Evidence for proangiogenic cellular and humoral systemic response in patients with acute onset of spinal cord injury

Acute spinal cord injury serum biomarkers in human and rat: a scoping systematic review

STUDY DESIGN

Scoping systematic review.

OBJECTIVES

To summarize the available experimental clinical and animal studies for the identification of all CSF and serum-derived biochemical markers in human and rat SCI models.

SETTING

Tehran, Iran.

METHODS

In this scoping article, we systematically reviewed the electronic databases of PubMed, Scopus, WOS, and CENTRAL to retrieve current literature assessing the levels of different biomarkers in human and rat SCI models.

RESULTS

A total of 19,589 articles were retrieved and 6897 duplicated titles were removed. The remaining 12,692 studies were screened by their title/abstract and 12,636 were removed. The remaining 56 were considered for full-text assessment, and 11 papers did not meet the criteria, and finally, 45 studies were included. 26 studies were human observational studies comprising 1630 patients, and 19 articles studied SCI models in rats, including 832 rats. Upon reviewing the literature, we encountered a remarkable heterogeneity in terms of selected biomarkers, timing, and method of measurement, studied models, extent, and mechanism of injury as well as outcome assessment measures.

CONCLUSIONS

The specific expression and distribution patterns of biomarkers in relation to spinal cord injury (SCI) phases, and their varied concentrations over time, suggest that cerebrospinal fluid (CSF) and blood biomarkers are effective measures for assessing the severity of SCI.

Immune Status of Individuals with Traumatic Spinal Cord Injury: A Systematic Review and Meta-Analysis

Individuals with spinal cord injury (SCI) have higher infection rates compared to those without SCI. In this review, the immune status difference between individuals with and without traumatic SCI is investigated by examining their peripheral immune cells and markers. PubMed, Cochrane, EMBASE, and Ovid MEDLINE were searched without language or date restrictions. Studies reporting peripheral immune markers' concentration and changes in functional capabilities of immune cells that compared individuals with and without SCI were included. Studies with participants with active infection, immune disease, and central nervous system (CNS) immune markers were excluded. The review followed the PRISMA guidelines. Effect estimates were measured by Weighted Mean Difference (WMD) using a random-effects model. Study quality was assessed using the National Heart, Lung, and Blood Institute Quality Assessment Tool. Fifty-four studies (1813 with SCI and 1378 without SCI) contributed to the meta-analysis. Leukocytes (n = 23, WMD 0.78, 95% CI 0.17; 1.38, I2 83%), neutrophils (n = 11, WMD 0.76, 95% CI 0.09; 1.42, I2 89%), C-reactive protein (CRP) (n = 12, WMD 2.25, 95% CI 1.14; 3.56, I2 95%), and IL6 (n = 13, WMD 2.33, 95% CI 1.20; 3.49, I2 97%) were higher in individuals with SCI vs. without SCI. Clinical factors (phase of injury, completeness of injury, sympathetic innervation impairment, age, sex) and study-related factors (sample size, study design, and serum vs. plasma) partially explained heterogeneity. Immune cells exhibited lower functional capability in individuals with SCI vs. those without SCI. Most studies (75.6%) had a moderate risk of bias. The immune status of individuals with SCI differs from those without SCI and is clinically influenced by the phase of injury, completeness of injury, sympathetic innervation impairment, age, and sex. These results provide information that is vital for monitoring and management strategies to effectively improve the immune status of individuals with SCI.

Serum Angiopoietin-2 level increase differs between polytraumatized patients with and without central nervous system injuries

Since endothelial cells rapidly release Angiopoietin-2 (Ang-2) in response to vascular injury and inflammatory stimuli, we aimed to investigate if its serum levels increase in polytraumatized patients. Our cohort study evaluated 28 blunt polytrauma survivors (mean age, 38.4 years; median ISS, 34) who were directly admitted to our level I trauma center in 2018. We assessed the serum Ang-2 level at admission and on days 1, 3, 5, 7, and 10 during hospitalization. Ang-2 was released into the circulation immediately after polytrauma. At admission (day 0), it amounted to 8286 ± 5068 pg/mL, three-and-a-half times the reference value of 2337 ± 650 pg/mL assessed in a healthy control group. Subgroup analysis provided a higher mean Ang-2 level in the CNSI group combining all patients suffering a brain or spinal cord injury compared to the non-CNSI group solely on day 0 [11083 ± 5408 pg/mL versus 3963 ± 2062 pg/mL; p < 0.001]. Whereas the mean Ang-2 level increased only in the non-CNSI group from day 0 to day 3 (p = 0.009), the respective curves showed similar continuous decreases starting with day 3. Multivariate logistic regression analysis revealed an association between the Ang-2 day 0 level and the presence of a CNSI (OR = 1.885; p = 0.048). ROC analysis provided a cutoff level of 5352 pg/mL. In our study group, serum Ang-2 levels assessed at admission differed between polytraumatized patients with and without brain or spinal cord injuries. Based on our findings, we consider serum Ang-2 levels an effective biomarker candidate for indicating CNSI in these patients at admission, worthy of further evaluation in large multicenter studies.

Antidepressants Promote and Prevent Cancers

The review states that antidepressants (ADs) increase brain-derived neurotrophic factor (BDNF) transmission concomitantly in the brain and the blood: ADs increasing BDNF synthesis in specific areas of the central nervous system (CNS) could presumably affect megakaryocyte's production of platelets. ADs increase BDNF levels in the CNS and improve mood. In the blood, ADs increase BDNF release from platelets. The hypothesis presented here is that the release of BDNF from platelets contributes to the ADs effects on neurogenesis and on tumor growth in the cancer disease. Oncological studies indicate that chemicals ADs exert an aggravating effect on the cancer disease, possibly by promoting proplatelets formation and enhancing BDNF release from platelets in the tumor.

Role of Angiopoietin-2 in Vascular Physiology and Pathophysiology

Angiopoietins 1–4 (Ang1–4) represent an important family of growth factors, whose activities are mediated through the tyrosine kinase receptors, Tie1 and Tie2. The best characterized are angiopoietin-1 (Ang1) and angiopoietin-2 (Ang2). Ang1 is a potent angiogenic growth factor signaling through Tie2, whereas Ang2 was initially identified as a vascular disruptive agent with antagonistic activity through the same receptor. Recent data demonstrates that Ang2 has context-dependent agonist activities. Ang2 plays important roles in physiological processes and the deregulation of its expression is characteristic of several diseases. In this review, we summarize the activity of Ang2 on blood and lymphatic endothelial cells, its significance in human physiology and disease, and provide a current view of the molecular signaling pathways regulated by Ang2 in endothelial cells.

Systemic microcirculation dysfunction after low thoracic spinal cord injury in mice

BACKGROUND

Spinal cord injury (SCI) disturbs the autonomic nervous system and induces dysfunction or failure of multiple organs. The systemic microcirculation disturbance that contributes to the complications associated with SCI remains to be clarified.

METHODS

We used male mice (29-32 g) and modified weight-drop injury at T10 to evaluate the systemic microcirculation dysfunction during the first 2 weeks after SCI. We determined permeability and microvascular blood flow in several organs and evaluated their vasomotor function. We also measured circulating endothelial cells (CECs), circulating endothelial progenitor cells (CEPCs), circulating pericyte progenitor cells (CPPCs), and serum proinflammatory cytokines.

RESULTS

The endothelial permeability of almost all organs increased after SCI. Microvascular blood flow decreased in the bladder and kidney and increased in the spleen and was accompanied by endothelial vasomotor dysfunction. SCI also induced an increase in CECs, CEPCs, and CPPCs in peripheral blood. Finally, we confirmed changes in a systemic cytokine profile (interleukin [IL]-3, IL-6, IL-10, IL-13, granulocyte colony-stimulating factor, and regulated on activation normal T cell expressed and secreted) after SCI.

CONCLUSIONS

These data indicate that a systemic microcirculation disturbance occurs after SCI. This information may play a key role in the development of effective therapeutic strategies for SCI.

Liver-Selective MMP-9 Inhibition in the Rat Eliminates Ischemia-Reperfusion Injury and Accelerates Liver Regeneration

Recruitment of liver sinusoidal endothelial cell progenitor cells (sprocs) from the bone marrow by vascular endothelial growth factor-stromal cell-derived factor-1 (VEGF-sdf-1) signaling promotes recovery from injury and drives liver regeneration. Matrix metalloproteinases (MMPs) can proteolytically cleave VEGF, which might inhibit progenitor cell recruitment, but systemic matrix metalloproteinase inhibition might prevent efflux of progenitors from the bone marrow. The hypothesis for this study was that liver-selective MMP-9 inhibition would protect the hepatic VEGF-sdf-1 signaling pathway, enhance bone marrow sproc recruitment, and thereby ameliorate liver injury and accelerate liver regeneration, whereas systemic MMP inhibition would impair bone marrow sproc mobilization and therefore have less benefit or be detrimental. We found that liver-selective MMP-9 inhibition accelerated liver regeneration after partial hepatectomy by 40%, whereas systemic MMP inhibition impaired liver regeneration. Liver-selective MMP-9 inhibition largely abolished warm ischemia-reperfusion injury. In the extended hepatectomy model, liver-selective MMP-9 inhibition restored liver sinusoidal endothelial cell integrity, enhanced liver regeneration, and reduced ascites. Liver-selective MMP-9 inhibition markedly increased recruitment and engraftment of bone marrow sprocs, whereas systemic MMP inhibition impaired mobilization of bone marrow sprocs and their hepatic engraftment. Hepatic MMP-9 proteolytically cleaved VEGF after partial hepatectomy. Liver-selective MMP-9 inhibition prevented VEGF cleavage and doubled protein expression of VEGF and its downstream signaling partner sdf-1. In contrast, systemic MMP inhibition enhanced recruitment and engraftment of infused allogeneic progenitors. Conclusion: Liver-selective MMP inhibition prevents proteolytic cleavage of hepatic VEGF, which enhances recruitment and engraftment of bone marrow sprocs after liver injury. This ameliorates injury and accelerates liver regeneration. Liver-selective MMP-9 inhibition may be a therapeutic tool for liver injury that damages the vasculature, whereas systemic MMP inhibition can enhance the benefit of stem cell therapy with endothelial progenitor cells.

Spleen Regulates Hematopoietic Stem/Progenitor Cell Functions Through Regulation of EGF in Cirrhotic Hypersplenism

BACKGROUND

Hematopoietic abnormality is a common cause of cirrhotic hypersplenism (CH) complications and death; it causes serious adverse effects and is associated with bleeding, anemia, infection in CH patients. However, the underlying mechanism is unclear.

AIMS

We aimed to investigate the effects of the spleen on hematopoiesis and hematopoietic stem/progenitor cells (HSPCs) in CH patients.

METHODS

Eleven CH patients were enrolled to assess the effects of the spleen on HSPC functions. Hematopoietic changes were examined by flow cytometry analysis. HSPC functions were detected with colony-forming assays and in vitro cell cultures. Enzyme-linked immunosorbent assay (ELISA) was used to test the concentration of epithelial growth factor (EGF).

RESULTS

The number of HSPCs was decreased in CH patients and was rescued after splenectomy. Serum from CH patients dysregulated HSPCs function, and serum from splenectomy patients restored the dysregulated HSPC function in vitro. The concentration of EGF was decreased in CH patients and was restored to normal level after splenectomy. EGF rescued the dysregulated HSPCs function in vitro.

CONCLUSIONS

The spleen can regulate the functions of HSPCs in CH patients by regulating EGF signaling. EGF may be a therapeutic target for CH treatment.

The Use of Endothelial Progenitor Cells for the Regeneration of Musculoskeletal and Neural Tissues

Endothelial progenitor cells (EPCs) derived from bone marrow and blood can differentiate into endothelial cells and promote neovascularization. In addition, EPCs are a promising cell source for the repair of various types of vascularized tissues and have been used in animal experiments and clinical trials for tissue repair. In this review, we focused on the kinetics of endogenous EPCs during tissue repair and the application of EPCs or stem cell populations containing EPCs for tissue regeneration in musculoskeletal and neural tissues including the bone, skeletal muscle, ligaments, spinal cord, and peripheral nerves. EPCs can be mobilized from bone marrow and recruited to injured tissue to contribute to neovascularization and tissue repair. In addition, EPCs or stem cell populations containing EPCs promote neovascularization and tissue repair through their differentiation to endothelial cells or tissue-specific cells, the upregulation of growth factors, and the induction and activation of endogenous stem cells. Human peripheral blood CD34(+) cells containing EPCs have been used in clinical trials of bone repair. Thus, EPCs are a promising cell source for the treatment of musculoskeletal and neural tissue injury.

The role of endoglin in post-ischemic revascularization

Following arterial occlusion, blood vessels respond by forming a new network of functional capillaries (angiogenesis), by reorganizing preexisting capillaries through the recruitment of smooth muscle cells to generate new arteries (arteriogenesis) and by growing and remodeling preexisting collateral arterioles into physiologically relevant arteries (collateral development). All these processes result in the recovery of organ perfusion. The importance of endoglin in post-occlusion reperfusion is sustained by several observations: (1) endoglin expression is increased in vessels showing active angiogenesis/remodeling; (2) genetic endoglin haploinsufficiency in humans causes deficient angiogenesis; and (3) the reduction of endoglin expression by gene disruption or the administration of endoglin-neutralizing antibodies reduces angiogenesis and revascularization. However, the precise role of endoglin in the several processes associated with revascularization has not been completely elucidated and, in some cases, the function ascribed to endoglin by different authors is controversial. The purpose of this review is to organize in a critical way the information available for the role of endoglin in several phenomena (angiogenesis, arteriogenesis and collateral development) associated with post-ischemic revascularization.

Wnt3a is critical for endothelial progenitor cell-mediated neural stem cell proliferation and differentiation

The present study aimed to determine whether co-culture with bone marrow‑derived endothelial progenitor cells (EPCs) affects the proliferation and differentiation of spinal cord-derived neural stem cells (NSCs), and to investigate the underlying mechanism. The proliferation and differentiation of the NSCs were evaluated by an MTT cell proliferation and cytotoxicity assay, and immunofluorescence, respectively. The number of neurospheres and the number of β‑tubulin III‑positive cells were detected by microscopy. The wingless‑type MMTV integration site family, member 3a (Wnt3a)/β-catenin signaling pathway was analyzed by western blot analysis and reverse transcription‑quantitative polymerase chain reaction to elucidate the possible mechanisms of EPC‑mediated NSC proliferation and differentiation. The results revealed that co‑culture with EPCs significantly induced NSC proliferation and differentiation. In addition, co‑culture with EPCs markedly induced the expression levels of Wnt3a and β‑catenin and inhibited the phosphorylation of glycogen synthase kinase 3β (GSK‑3β). By contrast, Wnt3a knockdown using a short hairpin RNA plasmid in the EPCs reduced EPC‑mediated NSC proliferation and differentiation, accompanied by inhibition of the EPC‑mediated expression of β‑catenin, and its phosphorylation and activation of GSK‑3β. Taken together, the findings of the present study demonstrated that Wnt3a was critical for EPC‑mediated NSC proliferation and differentiation.