Nikita Lomis | McGill University (original) (raw)
Address: Montreal, Quebec, Canada
less
Uploads
Papers by Nikita Lomis
The gut microflora is a community of trillions of bacterial cells synergistically inhabiting the ... more The gut microflora is a community of trillions of bacterial cells synergistically inhabiting the human gastrointestinal tract. These microbes contact everything that is consumed and release regulatory factors that affect host energy homeostasis, lipid and carbohydrate metabolism, activation of immune cells, oxidative state, epithelial cell wall integrity and even neurological signals. The gut microflora is essentially an independent organ supporting human health where imbalances in the gut community populations (dysbiosis) manifest in disease. Diabetes and neurodegenerative disorders such as Alzheimer's and Parkinson's disease share a similar molecular pathology rooted in gut microflora activity. Both of these conditions are associated with a dysbiosis characterized by low species diversity, a higher proportion of pathobionts at the expense of symbionts, an abundance of proinflammatory microbes and fewer butyrate-producing strains. Many of these factors can be ameliorated with Lactobacillus spp. and Bifidobacterium spp. probiotic treatment aimed to reestablish healthy gut microflora diversity. Indeed, certain commensal and pathogenic strains promote chronic low-grade inflammation that stresses cellular infrastructure eventually leading to apoptosis in both the pancreas and the brain. Also, lack of some beneficial fermentation products such as butyrate and ferulic acid initiates a cascade of events disrupting metabolic homeostasis. Finally, signaling initiated by the microflora and its metabolites has been shown to disrupt the delicate intracellular balance of PI3K/Akt/mTOR signaling, which fundamentally regulates events leading up to diabetes and neurodegenerative disease pathogenesis. The following review investigates the relationship between the manifestation and molecular signaling of diabetes and neurodegenerative disorders and how the balance of gut microflora populations is critical to both prevent and possibly treat these diseases.
Host body response to a foreign medical device plays a critical role in defining its fate post im... more Host body response to a foreign medical device plays a critical role in defining its fate post implantation. It is thus important to control host–material interactions by designing innovative implant surfaces. In the recent years, biochemical and topographical features have been explored as main target to produce this new type of bioinert or bioresponsive implants. The review discusses specific biofunctional materials and strategies to achieve a precise control over implant surface properties and presents possible solutions to develop next generation of implants, particularly in the fields of bone and cardiovascular therapy.
Human serum albumin nanoparticles (HSA-NPs) are widely-used drug delivery systems with applicatio... more Human serum albumin nanoparticles (HSA-NPs) are widely-used drug delivery systems with applications in various diseases, like cancer. For intravenous administration of HSA-NPs, the particle size, surface charge, drug loading and in vitro release kinetics are important parameters for consideration. This study focuses on the development of stable HSA-NPs containing the anti-cancer drug paclitaxel (PTX) via the emulsion-solvent evaporation method using a high-pressure homogenizer. The key parameters for the preparation of PTX-HSA-NPs are: the starting concentrations of HSA, PTX and the organic solvent, including the homogenization pressure and its number cycles, were optimized. Results indicate a size of 143.4 ˘ 0.7 nm and 170.2 ˘ 1.4 nm with a surface charge of´5.6 ˘ 0.8 mV and´17.4 ˘ 0.5 mV for HSA-NPs and PTX-HSA-NPs (0.5 mg/mL of PTX), respectively. The yield of the PTX-HSA-NPs was ~93% with an encapsulation efficiency of ~82%. To investigate the safety and effectiveness of the PTX-HSA-NPs, an in vitro drug release and cytotoxicity assay was performed on human breast cancer cell line (MCF-7). The PTX-HSA-NPs showed dose-dependent toxicity on cells of 52%, 39.3% and 22.6% with increasing concentrations of PTX at 8, 20.2 and 31.4 µg/mL, respectively. In summary, all parameters involved in HSA-NPs' preparation, its anticancer efficacy and scale-up are outlined in this research article.
The gut microflora is a community of trillions of bacterial cells synergistically inhabiting the ... more The gut microflora is a community of trillions of bacterial cells synergistically inhabiting the human gastrointestinal tract. These microbes contact everything that is consumed and release regulatory factors that affect host energy homeostasis, lipid and carbohydrate metabolism, activation of immune cells, oxidative state, epithelial cell wall integrity and even neurological signals. The gut microflora is essentially an independent organ supporting human health where imbalances in the gut community populations (dysbiosis) manifest in disease. Diabetes and neurodegenerative disorders such as Alzheimer's and Parkinson's disease share a similar molecular pathology rooted in gut microflora activity. Both of these conditions are associated with a dysbiosis characterized by low species diversity, a higher proportion of pathobionts at the expense of symbionts, an abundance of proinflammatory microbes and fewer butyrate-producing strains. Many of these factors can be ameliorated with Lactobacillus spp. and Bifidobacterium spp. probiotic treatment aimed to reestablish healthy gut microflora diversity. Indeed, certain commensal and pathogenic strains promote chronic low-grade inflammation that stresses cellular infrastructure eventually leading to apoptosis in both the pancreas and the brain. Also, lack of some beneficial fermentation products such as butyrate and ferulic acid initiates a cascade of events disrupting metabolic homeostasis. Finally, signaling initiated by the microflora and its metabolites has been shown to disrupt the delicate intracellular balance of PI3K/Akt/mTOR signaling, which fundamentally regulates events leading up to diabetes and neurodegenerative disease pathogenesis. The following review investigates the relationship between the manifestation and molecular signaling of diabetes and neurodegenerative disorders and how the balance of gut microflora populations is critical to both prevent and possibly treat these diseases.
Host body response to a foreign medical device plays a critical role in defining its fate post im... more Host body response to a foreign medical device plays a critical role in defining its fate post implantation. It is thus important to control host–material interactions by designing innovative implant surfaces. In the recent years, biochemical and topographical features have been explored as main target to produce this new type of bioinert or bioresponsive implants. The review discusses specific biofunctional materials and strategies to achieve a precise control over implant surface properties and presents possible solutions to develop next generation of implants, particularly in the fields of bone and cardiovascular therapy.
Human serum albumin nanoparticles (HSA-NPs) are widely-used drug delivery systems with applicatio... more Human serum albumin nanoparticles (HSA-NPs) are widely-used drug delivery systems with applications in various diseases, like cancer. For intravenous administration of HSA-NPs, the particle size, surface charge, drug loading and in vitro release kinetics are important parameters for consideration. This study focuses on the development of stable HSA-NPs containing the anti-cancer drug paclitaxel (PTX) via the emulsion-solvent evaporation method using a high-pressure homogenizer. The key parameters for the preparation of PTX-HSA-NPs are: the starting concentrations of HSA, PTX and the organic solvent, including the homogenization pressure and its number cycles, were optimized. Results indicate a size of 143.4 ˘ 0.7 nm and 170.2 ˘ 1.4 nm with a surface charge of´5.6 ˘ 0.8 mV and´17.4 ˘ 0.5 mV for HSA-NPs and PTX-HSA-NPs (0.5 mg/mL of PTX), respectively. The yield of the PTX-HSA-NPs was ~93% with an encapsulation efficiency of ~82%. To investigate the safety and effectiveness of the PTX-HSA-NPs, an in vitro drug release and cytotoxicity assay was performed on human breast cancer cell line (MCF-7). The PTX-HSA-NPs showed dose-dependent toxicity on cells of 52%, 39.3% and 22.6% with increasing concentrations of PTX at 8, 20.2 and 31.4 µg/mL, respectively. In summary, all parameters involved in HSA-NPs' preparation, its anticancer efficacy and scale-up are outlined in this research article.