The Effects of Granulocyte-Colony Stimulating Factor on Regeneration in Nerve Crush Injuries in Rats

Simple dysmood disorder, a mild subtype of major depression, is not an inflammatory condition: Depletion of the compensatory immunoregulatory system

BACKGROUND

A recent study conducted by the laboratory of the first author revealed that major depression is composed of two distinct subtypes: major dysmood disorder (MDMD) and simple dysmood disorder (SDMD). The latter is a less severe phenotype with fewer aberrant biological pathways. MDMD, but not SDMD, patients were identified to have highly sensitized cytokine/growth factor networks using stimulated whole blood cultures. However, no information regarding serum cytokines/chemokines/growth factors in SDMD is available.

OBJECTIVES

This case-control study compares 48 serum cytokines/chemokines/growth factors in academic students with SDMD (n = 64) and first episode (FE)-SDMD (n = 47) to those of control students (n = 44) using a multiplex assay.

FINDINGS

Both FE-SDMD and SDMD exhibited a notable inhibition of immune profiles, such as the compensatory immunoregulatory response system (CIRS) and alternative M2 macrophage and T helper-2 (Th-2) profiles. We observed a substantial reduction in the serum concentrations of five proteins: interleukin (IL)-4, IL-10, soluble IL-2 receptor (sIL-2R), IL-12p40, and macrophage colony-stimulating factor. A considerable proportion of the variability observed in suicidal behaviors (26.7 %) can be accounted for by serum IL-4, IL-10, and sIL-2R (all decreased), CCL11 (eotaxin) and granulocyte CSF (both increased). The same biomarkers (except for IL-10), accounted for 25.5 % of the variance in SDMS severity. A significant correlation exists between decreased levels of IL-4 and elevated ratings of the brooding type of rumination.

CONCLUSIONS

SDMD is characterized by the suppression of the CIRS profile, which signifies a disruption of immune homeostasis and tolerance, rather than the presence of an inflammatory response.

Major depressive disorder, neuroticism, suicidal behaviors, and depression severity are associated with cytokine networks and their intricate interactions with metabolic syndrome

OBJECTIVES

To identify alterations in the immune profiles in outpatients with major depression (MDD), and its associations with key features, such as suicidal ideation, neuroticism, cognitive symptoms, and the depression phenome while accounting for metabolic syndrome (MetS).

METHODS

In this case-control study, we assayed 48 serum cytokines, chemokines, and growth factors in 67 healthy controls and 66 MDD outpatients. Around 50 % of the outpatient MDD and control participants had a diagnosis of MetS.

RESULTS

Ten differentially expressed proteins (DEPs) were upregulated in outpatient MDD (i.e., CXCL12, tumor necrosis factor [TNF]β, platelet-derived growth factor [PDGF], CCL11, interleukins [IL]9, IL4, CCL5, CCL2, CCL4, IL1 receptor antagonist [IL1RN]), indicating an immune and defense response. Six DEPs were downregulated (vascular endothelial growth factor A [VEGFA], IL12, CCL3, colony stimulating factor [CSF]1, IL1B, nerve growth factor [NGF]), indicating lowered neurogenesis and neuron death regulation. Significant interactions between outpatient MDD and MetS caused a) substantial increases in IL4, IL17, TNF, TNFB, CCL2, CCL5, PDGF, IL1RN; and b) downregulation of VEGFA and FGF. A large part of the variance in neuroticism (26 %), suicidal behaviors (23 %), and the MDD phenome (31 %) was predicted by immunological data and interactions between MetS and CCL5, TNFB or VEGFA.

CONCLUSION

Outpatient MDD is characterized by a cytokine profile with neurotoxic potential which partly explains neuroticism, suicidal behaviors, and the phenome's severity. Lowered IL-10 and activated cytokine profiles with neurotoxic potential are characteristics of outpatient MDD and other depression phenotypes, including severe first-episode inpatient MDD. The presence of MetS in outpatient MDD considerably activates immune profiles with neurotoxic potential. Consequently, immune studies in MDD should always be performed in subjects with and without MetS.

Conductive conduit based on electrospun poly (l-lactide-co-D, l-lactide) nanofibers containing 4-aminopyridine-loaded molecularly imprinted poly (methacrylic acid) nanoparticles used for peripheral nerve regeneration

Using biocompatible polymer nanofibrous conduits with a controlled drug delivery have attracted much attention for peripheral nerve regeneration. This work was aimed at preparing electrospun poly (l-lactide-co-D, l-lactide) (PLDLLA) containing multi-walled carbon nanotubes (MWCNTs) and 4-aminopyridine (4-AP)-loaded molecularly imprinted nanoparticles (MIP_4-AP) as well as evaluating their performance in in vitro and in vivo assessments. After synthesis of MIP_4-AP based on poly (methacrylic acid) with imprinting factor of 1.78, it was incorporated into the PLDLLA/MWCNTs nanofibers to optimize. By adjusting the process variables, the average diameter and electrical conductivity of the nanofibrous sample were 92 nm and 2870 × 10^-7 S cm^-1, respectively. Afterward, 4-AP release of the optimum sample showed the presence of MIP_4-AP leading to initial burst release decrease and plateau level postpone up to 96 h. Moreover, the culture results of PC12 as neuroblastoma cell line on optimal PLDLLA/MWCNTs/MIP_4-AP nanofibrous sample revealed the highest cell proliferation without cytotoxicity compared to neat nanofibers. Eventually, the animal model experiment exhibited that the conductive conduit based on the optimum sample was able to repair the rat's sciatic nerve after four weeks in accordance with sciatic function index and histological studies.

The impact of trophic and immunomodulatory factors on oligodendrocyte maturation: Potential treatments for encephalopathy of prematurity

Encephalopathy of prematurity (EoP) is a major cause of morbidity in preterm neonates, causing neurodevelopmental adversities that can lead to lifelong impairments. Preterm birth-related insults, such as cerebral oxygen fluctuations and perinatal inflammation, are believed to negatively impact brain development, leading to a range of brain abnormalities. Diffuse white matter injury is a major hallmark of EoP and characterized by widespread hypomyelination, the result of disturbances in oligodendrocyte lineage development. At present, there are no treatment options available, despite the enormous burden of EoP on patients, their families, and society. Over the years, research in the field of neonatal brain injury and other white matter pathologies has led to the identification of several promising trophic factors and cytokines that contribute to the survival and maturation of oligodendrocytes, and/or dampening neuroinflammation. In this review, we discuss the current literature on selected factors and their therapeutic potential to combat EoP, covering a wide range of in vitro, preclinical and clinical studies. Furthermore, we offer a future perspective on the translatability of these factors into clinical practice.

The influence of drugs on peripheral nerve regeneration

Currently, there are no established adjuvant drugs for the acceleration of peripheral nerve regeneration. In this paper, we reviewed the literature from the last 10 years and described the drugs proved to accelerate the functional and histological regeneration of the peripheral nerves, either after trauma or in neuropathy experimental models. The vast majority of the studies were experimental with very few small clinical studies, which indicates the need for prospective randomized studies to identify the best drugs to use as adjuvants for nerve regeneration.

Combination of BMSCs-laden acellular nerve xenografts transplantation and G-CSF administration promotes sciatic nerve regeneration

Peripheral nerve gaps often lead to interrupted innervation, manifesting as severe sensory and motor dysfunctions. The repairs of the nerve injuries have not achieved satisfactory curative effects in clinic. The transplantation of bone marrow stromal cells (BMSCs)-laden acellular nerve xenografts (ANX) has been proven more effective than the acellular nerve allografting. Besides, granulocyte colony-stimulating factor (G-CSF) can inhibit inflammation and apoptosis, and thus is conducive to the microenvironmental improvement of axonal regeneration. This study aims to investigate the joint effect of BMSCs-seeded ANX grafting and G-CSF administration, and explore the relevant mechanisms. Adult SD rats were divided into five groups randomly: ANX group, ANX combined with G-CSF group, BMSCs-laden ANX group, BMSCs-laden ANX combined with G-CSF group, and autograft group. Eight weeks after transplantation, the detection of praxiology and neuroelectrophysiology was conducted, and then the morphology of the regenerated nerves was analyzed. The inflammatory response and apoptosis in the nerve grafts as well as the expression of the growth-promoting factors in the regenerated tissues were further assayed. G-CSF intervention and BMSCs implanting synergistically promoted peripheral nerve regeneration and functional recovery following ANX bridging, and the restoration effect was matchable with that of the autologous nerve grafting. Moreover, local inflammation was alleviated, the apoptosis of the seeded BMSCs was decreased, and the levels of the neuromodulatory factors were elevated. In conclusion, the union application of BMSCs-implanted ANX and G-CSF ameliorated the niche of neurotization and advanced nerve regeneration substantially. The strategy achieved the favorable effectiveness as an alternative to the autotransplantation.

Biodegradable and biocompatible cationic polymer delivering microRNA-221/222 promotes nerve regeneration after sciatic nerve crush

MicroRNA (miRNA) has great potential to treat a wide range of illnesses by regulating the expression of eukaryotic genes. Biomaterials with high transfection efficiency and low toxicity are needed to deliver miRNA to target cells. In this study, a biodegradable and biocompatible cationic polymer (PDAPEI) was synthetized from low molecular weight polyethyleneimine (PEI1.8kDa) cross-linked with 2,6-pyridinedicarboxaldehyde. PDAPEI showed a lower cytotoxicity and higher transfection efficiency than PEI25kDa in transfecting miR-221/222 into rat Schwann cells (SCs). The upregulation of miR-221/222 in SCs promoted the expression of nerve growth factor and myelin basic protein in vitro. The mouse sciatic nerve crush injury model was used to evaluate the effectiveness of PDAPEI/miR-221/222 complexes for nerve regeneration in vivo. The results of electrophysiological tests, functional assessments, and histological and immunohistochemistry analyses demonstrated that PDAPEI/miR-221/222 complexes significantly promoted nerve regeneration after sciatic nerve crush, specifically enhancing remyelination. All these results show that the use of PDAPEI to deliver miR-221/222 may provide a safe therapeutic means of treating nerve crush injury and may help to overcome the barrier of biomaterial toxicity and low efficiency often encountered during medical intervention.

Synergistic effects of G-CSF and bone marrow stromal cells on nerve regeneration with acellular nerve xenografts

Peripheral nerve defects result in severe denervation presenting sensory and motor functional incapacitation. Currently, a satisfactory therapeutic treatment promoting the repair of injured nerves is not available. As shown in our previous study, acellular nerve xenografts (ANX) implanted with bone marrow stromal cells (BMSCs) replaced allografts and promoted nerve regeneration. Additionally, granulocyte-colony stimulating factor (G-CSF) has been proven to mobilize supplemental cells and enhance vascularization in the niche. Thus, the study aimed to explore whether the combination of G-CSF and BMSC-laden ANX exhibited a synergistic effect. Adult Sprague-Dawley (SD) rats were randomly divided into five groups: ANX group, ANX combined with G-CSF group, BMSCs-laden ANX group, BMSCs-laden ANX combined with G-CSF group and autograft group. Electrophysiological parameters and weight ratios of tibialis anterior muscles were detected at 8 weeks post-transplantation. The morphology of the regenerated nerves was assayed, and growth-promoting factors present in the nerve grafts following G-CSF administration or BMSCs seeding were also investigated. Nerve regeneration and functional rehabilitation induced by the combination therapy were significantly advanced, and the rehabilitation efficacy was comparable with autografting. Moreover, the expression of Schwann cell markers, neurotrophic factors and neovessel markers in the nerve grafts was substantially increased. In conclusion, G-CSF administration and BMSCs transplantation synergistically promoted the regeneration of ANX-bridged nerves, which offers a superior strategy to replace autografts in repairing peripheral nerve injuries.