Complement system and the brain: Selected pathologies and avenues toward engineering of neurological nanomedicines

Physiological and Pathological Factors Affecting Drug Delivery to the Brain by Nanoparticles

The prevalence of neurological/neurodegenerative diseases, such as Alzheimer's disease is known to be increasing due to an aging population and is anticipated to further grow in the decades ahead. The treatment of brain diseases is challenging partly due to the inaccessibility of therapeutic agents to the brain. An increasingly important observation is that the physiology of the brain alters during many brain diseases, and aging adds even more to the complexity of the disease. There is a notion that the permeability of the blood-brain barrier (BBB) increases with aging or disease, however, the body has a defense mechanism that still retains the separation of the brain from harmful chemicals in the blood. This makes drug delivery to the diseased brain, even more challenging and complex task. Here, the physiological changes to the diseased brain and aged brain are covered in the context of drug delivery to the brain using nanoparticles. Also, recent and novel approaches are discussed for the delivery of therapeutic agents to the diseased brain using nanoparticle based or magnetic resonance imaging guided systems. Furthermore, the complement activation, toxicity, and immunogenicity of brain targeting nanoparticles as well as novel in vitro BBB models are discussed.

Toxicity of Carbon Nanotubes: Molecular Mechanisms, Signaling Cascades, and Remedies in Biomedical Applications

Carbon nanotubes (CNTs) are the most studied allotropic form of carbon. They can be used in various biomedical applications due to their novel physicochemical properties. In particular, the small size of CNTs, with a large surface area per unit volume, has a considerable impact on their toxicity. Despite of the use of CNTs in various applications, toxicity is a big problem that requires more research. In this Review, we discuss the toxicity of CNTs and the associated mechanisms. Physicochemical factors, such as metal impurities, length, size, solubilizing agents, CNTs functionalization, and agglomeration, that may lead to oxidative stress, toxic signaling pathways, and potential ways to control these mechanisms are also discussed. Moreover, with the latest mechanistic evidence described in this Review, we expect to give new insights into CNTs' toxicological effects at the molecular level and provide new clues for the mitigation of harmful effects emerging from exposure to CNTs.

Adult stem cells in psychiatric disorders - New discoveries in peripheral blood

The new area of research in psychiatric disorders is concerned with abnormal regeneration processes. The role of brain neurogenesis has been studied for decades. New discoveries, concerned with the pluripotency of VSEL cells and the role of factors involved in stem cell trafficking in peripheral blood create hope that it will be possible to develop a better understanding of the processes of neuroregeneration/neurodegeneration. There is an ongoing research investigating concentrations of: sphingosine -1-phosphate, SDF-1, elements of complement cascade, and stem cells in peripheral blood, including their possible connection to psychiatric disorders. Collected data, suggesting an abnormal course of regeneration processes in psychiatric disorders, raises hope of finding new potential markers of psychosis and anxiety disorders.

Assessment of Complement Cascade Components in Patients With Bipolar Disorder

Introduction: The immune system is undoubtedly involved in the pathogenesis of various psychiatric disorders, such as schizophrenia, bipolar disorder, or depression. Although its role is not fully understood, it appears that this area of research can help to understand the etiology of mental illness. One of the components of the human immune system is the complement system, which forms a part of the innate immune response. Physiologically, except for its essential protective role, it is a vital element in the regeneration processes, including neurogenesis. To date, few studies have tried to clarify the role of the complement cascade in mental disorders. Materials and Methods: We evaluated concentrations of C3a, C5a, and C5b-9 complement cascade components in the peripheral blood of 30 patients suffering from bipolar disorder (BD) for at least 10 years, in euthymia, who were not treated with lithium salts. In addition, we divided our study sample into BD type I (BD-I, 22 persons), and BD type II (BD-II, 8 patients). The control group consisted of 30 healthy volunteers matched for age, sex, BMI, and smoking habits. Results: Compared to healthy controls, BD patients had elevated concentrations of all the investigated components. Furthermore, in patients with BD-II, we observed higher concentrations of C5b-9 as compared to patients with BD-I. However, there was a significant effect of BD diagnosis only on the levels of C3a and C5a but not on the level of C5b-9 after adjustment for potential confounding factors. Conclusions: Increased concentrations of components C3a and C5a of the complement system in the investigated group as compared to healthy controls suggest involvement of the complement cascade in the pathogenesis of BD, and provides further evidence of immune system dysregulation in BD patients.

Mobilization of Peripheral Blood Stem Cells and Changes in the Concentration of Plasma Factors Influencing their Movement in Patients with Panic Disorder

In this paper we examined whether stem cells and factors responsible for their movement may serve as new biological markers of anxiety disorders. The study was carried out on a group of 30 patients diagnosed with panic disorder (examined before and after treatment), compared to 30 healthy individuals forming the control group. We examined the number of circulating HSCs (hematopoetic stem cells) (Lin−/CD45 +/CD34 +) and HSCs (Lin−/CD45 +/AC133 +), the number of circulating VSELs (very small embryonic-like stem cells) (Lin−/CD45−/CD34 +) and VSELs (Lin−/CD45−/AC133 +), as well as the concentration of complement components: C3a, C5a and C5b-9, SDF-1 (stromal derived factor) and S1P (sphingosine-1-phosphate). Significantly lower levels of HSCs (Lin−/CD45 +/AC133 +) have been demonstrated in the patient group compared to the control group both before and after treatment. The level of VSELs (Lin−/CD45−/CD133 +) was significantly lower in the patient group before treatment as compared to the patient group after treatment.

The levels of factors responsible for stem cell movement were significantly lower in the patient group compared to the control group before and after treatment. It was concluded that the study of stem cells and factors associated with their movement can be useful in the diagnostics of panic disorder, as well as differentiating between psychotic and anxiety disorders.

Poly(lactic acid)-based particulate systems are promising tools for immune modulation

Poly(lactic acid) (PLA) is one of the most successful and versatile polymers explored for controlled delivery of bioactive molecules. Its attractive properties of biodegradability and biocompatibility in vivo have contributed in a meaningful way to the approval of different products by the FDA and EMA for a wide range of biomedical and pharmaceutical applications, in the past two decades. This polymer has been widely used for the preparation of particles as delivery systems of several therapeutic molecules, including vaccines. These PLA vaccine carriers have shown to induce a sustained and targeted release of different bacterial, viral and tumor-associated antigens and adjuvants in vivo, triggering distinct immune responses. The present review intends to highlight and discuss the major advantages of PLA as a promising polymer for the development of potent vaccine delivery systems against pathogens and cancer. It aims to provide a critical discussion based on preclinical data to better understand the major effect of PLA-based carrier properties on their interaction with immune cells and thus their role in the modulation of host immunity.

STATEMENT OF SIGNIFICANCE

During the last decades, vaccination has had a great impact on global health with the control of many severe diseases. Polymeric nanosystems have emerged as promising strategies to stabilize vaccine antigens, promoting their controlled release to phagocytic cells, thus avoiding the need for multiple administrations. One of the most promising polymers are the aliphatic polyesters, which include the poly(lactic acid). This is a highly versatile biodegradable and biocompatible polymer. Products containing this polymer have already been approved for all food and some biomedical applications. Despite all favorable characteristics presented above, PLA has been less intensively discussed than other polymers, such as its copolymer PLGA, including regarding its application in vaccination and particularly in tumor immunotherapy. The present review discusses the major advantages of poly(lactic acid) for the development of potent vaccine delivery systems, providing a critical view on the main properties that determine their effect on the modulation of immune cells.

Identification and characteristic of three members of the C1q/TNF-related proteins (CTRPs) superfamily in Eudontomyzon morii

C1q is the target recognition protein of the classical complement pathway and a major connecting link between innate and acquired immunity. C1q and the multifunctional tumor necrosis factor (TNF) ligand family is of similar crystal structures, are designated the C1q/TNF-related proteins (CTRPs) superfamily. They are involved in processes as diverse as host defense, inflammation, apoptosis, autoimmunity, cell differentiation, organogenesis, hibernation and insulinresistant obesity. In this study, three members of the CTRPs superfamily were isolated and characterized in Yalu River lampreys (Eudontomyzon morii), and are respectively named LaC1qC, LaCTRP1, LaCTRP9. The full-length cDNAs of C1qC-like (LaC1qAL), CTRP1-like (LaCTRP1), and CTRP9-like (LaCTRP9) consist of 723, 762 and 825 bp of nucleotide sequence encoding polypeptides of 241, 254 and 275 amino acids, respectively. All-three proteins share three common domains: a signal peptide at the N terminus, a collagenous domain (characteristic Gly-X-Y repeats), and a C-terminal globular domain. In addition, the higher expression level of the three proteins in heart by RT-PCR and real-time PCR tissue profiling implied that they might involve in immune response or injury repair of the heart in lamprey.

Complement analysis 2016: Clinical indications, laboratory diagnostics and quality control

In recent years, complement analysis of body fluids and biopsies, going far beyond C3 and C4, has significantly enhanced our understanding of the disease process. Such expanded complement analysis allows for a more precise differential diagnosis and for critical monitoring of complement-targeted therapy. These changes are a result of the growing understanding of the involvement of complement in a diverse set of disorders. To appreciate the importance of proper complement analysis, it is important to understand the role it plays in disease. Historically, it was the absence of complement as manifested in severe infection that was noted. Since then complement has been connected to a variety of inflammatory disorders, such as autoimmune diseases and hereditary angioedema. While the role of complement in the rejection of renal grafts has been known longer, the significant impact of complement. In certain nephropathies has now led to the reclassification of some rare kidney diseases and an increased role for complement analysis in diagnosis. Even more unexpected is that complement has also been implicated in neural, ophtalmological and dermatological disorders. With this level of involvement in some varied and impactful health issues proper complement testing is clearly important; however, analysis of the complement system varies widely among laboratories. Except for a few proteins, such as C3 and C4, there are neither well-characterized standard preparations nor calibrated assays available. This is especially true for the inter-laboratory variation of tests which assess classical, alternative, or lectin pathway function. In addition, there is a need for the standardization of the measurement of complement activation products that are so critical in determining whether clinically relevant complement activation has occurred in vivo. Finally, autoantibodies to complement proteins (e.g. anti-C1q), C3 and C4 convertases (C3 and C4 nephritic factor) or to regulatory proteins (e.g. anti-C1inhibitor, anti-factor H) are important in defining autoimmune processes and diseases based on complement dysregulation. To improve the quality of complement laboratory analysis a standardization commmittee of the International Complement Society (ICS) and the International Union of Immunological Societies (IUIS) was formed to provide guidelines for modern complement analysis and standards for the development of international testing programs.

High levels of serum mannose-binding lectins are associated with the severity and clinical outcomes of severe traumatic brain injury

BACKGROUND

Mannose-binding lectin (MBL) is a key component of innate immunity. The expression of cortical MBL is up-regulated after clinical and experimental head trauma. This study aimed to assess the association of serum MBL levels with injury severity and long-term clinical outcomes after severe traumatic brain injury (STBI).

METHODS

Serum MBL levels were measured in 122 patients and 100 healthy controls. Multivariate analyses were used to analyze the relationship between serum MBL levels and trauma severity reflected by Glasgow Coma Scale scores as well as between serum MBL levels and 6-month mortality and unfavorable outcome (Glasgow Outcome Scale score: 1-3). A receiver operating characteristic (ROC) curve was structured to evaluate the prognostic predictive performance of serum MBL levels.

RESULTS

Compared with healthy controls, serum MBL levels of patients were markedly elevated. Using multivariate analyses, serum MBL levels were found to be associated closely with Glasgow Coma Scale (GCS) scores and MBL emerged as an independent predictor for 6-month mortality and unfavorable outcome. Under ROC curve, serum MBL levels and GCS scores possessed similar prognostic predictive values.

CONCLUSION

Increased serum level of MBL was independently associated with head trauma severity and long-term clinical outcomes of STBI.

Nanomedicine for the treatment of Alzheimer's disease

Alzheimer's disease affects more than 35 million people worldwide and this number is presumed to double by the year 2050. Currently, there is no efficient therapy for this disorder but a promising approach is represented by nanotechnology, easily multifunctionalizable devices with size in the order of billionth of meter. This review provides a concise survey on the nano-based strategies for Alzheimer's disease treatment, aiming at carrying drugs across the blood–brain barrier, in particular to target the metabolism of β-amyloid peptide, a pivotal player in this pathology.

Cancer nanomedicine and the complement system activation paradigm: anaphylaxis and tumour growth

A wide variety of nanocarriers and particularly cancer nanomedicines activate the complement system, which is the first line of the innate immune defence mechanism. Complement activation may induce inflammatory responses, but such responses arising from uncontrolled complement activation could be life threatening. Accordingly, the role of complement in initiation of adverse reactions to particulate and polymer therapeutics is receiving increasing attention. Furthermore, the involvement of complement-activation products in promoting tumour growth has also been indicated. This could be of serious concern for development of cancer nanomedicines and cancer nanotechnology initiatives. These concepts are reviewed with preliminary evidence that intra-tumoural accumulation of model long circulating nanoparticles could promote tumour growth.

Novel evidence for enhanced stem cell trafficking in antipsychotic-naïve subjects during their first psychotic episode

In this study, we tested the novel hypothesis that stem cells and those factors that modulate their trafficking may be biological markers for acute psychosis. Twenty-eight subjects during their first nonaffective psychotic episode were investigated before and after antipsychotic treatment and were compared with 35 healthy controls (CG); the psychotic group (PG) was divided into "schizophrenic" (SG) and "non-schizophrenic" (NG) subgroups. We examined the number of circulating Lin(-)/CD45(-)/CD34(+) and Lin(-)/CD45(-)/CD133(+) very small embryonic-like stem cells (VSELs), which express markers of the neural lineage, and also the plasma levels of factors that modulate their trafficking: the C3a, C5a, and C5b-9 activated complement cascade components, stromal-derived factor 1, and sphingosine-1-phosphate (S1P). We found that the mean numbers of Lin(-)/CD45(-)/CD34(+) VSELs and the plasma levels of S1P prior to treatment differ between the CG and PG and that these cells express markers of neural lineage. The number of Lin(-)/CD45(-)/CD133(+) VSELs in peripheral blood differed between the SG and NG prior to treatment. Using logistic regression analysis, we found that C3a and S1P are the best predictors of risk and are potential markers for the first psychotic episode. Furthermore, in the SG, the number of circulating Lin(-)/CD45(-)/CD34(+) VSELs and the S1P plasma level are the best predictors of risk and are proposed as novel markers for the first "schizophrenic" episode of psychosis.

Brain-targeted polymeric nanoparticles: in vivo evidence of different routes of administration in rodents

AIMS, MATERIALS & METHODS: The capacity of polymeric nanoparticles (NPs) to reach the target regardless of the administration route is a neglected field of investigation in pharmaceutical nanotechnology. Therefore, after having demonstrated in previous studies that glycopeptide-engineered NPs (g7-NPs) were able to reach the brain after intravenous administrations in rodents, this article aims to evaluate whether they can reach the CNS when administered by different routes.

RESULTS & CONCLUSIONS

The confocal microphotographs on murine brain sections showed the capability of g7-NPs to reach the target also after intraperitoneal, intranasal and oral administrations. This could open new vistas for the future application of g7-NPs in the therapeutic treatment of CNS diseases.

Perspectives on carbon nanotube-mediated adverse immune effects

Carbon nanotubes are entities of different morphology and aspect ratios with anisotropic character. Due to their unique electronic, photonic, mechanical and chemical properties, carbon nanotubes are receiving increasing attention in nanomedicine research where examples include site-specific drug and nucleic acid delivery, photodynamic therapy and photoacoustic molecular imaging. The interaction of carbon nanotubes with the immune system, which plays a key role in the recognition and elimination of foreign materials, and consequential responses, is of central importance for the proposed successful biomedical applications of nanotubes. Research in this avenue, however, is scant and the limited available data are rather contradictory. In this progress article we have collected some of the most important experimental results obtained thus far on carbon nanotube-mediated immune toxicity with an emphasis on cardiovascular exposure, including activation of the complement system, macrophage recognition and clearance, and overall effects on the functionality of different immune cells. Mapping these immune-related risks as well as understanding their molecular mechanisms is a crucial step in the development of any carbon nanotube-containing nanopharmaceuticals.