No abstract

Human mesenchymal stromal cells (hMSCs) are multipotent cells that have been proposed for cell therapies due to their immunosuppressive capacity that can be enhanced in the presence of interferon-gamma (IFN-γ). In this study, multilayers of heparin (HEP) and collagen (COL) (HEP/COL) were used as a bioactive surface to enhance the immunomodulatory activity of hMSCs using soluble IFN-γ. Multilayers were formed, via layer-by-layer assembly, varying the final layer between COL and HEP and supplemented with IFN-γ in the culture medium. We evaluated the viability, adhesion, real-time growth, differentiation, and immunomodulatory activity of hMSCs on (HEP/COL) multilayers. HMSCs viability, adhesion, and growth were superior when cultured on (HEP/COL) multilayers compared to tissue culture plastic. We also confirmed that hMSCs osteogenic and adipogenic differentiation remained unaffected when cultured in (HEP/COL) multilayers in the presence of IFN-γ. We measured the immunomodulatory activity of hMSCs by measuring the level of indoleamine 2,3-dioxygenase (IDO) expression. IDO expression was higher on (HEP/COL) multilayers treated with IFN-γ. Lastly, we evaluated the suppression of peripheral blood mononuclear cell (PBMC) proliferation when co-cultured with hMSCs on (HEP/COL) multilayers with IFN-γ. hMSCs cultured in (HEP/COL) multilayers in the presence of soluble IFN-γ have a greater capacity to suppress PBMC proliferation. Altogether, (HEP/COL) multilayers with IFN-γ in culture medium provides a potent means of enhancing and sustaining immunomodulatory activity to control hMSCs immunomodulation.

Microneedle patches are a promising source for transdermal diffusion of macromolecules and are designed to painlessly penetrate the skin. In this study, a biodegradable chitosan microneedle patch to deliver meloxicam for managing pain in cattle was tested. The potential of reuse of the polymeric solution to fabricate the patches, optimization of fabrication, morphological analysis of the microneedle patch and analysis of preservation of the chemical composition after sterilization were evaluated. In-vitro analysis consisted of studying in-vitro penetration mechanical properties, compression testing analysis of microneedle patch, and in-vitro drug release analysis. In-vivo studies were performed to analyze the dissolution capability of the microneedle patch. Results regarding the physical characteristics, chemical composition, and mechanical properties confirmed that rheological properties of the chitosan solution, present significant differences over time, demonstrating that reusing the solution on the fourth day results in failure patches. Morphological characteristics and chemical composition studies revealed that the process of sterilization (ethylene oxide gas) needed for implanting the patches into the skin did not affect the properties of microneedle patches. In-vitro studies showed that approximately 33.02 ± 3.88% of the meloxicam was released over 7 days. A full penetration of the microneedles into the skin can be obtained by applying approximately 3.2 N. In-vivo studies demonstrated that microneedle patches were capable of swelling and dissolving, exhibiting a dissolution percentage of more than 50% of the original height of microneedle after 7 days. No abnormal tissue, swelling, or inflammation was observed in the implanted area. The results of this work show that chitosan biodegradable microneedle patches may be useful to deliver meloxicam to improve pain management of cattle with positive effects for commercial manufacturing.

To evaluate meloxicam plasma concentrations using a microneedle patch, 12 pigs (initial BW = 2.5 ± 0.53 kg) were stratified into of 4 treatment groups. Treatment groups were: 1) pigs (n = 2) received 0.5 mg/kg meloxicam via oral drench (oral); 2) pigs (n = 2) received a patch with no meloxicam (placebo); 3) pigs (n = 4) received microneedle patch dosed at 2.5 mg/kg (low dose); and 4) pigs (n = 4) received 2 microneedle patches dosed at 5 mg/kg (high dose). Blood was collected for plasma analysis at 0, 2, 4, 8, 12, 24, 48, 72, 96, and 168 hours. Microneedle patches were adhered on the pinna of the ear after blood collection at 0 hour. Statistical analyses were performed using the MIXED procedure of SAS 9.4, assessing effects of treatment, time, and treatment × time interaction. Statistical significance was determined at P ≤ 0.05, with tendencies at 0.05 < P ≥ 0.1. There was a treatment × time interaction (P < 0.0001), with the oral treatment group having greater meloxicam plasma concentrations at 2, 4, and 8 hours than placebo, low dose, and high dose treatment groups (P < 0.0001), but there were no differences for 24, 48, 72, 96, and 168 hours (P > 0.1). The oral treatment group tended to have greater meloxicam plasma concentrations at 12 hours compared with placebo (P = 0.09), low dose (P = 0.054), and high dose (P = 0.054) treatment groups. There were no differences between placebo, low dose, and high dose treatment groups for any blood collection timepoint (P > 0.1). Meloxicam concentrations in plasma were detectable but low for both the low dose treatment group (0.21 ng/mL) and high dose treatment group (1.14 ng/mL). Research is continuing to determine the ideal meloxicam dosage needed on the patch to deliver desired plasma concentrations.