of meta-analysis indicated that AISC is an effective method for reducing shunt infection. We recommend that AISC should be considered for use in infants and high-risk groups. For adult patients, the choice for AISC could be determined based on the treatment cost.

Comparison of complications in cranioplasty with various materials: a systematic review and meta-analysis.

Objective: Meta-analysis to evaluate complications in the use of autogenous bone and bone substitutes and to compare bone substitutes, specifically HA, polyetheretherketone (PEEK) and titanium materials.Methods: Search of PubMed, Cochrane, Embase and Google scholar to identify all citations from 2010 to 2019 reporting complications regarding materials used in cranioplasty.Results: 20 of 2266 articles met the inclusion criteria, including a total of 2913 patients. The odds of overall complication were significantly higher in the autogenous bone group (n = 214/644 procedures, 33.2%) than the bone substitute groups (n = 116/436 procedures, 26.7%, CI 1.29-2.35, p < 0.05). In bone substitutes groups, there was no significant difference in overall complication rate between HA and Ti (OR, 1.2; 95% CI, 0.47-3.14, p = 0.69). PEEK has lower overall complication rates (OR, 0.51; 95% CI, 0.30-0.87, p = 0.01) and lower implant exposure rates (OR, 0.17; 95% CI, 0.06-0.53, p = 0.002) than Ti, but there was no significant difference in infection rates and postoperative hematoma rates.Conclusions: Cranioplasty is associated with high overall complication rates with the use of autologous bone grafts compared with bone substitutes. PEEK has a relatively low overall complication rates in substitutes groups, but still high infection rates and postoperative hematoma rates. Thus, autologous bone grafts should only be used selectively, and prospective long-term studies are needed to further refine a better material in cranioplasty.

Drug-eluting balloons versus drug-eluting stents for small vessel coronary artery disease: a meta-analysis.

OBJECTIVE: We aimed to conduct a network meta-analysis of treatments for small vessels coronary artery disease between drug-eluting balloon (DEB) and drug-eluting stent (DES). METHOD: A meta-analysis comparing DEB and DES outcomes was performed using the Medline, Embase, and Cochrane databases. The primary outcome was target lesion revascularization (TLR) or target vessel revascularization (TVR), and myocardial infarction (MI), death and major adverse cardiovascular events (MACE) were secondary outcomes. A total of six studies on 1813 patients were included. RESULTS: There was no significant difference in rates of TLR or TVR in the patients treated with the DEB strategy compares with the DES strategy [odds ratio (OR) = 0.96, 95% confidence interval (CI) 0.57-1.61, P = 0.89] within a follow-up period of 9-24 months. There was a significant reduction in rates of MI and death in the patients treated with a DCB strategy compared with those treated with a DES strategy (3.7%, 17 of 460 vs 6.1%, 36 of 595; 2.4%, 11 of 460 vs 6.1%, 36 of 595, respectively), and this difference was statistically significant (OR = 0.53, 95% CI 0.29-0.96, P = 0.04; OR = 0.44, 95% CI 0.22-0.88, P = 0.02, respectively). There was no difference between DEB and DES strategies in rates of MACE (OR = 0.94, 95% CI 0.66-1.33, P = 0.73). CONCLUSION: In summary, this study demonstrates that treatment of small vessel (diameter ≤ 3 mm) coronary artery disease (CAD) with DEB may lead to improving outcomes compared with the use of DES within a follow-up period of 9-24 months. Further large clinical trials are needed to verify this conclusion.

An abluminal biodegradable polymer sirolimus-eluting stent versus a durable polymer everolimus-eluting stent in patients undergoing coronary revascularization: 3-year clinical outcomes of a randomized non-inferiority trial.

The Cordimax stent has proved non-inferior to the Cypher Select durable polymer sirolimus-eluting stent for the primary endpoint of angiographic in-stent late luminal loss and in-stent mean diameter stenosis at 9 months. The trial was designed to compare the efficacy and safety of the Cordimax stent with the Xience V stent in patients undergoing coronary revascularization. This randomized, multicenter trial enrolled 3697 patients treated with Cordimax stent (2460 patients) and Xience V stent (1237 patients). The primary efficacy endpoint was a target-lesion failure (TLF) at 1 year and the primary safety endpoint was a composite of death or myocardial infarction (MI) at 3 years. 3399 patients (91.9%) completed 3-year follow-up. At 1 year, the primary efficacy endpoint occurred in 86 (3.5%) patients in the Cordimax group versus 40 (3.2%) patients in the Xience V group (0.3% absolute risk difference, 95% CI -1.0-1.5%, Pnon-inferiority < 0.0001). At 3 years, the primary safety endpoint occurred in 39 (1.6%) patients in the Cordimax group versus 19 (1.5%) patients in the Xience V group (0.05% absolute risk difference, 95% CI -0.8-0.9%, Pnon-inferiority < 0.0001). The incidence of target lesion revascularization was low in Cordimax group compared with Xience V group (3.6% versus 5.1%, P = 0.03). There were no differences between Cordimax and Xience V in terms of Cardiac death (0.3% versus 0.4%, P = 0.70), myocardial infarction (1.2% versus 0.9%, P = 0.37), and the stent thrombosis (0.4% versus 0.6%, P = 0.61). In conclusion, safety and efficacy outcomes of Cordimax stent were non-inferior to the Xience V stent 3 years after stent implantation.

Long-term in vivo study of biodegradable Zn-Cu stent: A 2-year implantation evaluation in porcine coronary artery.

In the present study, a novel biodegradable Zn-0.8Cu coronary artery stent was fabricated and implanted into porcine coronary arteries for up to 24 months. Micro-CT analysis showed that the implanted stent was able to maintain structural integrity after 6 months, while its disintegration occurred after 9 months of implantation. After 24 months of implantation, approximately 28 ±â€¯13 vol% of the stent remained. Optical coherence tomography and histological analysis showed that the endothelialization process could be completed within the first month after implantation, and no inflammation responses or thrombosis formation was observed within 24 months. Cross-section analysis indicated that the subsequent degradation products had been removed in the abluminal direction, guaranteeing that the strut could be replaced by normal tissue without the risk of contaminating the circulatory system, causing neither thrombosis nor inflammation response. The present work demonstrates that the Zn-0.8Cu stent has provided sufficient structural supporting and exhibited an appropriate degradation rate during 24 months of implantation without degradation product accumulation, thrombosis, or inflammation response. The results indicate that the Zn-0.8Cu coronary artery stent is promising for further clinical applications. STATEMENT OF SIGNIFICANCE: Although Zn and its alloys have been considered to be potential candidates of biodegradable metals for vascular stent use, by far, no Zn-based stent with appropriate medical device performance has been reported because of the low mechanical properties of zinc. The present work presents promising results of a Zn-Cu biodegradable vascular stent in porcine coronary arteries. The Zn-Cu stent fabricated in this work demonstrated adequate medical device performance both in vitro and in vivo and degraded at a proper rate without safety problems induced. Furthermore, large animal models have more cardiovascular similarities as humans. Results of this study may provide further information of the Zn-based stents for translational medicine research.

Dexamethasone Provides Effective Immunosuppression for Improved Survival of Retinal Organoids after Epiretinal Transplantation.

We investigated the efficacy of the immunosuppressants rapamycin (RAP) and dexamethasone (DEX) in improving the survival of retinal organoids after epiretinal transplantation. We first compared the immunosuppressive abilities of DEX and RAP in activated microglia in an in vitro setting. Following this, we used immunofluorescence, real-time polymerase chain reaction, and flow cytometry to investigate the effects of DEX and RAP on cells in the retinal organoids. Retinal organoids were then seeded onto poly(lactic-co-glycolic) acid (PLGA) scaffolds and implanted into rhesus monkey eyes (including a healthy individual and three monkeys with chronic ocular hypertension (OHT) induction) and subjected to different post-operative immunosuppressant treatments; 8 weeks after the experiment, histological examinations were carried out to assess the success of the different treatments. Our in vitro experiments indicated that both DEX and RAP treatments were equally effective in suppressing microglial activity. Although both immunosuppressants altered the morphologies of cells in the retinal organoids and caused a slight decrease in the differentiation of cells into retinal ganglion cells, the organoid cells retained their capacity to grow and differentiate into retinal tissues. Our in vivo experiments indicate that the retinal organoid can survive and differentiate into retinal tissues in a healthy rhesus monkey eye without immunosuppressive treatment. However, the survival and differentiation of these organoids in OHT eyes was successful only with the DEX treatment. RAP treatment was ineffective in preventing immunological rejection, and the retinal organoid failed to survive until the end of 8 weeks. DEX is likely a promising immunosuppressant to enhance the survival of epiretinal implants.

Meta-analysis of intracavitary electrocardiogram guidance for peripherally inserted central catheter placement.

BACKGROUND: Recently, intracavitary electrocardiogram technology has been applied to peripherally inserted central catheter placement and demonstrates many potential advantages. However, the tip positioning accuracy of intracavitary electrocardiogram technology compared to conventional X-ray method is unknown. OBJECTIVE: We did a meta-analysis to compare the tip positioning accuracy between intracavitary electrocardiogram technology and conventional X-ray method. DATA SOURCES: We searched several databases, including Cochrane Library, PubMed, Web of science, and Embase. Additional studies were identified through hand searches of bibliographies and Internet searches. All human studies published in full text, abstract, or poster form were eligible for inclusion. Search terms included peripherally inserted central catheter, PICC, intracavitary electrocardiogram, IC-ECG, EKG, ECG, and catheter tip location. STUDY ELIGIBILITY CRITERIA: Only randomized controlled trials of using intracavitary electrocardiogram technology versus X-ray method for peripherally inserted central catheter placement were included. All studies included adult patients aged at least 18 years. STUDY APPRAISAL AND SYNTHESIS METHODS: Independent extraction of articles by two authors using predefined data fields, including study quality indicators. Of the 178 citations identified, 5 studies that included 1672 patients met the eligibility criteria. It was found that statistical heterogeneity existed among the various studies (I2 = 16%, p < 0.00001); therefore, the fixed effect model was used in the meta-analysis (p < 0.05). The meta-analysis compared the tip positioning accuracy between intracavitary electrocardiogram technology and X-ray method and showed that intracavitary electrocardiogram technology had a better positioning accuracy (odds ratio: 2.88, 95% confidence interval: 2.15-3.87, p < 0.0001). LIMITATIONS: Only five randomized trial met inclusion criteria, and the lack of an incomplete search led to the publication bias seen in these results. CONCLUSION: The intracavitary electrocardiogram method had a more favorable positioning accuracy versus traditional X-ray method for peripherally inserted central catheter placement in adult patients. The intracavitary electrocardiogram can be a promising technique to guide tip positioning of peripherally inserted central catheter.

Radiofrequency Ablation Versus Antiarrhythmic Drug Therapy for Atrial Fibrillation: Meta-analysis of Safety and Efficacy.

BACKGROUND: Radiofrequency ablation (RFA) and antiarrhythmic drugs (AADs) are the main treatments used for atrial fibrillation (AF). In recent years, a number of articles comparing the 2 treatments have begun to emerge. Though, the influence of follow-up time in the meta-analysis was not considered in these articles. However, more recently, large-scale clinical trial articles have included follow-up with the patients up to 5 years after treatment. Therefore, the aim of this study was to assess the impact of variable follow-up times on the recurrence of AF by observing both the short-term and long-term efficacy and safety of catheter ablation and AADs for the treatment of AF. METHODS AND RESULTS: The primary investigators of eligible randomized controlled trials were invited to contribute standardized outcome data. Random effect summary estimates were calculated as standardized mean differences and odds ratios with 95% confidence intervals for continuous and binary outcomes. In this study, 9 randomized controlled trials (n = 1542 patients) were included. The rate of recurrence of AF with no limit on follow-up time, >12 months, >18 months, >24 months, >30 months, and approximately 36 months was compared. Furthermore, the gap between the RFA and AAD groups in the recurrence rate of AF was found to decrease inversely to follow-up time. When the follow-up time reached 24 months, the difference between RFA and AAD was relatively stable with an odds ratio of 0.45 (95% confidence interval: 0.32-0.62). Overall, RFA decreased adverse events in the remaining trials; however, AAD performed better in terms of safety and had fewer adverse events with RFA usually causing more serious complications. CONCLUSION: RFA is more advantageous in terms of recurrence rate of AF than drug therapy. In addition, the analysis suggests that this effect persists during long-term follow-up; however, these benefits appear to decrease with longer follow-up time. Finally, AAD performed better in terms of safety and had fewer adverse events.

Insertion of peripherally inserted central catheters with intracavitary electrocardiogram guidance: A randomized multicenter study in China.

INTRODUCTION: Ultrasound-guided venipuncture and tip location by intracavitary electrocardiogram have many advantages during the insertion of peripherally inserted central catheters, both in terms of safety and cost-effectiveness. Recently, a new tip-conductive peripherally inserted central catheters and new Doppler ultrasound device integrated with intracavitary electrocardiogram have been introduced into clinical practice in China. A randomized multicenter study (clinical trial no. NCT03230357) was performed to verify the feasibility and accuracy of intracavitary electrocardiogram, as performed with this new peripherally inserted central catheters and device. METHODS: Our study enrolled a total of 2250 adult patients in 10 different Chinese hospitals. The patients were randomly assigned to either the study group (intracavitary electrocardiogram) or the control group (anatomical landmark guidance) in a 2:1 allocation. Ultrasound was used in both groups for venipuncture and tip navigation. All patients underwent chest X-ray after the procedure to verify the position of the catheter tip. RESULTS: No insertion-related complications were reported in either group. In the study group, first-attempt successful tip location was 91.7% (95% confidence interval: 90.3%-93.1%), significantly higher than 78.9% (95% confidence interval: 76.0%-81.9%) observed in the control group (p < 0.001). As evaluated by post-procedural chest X-ray, tip location in the study group had a sensitivity of 99.3% (95% confidence interval: 98.8%-99.7%), significantly higher than 86.8% (95% confidence interval: 84.4%-89.2%) observed in the anatomical landmark group (p < 0.001). CONCLUSION: These results indicated that during peripherally inserted central catheters insertion in adult patients, tip location with intracavitary electrocardiogram guidance, as carried out by a new tip-conductive peripherally inserted central catheters and intracavitary electrocardiogram integrated ultrasound device, was more effective and more accurate than tip location using anatomical landmarks.

Meta-analysis of the incidence of lead dislodgement with conventional and leadless pacemaker systems.

INTRODUCTION: Leadless cardiac pacemaker (LCP) implantation using a transcatheter was recently developed to avoid pocket- and lead-related complications. Although a LCP has an active fixation mechanism using tines or a helix, LCP and lead dislodgement issues remain a major safety concern for patients. This article reviews the literature to determine the incidence of lead and LCP dislodgement. METHODS AND RESULTS: A total of 18 studies which included 17,321 patients undergoing conventional single- or dual-chamber pacemaker implantation and three studies which included 2,116 patients undergoing LCP device implantation were reviewed. The incidence of lead dislodgement ranged from 1% to 2.69% in individual studies with a mean of 1.63%, weighted mean of 1.71%, and median of 1.60 %. There was a relatively higher lead dislodgement rate between atrial and ventricular electrodes (odds ratio [OR], 3.56; 95% confidence interval [CI], 1.9-6.70; P  =  0.6; I2   =  0%), and between magnetic resonance imaging conditional and conventional leads (OR, 2.79; 95% CI, 1.30-5.99; P  =  0.16; I2   =  46%). The use of active fixation leads (OR, 1.06; 95% CI, 0.66-1.70; P  =  0.29; I2   =  20%) showed no significant difference in dislodgement risk compared to passive fixation leads. The incidence of LCP device dislodgement was 0%, 0.13%, and 1% in three leadless pacemaker studies. CONCLUSIONS: The incidence rates of conventional pacemaker lead dislodgement vary in individual studies with an overall high incidence. Use of the currently available LCP systems appears to result in a lower rate of device dislodgement. This may reflect the effectiveness of this novel technology and the fixation design of LCP devices.

Establishing a Surgical Procedure for Rhesus Epiretinal Scaffold Implantation with HiPSC-Derived Retinal Progenitors.

BACKGROUND: To develop an effective surgical procedure for cellular scaffold epiretinal implantation in rhesus, facilitating subsequent epiretinal stem cell transplantation. METHODS: Retinal progenitors were seeded onto a poly(lactic-co-glycolic) acid (PLGA) scaffold. First, the cellular scaffolds were delivered by 18G catheter or retinal forceps into rabbit epiretinal space (n = 50). Then, the cell survival rate was evaluated by Cell Counting Kit-8 (CCK-8). Second, three methods of scaffold fixation, including adhesion after gas-liquid exchange (n = 1), tamponade by hydrogel (n = 1), and fixation by retinal tacks (n = 4), were performed in rhesus monkeys. After one month, fundus photography and SD-OCT were performed to assess the outcomes, and histological examination was performed to evaluate proliferation. RESULTS: The cell survival rate was significantly higher in the catheter group. Follow-up examination showed that retinal tack fixation was the only method to maintain the scaffolds attached to host retina for at least 3 weeks, which is the minimal time required for cell integration. Histological staining demonstrated slight glial fibrillary acidic protein (GFAP) accumulation in the retinal tack insertion area. CONCLUSIONS: The established surgical procedure offers a new insight into research of epiretinal cell replacement therapy in rhesus eyes. The successful delivery and long-term fixation provide a prerequisite for cell migration and integration.

HiPSC-derived retinal ganglion cells grow dendritic arbors and functional axons on a tissue-engineered scaffold.

Numerous therapeutic procedures in modern medical research rely on the use of tissue engineering for the treatment of retinal diseases. However, the cell source and the transplantation method are still a limitation. Previously, it was reported that a self-organizing three-dimensional neural retina can be induced from human-induced pluripotent stem cells (hiPSCs). In this study, we disclose the generation of retinal ganglion cells (RGCs) from the neural retina and their seeding on a biodegradable poly (lactic-co-glycolic acid) (PLGA) scaffold to create an engineered RGC-scaffold biomaterial. Moreover, we explored the dendritic arbor, branching point, functional axon and action potential of the biomaterial. Finally, the cell-scaffold was transplanted into the intraocular environment of rabbits and rhesus monkeys. STATEMENT OF SIGNIFICANCE: As a part of the mammalian central nervous system (CNS), the retinal ganglion cell (RGC) shows little regenerative capacity. With the use of medical biomaterial for cells seeding and deliver, a new domain is now emerging that uses tissue engineering therapy for retinal disease. However, previous studies utilized RGCs from rodent model, which has limitations for human disease treatment. In the present study, we generated RGCs from hiPSCs-3D neural retina and then seeded these RGCs on PLGA scaffold to create an engineered RGC-scaffold biomaterial. Moreover, we assessed the transplantation method for biomaterial in vivo. Our study provides a technique to produce the engineered human RGC-scaffold biomaterial.