Celiac Disease: A Challenging Disease for Pharmaceutical Scientists

ABSTRACT: Celiac disease (CD) is an immune-mediated enteropathy triggered by the ingestion of gluten-containing grains that affects ~1% of the white ethnic population. In the last decades, a rise in prevalence of CD has been observed that cannot be fully explained by improved diagnostics. Genetic predisposition greatly influences the susceptibility of individuals towards CD, though environmental factors also play a role. With no pharmacological treatments available, the only option to keep CD in remission is a strict and permanent exclusion of dietary gluten. Such a gluten-free diet is difficult to maintain because of gluten's omnipresence in food (e.g., additive in processed food). The development of adjuvant therapies which would permit the intake of small amounts of gluten would be desirable to improve the quality of life of patients on a gluten-free diet. Such therapies include gluten-degrading enzymes, polymeric binders, desensitizing vaccines, anti-inflammatory drugs, transglutaminase 2 inhibitors, and HLA-DQ2 blockers. However, many of these approaches pose pharmaceutical challenges with respect to drug formulation and stability, or application route and dosing interval. This perspective article discusses how pharmaceutical scientists may deal with these challenges and contribute to the implementation of novel therapeutic options for patients with C

Improving the Stability and Activity of Oral Therapeutic Enzymes—Recent Advances and Perspectives

Exogenous, orally-administered enzymes are currently in clinical use or under development for the treatment of pathologies, such as celiac disease and phenylketonuria. However, the administration of therapeutic enzymes via the oral route remains challenging due to potential inactivation of these fragile macromolecular entities in the harsh environment of the gastrointestinal tract. Enzymes are particularly sensitive because both proteolysis and unfolding can lead to their inactivation. Current efforts to overcome these shortcomings involve the application of gastro-resistant delivery systems and the modification of enzyme structures by polymer conjugation or protein engineering. This perspective manuscript reviews and critically discusses recent progress in the oral delivery of therapeutic enzymes, whose substrate is localized in the gastrointestinal tract

Dynamics of lymphatic regeneration and flow patterns after lymph node dissection

Knowledge about the mechanisms of regeneration of the lymphatic vasculature after surgical trauma is essential for the development of strategies for the prevention and therapy of lymphedema. However, little is known about the alterations of lymphatic flow directly after surgical trauma. We investigated lymphatic function in mice using near-infrared imaging for a period of 4weeks after surgeries that mimic sentinel lymph node biopsy (SLNB) or axillary lymph node dissection (ALND), by removal of the popliteal lymph node (LN) alone or together with the popliteal fat pad, respectively. SLNB-like surgery did not cause changes in lymphatic drainage in the majority of cases. In contrast, lymphatic drainage impairment shown by collecting vessel rupture, dermal backflow and rerouting of lymph flow via collateral vessels were observed after ALND-like surgery. All collateral vessels drained to the inguinal LN. These results indicate that less invasive surgery prevents lymphatic decompensation. They also reveal the development and maturation of collateral lymphatic vessels after extensive surgical trauma, which reroute the flow of lymph towards a different LN. These findings might be helpful for the development of strategies to prevent and/or treat post-surgical lymphedem

Synthesis of Functionalized Few-Layer Graphene Through Fast Electrochemical Expansion of Graphite

International audienc

Nanonization of megestrol acetate by laser fragmentation in aqueous milieu

Faculté de PharmacieNanonization is a simple and effective method to improve dissolution rate and oral bioavailability of drugs with poor water solubility. There is growing interest to downscale the nanocrystal production to enable early preclinical evaluation of new drug candidates when compound availability is scarce. The purpose of the present study was to investigate laser fragmentation to form nanosuspensions in aqueous solution of the insoluble model drug megestrol acetate (MA) using very little quantities of the drug. Laser fragmentation was obtained by focusing a femtosecond (fs) or nanosecond (ns) laser radiation on a magnetically stirred MA suspension in water or aqueous solution of a stabilizing agent. The size distribution and physicochemical properties of the drug nanoparticles were characterized, and the in vitro dissolution and in vivo oral pharmacokinetics of a laser fragmented formulation were evaluated. A MA nanosuspension was also prepared by media milling for comparison purpose. For both laser radiations, smaller particles were obtained as the laser power was increased, but at a cost of higher degradation. Significant nanonization was achieved after a 30-min fs laser treatment at 250 mW and a 1-h ns laser treatment at 2500 mW. The degradation induced by the laser process of the drug was primarily oxidative in nature. The crystal phase of the drug was maintained, although partial loss of crystallinity was observed. The in vitro dissolution rate and in vivo bioavailability of the laser fragmented formulation were similar to those obtained with the nanosuspension prepared by media milling, and significantly improved compared to the coarse drug powder. It follows that this laser nanonization method has potential to be used for the preclinical evaluation of new drug candidates.IRSC - CRNS

Dynamics of lymphatic regeneration and flow patterns after lymph node dissection.

Knowledge about the mechanisms of regeneration of the lymphatic vasculature after surgical trauma is essential for the development of strategies for the prevention and therapy of lymphedema. However, little is known about the alterations of lymphatic flow directly after surgical trauma. We investigated lymphatic function in mice using near-infrared imaging for a period of 4 weeks after surgeries that mimic sentinel lymph node biopsy (SLNB) or axillary lymph node dissection (ALND), by removal of the popliteal lymph node (LN) alone or together with the popliteal fat pad, respectively. SLNB-like surgery did not cause changes in lymphatic drainage in the majority of cases. In contrast, lymphatic drainage impairment shown by collecting vessel rupture, dermal backflow and rerouting of lymph flow via collateral vessels were observed after ALND-like surgery. All collateral vessels drained to the inguinal LN. These results indicate that less invasive surgery prevents lymphatic decompensation. They also reveal the development and maturation of collateral lymphatic vessels after extensive surgical trauma, which reroute the flow of lymph towards a different LN. These findings might be helpful for the development of strategies to prevent and/or treat post-surgical lymphedema

Decline of lymphatic vessel density and function in murine skin during aging.

Lymphatic vessels play important roles in the pathogenesis of many conditions that have an increased prevalence in the elderly population. However, the effects of the aging process on the lymphatic system are still relatively unknown. We have applied non-invasive imaging and whole-mount staining techniques to assess the lymphatic vessel function and morphology in three different age groups of mice: 2 months (young), 7 months (middle-aged), and 18 months (aged). We first developed and validated a new method to quantify lymphatic clearance from mouse ear skin, using a lymphatic-specific near-infrared tracer. Using this method, we found that there is a prominent decrease in lymphatic vessel function during aging since the lymphatic clearance was significantly delayed in aged mice. This loss of function correlated with a decreased lymphatic vessel density and a reduced lymphatic network complexity in the skin of aged mice as compared to younger controls. The blood vascular leakage in the skin was slightly increased in the aged mice, indicating that the decreased lymphatic function was not caused by a reduced capillary filtration in aged skin. The decreased function of lymphatic vessels with aging might have implications for the pathogenesis of a number of aging-related diseases

Tyrosine-based rivastigmine-loaded organogels in the treatmant of Alzheimer's disease

Faculté de PharmacieOrganogels can be prepared by immobilizing an organic phase into a threedimensional network coming from the self-assembly of a low molecular weight gelator molecule. In this work, an injectable subcutaneous organogel system based on safflower oil and a modified-tyrosine organogelator was evaluated in vivo for the delivery of rivastigmine, an acetylcholinesterase (AChE) inhibitor used in the treatment of Alzheimer’s disease. Different implant formulations were injected and the plasmatic drug concentration was assayed for up to 35 days. In parallel, the inhibition of AChE in different brain sections and the biocompatibility of the implants were monitored. The pharmacokinetic profiles were found to be influenced by the gel composition, injected dose and volume of the implant. The sustained delivery of rivastigmine was accompanied by a significant prolonged inhibition of AChE in the hippocampus, a brain structure involved in memory. The implant induced only a minimal to mild chronic inflammation and fibrosis, which was comparable to poly(D,L-lactide-co-glycolide) in situ-forming implants. These findings suggest that tyrosine-based organogels could represent an alternative approach to current formulations for the sustained delivery of cholinesterase inhibitors.IRS

Non-invasive dynamic near-infrared imaging and quantification of vascular leakage in vivo

Preclinical vascular research has been hindered by a lack of methods that can sensitively image and quantify vascular perfusion and leakage in vivo. In this study, we have developed dynamic near-infrared imaging methods to repeatedly visualize and quantify vascular leakage in mouse skin in vivo, and we have applied these methods to transgenic mice with overexpression of vascular endothelial growth factors VEGF-A or -C. Near-infrared dye conjugates were developed to identify a suitable vascular tracer that had a prolonged circulation lifetime and slow leakage into normal tissue after intravenous injection. Dynamic simultaneous imaging of ear skin and a large blood vessel in the leg enabled determination of the intravascular signal (blood volume fraction) from the tissue signal shortly after injection and quantifications of vascular leakage into the extravascular tissue over time. This method allowed for the sensitive detection of increased blood vascularity and leakage rates in K14-VEGF-A transgenic mice and also reliably measured inflammation-induced changes of vascularity and leakage over time in the same mice. Measurements after injection of recombinant VEGF-A surprisingly revealed increased blood vascular leakage and lymphatic clearance in K14-VEGF-C transgenic mice which have an expanded cutaneous lymphatic vessel network, potentially indicating unanticipated effects of lymphatic drainage on vascular leakage. Increased vascular leakage was also detected in subcutaneous tumors, confirming that the method can also be applied to deeper tissues. This new imaging method might facilitate longitudinal investigations of the in vivo effects of drug candidates, including angiogenesis inhibitors, in preclinical disease model

Risk assessment of biogas in kitchens

International audienceThe health risk associated with human exposure to pollutants while using biogas for cooking was assessed following the methodology described by the US - National Research Council. Information of hazardous compounds and compositions of several biogas types were extracted from scientific literature. Compositions were dependent on the biogas origin (production process). First, a quantitative approach was conducted to identify substances with a high health risk based on their Human Toxicity Values. Then, a subsequent qualitative analysis was performed to complete the health risk assessment based on other toxicology data, effectiveness of purification processes, variability of the waste materials used for biogas generation and, when possible, a comparison with natural gas. The main conclusion of the study was that the injection in the grid of upgraded biogas originating from household and organic waste landfills, did not present an increase of health risks when compared to the domestic use of natural gas