Hyaluronic acid (HA), an excellent biomaterial with unique bio properties, is currently one of the most interesting polymers for many biomedical and cosmetic applications. However, several of its potential benefits are limited as it is rapidly degraded by hyaluronidase enzymes. To improve the half-life and consequently increase performance, native HA has been modified through cross-linking reactions with a natural and biocompatible amino acid, Ornithine, to overcome the potential toxicity commonly associated with traditional linkers. 2-chloro-dimethoxy-1,3,5-triazine/4-methylmorpholine (CDMT/NMM) was used as an activating agent. The new product (HA–Orn) was extensively characterized to confirm the chemical modification, and rheological analysis showed a gel-like profile. In vitro degradation experiments showed an improved resistance profile against enzymatic digestions. Furthermore, in vitro cytotoxicity studies were performed on lung cell lines (Calu-3 and H441), which showed no cytotoxicity.

Introduction: Gene therapy is a potential alternative to treat a number of diseases. Different hurdles are associated with aerosol gene delivery due to the susceptibility of plasmid DNA (pDNA) structure to be degraded during the aerosolization process. Different strategies have been investigated in order to protect and efficiently deliver pDNA to the lungs using non-viral vectors. To date, no successful therapy involving non-viral vectors has been marketed, highlighting the need for further investigation in this field. Areas covered: This review is focused on the formulation and delivery of DNA to the lungs, using non-viral vectors. Aerosol gene formulations are divided according to the current delivery systems for the lung: nebulizers, dry powder inhalers and pressurized metered dose inhalers; highlighting its benefits, challenges and potential application. Expert opinion: Successful aerosol delivery is achieved when the supercoiled DNA structure is protected during aerosolization. A formulation strategy or compounds that can protect, stabilize and efficiently transfect DNA into the cells is desired in order to produce an effective, low-cost and safe formulation. Nebulizers and dry powder inhalers are the most promising approaches to be used for aerosol delivery, due to the lower shear forces involved. In this context it is also important to highlight the importance of considering the ‘pDNA-formulation-device system’ as an integral part of the formulation development for a successful nucleic acid delivery.

The use of cell-penetrating peptides (CPPs) in combination with nanoparticles (NPs) shows great potential for intracellular delivery of DNA. Currently, its application is limited due to the potential toxicity and unknown long-term side effects. In this study NPs prepared using a biodegradable polymer, poly(lactic–co–glycolic acid (PLGA) in association with a CPP, was assessed on two lung epithelial cell lines (adenocarcinomic human alveolar basal epithelial cells (A549) and normal bronchial epithelial cells (Beas-2B cells)). Addition of CPP was essential for intracellular internalization. No effects were observed on the mitochondrial activity and membrane integrity. Cells exposed to the NPs–DNA–CPP showed low inflammatory response, low levels of apoptosis and no activation of caspase-3. Increase in necrotic cells (between 10%–15%) after 24 h of incubation and increase in autophagy, induced by NPs–DNA–CPP, are likely to be related to the lysosomal escape mechanism. Although oxidative stress is one of the main toxic mechanisms of NPs, NPs–DNA–CPP showed decreased reactive oxygen species (ROS) production on Beas-2B cells, with potential antioxidant effect of CPP and no effect on A549 cells. This NP system appears to be safe for intracellular delivery of plasmid DNA to the lung epithelial cells. Further investigations should be conducted in other lung-related systems to better understand its potential effects on the lungs.

Evidence from in vitro and animal studies indicates that conjugated linoleic acid (CLA) possesses anti-diabetic properties, which appear to be attributed to cis-9, trans-11 CLA, the major CLA isomer in ruminant fat. However, there is a shortage of studies addressing CLA from natural source. The present study aimed to evaluate the effects of butter naturally enriched in cis-9, trans-11 CLA on parameters related to glucose tolerance, insulin sensitivity and dyslipidemia in rats. Forty male Wistar rats were randomly assigned to the following dietary treatments (n = 10/group), for 60 days: 1) Normal fat-Soybean oil (NF-So): diet containing 4.0% soybean oil (SO); 2) High Fat-Control Butter (HF-Cb): diet containing 21.7% control butter and 2.3% SO; 3) High Fat-CLA enriched Butter (HF-CLAb): diet containing 21.7% cis-9, trans-11 CLA-enriched butter and 2.3% SO; and 4) High fat-Soybean oil (HF-So): diet containing 24.0% SO. HF-Cb and HF-CLAb diets contained 0.075% and 0.235% of cis-9, trans-11 CLA, respectively. HF-CLAb-fed rats had lower serum insulin levels at fasting than those fed with the HF-Cb diet, while the PPARγ protein levels in adipose tissue was increased in HF-CLAb-fed rats compared to HF-Cb-fed rats. Furthermore, R-QUICK was lower in HF-Cb than in NF-So group, while no differences in R-QUICK were observed among NF-So, HF-CLAb and HF-So groups. Serum HDL cholesterol levels were higher in HF-CLAb-fed rats than in those fed NF-So, HF-Cb and HF-So diets, as well as higher in NF-So-fed rats than in HF-Cb and HF-So-fed rats. HF-CLAb, HF-Cb and HF-So diets reduced serum LDL cholesterol levels when compared to NF-So, whereas serum triacylglycerol levels were increased in HF-CLAb. Feeding rats on a high-fat diet containing butter naturally enriched in cis-9, trans-11 CLA prevented hyperinsulinemia and increased HDL cholesterol, which could be associated with higher levels of cis-9, trans-11 CLA, vaccenic acid, oleic acid and lower levels of short and medium-chain saturated fatty acids from butter naturally modified compared to control butter. On the other hand CLA-enriched butter also increased serum triacylglycerol levels, which could be associated with concomitant increases in the content of trans-9 and trans-10 C18:1 isomers in the CLA-enriched butter.