INVESTIGATION OF LIGAND SIZE ON TARGETED PLGA NANOPARTICLES FOR HER2 BREAST CANCER: TRASTUZUMAB AND ITS ScFv ANTI-HER2 ANTIBODY

This research focuses on assessing the effect of various formulation parameters on targeting human epidermal growth factor receptor-2 (HER2) specifically in breast cancer. Poly (D, L-lactide-co-glycolide) (PLGA) polymer, which is approved by FDA, was used to form nanoparticles (NPs) encapsulating docetaxel (DOC) as chemotherapy. HER2 antibody moieties, either whole IgG (TrAb) or single chain fragment variable (ScFv), were decorated on the PLGA NPs surface and evaluated in terms of their ability to target HER2 breast cancer cells. We observed the effects of these NPs against different cell lines (MCF-7 and SK-BR-3). Thus, ligand modified structurally concealed PLGA NPs could be a promising delivery tool for targeting HER2 breast tumor in vitro that improves the release of chemotherapy while reducing the systemic side effects. A solvent evaporation procedure was adjusted to form NP formulations using both ester and carboxylic acid terminated PLGA. Incorporation of ligands (TrAb or ScFv) was conducted through chemical covalent conjugation processes by using different cross-linkers bis(sulfo-succinimidyl) (BS3) or N-hydroxysuccinimide esters (NHS) and 1-ethyl-3-(-3-dimethylaminopropyl) carbodiimide hydrochloride (EDC). The size, zeta potential, polydispersity index, which were determined for the physicochemical characterizations. The physicochemical characterizations of formulations were executed to assess the effects of different ligands in vitro for drug targeting. Also, Fourier Transform Infrared (FTIR) was used to conform the covalent bond insertion between the linkers and ligands (TrAb or ScFv). DOC loading was quantified by a fully validated mass spectrometry method and antibody (Ab) quantification was performed by using the bicinchoninic acid (BCA) assay. Moreover, in vitro drug release profile was assessed. In vitro cellular targeting was examined by measuring the level of HER2 expression through Fluorescence-activated cell sorting (FACS) in two cell lines as well as western blot analysis. Cytotoxicity assay was performed in SK-BR-3 cell line for all the formulations. Modified PLGA NPs showed a mean diameter particle size below 400 nm with approximately neutral zeta potential; for example, ScFv-DOC-Ester PLGA NPs formulation size was 312 8.769 nm, and their zeta potential was 0.024 0.075 mV. The average size of the acidic PLGA TrAb-DOC NPs was 382.5 21.5 nm, and their zeta potential was 0.045 0.037 mV. DOC encapsulation efficiency reached up to 65% to 85% depending on the type of the NPs formulations, and the amount of anti-HER2 attachment efficiency exceeded 40%. The cellular targeting of nanoparticles was studied using two cell lines MCF-7 (low HER2 expression) and SK-BR-3 (high HER2 expression), and different levels of HER2 expression were evaluated. The significant reduction in the level of HER2 expression was observed for all modified NPs formulations in HER2 overexpressed SK-BR-3 cells. Overall, in vitro targeting further demonstrated that modified NPs accumulated DOC in tumor cell line more efficiently than conventional medication. The TrAb conjugated to DOC modified NPs formulations were able to increase the HER2 targeting for DOC compared to ScFv modified NPs. In SK-BR-3 cells, the cytotoxicity of modified NPs was more potent than the conventional DOC due to the targeting, and slow release of DOC from the modified NPs. This system has the potential of improving the targeting and the release of chemotherapeutic drugs into the tumor cells while reducing the side effects caused by affecting healthy tissues. Our data demonstrated that the high affinity for anti-HER2 modified PLGA NPs formulations to efficiently and explicitly target DOC to the HER2 overexpressing cancer cells can be exploited as a potential strategy for chemotherapeutic drug delivery system for HER2 overexpressing breast cancers. Thus, ligand modified structurally concealed PLGA NPs could be a promising delivery tool for targeting HER2 breast tumor in vivo that improves the release of chemotherapy while reducing the systemic side effects

Syringopleural Shunt Insertion Using a Minimally Invasive Approach: Technical Note, Case Series, and Review of the Literature

Objective Syringomyelia is a rare neurosurgical condition that could benefit from insertion of a syringopleural shunt in selected symptomatic cases. Treatment of syringomyelia through minimally invasive intervention is an attractive alternative to open approach. The objective of this report is to demonstrate the technical aspect, assess the feasibility, outcomes, and complications of syringopleural shunt insertion through minimally invasive surgical (MIS) approach. Methods Single-center retrospective chart review was done on patients with syringomyelia who underwent insertion of syringopleural shunts using the Metrx QuadrantTM retractor system from January 1, 2008 to April 1, 2020. A technical report of the steps of the surgical intervention is also described. Results Ten procedures were performed on 9 patients with a mean follow-up of 7.2 years. The etiologies of syringomyelia included post-traumatic, Chiari malformation, idiopathic, and diastematomyelia. All patients underwent correction of underlying etiologies prior to insertion of syringopleural shunts. Six patients (67%) had sustained neurological improvement, and 3 (33%) had halted progression of myelopathy. One patient was admitted for urgent removal of newly inserted syringopleural shunt due to immediate postoperative neurological decline and subsequently returned to their neurological baseline. The remaining eight patients were discharged on the same day of surgery. Conclusion Minimally invasive techniques have not been widely utilized in the treatment of syringomyelia. Our case series presents a novel, minimally invasive technique for the insertion of a syringopleural shunt, with reduced hospital stay and durable outcomes. Further, our series demonstrates that this technique is feasible and safe in appropriately selected patients

Vitamin D Promotes Skeletal Muscle Regeneration and Mitochondrial Health

Vitamin D is an essential nutrient for the maintenance of skeletal muscle and bone health. The vitamin D receptor (VDR) is present in muscle, as is CYP27B1, the enzyme that hydroxylates 25(OH)D to its active form, 1,25(OH)D. Furthermore, mounting evidence suggests that vitamin D may play an important role during muscle damage and regeneration. Muscle damage is characterized by compromised muscle fiber architecture, disruption of contractile protein integrity, and mitochondrial dysfunction. Muscle regeneration is a complex process that involves restoration of mitochondrial function and activation of satellite cells (SC), the resident skeletal muscle stem cells. VDR expression is strongly upregulated following injury, particularly in central nuclei and SCs in animal models of muscle injury. Mechanistic studies provide some insight into the possible role of vitamin D activity in injured muscle. In vitro and in vivo rodent studies show that vitamin D mitigates reactive oxygen species (ROS) production, augments antioxidant capacity, and prevents oxidative stress, a common antagonist in muscle damage. Additionally, VDR knockdown results in decreased mitochondrial oxidative capacity and ATP production, suggesting that vitamin D is crucial for mitochondrial oxidative phosphorylation capacity; an important driver of muscle regeneration. Vitamin D regulation of mitochondrial health may also have implications for SC activity and self-renewal capacity, which could further affect muscle regeneration. However, the optimal timing, form and dose of vitamin D, as well as the mechanism by which vitamin D contributes to maintenance and restoration of muscle strength following injury, have not been determined. More research is needed to determine mechanistic action of 1,25(OH)D on mitochondria and SCs, as well as how this action manifests following muscle injury in vivo. Moreover, standardization in vitamin D sufficiency cut-points, time-course study of the efficacy of vitamin D administration, and comparison of multiple analogs of vitamin D are necessary to elucidate the potential of vitamin D as a significant contributor to muscle regeneration following injury. Here we will review the contribution of vitamin D to skeletal muscle regeneration following injury