Biodegradable polymers and platelet-rich plasma causing visual impairment: a literature review.

BACKGROUND: Dermal fillers are widely used for facial rejuvenation and esthetic enhancement, offering temporary solutions for aging and volume loss. Despite their general safety, a rare but severe complication associated with these fillers is visual impairment, including blindness. This underscores the need for a thorough understanding of risks associated with various filler materials. Historical cases of blindness following filler injections date back to 1963, with increasing reports linked to the expansion of the cosmetic filler industry. While hyaluronic acid (HA) and autologous fat have been extensively studied, other fillers such as calcium hydroxylapatite and poly-l-lactic acid (PLLA) are less understood. OBJECTIVE: This systematic review aims to address gaps in the literature by providing a comprehensive overview of visual impairment caused by fillers other than HA and autologous fat. We systematically examine the prevalence, causes, clinical features, and treatment outcomes associated with these less common fillers. MATERIALS AND METHODS: A comprehensive literature search was conducted across databases including PubMed, Scopus, and Google Scholar using terms related to visual impairment and dermal fillers. Studies published between 2014 and 2021, including observational studies and case reports, were included. Studies were selected based on predefined inclusion and exclusion criteria, and a PRISMA flow diagram was used to illustrate the study selection process. RESULTS: The review identifies and summarizes cases of visual impairment associated with calcium hydroxylapatite, poly-d,l-lactic acid (PDLLA), and PLLA fillers. Key findings reveal that visual impairment following these fillers is rare but can occur suddenly or within a few days of the procedure. Cases of delayed onset up to two weeks are also noted, emphasizing the need for extended post-procedure monitoring. DISCUSSION: The review highlights unique insights into the risks associated with non-HA fillers, such as the heightened risk in the periorbital region and other facial areas. It explores mechanisms of complications, including retrograde flow of emboli leading to retinal ischemia. The discussion also covers emergency protocols and preventative measures, providing valuable guidance for managing and mitigating risks. CONCLUSIONS: Visual impairment caused by fillers other than HA and autologous fat, while rare, represents a serious complication that requires careful attention. This review contributes new perspectives on the differential risks of various fillers, symptom onset variability, and anatomical risk factors. Emphasizing the importance of proper patient selection, technique, and monitoring, it calls for further research to better understand and prevent these complications, ultimately aiming for safer and more effective use of soft-tissue fillers.

A Clinical Histology Study Evaluating the Biostimulatory Activity Longevity of Injectable Poly-L-Lactic Acid for Facial Rejuvenation.

BACKGROUND: Poly-L-lactic acid (PLLA) is an injectable filler used for restoring facial fat volume loss that improves skin quality. OBJECTIVE: To evaluate the histological changes underlying the observed improvement in skin quality after repeated PLLA injections. METHODS: Ten healthy women were enrolled in this randomized, placebo-controlled, single-center study. Eligible subjects received 3 treatments every 4 weeks with either PLLA (treatment group) or saline (control group) injections, into both sides of the face. Follow-up visits were at week 18 after the last treatment. Assessments included live ratings, patient questionnaires, three-dimensional microtopography imaging analysis, and histological analysis from biopsies taken before and after PLLA treatment. RESULTS: At the 18-week follow-up, there was a significant improvement in investigator- and subject-rated global aesthetic improvement (GAIS) scores, as well as a decrease in wrinkle severity in PLLA-treated but not placebo-treated patients. Skin quality parameters of erythema, pore size, and roughness were significantly improved from baseline and compared with placebo at the 18-week follow-up as assessed by microtopographic analysis and investigator ratings. Histologic analysis revealed increased tissue remodeling and angiogenesis in PLLA-treated tissues at the 18-week follow-up and decreased elastin fragmentation compared with baseline. No treatment-related adverse events occurred. CONCLUSION: Repeated PLLA treatments may improve skin quality through tissue remodeling and neovascularization. J Drugs Dermatol. 2024;23(9):729-734. doi:10.36849/JDD.8057.

Lactobacillus casei displaying MCP2α and FlaC delivered by PLA microspheres effectively enhances the immune protection of largemouth bass (Micropterus salmoides) against LMBV infection.

Largemouth bass ranavirus (LMBV) seriously affects the development of largemouth bass (Micropterus salmoides) industry and causes huge economic losses. Oral vaccine can be a promising method for viral disease precaution. In this study, MCP2α was identified as a valuable epitope region superior to MCP and MCP2 of LMBV by neutralizing antibody experiments. Then, recombinant Lactobacillus casei expressing the fusion protein MCP2αC (MCP2α as antigen, C represents flagellin C from Aeromonas hydrophila as adjuvant) on surface was constructed and verified. Further, PLA microsphere vaccine loading recombinant MCP2αC L. casei was prepared. The PLA microspheres vaccine were observed by scanning electron microscopy and showed a smooth, regular spherical surface with a particle size distribution between 100 and 200 µm. Furthermore, we evaluated the tolerance of PLA-MCP2αC vaccine in simulated gastric fluid and simulated intestinal fluid, and the results showed that PLA-MCP2αC can effectively resist the gastrointestinal environment. Moreover, the protective effect of PLA-MCP2αC against LMBV was evaluated after oral immunization and LMBV challenge. The results showed that PLA-MCP2αC effectively up-regulated the activity of serum biochemical enzymes (T-SOD, T-AOC, LZM, complement C3) and induced the mRNA expression of representative immune genes (IL-1ß, TNF-α, IFN-γ, MHC-IIα, Mx, IgM) in spleen and head kidney tissues. The survival rate of largemouth bass vaccinated with PLA-MCP2αC increased from 24 % to 68 %. Meanwhile, PLA-MCP2αC inhibited the LMBV burden in spleen, head kidney and liver tissues and attenuated tissue damage in spleen. These results suggested that PLA-MCP2αC can be used as a candidate oral vaccine against LMBV infection in aquaculture.

Intralesional hyaluronidase injection to relieve non-hyaluronic acid filler-induced vascular adverse events.

BACKGROUND: Vascular adverse events (VAEs) occurring during injections of soft-tissue fillers are still considered a challenging issue for both patients and practitioners. Hyaluronidase can dissolve hyaluronic acid (HA)-based soft-tissue fillers during a VAE. For VAEs induced by non-HA fillers, the absence of an "antidote" is regarded as exceptionally challenging. METHODS: This multicenter study describes a case series of three VAEs induced by non-HA fillers, for which ultrasound-guided hyaluronidase injections were incorporated into the treatment approach. RESULTS: Two cases of calcium hydroxylapatite and one case of poly-L-lactic acid-induced VAEs are described, all of which were resolved without necrosis or scarring using a treatment approach with ultrasound-guided hyaluronidase injections. CONCLUSIONS: Unlike the mechanical hypothesis, which assumes filler particles travel antegrade to block arterioles in a large skin area, we hypothesize vasoconstriction as the pivot in VAEs. Filler injection-induced spasms could lead to long-lasting vasoconstriction of the perforator arteries stemming from the central facial arteries. Our results underscore that perforasome vasoconstriction might be the leading cause of the ischemia and subsequent necrosis in VAEs and that relaxation of these perforasomes, rather than dissolving the filler material, resolves the clinical symptoms associated with VAEs.

Poly­d,l­lactic acid­enhanced atrophic scar treatment via transdermal microjet drug delivery in Asians.

BACKGROUND: Acne vulgaris often results in permanent scars, with atrophic scars being the most common type and posing a significant therapeutic challenge due to their prevalence and impact on patients' quality of life. Various treatment options exist, including the use of poly-d,l-lactic acid delivered via different methods. OBJECTIVE: This study aimed to assess the efficacy and safety of poly-d,l-lactic acid delivered via laser-assisted needle-free microjet injection for treating atrophic scars. METHODS: Five Korean participants with atrophic facial scars were recruited. Poly-d,l-lactic acid solution was administered via the Mirajet system in five sessions, with clinical assessments conducted at baseline, before each session, and at 12-week and 22-week follow-ups. Outcome measures included the Global Aesthetic Improvement Scale and patient satisfaction scores. RESULTS: Positive results were observed at the 12-week and 22-week follow-ups, with high patient satisfaction and improvements in atrophic scars and skin texture. Mild discomfort and transient side effects were reported, with no adverse events observed during the follow-up period. CONCLUSION: Poly-d,l-lactic acid delivered by a laser-assisted needle-free microjet injector was judged to be effective for improving atrophic the facial area. Further research, particularly through randomized controlled trials, is needed to validate these findings and assess the longer-term safety and sustainability of outcomes.

Intra-articular hydrogel formulation prolongs the in vivo stability of Toll-like receptor antagonistic peptides for rheumatoid arthritis treatment.

Rheumatoid arthritis (RA) is an autoimmune disease characterized by systemic inflammation that primarily affects joint tissue and requires frequent medication. Recently, we developed cyclic phage-display-derived inhibitory peptides (CPs), which act as Toll-like Receptor 4 antagonists. These CPs exhibited therapeutic efficacy against joint diseases by alleviating inflammatory factors. Nonetheless, CP exhibits in vivo instability and a short half-life. Therefore, this study sought to improve the in vivo stability of CP, thereby reducing the frequency of CP administration through the development of an injectable hydrogel depot formulation. To improve in vivo stability, CP was chemically conjugated to hyaluronic acid (HA-CP) and subsequently mixed into a temperature-sensitive hydrogel [methoxy polyethylene glycol-b-poly(ε-caprolactone)-ran-poly(lactide) (PC)] as an injectable depot (PC+(HA-CP)). For comparison, CP was physically mixed with HA and PC (PC+(HA+CP)). Both PC+(HA-CP) and PC+(HA+CP) were found to rapidly form depots upon injection into the joint space. Cell viability assays confirmed the non-toxic nature of PC+(HA-CP) and PC+(HA+CP), whereas both formulations exhibited inhibition of inflammatory factors. Furthermore, PC+(HA-CP) retained CP for a longer duration compared to PC+(HA+CP) in the presence of hyaluronidase and within the RA joint space. Following intra-articular injection, both the PC+(HA-CP) and PC+(HA+CP) depots exhibited reductions in RA symptoms, cartilage regeneration, and suppression of pro-inflammatory cytokine levels. Specifically, by extending the in vivo retention of CP, PC+(HA-CP) demonstrated superior RA treatment efficacy compared to PC+(HA+CP). In conclusion, intra-articular injection of PC+(HA-CP) was validated as an effective strategy for treating RA, owing to its ability to prolong the in vivo retention of CP. This approach holds promise for improving RA management and patient outcomes.

Complications of collagen biostimulators in Brazil: Description of products, treatments, and evolution of 55 cases.

BACKGROUND: Complications of temporary and permanent fillers have been extensively studied. However, there is a lack of comparative data regarding poly-L-lactic acid (PLLA), calcium hydroxyapatite (CaHA), and polycaprolactone (PCL) known as collagen biostimulators. AIMS: This study addressed the complications of collagen biostimulators concerning their diagnosis, type of product, treatment, and monitoring. PATIENTS/METHODS: An electronic questionnaire was sent to Brazilian dermatologic ultrasound experts to identify complications related to biostimulators. The type of biostimulator, location of application, number of vials injected, application plan, time between injection treatment and complication, injector profile, treatment, and prognosis were assessed. RESULTS: Fifty-five cases were identified, of which 49.1% were caused by PLLA-Elleva®, 23.6% by CaHA (alone or combined with hyaluronic acid), 20.0% by PLLA-Sculptra®, and 7.3% by PCL. The most affected area was the face (72.7%), with nodules being the most common clinical form (89.1%), generally occurring late (60.0%) (>1 month). Only one case was injected at an incorrect depth (musculoaponeurotic system-SMAS). Despite several treatments, including saline (45.5%), hyaluronidase (25.5%), diluted corticosteroids (23.6%), and energy-based devices (10.9%), only five cases showed complete resolution. Hyaluronidase was beneficial in complications related to fillers when there was an association of calcium hydroxyapatite with hyaluronic acid (p < 0.01). CONCLUSIONS: Complications from collagen biostimulators were more common on the face, typically manifesting about 1 month after treatment. These issues seemed to be related more to the properties of the products rather than inadequate technique. Furthermore, hyaluronidase demonstrated efficacy only in cases where there was an association with HA.

Effective improvement methods for striae distensae: A novel approach utilizing laser-induced micro-jet injectors with poly-d,l-lactic acid.

INTRODUCTION: Striae distensae (SD), or stretch marks, result from rapid stretching of the skin due to various factors. Conventional treatments often yield unsatisfactory results, leading to the exploration of alternative methods. Laser-induced microjet technology offers a promising approach for drug delivery to target areas. This study investigates the efficacy of using a microjet injector with poly-d,l-lactic acid for treating SD. METHODS: Four female participants with SD were treated with poly-d,l-lactic acid solution using a microjet injector over five sessions. Patients were assessed based on severity scales before and after treatment. Topical anesthetics were applied to minimize discomfort. Injection techniques were optimized to reduce side effects such as bleeding and pain. RESULTS: All patients showed significant improvement in SD appearance after 5-7 treatments. Assessment scales indicated positive outcomes both immediately after treatment and at the 32-week follow-up. Minimal side effects, primarily petechiae, were observed. DISCUSSION: Laser-induced microjet technology offers several advantages, including rapid drug delivery and mechanotransduction effects, promoting skin regeneration. Poly-d,l-lactic acid injections demonstrated effectiveness in treating SD, particularly when delivered via microjet injectors. Patients expressed high satisfaction due to the procedure's minimal invasiveness and quick recovery. CONCLUSION: Utilizing a needleless microjet injector with poly-d,l-lactic acid shows promise as a treatment for SD, typically requiring 5-7 sessions for optimal results. Mild petechiae may occur as a common side effect. This approach offers an effective and minimally invasive alternative for addressing this common cosmetic concern.

Effect of electrospun poly (L-lactide-co-caprolactone) and formulated porcine fibrinogen for diabetic foot ulcers.

Diabetic foot ulcers were a significant complication of diabetes and were accompanied by delayed wound healing. To compare the effect of topical application electrospun poly (L-lactide-co-caprolactone) and formulated porcine fibrinogen (PLCL/Fg) dressing with alginate dressing when treating diabetic foot ulcers (DFUs). A single-center, prospective, randomized, patient-blinded clinical trial was conducted from July 1, 2023, to December 26, 2023. The clinical trial registration was completed on August 28, 2023 (ClinicalTrials.gov Identifier: NCT06014437). The eligible patients with DFUs of 1-20 cm2 present for at least 1 month and with Wagner grade 1 or 2. They were randomized 1:1 to receive PLCL/Fg or alginate dressing. Participants received PLCL/Fg dressing 1-3 times per week or alginate dressing 3 times per week for 12 weeks. A total of 52 patients (33 men [63.5 %]; mean [SD] age, 63.1 [11.9] years; mean [SD] diabetes time, 8.3 [4.6] years) with DFUs were assessed for this study. The DFUs classified as Wagner grade 1 or 2 (mean [SD] ulcer area, 3.8 [3.2] cm2) were randomized to receive either the PLCL/Fg dressing (n = 26) or the alginate dressing (n = 26) for as long as 12 weeks. In this study, the incidence of complete healing included 22 patients (91.7 %) in the PLCL/Fg group and 14 (63.6 %) in the alginate group during the 12-week treatment period (P = 0.003). The treatment-related adverse events that occurred were 5 (20.8 %) in the PLCL/Fg group and 4 (18.1 %) in the comparator group. In this randomized clinical trial, PLCL/Fg dressing showed beneficial effects in DFUs treatment of wound surface reduction and regulating the wound microenvironment.

Subconjunctival injection of rapamycin-loaded polymeric microparticles for effective suppression of noninfectious uveitis in rats.

Noninfective uveitis is a major cause of vision impairment, and corticosteroid medication is a mainstay clinical strategy that causes severe side effects. Rapamycin (RAPA), a potent immunomodulator, is a promising treatment for noninfective uveitis. However, because high and frequent dosages are required, it is a great challenge to implement its clinical translation for noninfective uveitis therapy owing to its serious toxicity. In the present study, we engineered an injectable microparticulate drug delivery system based on biodegradable block polymers (i.e., polycaprolactone-poly (ethylene glycol)-polycaprolactone, PCEC) for efficient ocular delivery of RAPA via a subconjunctival injection route and investigated its therapeutic efficacy in an experimental autoimmune uveitis (EAU) rat model. RAPA-PCEC microparticles were fabricated using the emulsion-evaporation method and thoroughly characterized using scanning electron microscopy, fourier transform infrared spectroscopy, X-ray diffraction, and differential scanning calorimetry. The formed microparticles exhibited slow in vitro degradation over 28 days, and provided both in vitro and in vivo sustained release of RAPA over 4 weeks. Additionally, a single subconjunctival injection of PCEC microparticles resulted in high ocular tolerance. More importantly, subconjunctival injection of RAPA-PCEC microparticles significantly attenuated the clinical signs of EAU in a dose-dependent manner by reducing inflammatory cell infiltration (i.e., CD45+ cells and Th17 cells) and inhibiting microglial activation. Overall, this injectable microparticulate system may be promising vehicle for intraocular delivery of RAPA for the treatment of noninfective uveitis.

Polymeric nanofiber leveraged co-delivery of anti-stromal PAK1 inhibitor and paclitaxel enhances therapeutic effects in stroma-rich 3D spheroid models.

The role of tumor stroma in solid tumors has been widely recognized in cancer progression, metastasis and chemoresistance. Cancer-associated fibroblasts (CAFs) play a crucial role in matrix remodeling and promoting cancer cell stemness and resistance via reciprocal crosstalk. Residual tumor tissue after surgical removal as well as unresectable tumors face therapeutic challenges to achieve curable outcome. In this study, we propose to develop a dual delivery approach by combining p21-activated kinase 1 (PAK1) inhibitor (FRAX597) to inhibit tumor stroma and chemotherapeutic agent paclitaxel (PTX) to kill cancer cells using electrospun nanofibers. First, the role of the PAK1 pathway was established in CAF differentiation, migration and contraction using relevant in vitro models. Second, polycaprolactone polymer-based nanofibers were fabricated using a uniaxial electrospinning technique to incorporate FRAX597 and/or PTX, which showed a uniform texture and a prolonged release of both drugs for 16 days. To test nanofibers, stroma-rich 3D heterospheroid models were set up which showed high resistance to PTX nanofibers compared to stroma-free homospheroids. Interestingly, nanofibers containing PTX and FRAX597 showed strong anti-tumor effects on heterospheroids by reducing the growth and viability by > 90 % compared to either of single drug-loaded nanofibers. These effects were reflected by reduced intra-spheroidal expression levels of collagen 1 and α-smooth muscle actin (α-SMA). Overall, this study provides a new therapeutic strategy to inhibit the tumor stroma using PAK1 inhibitor and thereby enhance the efficacy of chemotherapy using nanofibers as a local delivery system for unresectable or residual tumor. Use of 3D models to evaluate nanofibers highlights these models as advanced in vitro tools to study the effect of controlled release local drug delivery systems before animal studies.

Facial Skin Rejuvenation Using Poly- dl -Lactic Acid Injected With a Laser-Generated Needle-Free Microjet Injector.

BACKGROUND: A laser-induced needle-free microjet injector was developed for rapid, high-speed drug delivery of microliters into the skin. OBJECTIVE: This study evaluated the clinical rejuvenation effect of repeated dermal injections of the collagen simulator poly- dl -lactic acid (PDLA) using a laser-induced needle-free microjet injector. METHODS: Five PDLA injection sessions using a laser-induced needle-free microjet injector were conducted in patients concerned about aging skin. Facial uplifting, darkness, redness, roughness, pore size, subjective satisfaction, and side effects were evaluated before each session and 4 weeks after treatment completion. Histological evaluation was also performed with immunohistochemical staining of collagen and elastic fibers. RESULTS: The clinical results of 27 female patients were evaluated. The treatment resulted in a noticeable skin surface uplifting (0.711 ± 0.42 mm) and significant improvements in darkness ( p = .013), redness ( p = .009), and roughness ( p = .036), with no significant difference in the pore size ( p = .770). Patients were reported being satisfied with the overall therapeutic effects, despite mild and tolerable adverse effects. Histological findings revealed growth and thickening of collagen and elastic fibers, with marked increase in collagen I and III levels. CONCLUSION: Repeated dermal injections of PDLA using a laser-induced microjet injector offer excellent drug delivery, achieving high efficacy in skin rejuvenation, patient satisfaction, and safety.

Toward a solid microneedle patch for rapid and enhanced local analgesic action.

Analgesic creams find widespread application as adjuncts for localized anesthesia prior to surgical procedures. Nevertheless, the onset of analgesic action is protracted due to the skin barrier's inherent characteristics, which necessitates prolonged intervals of patient and clinician waiting, consequently impinging upon patient compliance and clinician workflow efficiency. In this work, a biodegradable microneedles (MNs) patch was introduced to enhance the intradermal administration of lidocaine cream to achieve rapid analgesia through a minimally invasive and conveniently accessible modality. The polylactic acid (PLA) MNs were mass-produced using a simple hot-pressing method and served the purpose of creating microchannels across the skin's surface for rapid absorption of lidocaine cream. Optical and electron microscopes were applied to meticulously scrutinize the morphology of the fabricated MNs, and the comprehensive penetration tests involving dynamometer tests, evaluation on porcine cadaver skin, artificial film, optical coherence tomography (OCT), transepidermal water loss, and analysis on rats' skins, demonstrated the robust mechanical strength of PLA MNs for successful intradermal penetration. The behavioral pain sensitivity tests on living rats using Von Frey hair filaments revealed that the MN-assisted lidocaine treatment expeditiously accelerated the onset of action from 40 to 10 min and substantially enhanced the efficacy of localized anesthesia. Furthermore, different treatment protocols encompassing the sequence of drug application relative to MN treatment, MN dimensions, and the frequency of MN insertions exhibited noteworthy influence on the resultant local anesthesia efficacy. Together, these results demonstrated that the lidocaine cream followed by diverse PLA MN treatments would be a promising strategy for rapid clinical local anesthesia with wide-ranging applications.

Development, Characterization, and In Vitro Evaluation of Cytotoxic Activity of Rutin Loaded PCL-PEG Nanoparticles Against Skov3 Ovarian Cancer Cell.

BACKGROUND AND PURPOSE: Rutin (RUT) is one of the phenolic compounds found in the invasive plant species, Carpobrotus edulis. Several studies have confirmed numerous pharmacological properties of RUT, including antioxidant, antidiabetic, anti-inflammatory, antimicrobial and anticancer activities. As a result, the goal of this work was to make RUT-loaded PCL-PEG and test its anti-cancer effects against the Skov3 human ovarian cancer cell line. MATERIALS AND METHODS: The NPs were made using the W1/O/W2 process, and their physicochemical properties were assessed by FE-SEM, FTIR, and DLS. MTT assay were used to investigate the anti-proliferative characteristics of drug-loaded NPs. Real-time PCR was also utilized to  examine the expression levels of apoptotic genes including caspase-8, -9, -3, and Bax, as well as anti-apoptotic genes like Bcl-2. RESULTS: Cytotoxicity testing revealed that RUT-loaded PCL-PEG improved cytotoxicity in a dose- and time-dependent manner. In treated MDA-MB-231 cells with RUT-loaded PCL-PEG, there was a significant up-regulation of caspase-8, -9, -3, and Bax genes compared to treated cells with free RUT. CONCLUSION: Finally, RUT-loaded PCL-PEG NPs are recommended as ideal delivery nanocarriers for enhancing RUT's anticancer characteristics for ovarian cancer treatment.

Systemic delivery of siRNA to the colon using peptide modified PEG-PCL polymer micelles for the treatment of ulcerative colitis.

Ulcerative colitis (UC) is a refractory inflammatory bowel disease that causes inflammation and ulcers in the digestive tract, and significantly reduces the patient's quality of life. While existing UC treatments have many challenges, nanotechnology, and small interfering RNA (siRNA) based formulations are novel and promising for UC treatment. We previously reported that intravenous administration of MPEG-PCL-CH2R4H2C nanomicelles had high inflammatory site accumulation and remarkable therapeutic effects on rheumatoid arthritis by a phenomenon similar to enhanced permeability and retention effect. In this study, we investigated the effects of siRNA delivered using MPEG-PCL-CH2R4H2C nanomicelles through intravenous administration to the inflammation site of dextran sulfate sodium-induced colitis mice. The MPEG-PCL-CH2R4H2C micelles had optimum physical properties and high siRNA compaction ability. Moreover, model-siRNA delivered through MPEG-PCL-CH2R4H2C showed higher accumulation in the inflammatory site than that of the naked siRNA. Furthermore, intravenous administration of MPEG-PCL-CH2R4H2C/siRelA micelles, targeting siRelA, a subunit of NF-κB, significantly decreased the shortening of large intestine, clinical score, and production of inflammatory cytokines compared the 5-ASA and naked siRelA. These results suggest that MPEG-PCL-CH2R4H2C is a useful carrier for the systemic delivery and accumulation of siRNA, thus improving its therapeutic effect.

Novel brain-targeted nanomicelles for anti-glioma therapy mediated by the ApoE-enriched protein corona in vivo.

BACKGROUND: The interactions between nanoparticles (NPs) and plasma proteins form a protein corona around NPs after entering the biological environment, which provides new biological properties to NPs and mediates their interactions with cells and biological barriers. Given the inevitable interactions, we regard nanoparticle‒protein interactions as a tool for designing protein corona-mediated drug delivery systems. Herein, we demonstrate the successful application of protein corona-mediated brain-targeted nanomicelles in the treatment of glioma, loading them with paclitaxel (PTX), and decorating them with amyloid ß-protein (Aß)-CN peptide (PTX/Aß-CN-PMs). Aß-CN peptide, like the Aß1-42 peptide, specifically binds to the lipid-binding domain of apolipoprotein E (ApoE) in vivo to form the ApoE-enriched protein corona surrounding Aß-CN-PMs (ApoE/PTX/Aß-CN-PMs). The receptor-binding domain of the ApoE then combines with low-density lipoprotein receptor (LDLr) and LDLr-related protein 1 receptor (LRP1r) expressed in the blood-brain barrier and glioma, effectively mediating brain-targeted delivery. METHODS: PTX/Aß-CN-PMs were prepared using a film hydration method with sonication, which was simple and feasible. The specific formation of the ApoE-enriched protein corona around nanoparticles was characterized by Western blotting analysis and LC-MS/MS. The in vitro physicochemical properties and in vivo anti-glioma effects of PTX/Aß-CN-PMs were also well studied. RESULTS: The average size and zeta potential of PTX/Aß-CN-PMs and ApoE/PTX/Aß-CN-PMs were 103.1 nm, 172.3 nm, 7.23 mV, and 0.715 mV, respectively. PTX was efficiently loaded into PTX/Aß-CN-PMs, and the PTX release from rhApoE/PTX/Aß-CN-PMs exhibited a sustained-release pattern in vitro. The formation of the ApoE-enriched protein corona significantly improved the cellular uptake of Aß-CN-PMs on C6 cells and human umbilical vein endothelial cells (HUVECs) and enhanced permeability to the blood-brain tumor barrier in vitro. Meanwhile, PTX/Aß-CN-PMs with ApoE-enriched protein corona had a greater ability to inhibit cell proliferation and induce cell apoptosis than taxol. Importantly, PTX/Aß-CN-PMs exhibited better anti-glioma effects and tissue distribution profile with rapid accumulation in glioma tissues in vivo and prolonged median survival of glioma-bearing mice compared to those associated with PMs without the ApoE protein corona. CONCLUSIONS: The designed PTX/Aß-CN-PMs exhibited significantly enhanced anti-glioma efficacy. Importantly, this study provided a strategy for the rational design of a protein corona-based brain-targeted drug delivery system. More crucially, we utilized the unfavorable side of the protein corona and converted it into an advantage to achieve brain-targeted drug delivery.

Controlled Delivery of Pan-PAD-Inhibitor Cl-Amidine Using Poly(3-Hydroxybutyrate) Microspheres.

This study deals with the process of optimization and synthesis of Poly(3-hydroxybutyrate) microspheres with encapsulated Cl-amidine. Cl-amidine is an inhibitor of peptidylarginine deiminases (PADs), a group of calcium-dependent enzymes, which play critical roles in a number of pathologies, including autoimmune and neurodegenerative diseases, as well as cancer. While Cl-amidine application has been assessed in a number of in vitro and in vivo models; methods of controlled release delivery remain to be investigated. P(3HB) microspheres have proven to be an effective delivery system for several compounds applied in antimicrobial, wound healing, cancer, and cardiovascular and regenerative disease models. In the current study, P(3HB) microspheres with encapsulated Cl-amidine were produced in a size ranging from ~4-5 µm and characterized for surface morphology, porosity, hydrophobicity and protein adsorption, in comparison with empty P(3HB) microspheres. Cl-amidine encapsulation in P(3HB) microspheres was optimized, and these were found to be less hydrophobic, compared with the empty microspheres, and subsequently adsorbed a lower amount of protein on their surface. The release kinetics of Cl-amidine from the microspheres were assessed in vitro and expressed as a function of encapsulation efficiency. There was a burst release of ~50% Cl-amidine in the first 24 h and a zero order release from that point up to 16 days, at which time point ~93% of the drug had been released. As Cl-amidine has been associated with anti-cancer effects, the Cl-amidine encapsulated microspheres were assessed for the inhibition of vascular endothelial growth factor (VEGF) expression in the mammalian breast cancer cell line SK-BR-3, including in the presence of the anti-proliferative drug rapamycin. The cytotoxicity of the combinatorial effect of rapamycin with Cl-amidine encapsulated P(3HB) microspheres was found to be 3.5% more effective within a 24 h period. The cells treated with Cl-amidine encapsulated microspheres alone, were found to have 36.5% reduction in VEGF expression when compared with untreated SK-BR-3 cells. This indicates that controlled release of Cl-amidine from P(3HB) microspheres may be effective in anti-cancer treatment, including in synergy with chemotherapeutic agents. Using controlled drug-delivery of Cl-amidine encapsulated in Poly(3-hydroxybutyrate) microspheres may be a promising novel strategy for application in PAD-associated pathologies.

Dose dependent safety implications and acute intravenous toxicity of aminocellulose-grafted-polycaprolactone coated gelatin nanoparticles in mice.

Polymeric nanoparticles (NPs) are the most widely researched nanoformulations and gained broad acceptance in nanotherapeutics for targeted drug delivery and theranostics. However, lack of regulations, guidelines, harmonized standards, and limitations with their employability in clinical circumstances necessitates an in-depth understanding of their toxicology. Here, we examined the in-vivo toxicity of core-shell polymeric NPs made up of gelatin core coated with an outer layer of aminocellulose-grafted polycaprolactone (PCL-AC) synthesized for drug delivery purposes in inflammatory disorders. Nanoparticles were administered intravenously in Swiss albino mice, in multiple dosing (10, 25, and 50 mg/kg body weight) and outcomes of serum biochemistry analysis and histopathology evaluation exhibited that the highest 50 mg/kg administration of NPs altered biochemistry and histopathology aspects of vital organs, while doses of 10 and 25 mg/kg were safe and biocompatible. Further, mast cell (toluidine blue) staining confirmed that administration of the highest dose enhanced mast cell infiltration in tissues of vital organs, while lower doses did not exhibit any of these alterations. Therefore, the results of the present study establish that the NPs disposal in-vivo culminates into alterations in organ structure and function consequences such that lower doses are quite biocompatible and do not demonstrate any structural or functional toxicity while some toxicological effects start appearing at the highest dose.

Bone Marrow Mesenchymal Stem Cell Condition Medium Loaded on PCL Nanofibrous Scaffold Promoted Nerve Regeneration After Sciatic Nerve Transection in Male Rats.

Nowadays, researchers pay a vast deal of attention to neural tissue regeneration due to its tremendous effect on the patient's life. There are many strategies, from using conventional autologous nerve grafts to the newly developed methods for reconstructing damaged nerves. Among the various therapeutic methods, incorporating highly potent biomolecules and growth factors, the damaged nerve site would promote nerve regeneration. The aim was to examine the efficiency of a mesenchymal stem cell condition medium (MSC-CM) loaded on a 3D-polycaprolactone (PCL) scaffold as a nerve conduit in an axotomy rat model. Twenty-four mature male rats were classified into four groups: controls (the animals of this group were intact), axotomy (10 mm piece of the nerve was removed), axotomy (10-mm piece of the nerve was removed) + scaffold, and axotomy (10-mm piece of the nerve was removed) + MSC-CM-loaded scaffold. We followed up nerve motor function using a sciatic function index and electromyography activity of the gastrocnemius muscle. At 12 weeks post axotomy, sciatic nerve and dorsal root ganglion specimens and L4 and L5 spinal cord segments were separated from the rats and were analyzed by stereological, immunohistochemistry, and RT-PCR procedures. The rats of the axotomy group presented the expected gross locomotor deficit. Stereological parameters, immunohistochemistry of GFAP, and gene expression of S100, NGF, and BDNF were significantly enhanced in the CM-loaded scaffold group compared with the axotomy group. The most observed similarity was noted between the results of the control group and the CM-loaded scaffold group. Our results support the potential applicability of MSC-CM-loaded PCL nanofibrous scaffold to treat peripheral nerve injury (PNI).

(4-Aminopyridine)-PLGA-PEG as a Novel Thermosensitive and Locally Injectable Treatment for Acute Peripheral Nerve Injury.

Traumatic peripheral nerve injury (TPNI) represents a major medical problem that results in loss of motor and sensory function, and in severe cases, limb paralysis and amputation. To date, there are no effective treatments beyond surgery in selective cases. In repurposing studies, we found that daily systemic administration of the FDA-approved drug 4-aminopyridine (4-AP) enhanced functional recovery after acute peripheral nerve injury. This study was aimed at constructing a novel local delivery system of 4-AP using thermogelling polymers. We optimized a thermosensitive (4-AP)-poly(lactide-co-glycolide)-b-poly(ethylene glycol)-b-poly(lactide-co-glycolide) (PLGA-PEG-PLGA) block copolymer formulation. (4-AP)-PLGA-PEG exhibited controlled release of 4-AP both in vitro and in vivo for approximately 3 weeks, with clinically relevant safe serum levels in animals. Rheological investigation showed that (4-AP)-PLGA-PEG underwent a solution to gel transition at 32 °C, a physiologically relevant temperature, allowing us to administer it to an injured limb while subsequently forming an in situ gel. A single local administration of (4-AP)-PLGA-PEG remarkably enhanced motor and sensory functional recovery on post-sciatic nerve crush injury days 1, 3, 7, 14, and 21. Moreover, immunohistochemical studies of injured nerves treated with (4-AP)-PLGA-PEG demonstrated an increased expression of neurofilament heavy chain (NF-H) and myelin protein zero (MPZ) proteins, two major markers of nerve regeneration. These findings demonstrate that (4-AP)-PLGA-PEG may be a promising long-acting local therapeutic agent in TPNI, for which no pharmacologic treatment exists.