Lipid nanocarrier targeting activated macrophages for antiretroviral therapy of HIV reservoir.

Aim: To develop lipid nano-antiretrovirals (LNAs) for the treatment of HIV-infected macrophages. Materials & methods: LNAs were prepared with docosahexaenoic acid to facilitate brain penetration and surface-decorated with folate considering that infected macrophages often overexpress folate receptors. Results: Folate-decorated LNAs loading rilpivirine (RPV) were efficiently taken up by folate receptor-expressing cell types including activated macrophages. The intracellular Cmax of the RPV-LNAs in activated macrophages was 2.54-fold and the area under the curve was 3.4-fold versus free RPV, translating to comparable or higher (p < 0.01; RPV ≤6.5 ng/ml) activities against HIV infectivity and superior protection (p < 0.05) against HIV cytotoxicity. LNAs were also effective in monocyte-derived macrophages. Conclusion: These findings demonstrate the potential of LNAs for the treatment of infected macrophages, which are key players in HIV reservoirs.

HIV can infect and hide inside certain types of white blood cells that make up the immune system and help defend our body, such as macrophages. Because these infected cells tend to carry the virus to certain organs where antiviral drugs have a hard time reaching, the virus is able to avoid treatment from the drug. In this study, the authors developed very small devices known as nanocarriers to carry antiviral drugs. These nanocarriers were designed to seek out infected macrophages. The nanocarriers were successfully built with oils and lipids that are safe for patients and could easily deliver antiviral drugs to macrophages infected by HIV. Excellent anti-HIV effects were observed using these nanocarriers. In summary, the authors developed a promising device with the potential to fight HIV in a smart and safe manner.

Polypharmacy and cumulative anticholinergic burden in older adults hospitalized with fall.

Introduction: Polypharmacy is a growing phenomenon associated with adverse effects in older adults. We assessed the potential confounding effects of cumulative anticholinergic burden (ACB) in patients who were hospitalized with falls. Methods: A noninterventional, prospective cohort study of unselected, acute admissions aged ≥ 65 years. Data were derived from electronic patient health records. Results were analyzed to determine the frequency of polypharmacy and degree of ACB and their relationship to falls risk. Primary outcomes were polypharmacy, defined as prescription of 5 or more regular oral medications, and ACB score. Key Results: Four hundred eleven (411) consecutive subjects were included, mean age 83.8 ± 8.0 years: 40.6% men. There were 38.4% patients who were admitted with falls. Incidence of polypharmacy was 80.8%, (88.0% and 76.3% among those admitted with and without fall, respectively). Incidence of ACB score of 0, 1, 2, ≥ 3 was 38.7%, 20.9%, 14.6%, and 25.8%, respectively. On multivariate analysis, age [odds ratio (OR) = 1.030, 95% CI:1.000 ~ 1.050, P = 0.049], ACB score (OR = 1.150, 95% CI:1.020 ~ 1.290, P = 0.025), polypharmacy (OR = 2.140, 95% CI:1.190 ~ 3.870, P = 0.012), but not Charlson Comorbidity Index (OR = 0.920, 95% CI:0.810 ~ 1.040, P = 0.172) were significantly associated with higher falls rate. Of patients admitted with falls, 29.8% had drug-related orthostatic hypotension, 24.7% had drug-related bradycardia, 37.3% were prescribed centrally acting drugs, and 12.0% were taking inappropriate hypoglycemic agents. Conclusion: Polypharmacy results in cumulative ACB and both are significantly associated with falls risk in older adults. The presence of polypharmacy and each unit rise in ACB score have a stronger effect of increasing falls risk compared to age and comorbidities.

Development of a high payload, cancer-targeting liposomes of methyl aminolevulinate for intraoperative photodynamic diagnosis/therapy of peritoneal carcinomatosis.

Methyl aminolevulinate (MAL) is a photosensitizer topically used for photodynamic diagnosis (PDD) and photodynamic therapy (PDT) of skin pre-cancers and cancers. In this study, our goal is to expand the application of MAL to dual intraoperative PDD and PDT of peritoneal carcinomatosis. A new liposomal MAL formulation (lipMAL) designed for systemic or intraperitoneal administration was developed. LipMALs prepared by ammonium sulfate gradient technique achieved MAL payload up to 18% (w/w) with drug encapsulation efficiency in the range of 15.1-31.5%. All lipMALs demonstrated controlled MAL release behavior, and achieved strong fluorescence in cancer cells (SKOV3) but minimal fluorescence in non-cancer peritoneal cells (B14FAF28-G3). LipMALs led to significantly higher fluorescence levels than free MAL groups (P < 0.05), up to 6.8-fold of the free MAL fluorescence levels in SKOV3 cells. The PDD performance of lipMALs was also compared with free MAL in SKOV3/ B14FAF28-G3 co-cultures simulating ovarian cancer micrometastases on peritoneal surface. The lipMAL-treated cancer colonies glew more brightly than the free MAL treated colonies and were clearly distinguishable from the dim peritoneum background with unaided eyes. LipMAL also achieved significantly stronger anticancer PDT effects than free MAL both in terms of cell viability and colony-formation (P < 0.05) while demonstrating minimal dark toxicity. To conclude, a new promising aid for the surgeons to achieve more complete resection of tumors and PC micrometastases and clean up any residual cancer cells undetected was developed.

Incorporation of docosahexaenoic acid (DHA) enhances nanodelivery of antiretroviral across the blood-brain barrier for treatment of HIV reservoir in brain.

Although the newer antiretroviral (ARV) drugs are highly active against the human immunodeficiency virus (HIV) in the body compartment, they often fail to effectively tackle the HIV reservoir in the brain because of inefficient penetration to the blood-brain barrier (BBB). In this study, we investigated the potential benefits of incorporating docosahexaenoic acid (DHA), an omega-3 fatty acid essential for brain development, in lipid nanocarriers for facilitating the BBB passage of an ARV darunavir. The resulting nanocarriers (nanoARVs) containing 5-15% DHA were 90-140 nm in size, had high darunavir payload (~11-13% w/w), good stability and minimal cellular toxicity, and could be further decorated with transferrin (Tf) for Tf-receptor targeting. In BBB models of hCMEC/d3 cells, nanoARVs with higher DHA content achieved increased nanocarrier uptake and up to 8.99-fold higher darunavir permeation than free darunavir. In animals, nanoARVs were able to achieve 3.38-5.93-fold increase in brain darunavir level over free darunavir. Tf-conjugated nanoARVs also achieved significantly higher anti-HIV activity than free darunavir (viral titer 2 to 2.6-fold higher in latter group). Comparison of DHA incorporation and Tf-receptor targeting showed that while both strategies could enhance the cellular uptake and brain accumulation of the nanocarriers, DHA was more effective (P < 0.05) for improving BBB permeation and brain accumulation of the darunavir payload. Substituting DHA with another oil noticeably reduced the cellular uptake of nanoARVs. Overall, this proof-of-concept study has supported the development of DHA-based nanoARVs as an effective, safe yet technically simple strategy to enhance brain delivery of darunavir and potentially other lipophilic ARVs for treatment of HIV reservoir.

Enhanced eradication of intracellular and biofilm-residing methicillin-resistant Staphylococcus aureus (MRSA) reservoirs with hybrid nanoparticles delivering rifampicin.

Osteomyelitis carries a high risk of recurrence even after extended, aggressive antibiotic therapy. One of the key challenges is to eradicate the reservoirs of methicillin-resistant Staphylococcus aureus (MRSA) inside the host bone cells and their biofilms. Our goal is to develop rifampicin loaded lipid-polymer hybrid nanocarriers (Rf-LPN) and evaluate if they can achieve enhanced rifampicin delivery to eradicate these intracellular and biofilm-residing MRSA. After optimization of the composition, Rf-LPN demonstrated size around 110 nm in diameter that remained stable in serum-supplemented medium, drug payload up to 11.7% and sustained rifampicin release for 2 weeks. When comparing Rf-LPN with free rifampicin, moderate but significant (p < 0.05) improvement of the activities against three osteomyelitis-causing bacteria (USA300-0114, CDC-587, RP-62A) in planktonic form were observed. In comparison, the enhancements in the activities against the biofilms and intracellular MRSA by Rf-LPN were even more substantial. The MBEC50 values against USA300-0114, CDC-587, and RP-62A were 42 vs 155, 70 vs 388, and 265 ng/ml vs over 400 ng/ml, respectively, and up to 18.5-fold reduction in the intracellular MRSA counts in osteoblasts was obtained. Confocal microscope images confirmed extensive accumulation of Rf-LPN inside the biofilm matrix and MRSA-infected osteoblasts. Overall, in this proof-of-concept study we have developed and validated the strategy to exploit the nanoparticle-cell and nanoparticle-biofilm interactions with a new rifampicin nanoformulation for prevention of osteomyelitis recurrence and chronicity caused by the elusive MRSA.

Lipid-polymer hybrid nanoparticles carrying linezolid improve treatment of methicillin-resistant Staphylococcus aureus (MRSA) harbored inside bone cells and biofilms.

Methicillin-resistant Staphylococcus aureus (MRSA) is the most prevalent pathogen causing osteomyelitis. The tendency of MRSA to evade standard antibiotic treatment by hiding inside bone cells and biofilms is a major cause of frequent osteomyelitis recurrence. In this study, we developed a lipid-polymer hybrid nanoparticle loading the antibiotic linezolid (LIN-LPN), and focused on evaluating if this new nanoantibiotic can achieve significant in vitro activities against these intracellular and biofilm-embedded MRSA. The optimal LIN-LPN formulation demonstrated both high linezolid payload (12.0% by weight of nanoparticles) and controlled release characteristics (gradually released the entrapped antibiotic in 120 h). Although it achieved lower activities against bacteria including USA300-0114, CDC-587, RP-62A in planktonic form, it was substantially superior against the intracellular MRSA reservoir inside osteoblast cells. The differences of intracellular activities between LIN-LPN and linezolid were 87.0-fold, 12.3-fold, and 12.6-fold in CFU/ml (p < 0.05 or < 0.01) at 2 µg/ml, 4 µg/ml, and 8 µg/ml linezolid concentrations, respectively. LIN-LPN also suppressed the MRSA biofilm growth to 35-60% of the values achieved with free linezolid (p < 0.05). These enhanced intracellular and anti-biofilm activities of LIN-LPN were likely contributed by the extensive accumulation of LIN-LPN inside the MRSA-infected osteoblasts and biofilms as revealed in the confocal microscope images. The study thus validates the feasibility of exploiting the good nanoparticle-host cell and nanoparticle-biofilm interactions for improving the antibiotic drug activities against the poorly accessible bacteria, and supports LIN-LPN as a new alternative therapy for preventing the recurrence of MRSA-mediated bone infections.

Therapeutic Nanotechnology for Bone Infection Treatment - State of the Art.

Despite extended, aggressive use of conventional antibiotics, drug treatment of bone infections frequently fails as a combined result of the widespread of drug-resistant bacteria, poor accessibility of many antimicrobials to the deeper portion of the bones, the ease of biofilm formation on the bone surface, and high risk of drug toxicity. Emerging therapeutic nanotechnology offers potential solutions to these issues. In recent years, a number of nanoantimicrobials, i.e. nanoscale devices with intrinsic antibacterial activities or capacity for delivering antibiotics, have been developed for the treatment and prevention of bone infections. These nanoantimicrobials can be designed to have controlled and sustained drug release kinetics, surface-modifications for bone or bacteria targeting, and increased affinity for biofilms. Given the potential value of nanoantimicrobials, clinical application of nanoantimicrobials for bone infection treatment remains scant when compared with the number of ongoing research. It is, therefore, a good time to carefully examine this promising yet relatively uncharted area. This review will extensively discuss the development and state of the art of different classes of nanoantimicrobials for bone infections with emphasis on the treatment aspect and identify the factors that prevent the clinical translation of nanoantimicrobial therapy from bench to bedside.

Nanomedicine applications in the treatment of breast cancer: current state of the art.

Breast cancer is the most common malignant disease in women worldwide, but the current drug therapy is far from optimal as indicated by the high death rate of breast cancer patients. Nanomedicine is a promising alternative for breast cancer treatment. Nanomedicine products such as Doxil® and Abraxane® have already been extensively used for breast cancer adjuvant therapy with favorable clinical outcomes. However, these products were originally designed for generic anticancer purpose and not specifically for breast cancer treatment. With better understanding of the molecular biology of breast cancer, a number of novel promising nanotherapeutic strategies and devices have been developed in recent years. In this review, we will first give an overview of the current breast cancer treatment and the updated status of nanomedicine use in clinical setting, then discuss the latest important trends in designing breast cancer nanomedicine, including passive and active cancer cell targeting, breast cancer stem cell targeting, tumor microenvironment-based nanotherapy and combination nanotherapy of drug-resistant breast cancer. Researchers may get insight from these strategies to design and develop nanomedicine that is more tailored for breast cancer to achieve further improvements in cancer specificity, antitumorigenic effect, antimetastasis effect and drug resistance reversal effect.

Enhanced neuroprotection with decellularized brain extracellular matrix containing bFGF after intracerebral transplantation in Parkinson's disease rat model.

Extracellular matrix-based biomaterials have many advantages over synthetic polymer materials for regenerative medicine applications. In central nervous system (CNS), basic fibroblast growth factor (bFGF) is widely studied as a potential agent for Parkinson's disease (PD). However, the poor stability of bFGF hampered its clinical use. In this study, CNS-derived biologic scaffold containing bFGF was used to enhance and extend the neuroprotective effect of bFGF on PD targeted therapy. Decellularized brain extracellular matrix (dcBECM) was prepared by chemical extraction. The biocompatibility of dcBECM was evaluated using CCK-8 assay and magnetic resonance imaging (MRI). The controlled-release behavior of dcBECM containing bFGF (bFGF+dcBECM) was confirmed by ELISA assay. Furthermore, the cytocompatibility and neuroprotective effect of bFGF+dcBECM was evaluated in vitro and in vivo. From results, dcBECM showed a three-dimensional network structure with high biocompatibility. MRI of dcBECM implanted rats showed nearly seamless fusion of dcBECM with the adjoining tissues. The cumulative release rate of bFGF+dcBECM in vitro reached to 75.88% at 10h and maintained sustained release trend during the observation. ELISA results in vivo further confirmed the sustained-release behavior (from 12h to 3d) of bFGF+dcBECM in brain tissues. Among the experimental groups, bFGF+dcBECM group showed the highest cell survival rate of PD model cells, improved behavioral recovery and positive expressions of neurotrophic proteins in PD recovered rats. In conclusion, sustained neuroprotection in PD rats was achieved by using bFGF+dcBECM. The combination of dcBECM and bFGF would be a promising therapeutic strategy to realize an effective and safe alternative for CNS disease treatment.

A biodistribution study of solid lipid-polyethyleneimine hybrid nanocarrier for cancer RNAi therapy.

Solid lipid-polymer hybrid nanocarrier (LPN) was previously reported to achieve high siRNA transfection efficiency and induce sustained RNAi-based chemosensitizing effect at cellular level. In this study, our objectives were to evaluate the in vivo biodistribution of LPNs in a prostate cancer model and determine the factors that potentially affect tumor penetration by LPNs. The LPN formulation with the highest transfection efficiency (64%) and stability was selected for the study. Mice bearing tumors of PC-3Mcells were treated with LPNs labeled with IR780 or AF647-siRNA. Near infrared imaging showed that LPNs achieved favorable in vivo biodistribution with high tumor/low organ ratios. LPN accumulation was also observed in liver metastatic tissue. Result of extravasation study confirmed that encapsulated siRNA molecules were able to escape into the tumor tissue at the extravascular area. When LPN levels in large (volume>750mm3) and small (<500mm3) tumors were compared, no significant difference was observed. However, both docetaxel pretreatment (72hbefore LPN) and concurrent docetaxel treatment significantly enhanced the tumor LPN levels by 3.9- and 3.1-fold, respectively (both p<0.01). In conclusion, LPN is a promising carrier system to deliver RNAi therapy to solid malignancies that also receive chemotherapy.

Development and evaluation of viscosity-enhanced nanocarrier (VEN) for oral insulin delivery.

Solid lipid nanoparticles (SLN) have demonstrated good potential for oral peptide delivery. However, their hydrophobic nature generally accounts for low peptide entrapment efficiency (EE%). In this study, a new strategy was adopted to improve peptide EE% by incorporating a hydrophilic viscosity-enhancing agent (VA) within SLN cores to develop viscosity enhanced nanocarriers (VEN). Three agents namely, propylene glycol (PG), polyethylene glycol (PEG) 400 and PEG 600, were tested with human insulin serving as a model peptide drug. The effects of VA were both concentration- and type-dependent. 70% w/w PG had achieved the highest EE% (54.5%), versus the two PEGs, compared to only 20.4% in unmodified SLN. PG based VEN had demonstrated good dispersion stability at gastrointestinal (GI) pHs and preferential uptake by intestinal Caco2 cells while showing low cytotoxicity. Additionally, they preserved the integrity of insulin and significantly protected it against GI enzymatic degradation. Freeze dried VEN had shown good stability upon storage at -20°C. Orally administered insulin-VEN had achieved good hypoglycemic effect in fasted rats with relative bioavailability of 5.1%. To conclude, an easily implementable technique to improve peptide entrapment within SLN has been validated, and the resulting VEN had proved promising efficacy for oral peptide delivery.

Nanomedicine of synergistic drug combinations for cancer therapy - Strategies and perspectives.

Nanomedicine of synergistic drug combinations has shown increasing significance in cancer therapy due to its promise in providing superior therapeutic benefits to the current drug combination therapy used in clinical practice. In this article, we will examine the rationale, principles, and advantages of applying nanocarriers to improve anticancer drug combination therapy, review the use of nanocarriers for delivery of a variety of combinations of different classes of anticancer agents including small molecule drugs and biologics, and discuss the challenges and future perspectives of the nanocarrier-based combination therapy. The goal of this review is to provide better understanding of this increasingly important new paradigm of cancer treatment and key considerations for rational design of nanomedicine of synergistic drug combinations for cancer therapy.

Methocel-Lipid Hybrid Nanocarrier for Efficient Oral Insulin Delivery.

Even with the use of double-emulsion technique for preparation, the hydrophobic nature of solid lipid nanoparticles (SLNs) limits their encapsulation efficiency (EE%) for peptides such as insulin. In this study, we hypothesize that inclusion of Methocel into SLN to form Methocel-lipid hybrid nanocarriers (MLNs) will significantly enhance insulin EE% without compromising the various characteristics of SLN favorable for oral drug delivery. Our data show that incorporation of 2% wt/wt of Methocel A15C had doubled insulin EE% (around 40%) versus conventional SLN prepared using standard double emulsion technique. MLN significantly protected the entrapped insulin against chymotrypsin degradation at gastrointestinal pH. Using intestinal epithelial cells Caco2 as a model, it was shown that MLN could be extensively taken up by Caco2 cells while demonstrating low cytotoxicity. The results indicate that MLN have preserved the key advantages of SLN (biocompatibility, low cytotoxicity, good drug protection, and good interaction with cells) while overcoming their key limitation for efficient peptide entrapment. Based on this, MLN may serve as a promising nanocarrier for oral delivery of peptides.

Glioma-targeted therapy using Cilengitide nanoparticles combined with UTMD enhanced delivery.

Malignant gliomas especially glioblastoma (GBM) are poorly responsive to the current treatments. Cilengitide (CGT) is a cyclic pentapeptide that demonstrated efficacy for GBM treatment by targeting the integrins avß3 and avß5 over-expressed on GBM cells. However, clinical translation of this therapy has been limited by issues including fast blood clearance, high kidney and liver uptake, poor blood-brain barrier (BBB) penetration, low tumor specificity and rapid washout from tumors. In this study, these issues were tackled in an integrated manner using a multi-stage strategy combining ultrasound-targeted microbubble destruction (UTMD) with CGT nanotherapy. CGT nanoparticles (CGT-NP) prepared using gelatin and Poloxamer 188-grafted heparin copolymer demonstrated significant apoptotic and cytotoxic effects in C6 GBM cells. Biodistribution study in a rat GBM model demonstrated buildup of high CGT level in tumors subjected to CGT-NP+UTMD combined therapy. The tumor CGT level in these animals was increased over 3-fold, tumor retention of CGT prolonged and renal clearance significantly reduced when compared with free CGT with or without UTMD. CGT-NP+UTMD treatment was further shown to extend the median survival period from less than 20days in the control and about 30days in free CGT group to about 80days. This was achieved with low CGT dosing level (2mg/kg twice weekly). In situ monitoring of GFAP, Ki67, caspase-3, Beclin-1, and LC-3 in the tumor samples together with TUNEL assay, transmission electron microscope imaging and Western blot assay all demonstrated high apoptotic and autophagy activities induced by the combined therapy. In conclusion, this study has provided extensive preclinical data supporting the use of this combined therapy to overcome the limitations of standard CGT treatment of gliomas.

Intranasal delivery of bFGF with nanoliposomes enhances in vivo neuroprotection and neural injury recovery in a rodent stroke model.

Basic fibroblast growth factor (bFGF) may protect stroke patients from cerebral ischemia-reperfusion (I/R) injury. In this study, we report the intranasal use of novel nanoliposomes for the brain delivery of bFGF in a rat model of cerebral I/R. Compared with free bFGF, nanoliposomal therapy was able to significantly improve bFGF accumulation in brain tissues (p<0.05) including the most affected ischemic penumbra regions (e.g. hippocampus, pallium). After intranasal bFGF-nanoliposomal treatment for 3 consecutive days, functional recovery as indicated by improved neurologic deficit score and spontaneous locomotor activity was observed, and the stroke infarct volume was nearly halved (p<0.001) which persisted after 21days. These neuroprotective effects could be blocked by the PI3-K/Akt inhibitor LY294002, indicating the involvement of PI3-K/Akt activation in the therapeutic action. Overall, our results support the intranasal use of nanoliposomal bFGF as an efficient, non-invasive means to bypass the blood-brain barrier for ischemic stroke treatment.

Using NGF heparin-poloxamer thermosensitive hydrogels to enhance the nerve regeneration for spinal cord injury.

OBJECTIVE: Nerve growth factor (NGF) has potential in spinal cord injury (SCI) therapy, but limited by the poor physicochemical stability and low ability to cross the blood spinal cord barrier. Novel heparin-poloxamer (HP) thermo-sensitive hydrogel was constructed to enhance the NGF regeneration on SCI. METHOD: NGF-HP thermo-sensitive hydrogel was prepared and related characteristics including gelation temperature, rheological behavior and micromorphology were measured. Local NGF delivery to the injured spinal cord was achieved by in situ injection in the injured space. The cellular uptake of NGF-HP hydrogel was evaluated with PC12 cells in vitro. Pathologic characteristics and neuron regeneration effects on the SCI rats were studied to evaluate the enhanced therapy of NGF-HP hydrogel. Endoplasmic reticulum (ER) stress-induced apoptosis was analyzed to explore the related mechanism in SCI regeneration. RESULTS: NGF-HP hydrogel showed good morphology and stable bioactivity of NGF in vitro. NGF-HP hydrogel combined treatment significantly enhanced the efficiency of NGF cellular uptake (P<0.05) without obvious cytotoxicity. Significant improvements in both neuron functions and tissue morphology on the SCI rats were observed in NGF-HP hydrogel group. Compared with free HP hydrogel and NGF treatment groups, NGF-HP hydrogel group showed significant inhibition on the formation of glial scars in the extreme crushed rat SCI model. The neuroprotective effects of NGF-HP were related to the inhibition of chronic ER stress-induced apoptosis. CONCLUSIONS: HP hydrogel combined with orthotopic injection technique might be an effective method to deliver NGF into the injured site, which will provide an effective strategy for SCI regeneration. STATEMENT OF SIGNIFICANCE: Spinal cord injury (SCI) is a devastating condition that can lead to sudden loss of sensory and autonomic function. Current treatment includes decompression surgery, injury stabilization, secondary complications prevention and rehabilitation. However, neurological recovery is limited. Nerve growth factor (NGF) has potential in SCI therapy, but limited by the poor physicochemical stability and low ability to cross the blood spinal cord barrier. Hydrogels have good affinity and compatibility to biological tissue. In this study, we developed a novel heparin-poloxamer (HP) thermo-sensitive hydrogel to enhance the spinal cord regeneration of NGF. From SCI rat experiment, HP hydrogel combined with orthotopic injection technique showed best neuroprotective effects among experimental groups. This novel combined technique will provide an effective strategy for SCI regeneration.

Prevent diabetic cardiomyopathy in diabetic rats by combined therapy of aFGF-loaded nanoparticles and ultrasound-targeted microbubble destruction technique.

Acidic fibroblast growth factor (aFGF) has shown the great potential to prevent the structural and functional injuries caused by diabetic cardiomyopathy (DCM). The present study sought to investigate the preclinical performance and mechanism of the combination therapy of aFGF-nanoparticles (aFGF-NP) and ultrasound-targeted microbubble destruction (UTMD) technique for DCM prevention. From Mason staining and TUNEL staining, aFGF-NP+UTMD group showed significant differences from the diabetes group and other groups treated with aFGF or aFGF-NP. The cardiac collagen volume fraction (CVF) and cardiac myocyte apoptosis index in aFGF-NP+UTMD group reduced to 4.15% and 2.31% respectively, compared with those in the diabetes group (20.5% and 11.3% respectively). Myocardial microvascular density (MCD) in aFGF-NP+UTMD group was up to 35n/hpf, much higher than that in the diabetes group (14n/hpf). The diabetes group showed similar results (MCD, CVF and cardiac myocyte apoptosis index) to other aFGF treatment groups (free aFGF±UTMD or aFGF-NP). Indexes from transthoracic echocardiography and hemodynamic evaluation also proved the same conclusion. These results confirmed that the abnormalities including diastolic dysfunctions, myocardial fibrosis and metabolic could be suppressed by the different extents of twice weekly aFGF treatments for 12 consecutive weeks (free aFGF or aFGF-NP±UTMD), with the strongest improvements observed in the aFGF-NP+UTMD group. Western blot and immunohistochemical analyses of heart tissue samples further revealed the high efficiency of heart-targeted delivery and effective cardioprotection with this combination approach. Overall, this study has generated supportive data that are critical for the translation of a promising DCM prevention strategy.

Lipid-Based Nanocarriers for RNA Delivery.

RNA-interference (RNAi) agents such as small-interfering RNA (siRNA) and micro-RNA (miRNA) have strong potential as therapeutic agents for the treatment of a broad range of diseases such as malignancies, infections, autoimmune diseases and neurological diseases that are associated with undesirable gene expression. In recent years, several clinical trials of RNAi therapeutics especially siRNAs have been conducted with limited success so far. For systemic administration of these poorly permeable and easily degradable macromolecules, it is obvious that a safe and efficient delivery platform is highly desirable. Because of high biocompatibility, biodegradability and solid track record for clinical use, nanocarriers made of lipids and/or phospholipids have been commonly employed to facilitate RNA delivery. In this article, the key features of the major sub-classes of lipid-based nanocarriers, e.g. liposomes, lipid nanoparticles and lipid nanoemulsions, will be reviewed. Focus of the discussion is on the various challenges researchers face when developing lipid-based RNA nanocarriers, such as the toxicity of cationic lipids and issues related to PEGylated lipids, as well as the strategies employed in tackling these challenges. It is hoped that by understanding more about the pros and cons of these most frequently used RNA delivery systems, the pharmaceutical scientists, biomedical researchers and clinicians will be more successful in overcoming some of the obstacles that currently limit the clinical translation of RNAi therapy.