Poloxamer 188 decreases membrane toxicity of mutant SOD1 and ameliorates pathology observed in SOD1 mouse model for ALS

Vepoloxamer improves functional recovery in rat after traumatic brain injury: A dose-response and therapeutic window study

Traumatic brain injury (TBI) is a major cause of death and disability worldwide. There are no effective therapies available for TBI patients. Vepoloxamer is an amphiphilic polyethylene-polypropylene-polyethylene tri-block copolymer that seals membranes and restores plasma membrane integrity in damaged cells. We previously demonstrated that treatment of TBI rats with Vepoloxamer improves functional recovery. However, additional studies are needed to potentially translate Vepoloxamer treatment from preclinical studies into clinical applications. We thus conducted a study to investigate dose-response and therapeutic window of Vepoloxamer on functional recovery of adult rats after TBI. To identify the most effective dose of Vepoloxamer, male Wistar adult rats with controlled cortical impact (CCI) injury were randomly treated with 0 (vehicle), 100, 300, or 600 mg/kg of Vepoloxamer, administered intravenously (IV) at 2 h after TBI. We then performed a therapeutic window study in which the rats were treated IV with the most effective single dose of Vepoloxamer at different time points of 2 h, 4 h, 1 day, or 3 days after TBI. A battery of cognitive and neurological tests was performed. Animals were killed 35 days after TBI for histopathological analysis. Dose-response experiments showed that Vepoloxamer at all three tested doses (100, 300, 600 mg/kg) administered 2 h post injury significantly improved cognitive functional recovery, whereas Vepoloxamer at doses of 300 and 600 mg/kg, but not the 100 mg/kg dose, significantly reduced lesion volume compared to saline treatment. However, Vepoloxamer at 300 mg/kg showed significantly improved neurological and cognitive outcomes than treatment with a dose of 600 mg/kg. In addition, our data demonstrated that the dose of 300 mg/kg of Vepoloxamer administered at 2 h, 4 h, 1 day, or 3 days post injury significantly improved neurological function compared with vehicle, whereas Vepoloxamer administered at 2 h or 4 h post injury significantly improved cognitive function compared with the 1-day and 3-day treatments, with the most robust effect administered at 2 h post injury. The present study demonstrated that Vepoloxamer improves functional recovery in a dose-and time-dependent manner, with therapeutic efficacy compared with vehicle evident even when the treatment is initiated 3 days post TBI in the rat.

Poloxamer-188 Exacerbates Brain Amyloidosis, Presynaptic Dystrophies, and Pathogenic Microglial Activation in 5XFAD Mice

Background:

Alzheimer’s disease (AD) is initiated by aberrant accumulation of amyloid beta (Aβ) protein in the brain parenchyma. The microenvironment surrounding amyloid plaques is characterized by the swelling of presynaptic terminals (dystrophic neurites) associated with lysosomal dysfunction, microtubule disruption and impaired axonal transport. Aβ-induced plasma membrane damage and calcium influx could be potential mechanisms underlying dystrophic neurite formation.

Objective:

We tested whether promoting membrane integrity by brain administration of a safe FDA approved surfactant molecule poloxamer-188 (P188) could attenuate AD pathology in vivo.

Methods:

Three-month-old 5XFAD male mice were administered several concentrations of P188 in the brain for 42 days with mini-osmotic pumps. After 42 days, mice were euthanized and assessed for amyloid pathology, dystrophic neurites, pathogenic microglia activation, tau phosphorylation and lysosomal / vesicular trafficking markers in the brain.

Results:

P188 was lethal at the highest concentration of 10mM. Lower concentrations of P188 (1.2, 12 and 120μM) were well tolerated. P188 increased brain Aβ burden, potentially through activation of the γ-secretase pathway. Dystrophic neurite pathology was exacerbated in P188 treated mice as indicated by increased LAMP1 accumulation around Aβ deposits. Pathogenic microglial activation was increased by P188. Total tau levels were decreased by P188. Lysosomal enzyme cathepsin D and calcium-dependent vesicular trafficking regulator synaptotagmin-7 (SYT7) were dysregulated upon P188 administration.

Conclusion:

P188 brain delivery exacerbated amyloid pathology, dystrophic neurites and pathogenic microglial activation in 5XFAD mice. These effects correlated with lysosomal dysfunction and dysregulation of plasma membrane vesicular trafficking. P188 is not a promising therapeutic strategy against AD pathogenesis.

Poloxamer 188 (P188), A Potential Polymeric Protective Agent for Central Nervous System Disorders: A Systematic Review

Poloxamer 188 (P188) is an FDA-approved biocompatible block copolymer composed of repeating units of Poly(Ethylene Oxide) (PEO) and poly(propylene oxide) (PPO). Due to its amphiphilic nature and high Hydrophile-Lipophile Balance (HLB) value of 29, P188 is used as a stabilizer/emulsifier in many cosmetics and pharmaceutical preparations. While the applications of P188 as an excipient are widely explored, the data on the pharmacological activity of P188 are scarce. Notably, the neuroprotective potential of P188 has gained a lot of interest. Therefore, this systematic review is aimed at summarizing evidence of neuroprotective potential of P188 in CNS disorders. The PRISMA model was used, and five databases (Google Scholar, Scopus, Wiley Online Library, ScienceDirect, and PubMed) were searched with relevant keywords. The search resulted in 11 articles, which met the inclusion criteria. These articles described the protective effects of P188 on traumatic brain injury or mechanical injury in cells, neurotoxicity, Parkinson's disease, Amyotrophic lateral sclerosis (ALS), and ischemia/ reperfusion injury from stroke. All the articles were original research in experimental or pre-clinical stages using animal models or in vitro systems. The reported activities demonstrated the potential of P188 as a neuroprotective agent in improving CNS conditions such as neurodegeneration.

Inhalation of dimethyl fumarate-encapsulated solid lipid nanoparticles attenuate clinical signs of experimental autoimmune encephalomyelitis and pulmonary inflammatory dysfunction in mice

RATIONALE

The FDA-approved Dimethyl Fumarate (DMF) as an oral drug for Multiple Sclerosis (MS) treatment based on its immunomodulatory activities. However, it also caused severe adverse effects mainly related to the gastrointestinal system.

OBJECTIVE

Investigated the potential effects of solid lipid nanoparticles (SLNs) containing DMF, administered by inhalation on the clinical signs, central nervous system (CNS) inflammatory response, and lung function changes in mice with experimental autoimmune encephalomyelitis (EAE).

MATERIALS AND METHODS

EAE was induced using MOG35-55 peptide in female C57BL/6J mice and the mice were treated via inhalation with DMF-encapsulated SLN (CTRL/SLN/DMF and EAE/SLN/DMF), empty SLN (CTRL/SLN and EAE/SLN), or saline solution (CTRL/saline and EAE/saline), every 72 h during 21 days.

RESULTS

After 21 days post-induction, EAE mice treated with DMF-loaded SLN, when compared with EAE/saline and EAE/SLN, showed decreased clinical score and weight loss, reduction in brain and spinal cord injury and inflammation, also related to the increased influx of Foxp3+ cells into the spinal cord and lung tissues. Moreover, our data revealed that EAE mice showed signs of respiratory disease, marked by increased vascular permeability, leukocyte influx, production of TNF-α and IL-17, perivascular and peribronchial inflammation, with pulmonary mechanical dysfunction associated with loss of respiratory volumes and elasticity, which DMF-encapsulated reverted in SLN nebulization.

CONCLUSION

Our study suggests that inhalation of DMF-encapsulated SLN is an effective therapeutic protocol that reduces not only the CNS inflammatory process and disability progression, characteristic of EAE disease, but also protects mice from lung inflammation and pulmonary dysfunction.

Poloxamer 188 Attenuates Ischemia-Reperfusion-Induced Lung Injury by Maintaining Cell Membrane Integrity and Inhibiting Multiple Signaling Pathways

Background: Poloxamer 188 (P188) possesses anti-inflammatory properties and can help to maintain plasma membrane function. P188 has been reported to exert beneficial effects in the treatment of various disorders. However, the effects of P188 in ischemia/reperfusion (IR)-induced acute lung injury have not been examined.

Methods: We investigated the ability of P188 to attenuate IR-induced acute lung injury in rats and hypoxia/reoxygenation (HR) injury in murine epithelial cells. Isolated perfused rat lungs were exposed to 40 min ischemia followed by 60 min reperfusion to induce IR injury.

Results: IR led to lung edema, increased pulmonary arterial pressure, promoted lung tissue inflammation and oxidative stress, and upregulated the levels of TNF-α, IL-6 and CINC-1, and increased Lactic dehydrogenase (LDH) activity in bronchoalveolar lavage fluid. IR also downregulated the levels of inhibitor of κB (IκB-α), upregulated nuclear factor (NF)-κB (NF-κB), and promoted apoptosis in lung tissues. P188 significantly suppressed all these effects. In vitro, P188 also exerted a similar effect in murine lung epithelial cells exposed to HR. Furthermore, P188 reduced the number of propidium iodide-positive cells, maintained cell membrane integrity, and enhanced cell membrane repair following HR.

Conclusion: We conclude that P188 protects against lung IR injury by suppressing multiple signaling pathways and maintaining cell membrane integrity.

Poloxamer 188 exerts a cryoprotective effect on rooster sperm and allows decreasing glycerol concentration in the freezing extender

Glycerol is the most widely used cryoprotectant for rooster sperm because it declines the mechanical damage to sperm during the freezing process. Despite its high molecular weight and viscosity, which may be cytotoxic, glycerol can cause damage to cells during the cryopreservation process, resulting in less fertility. Poloxamer 188 (P188) is an embryo cryopreservation supplement effective in many species and also for cell lines and plant cells. We tested the suitability of P188 in the cryopreservation of rooster sperm, considering post-thawing motility, abnormalities, membrane functionality (hypo-osmotic swelling test), mitochondrial activity, viability, apoptosis status, reactive oxygen species production, and ATP content after thawing and the fertility and hatchability after AI. We carried out a factorial experiment with glycerol concentrations of 2% glycerol (G2) and 8% glycerol (G8) and P188 concentrations of 0% (P0), 0.1% (P0.1), 0.5% (P0.5), and 1% (P1) as fixed effects, with replicate (seven) as a random effect. Interactions between glycerol and P188 were found, with G2P1 yielding higher quality and fertility. G8P0.5 yielded better in most parameters, however, not reaching G2P1. G2P1 showed significantly higher results for total and progressive motility, kinetic parameters (average path velocity, straight-line velocity, and linearity), membrane functionality, viability, mitochondrial activity, and ATP content and lower apoptosis, dead sperm, and reactive oxygen species production. G2P1 resulted in the highest percentages of fertilized and hatched eggs, with no effects in the hatched eggs ratio. Interestingly, G2 was less efficient in many parameters than G8 when combined with P0 and P0.1, being equivalent to G8 with P0.5 and superior to any G8 treatment as G2P1. In conclusion, P188 could improve rooster semen cryopreservation and allow reduction of glycerol in extenders, with a consequent impact in the poultry industry.

Cardiac Muscle Membrane Stabilization in Myocardial Reperfusion Injury

•

In myocardial ischemia, the integrity of the cardiac sarcolemma is severely stressed in the critical earliest moments upon reperfusion. Bolstering sarcolemma integrity improves myocyte survival.

•

This review focuses on cardiac sarcolemma stability and its role as a therapeutic target in ischemia-reperfusion injury.

•

Synthetic block copolymers have been shown to interface with the muscle membrane to confer membrane stabilization during stress.

•

Integrated multidisciplinary research teams, spanning cardiology, physiology, chemistry, and chemical engineering are essential to guide future mechanistic and translational studies of novel chemical-based membrane stabilizers for preserving viable heart muscle during ischemia-reperfusion injury in human patients.

The phospholipid bilayer membrane that surrounds each cell in the body represents the first and last line of defense for preserving overall cell viability. In several forms of cardiac and skeletal muscle disease, deficits in the integrity of the muscle membrane play a central role in disease pathogenesis. In Duchenne muscular dystrophy, an inherited and uniformly fatal disease of progressive muscle deterioration, muscle membrane instability is the primary cause of disease, including significant heart disease, for which there is no cure or highly effective treatment. Further, in multiple clinical forms of myocardial ischemia-reperfusion injury, the cardiac sarcolemma is damaged and this plays a key role in disease etiology. In this review, cardiac muscle membrane stability is addressed, with a focus on synthetic block copolymers as a unique chemical-based approach to stabilize damaged muscle membranes. Recent advances using clinically relevant small and large animal models of heart disease are discussed. In addition, mechanistic insights into the copolymer-muscle membrane interface, featuring atomistic, molecular, and physiological structure-function approaches are highlighted. Collectively, muscle membrane instability contributes significantly to morbidity and mortality in prominent acquired and inherited heart diseases. In this context, chemical-based muscle membrane stabilizers provide a novel therapeutic approach for a myriad of heart diseases wherein the integrity of the cardiac muscle membrane is at risk.

Preparation, characterization, and in vitro/vivo evaluation of polymer-assisting formulation of atorvastatin calcium based on solid dispersion technique

Due to low solubility and bioavailability, atorvastatin calcium is confronted with challenge in conceiving appropriate formulation. Solid dispersion of atorvastatin calcium was prepared through the solvent evaporation method, with Poloxamer 188 as hydrophilic carriers. This formulation was then characterized by scanning electron microscopy, differential scanning calorimetry, powder X-ray diffraction and fourier transform infrared spectroscopy. Moreover, all these studies suggested the conversion of crystalline atorvastatin calcium. In addition, the drug solubility studies as well as dissolution rates compared with bulk drug and market tablets Lipitor were also examined. Furthermore, the study investigated the pharmacokinetics after oral administration of Lipitor and solid dispersion. And the AUC_0–8 h and C_max increased after taking ATC-P188 solid dispersion orally compared with that of Lipitor. All these could be demonstrated that ATC-P188 solid dispersions would be prospective means for enhancing higher oral bioavailability of ATC.

Muscle membrane integrity in Duchenne muscular dystrophy: recent advances in copolymer-based muscle membrane stabilizers

The scientific premise, design, and structure-function analysis of chemical-based muscle membrane stabilizing block copolymers are reviewed here for applications in striated muscle membrane injury. Synthetic block copolymers have a rich history and wide array of applications from industry to biology. Potential for discovery is enabled by a large chemical space for block copolymers, including modifications in block copolymer mass, composition, and molecular architecture. Collectively, this presents an impressive chemical landscape to leverage distinct structure-function outcomes. Of particular relevance to biology and medicine, stabilization of damaged phospholipid membranes using amphiphilic block copolymers, classified as poloxamers or pluronics, has been the subject of increasing scientific inquiry. This review focuses on implementing block copolymers to protect fragile muscle membranes against mechanical stress. The review highlights interventions in Duchenne muscular dystrophy, a fatal disease of progressive muscle deterioration owing to marked instability of the striated muscle membrane. Biophysical and chemical engineering advances are presented that delineate and expand upon current understanding of copolymer-lipid membrane interactions and the mechanism of stabilization. The studies presented here serve to underscore the utility of copolymer discovery leading toward the therapeutic application of block copolymers in Duchenne muscular dystrophy and potentially other biomedical applications in which membrane integrity is compromised.