The great migration of bone marrow-derived stem cells toward the ischemic brain: therapeutic implications for stroke and other neurological disorders

Accumulating laboratory studies have implicated the mobilization of bone marrow (BM)-derived stem cells in brain plasticity and stroke therapy. This mobilization of bone cells to the brain is an essential concept in regenerative medicine. Over the past ten years, mounting data have shown the ability of bone marrow-derived stem cells to mobilize from BM to the peripheral blood (PB) and eventually enter the injured brain. This homing action is exemplified in BM stem cell mobilization following ischemic brain injury. Various BM-derived cells, such as hematopoietic stem cells (HSCs), mesenchymal stem cells (MSCs), endothelial progenitor cells (EPCs) and very small embryonic-like cells (VSELs) have been demonstrated to exert therapeutic benefits in stroke. Here, we discuss the current status of these BM-derived stem cells in stroke therapy, with emphasis on possible cellular and molecular mechanisms of action that mediate the cells' beneficial effects in the ischemic brain. When possible, we also discuss the relevance of this therapeutic regimen in other central nervous system (CNS) disorders.     

Unexplained week-to-week variation in BNP and NT-proBNP is low in chronic heart failure patients during steady state

BACKGROUND: The usefulness of brain-natriuretic-peptide (BNP) and N-terminal-pro-brain-natriuretic-peptide (NT-proBNP) for monitoring of chronic heart failure (CHF) patients has been questioned because of high levels of unexplained variation. AIMS: Week-to-week total variance (CV(T)), unexplained variation (CV(I)), reference change values (RCV), index of individualities (IOI) and number of samples (N) with week-to-week intervals needed to estimate the underlying homeostatic set point (+/-15%) for BNP and NT-proBNP were calculated in pre-specified stable CHF patients. METHODS AND RESULTS: We measured plasma concentrations of BNP and NT-proBNP, clinical and laboratory variables in 20 CHF patients with a 7-days interval. Only patients considered to be in steady state were included. The CV(I) was 15% (BNP) and 8% (NT-proBNP). CV(T) was 16% (BNP) and 8% (NT-proBNP) and RCV was 43% (BNP) and 23% (NT-proBNP). IOI was 0.14 for BNP and 0.03 for NT-proBNP and N was 1 for BNP and 1 for NT-proBNP. CONCLUSIONS: Our data demonstrate that unexplained variation of BNP and NT-proBNP is low in CHF patients during steady state, which is a prerequisite for the use of these peptides for monitoring of the disease.     

Anaemia and renal dysfunction are independently associated with BNP and NT-proBNP levels in patients with heart failure

BACKGROUND: Anaemia may affect B-type natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) levels, but this has not been well described in heart failure (HF) patients without the exclusion of patients with renal dysfunction. AIMS: To study the influence of both anaemia and renal function on BNP and NT-proBNP levels in a large group of hospitalised HF patients. METHODS AND RESULTS: We studied 541 patients hospitalised for HF (mean age 71+/-11 years, 62% male, and left ventricular ejection fraction 0.33+/-0.14). Of these patients, 30% (n=159) were anaemic (women: Hb<7.5 mmol/l, men: Hb<8.1 mmol/l). Of the 159 anaemic patients, 73% had renal dysfunction (eGFR<60 ml/min/1.73 m2) and of the non-anaemic patients, 57% had renal dysfunction. BNP and NT-proBNP levels were measured in all patients before discharge. In multivariable analyses both plasma haemoglobin and eGFR were independently related to the levels of BNP and NT-proBNP (standardised beta's of -0.16, -0.14 [BNP] and -0.19, -0.26 [NT-proBNP] respectively, P-values<0.01). CONCLUSION: Anaemia and renal dysfunction are related to increased BNP and NT-proBNP levels, independent of the severity of HF. These results indicate that both anaemia and renal dysfunction should be taken into consideration during the interpretation of BNP and NT-proBNP levels in HF patients.     

Dynamic patterns of neurotrophin 3 expression in the postnatal mouse inner ear

Recent studies indicate that neurotrophin 3 (NT3) may be important for the maintenance and function of the adult inner ear, but the pattern of postnatal NT3 expression in this organ has not been characterized. We used a reporter mouse in which cells expressing NT3 also express beta-galactosidase, allowing for their histochemical visualization, to determine the pattern of NT3 expression in cochlear and vestibular organs. We analyzed animals from birth (P0) to adult (P135). At P0, NT3 was strongly expressed in supporting cells and hair cells of all vestibular and cochlear sense organs, Reissner's membrane, saccular membrane, and the dark cells adjacent to canal organs. With increasing age, staining disappeared in most cell types but remained relatively high in inner hair cells (IHCs) and to a lesser extent in IHC supporting cells. In the cochlea, by P0 there is a longitudinal gradient (apex > base) that persists into adulthood. In vestibular maculae, staining gradients are: striolar > extrastriolar regions and supporting cells > hair cells. By P135, cochlear staining is restricted to IHCs and their supporting cells, with stronger expression in the apex than the base. By the same age, in the vestibular organs, NT3 expression is weak and restricted to saccular and utricular supporting cells. These results suggest that NT3 might play a long-term role in the maintenance and functioning of the adult auditory and vestibular systems and that supporting cells are the main source of this factor in the adult.     

Activation of Toll-like receptor-3 induces interferon-λ expression in human neuronal cells

We examined the gene expression and regulation of type III human interferon (IFN), IFN-λ, in human neuronal cells. Human neuronal cells expressed endogenous IFN-λ1 but not IFN-λ2/3. Upon the activation of Toll-like receptor (TLR)-3 expressed in the neuronal cells by polyriboinosinic polyribocytidylic acid (PolyI:C), both IFN-λ1 and IFN-λ2/3 expression was significantly induced. The activation of TLR-3 also exhibited antiviral activity against pseudotyped human immunodeficiency virus (HIV)-1 infection of the neuronal cells. Human neuronal cells also expressed functional IFN-λ receptor complex, interleukin-28 receptor α subunit (IL-28Rα) and IL-10Rβ, as evidenced by the observations that exogenous IFN-λ treatment inhibited pseudotyped HIV-1 infection of the neuronal cells and induced the expression of apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like (APOBEC)3G/3F, the newly identified anti-HIV-1 cellular factors. These data provide direct and compelling evidence that there is intracellular expression and regulation of IFN-λ in human neuronal cells, which may have an important role in the innate neuronal protection against viral infections in the CNS.     

Presynaptic neurotrophin-3 increases the number of tectal synapses,vesicle density,and number of docked vesicles in chick embryos

To determine whether presynaptically derived neurotrophins may contribute to synaptic plasticity, we examined whether neurotrophin-3 (NT-3) changed the number, size, vesicle content, or vesicle distribution of synapses within the retinorecipient layers of the chick optic tectum. In this system, endogenous NT-3 derives presynaptically from retinal ganglion cell axons. Retinotectal synapses comprise the majority of synapses in superficial tectal layers, as demonstrated by destruction of retinotectal input by intraocular application of the drug monensin. To examine the effect of increased or decreased levels of NT-3, either exogenous NT-3 or monoclonal NT-3 blocking antibodies were injected into the optic tectum of 19-day-old chick embryos, spiked with radiolabeled protein to verify the success of injections and estimate effective concentrations. After 48 hours, the ultrastructure of superficial tectal layers was analyzed and compared with samples from control tecta injected with cytochrome C. NT-3 increased the number of synapses, synaptic vesicles/profile, synaptic vesicle densities, the number of docked vesicles, and the length of the synaptic profile. Deprivation of anterogradely transported endogenous NT-3 with NT-3 antibodies resulted in the opposite effect: decreased numbers of synapses, decreased vesicle densities, and decreased numbers of docked vesicles. Brain-derived neurotrophic factor (BDNF) had a largely different effect than NT-3. BDNF increased the density of vesicles and deprivation of endogenous TrkB ligands with TrkB fusion protein reduced the density of vesicles in the synapses, without effects on synapse number or docked vesicles. We conclude that anterogradely transported NT-3 affects synapse strength in a way that differs from that of presumably postsynaptic-derived BDNF.     

Hybridizing behavioral models: A possible solution to some problems in neurophenotyping research?

The use of batteries of single-domain tests for neurophenotyping research is a common strategy to achieve higher data density and explore different behavioral domains. This approach, however, is accompanied by several methodological challenges, briefly discussed here. As an alternative, this paper advocates the wider use of extensive "hybrid" protocols that assess multiple domains in parallel, or logically/logistically combine experimental paradigms, in a way that disproportionately maximizes the number of tested phenotypes per experimental manipulation. Several examples of this approach are given in this paper, demonstrating the potential to reduce time, cost and subject requirements for the experiments. Offering behavioral analyses that are lacking in the standard single-domain tests, such "hybrid" models enable innovative modeling of neuropsychiatric disorders by more thorough and broader investigation of complex phenotypical characteristics.     

Effect of Retinoic Acid on Ferritin H Expression During Brain Development and Neuronal Differentiation

Abstract

We have previously shown that brain ferritin H expression, which has been associated with iron utilization, is developmentally regulated. Because retinoic acid (RA) regulates gene expression and is involved in cellular differentiation, we tested the hypothesis that RA regulates ferritin H during brain development and neuronal differentiation. RA, administered to rats on postnatal day 1, produced a 4-fold increase in brain ferritin H mRNA (p<0.01) after 24 h. To examine whether RA-stimulated neuronal differentiation contributed to this up-regulation, ferritin and ferritin H mRNA were measured in human neuronal precursor cells (NTera-2, NT2) before and after 4-weeks of RA-stimulated differentiation into post-mitotic neurons. Differentiation resulted in a 2-fold increase in both ferritin and ferritin H mRNA (p<0.05). Immunocytochemistry and Northern analysis showed significant elevations in ferritin expression that began as early as 24 h after RA treatment. While there was also a significant increase in the labile iron pool after RA treatment, this did not occur until 72 h. These data show that RA regulates ferritin H expression during rat brain development and neuronal differentiation and suggests a new role for RA in brain iron metabolism.     

牙本质粘接剂直接盖髓的动物实验研究

目的：通过动物实验比较传统盖髓剂Ca（OH）：与2种牙本质粘接剂：Prime＆Bond NT和Gluma Comfort Bond直接盖髓的效果，观察牙髓对材料刺激的反应。方法：选用3条杂种犬共45颗牙进行盖髓实验，每条犬分为3组，5颗牙／组：第1组为Prime＆Bond NT，第2组为Gluma Comfort Bond，第3组采用Ca（OH）2对照。机械穿髓后，大量生理盐水冲洗，分别采用3种材料盖髓，玻璃离子充填。3只狗分别于7d、28d、70d处死，HE染色后光学显微镜观察。结果：7d：3组盖髓材料均有炎症反应；28d：2种粘接剂盖髓组均仍可以看到大量炎症细胞浸润，在穿髓孔附近牙髓坏死、消失。Ca（OH）2组也均有少量炎症细胞浸润；70d：2种粘接剂盖髓组均在穿髓孔附近出现牙髓坏死、消失。Ca（OH）2组在穿髓孔附近出现了钙化组织。结论：实验结果显示，牙本质粘接剂对牙髓具有较强的刺激性，不宜用于直接盖髓。     

眼镜蛇神经毒的分离、纯化及其镇痛作用

中华眼镜蛇粗毒经二次CM-Sephadex C25柱层析分离、纯化获得眼镜蛇神经毒。聚丙烯酰胺圆盘电泳显示一条区带。在小鼠热板模型及大鼠电尾嘶叫模型,眼镜蛇神经毒显示有镇痛作用,并有剂量-效应关系。