Peripheral nervous system lymphatic vessels: A simple delivery route to promote nerve regeneration

The structural and functional features of lymphatic vessels in the peripheral nervous system (pLVs) is still unclear. Here, we clarify the existence of pLVs in rats, PROX1-EGFP transgenic mice and human, and exhibit a clear three-dimensional structure for helping understand its structural features. Moreover, two specific phenotypes of lymphatics endothelial cells (Rnd1Hi LECs and Ccl21Hi LECs) in peripheral nerves are well characterized by single-cell sequencing. Subsequently, the ability of trans-lymphatic delivery to peripheral nerves via pLVs has been dynamically demonstrated. After peripheral nerve injury (PNI), extensive lymphangiogenesis occurs in the lesion area and further enhances the efficiency of retrograde lymphatic-nerve transport. In PNI animal models, subcutaneously footpad-injected exosomes are efficiently delivered to sciatic nerve via pLVs which can promote nerve regeneration. The trans-lymphatic delivery to peripheral nerves via pLVs can subtly bypass BNB which provides an easy and alternative delivery route for PNI treatment.

Routes of Stem Cell Administration

Stem cells are very promising for the treatment of a plethora of human diseases. Numerous clinical studies have been conducted to assess the safety and efficacy of various stem cell types. Factors that ensure successful therapeutic outcomes in patients are cell-based parameters such as source, viability, and number, as well as frequency and timing of intervention and disease stage. Stem cell administration routes should be appropriately chosen as these can affect homing and engraftment of the cells and hence reduce therapeutic effects, or compromise safety, resulting in serious adverse events. In this chapter, we will describe the use of stem cells in organ repair and regeneration, in particular, the liver and the available routes of cell delivery in the clinic for end-stage liver diseases. Factors affecting homing and engraftment of stem cells for each administration route will be discussed.

Non-invasive ways of administering insulin

BACKGROUND AND AIMS

Insulin is crucial in the management of diabetes. However, requires injection which itself comes with some challenges. Alternative delivery routes have been investigated that are needle-free, with enhanced absorption and bioavailability. This review presents novel non-invasive insulin administration approaches that overcome some hurdles, as well as delineating their advantages and disadvantages.

METHODS

Information was primarily gathered by employing various PubMed scholarly articles for real-world examples in addition to data extraction from supplementary manuscripts. Articles were evaluated between 1958 and 2022. An introductive approach was used to identify matters related to the concept of different ways of administering insulin.

RESULTS

Approaches aim to administer insulin in a safe, stable, and easy to use form, whether via oral, buccal, intranasal, oral inhalation, transdermal, ocular, rectal, or vaginal routes. Some have been shown to clinically improve blood glucose levels, while others are still in the investigational stage.

CONCLUSION

Many approaches have been taken in an attempt to overcome physical barriers of insulin delivery. Some of these systems discussed may reach the market in the future and assist the millions of people who currently take subcutaneous injections of insulin.

Brain Distribution of Drugs: Brain Morphology, Delivery Routes, and Species Differences

Neuropharmacokinetics considers cerebral drug distribution as a critical process for central nervous system drug action as well as for drug penetration through the CNS barriers. Brain distribution of small molecules obeys classical rules of drug partition, permeability, binding to fluid proteins or tissue components, and tissue perfusion. The biodistribution of all drugs, including both small molecules and biologics, may also be influenced by specific brain properties related to brain anatomy and physiological barriers, fluid dynamics, and cellular and biochemical composition, each of which can exhibit significant interspecies differences. All of these properties contribute to select optimal dosing paradigms and routes of drug delivery to reach brain targets for classical small molecule drugs as well as for biologics. The importance of these properties for brain delivery and exposure also highlights the need for efficient new analytical technologies to more comprehensively investigate drug distribution in the CNS, a complex multi-compartmentalized organ system.

Potential in vivo delivery routes of postbiotics

Bioactive micro- and macro-molecules (postbiotics) derived from gut beneficial microbes are among natural chemical compounds with medical significance. Currently, a unique therapeutic strategy has been developed with an emphasis on the small molecular weight biomolecules that are made by the microbiome, which endow the host with several physiological health benefits. A large number of postbiotics have been characterized, which due to their unique pharmacokinetic properties in terms of controllable aspects of the dosage and various delivery routes, could be employed as promising medical tools since they exert both prevention and treatment strategies in the host. Nevertheless, there are still main challenges for the in vivo delivery of postbiotics. Currently, scientific literature confirms that targeted delivery systems based on nanoparticles, due to their appealing properties in terms of high biocompatibility, biodegradability, low toxicity, and significant capability to carry both hydrophobic and hydrophilic postbiotics, can be used as a novel and safe strategy for targeted delivery or/and release of postbiotics in various (oral, intradermal, and intravenous) in vivo models. The in vivo delivery of postbiotics are in their emerging phase and require massive investigation and randomized double-blind clinical trials if they are to be applied extensively as treatment strategies. This manuscript provides an overview of the various postbiotic metabolites derived from the gut beneficial microbes, their potential therapeutic activities, and recent progressions in the drug delivery field, as well as concisely giving an insight on the main in vivo delivery routes of postbiotics.

Gene therapy for neurodegenerative disorders: advances, insights and prospects

Gene therapy is rapidly emerging as a powerful therapeutic strategy for a wide range of neurodegenerative disorders, including Alzheimer's disease (AD), Parkinson's disease (PD) and Huntington's disease (HD). Some early clinical trials have failed to achieve satisfactory therapeutic effects. Efforts to enhance effectiveness are now concentrating on three major fields: identification of new vectors, novel therapeutic targets, and reliable of delivery routes for transgenes. These approaches are being assessed closely in preclinical and clinical trials, which may ultimately provide powerful treatments for patients. Here, we discuss advances and challenges of gene therapy for neurodegenerative disorders, highlighting promising technologies, targets, and future prospects.

[Chinese experts consensus on clinical practice of the selection and establishment of fecal microbiota transplantation delivery routes]

Fecal microbiota transplantation (FMT) has gradually shown application prospects in the treatment of intestinal and extraintestinal diseases. In order to standardized FMT operation, based on the clinical experience of the Tenth People's Hospital Affiliated to Tongji University, combined with domestic and foreign literature, Parenteral and Enteral Nutrition Branch of Chinese Medical Association, Enhanced Recovery after Surgery Branch of China International Health Care Promotion Exchange Association, China Microecological Treatment Innovation Alliance, and Microecology Committee of Shanghai Preventive Medicine Association to formulated the" Chinese experts consensus on clinical practice of the selection and establishment of fecal microbiota transplantation delivery routes". It includes four parts: the selection of delivery route, the methodology of transplantation path establishment, the clinical application, and the monitoring of adverse events.

Delivery routes for probiotics: Effects on broiler performance, intestinal morphology and gut microflora

Four delivery routes, via, feed, water, litter and oral gavage, were examined for their efficacy in delivering a novel probiotic of poultry origin, Lactobacillus johnsonii, to broilers. Seven treatments of 6 replicates each were allocated using 336 one-day-old Cobb broiler chicks. The treatments consisted of a basal diet with the probiotic candidate, L. johnsonii, added to the feed, and three treatments with L. johnsonii added to the drinking water, sprayed on the litter, or gavaged orally. In addition, a positive control treatment received the basal diet supplemented with zinc-bacitracin (ZnB, 50 mg/kg). The probiotic strain of L. johnsonii was detected in the ileum of the chicks for all four delivery routes. However, the addition of L. johnsonii as a probiotic candidate did not improve body weight gain, feed intake and feed conversion ratio of broiler chickens raised on litter during the 5-week experimental period regardless of the route of administration. The probiotic treatments, regardless of the routes of delivery, affected (P < 0.05) the pH of the caecal digesta and tended (P = 0.06) to affect the pH of the ileal digesta on d 7, but the effect disappeared as the birds grew older. All probiotic treatments reduced the number of Enterobacteria in the caeca on d 21, and tended (P < 0.054) to reduce it in the ileum and caeca on d 7 and in the ileum on d 21 compared with the controls. The probiotic also tended to increase the number of lactic acid bacteria and lactobacilli in the ileum and caeca on d 7, but this trend was not evident on d 21. The trend appeared most pronounced when the probiotic was delivered orally or via litter. The probiotic also decreased (P < 0.05) the population of Clostridium perfringens rapidly from an early age to d 21 in the caeca, leading to a 3-fold decrease in the number of C. perfringens between d 7 and 21. It also showed that the probiotic treatment presented the lowest number of C. perfringens in the caeca. Delivery of the probiotic through feed, water and litter increased (P < 0.01) the weight of the pancreas on d 21, but the probiotic did not affect other morphometric parameters of the gut. Furthermore, the probiotic did not affect the pH and the concentrations of short chain fatty acids and lactic acid in either the ileum or caeca.