The effect of electro-acupuncture on pro-oxidant antioxidant balance values in overweight and obese subjects: a randomized controlled trial study.

Objective To undertake a randomized controlled trial in 196 obese subjects to examine the effect of electro-acupuncture on serum pro-oxidant antioxidant balance (PAB) values. Methods Subjects received authentic acupuncture (cases) or sham acupuncture (controls) for 6 weeks in combination with a low-calorie diet. In the following 6 weeks, they received the low-calorie diet alone. Serum PAB was measured at baseline, and 6 and 12 weeks later. Results We found that serum PAB values decreased significantly in the group receiving the authentic acupuncture compared to the sham treatment (p<0.001) at week 6, and whilst serum PAB increased significantly (p<0.05) in the second phase of the study, a significant difference between two groups remained at 12 weeks (p<0.05). Conclusions Electro-acupuncture in combination with a low-calorie diet was more effective at reducing serum PAB values in obese subjects compared to diet alone. Further work is required to determine the mechanism by which electro-acupuncture has this effect.

Impaired long-term potentiation in the prefrontal cortex of Huntington's disease mouse models: rescue by D1 dopamine receptor activation.

BACKGROUND: The introduction of gene testing for Huntington's disease (HD) has enabled the neuropsychiatric and cognitive profiling of human gene carriers prior to the onset of overt motor and cognitive symptoms. Such studies reveal an early decline in working memory and executive function, altered EEG and a loss of striatal dopamine receptors. Working memory is processed in the prefrontal cortex and modulated by extrinsic dopaminergic inputs. OBJECTIVE: We sought to study excitatory synaptic function and plasticity in the medial prefrontal cortex of mouse models of HD. METHODS: We have used 2 mouse models of HD, carrying 89 and 116 CAG repeats (corresponding to a preclinical and symptomatic state, respectively) and performed electrophysiological field recording in coronal slices of the medial prefrontal cortex. RESULTS: We report that short-term synaptic plasticity and long-term potentiation (LTP) are impaired and that the severity of impairment is correlated with the size of the CAG repeat. Remarkably, the deficits in LTP and short-term plasticity are reversed in the presence of a D(1) dopamine receptor agonist (SKF38393). CONCLUSION: In a previous study, we demonstrated that a deficit in long-term depression (LTD) in the perirhinal cortex could also be reversed by a dopamine agonist. These and our current data indicate that inadequate dopaminergic modulation of cortical synaptic function is an early event in HD and may provide a route for the alleviation of cognitive dysfunction.

The neuropathology of autism: where do we stand?

The neurobiology and neuropathology of the autism spectrum disorders (ASD) remain poorly defined. Brain imaging studies suggest that the deficits in social cognition, language, communication and stereotypical patterns of behaviour that are manifest in individuals with ASD, are related to functional disturbance and 'disconnectivity', affecting multiple brain regions. These impairments are considered to arise as a consequence of abnormal pre- and postnatal development of a distributed neural network. Examination of the brain post mortem continues to provide fundamental information concerning the cellular and subcellular alterations that take place in the brain of autistic individuals. Neuropathological observations that have emerged over the past decade also point towards early pre- and postnatal developmental abnormalities that involve multiple regions of the brain, including the cerebral cortex, cortical white matter, amygdala, brainstem and cerebellum. However, the neuropathology of autism is yet to be clearly defined, and there are several areas that remain open to further investigation. In this respect, more concerted efforts are required to examine the various aspects of cellular pathology affecting the brain in autism. This paper briefly highlights four key areas that warrant further evaluation.

The origin and cell lineage of microglia: new concepts.

Despite intense study, the precise origin and cell lineage of microglia, the resident mononuclear phagocytes of the nervous system, are still a matter for debate. Unlike macroglia (astrocytes and oligodendrocytes) and neurons, which are derived from neuroectoderm, microglial progenitors arise from peripheral mesodermal (myeloid) tissue. The view still commonly held is that tissue-resident mononuclear phagocytes (including microglia) are derived from circulating blood monocytes and these take up residence late in gestation and postnatally. However, microglial progenitors colonise the nervous system primarily during embryonic and fetal periods of development. Recent evidence indicates differences between the lineage of mononuclear phagocytes during the embryonic and fetal period from that in the neonate and adult-mononuclear phagocytes that take up residence within tissues are derived from a lineage of myeloid cells that is independent of the monocyte lineage. Our own findings on the development and differentiation of microglial progenitors, taken together with findings by other investigators, and in the context of the heterogeneity between myeloid differentiation in the fetus and in the adult, support the view that microglia are derived prenatally from mesodermal progenitors that are distinct from monocytes. Furthermore, microglial progenitors colonise the nervous system via extravascular routes initially. These findings challenge the concept that resident microglia in the nervous system are derived from circulating blood monocytes. Work is still underway to establish the tissue of origin and lineage of microglial progenitors in vivo. This information is critical not only from a developmental perspective, but significantly from a therapeutic viewpoint, as (i) the unique property of microglial progenitors to colonise the nervous system from the periphery allows these cells to be exploited as a biological and non-invasive means for cell therapy by delivering genes to the nervous system (microglial engraftment), and (ii) there are indications that microglial progenitors are specifically able to home to the nervous system. Use of microglial progenitors for therapeutic purposes becomes feasible only if the origin and cell lineage of these microglial progenitors are known and these cells can be isolated and manipulated in vitro (i.e., to express specific trophic factors) prior to therapeutic transfer (e.g., intravenously) in vivo. In this paper, we shall briefly consider the existing concepts on the origin and lineage of microglial progenitors and discuss new hypotheses in the light of emerging data that suggest clear differences between fetal and adult ontogeny of myeloid cells.

Subdural hematoma (SDH): assessment of macrophage reactivity within the dura mater and underlying hematoma.

OBJECTIVES: Macrophages are an inherent component of the dura mater, and can be characterised in cases of subdural hematoma (SDH) by their progressive and varying accumulation within areas of damage. Gross and histological methods used to determine the age of SDH are inexact. These are in part due to the active nature of such lesions and the diverse manner in which trauma victims respond to injury. Correct diagnosis has obvious medico-legal implications. However, there is as yet no specific diagnostic method that allows the age of SDH to be reliably determined. This study investigated the progressive and orderly pattern of reactivity of resident and infiltrating dural macrophages that occurs in response to injury associated with SDH. MATERIALS: 26 postmortem cases of traumatic SDH were examined with survival times (onset of trauma to death) ranging from a few hours and up to 31 days. METHODS: Macrophage reactivity associated with the dura mater and the underlying hematoma was determined using CD68 and MHC class II immunohistochemistry and the qualitative and quantitative findings compared with the presence of iron detected using conventional Perl's Prussian blue method. RESULTS: The results show that CD68 and MHC class II are differentially expressed within the dura mater and hematoma in SDH, and that the expression of MHC class II is markedly upregulated in the inner aspect of the dura mater within the initial 24 hours following injury. CD68 expression can be detected quantitatively in the hematoma, 24-48 hours after SDH, and within the dura following this period. Linear regression analysis further revealed a significant and positive association between the expression of MHC class II or CD68 antigens and the progressive survival of SDH up to 31 days post-injury, which was not seen with Perl's histochemical method. The expression of MHC class II antigen was a distinguishing, and quantifiable feature particularly localized within the inner aspect of the dura from a very early stage in the progression of SDH. Widespread, diffuse and cellular MHC class II reactivity was particularly noted within the inner aspect of the dura mater in cases of SDH with survival > 10 days. Since only a proportion of this widespread immunoreactivity was accounted for by macrophages (considering CD68 immunoreactivity), a large component of this activity was more likely to be due to the reorganisation and activation of fibroblasts within inner dural layers (dural border layer), known to upregulate expression of MHC class II molecules. CONCLUSIONS: The expression of CD68 and MHC class II antigens provides a more informative picture of the progression of pathology associated with SDH, and may be used in conjunction with other clinicopathological factors, in further investigations that attempt to date SDH according to defined histopathological characteristics.

In vitro expression of major histocompatibility class I and class II antigens by conditionally immortalized murine neural stem cells.

The expression of major histocompatibility complex (MHC) antigens on the surface of cells is intimately linked to in vivo graft survival. It has been previously shown that the conditionally immortalized temperature-sensitive Maudsley hippocampal clone 36 (MHP36) neural stem cells show good long-term graft survival and do not elicit an acute immunological response following transplantation. Here we report that MHP36 cells express both MHC class I and class II antigens when grown in culture under proliferative conditions (33 degrees C), whereas cells with a differentiated morphology in the non-proliferative (37-39 degrees C) condition express low to undetectable levels of either MHC molecules. However, morphologically undifferentiated cells persisting under non-proliferating conditions continued to express both MHC antigens. The downregulation of MHC antigens upon differentiation following cell transplantation could therefore contribute to the graft survival of MHP36 cells.

Motility and ramification of human fetal microglia in culture: an investigation using time-lapse video microscopy and image analysis.

Microglia are mononuclear phagocytes of the central nervous system and are considered to derive from circulating bone marrow progenitors that colonize the developing human nervous system in the second trimester. They first appear as ameboid forms and progressively differentiate to process-bearing "ramified" forms with maturation. Signals driving this transformation are known to be partly derived from astrocytes. In this investigation we have used cocultures of astrocytes and microglia to demonstrate the relationship between motility and morphology of microglia associated with signals derived from astrocytes. Analysis of progressive cultures using time-lapse video microscopy clearly demonstrates the dynamic nature of microglia. We observe that ameboid microglial cells progressively ramify when cocultured with astrocytes, mirroring the "differentiation" of microglia in situ during development. We further demonstrate that individual cells undergo morphological transformations from "ramified" to "bipolar" to "tripolar" and "ameboid" states in accordance with local environmental cues associated with astrocytes in subconfluent cultures. Remarkably, cells are still capable of migration at velocities of 20-35 microm/h in a fully ramified state overlying confluent astrocytes, as determined by image analysis of motility. This is in keeping with the capacity of microglia for a rapid response to inflammatory cues in the CNS. We also demonstrate selective expression of the chemokines MIP-1alpha and MCP-1 by confluent human fetal astrocytes in cocultures and propose a role for these chemotactic cytokines as regulators of microglial motility and differentiation. The interchangeable morphological continuum of microglia supports the view that these cells represent a single heterogeneous population of resident mononuclear phagocytes capable of marked plasticity.

Expression of beta-chemokines and chemokine receptors in human fetal astrocyte and microglial co-cultures: potential role of chemokines in the developing CNS.

Chemokines play specific roles in directing the recruitment of leukocyte subsets into inflammatory foci within the central nervous system (CNS). The involvement of these cytokines as mediators of inflammation is widely accepted. Recently, it has become evident that cells of the CNS (astrocytes, microglia, and neurons) not only synthesize, but also respond functionally or chemotactically to chemokines. We previously reported developmental events associated with colonization of the human fetal CNS by mononuclear phagocytes (microglial precursors), which essentially takes place within the first two trimesters of life. As part of the array of signals driving colonization, we noted specific anatomical distribution of chemokines and chemokine receptors expressed during this period. In order to further characterize expression of these molecules, we have isolated and cultured material from human fetal CNS. We demonstrate that unstimulated subconfluent human fetal glial cultures express high levels of CCR2 and CXCR4 receptors in cytoplasmic vesicles. Type I astrocytes, and associated ameboid microglia in particular, express high levels of surface and cytoplasmic CXCR4. Of the chemokines tested (MIP-1alpha, MIP-1beta, MCP-1, MCP-3, RANTES, SDF-1, IL-8, IP-10), only MIP-1alpha, detected specifically on microglia, was expressed both constitutively and consistently. Low variable levels of MCP-1, MIP-1alpha, and RANTES were also noted in unstimulated glial cultures. Recombinant human chemokines rhMCP-1 and rhMIP-1alpha also displayed proliferative effects on glial cultures at [10 ng/ml], but displayed variable effects on CCR2 levels on these cells. rhMCP-1 specifically upregulated CCR2 expression on cultured glia at [50 ng/ml]. It is gradually becoming evident that chemokines are important in embryonic development. The observation that human fetal glial cells and their progenitors express specific receptors for chemokines and can be stimulated to produce MCP-1, as well as proliferate in response to chemokines, supports a role for these cytokines as regulatory factors during development.

Microglia and the pathogenesis of spongiform encephalopathies.

Alterations in the phenotype and function of microglia, the resident mononuclear phagocytes of the central nervous system, are among the earliest indications of pathology within the brain and spinal cord. The prion diseases, also known as spongiform encephalopathies, are fatal neurodegenerative disorders with sporadic, genetic or acquired infectious manifestations. A hallmark of all prion diseases is the aberrant metabolism and resulting accumulation of the prion protein. Conversion of the normal cellular protein [PrP(c)] into the abnormal pathogenic (or disease-causing) isoform [PrP(Sc)] involves a conformational alteration whereby the alpha-helical content is transformed into beta-sheet. The histological characteristics of these disorders are spongiform change, astrocytosis, neuronal loss and progressive accumulation of the protease-resistant prion isoform. An additional upregulation in microglial response has been reported in Kuru, Creutzfeldt-Jakob disease (CJD), Gerstmann-Sträussler-Scheinker syndrome (GSS), scrapie, in transgenic murine models and in culture, where microglial activation often accompanies prion protein deposition and neuronal loss. This article will review the roles of microglia in spongiform encephalopathies.

Expression of the beta-chemokine receptors CCR2, CCR3 and CCR5 in multiple sclerosis central nervous system tissue.

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS) characterised by perivascular inflammatory cell infiltrates and plaques of demyelination. Chemokines have been shown to play an important role in the activation and directional migration of cells to sites of CNS inflammation. The action of chemokines requires the expression of their complementary chemokine receptors by their target cells. We have examined the expression of the beta-chemokine receptors CCR2, CCR3 and CCR5 in post-mortem MS CNS tissue using single- and double-labelling immunocytochemistry techniques. Low levels of CCR2, CCR3 and CCR5 were expressed by microglial cells throughout control CNS tissue. In chronic active MS lesions CCR2, CCR3 and CCR5 were associated with foamy macrophages and activated microglia. CCR2 and CCR5 were also present on large numbers of infiltrating lymphocytes. A smaller number of CCR3-positive lymphocytes were present, but we also noted CCR3 and CCR5 on astrocytes in five of the 14 cases of MS investigated, particularly associated with processes around vessels and at the glia limitans. Ligands for CCR2 and CCR3 include MCP-1 and MCP-3 which were co-localised around vessels with the infiltrating leukocytes, but were also present in unaffected areas of cortex. The elevated expression of CCR2, CCR3 and CCR5 in the CNS in MS suggests these beta-chemokine receptors and their ligands play a role in the pathogenesis of MS.

Colonisation of the developing human brain and spinal cord by microglia: a review.

Microglia are the immune effector cells of the nervous system. The prevailing view is that microglia are derived from circulating precursors in the blood, which originate from the bone-marrow. Colonisation of the central nervous system (CNS) by microglia is an orchestrated response during human fetal development related to the maturation of the nervous system. It coincides with vascularisation, formation of radial glia, neuronal migration and myelination primarily in the 4th-5th months and beyond. Microglial influx generally conforms to a route following white matter tracts to gray areas. We have observed that colonisation of the spinal cord begins around 9 weeks, with the major influx and distribution of microglia commencing around 16 weeks. In the cerebrum, colonisation is in progress during the second trimester, and ramified microglial forms are widely distributed within the intermediate zone by the first half of intra-uterine life (20-22 weeks). A distinct pattern of migration occurs along radial glia, white matter tracts and vasculature. The distribution of these cells is likely to be co-ordinated by spatially and temporally regulated, anatomical expression of chemokines including RANTES and MCP-1 in the cortex; by ICAM-2 and PECAM on radiating cerebral vessels and on capillaries within the germinal layer, and apoptotic cell death overlying this region. The phenotype and functional characteristics of fetal microglia are also outlined in this review. The need for specific cellular interactions and targeting is greater within the central nervous system than in other tissues. In this respect, microglia may additionally contribute towards CNS histogenesis.

Microglia in the human fetal spinal cord--patterns of distribution, morphology and phenotype.

Microglia, the intrinsic macrophages of the nervous system, colonise the cerebrum around the second trimester in man. In order to determine the extent of microglial influx into the nervous system, we have examined their distribution within the human fetal spinal cord in relation to astrocytic and vascular development between 9 and 16 weeks of gestation, using conventional immunohistochemistry [CD11b; CD45; CD64; CD68; ICAM-1; ICAM-2; VCAM-1; PECAM; GFAP; vimentin] and lectin histochemistry [RCA-1]. Microglia are identifiable by 9 weeks, within the ventricular/sub-ventricular zones. Human fetal microglia display heterogeneity in phenotype and are more readily identified by CD68 in the spinal cord. There is a marked influx of cells dorsal and ventral to the neural cavity, from the marginal layer [meninges/connective tissue] with advancing gestational age, with greatest cell densities towards the end of the time period in this study. This inward migration is associated with progressive vascularisation, ICAM-2 expression and co-localises with GFAP and vimentin positive radial glia. The patterns of microglial migration in human fetal cord differ from that within the cerebrum, but generally conform to a route following white to gray matter.

Expression of adhesion molecules on human fetal cerebral vessels: relationship to microglial colonisation during development.

Microglia represent the primary immune effector cells of the adult central nervous system (CNS). The origin of these cells has been a subject of intense debate over the last century. However, immunohistochemical and chimera developmental studies in rodents support the hypothesis that microglia are monocytic in origin. There have been relatively few studies to date on microglia in human fetal development, and the mechanisms by which microglial precursors enter the developing CNS are as yet unknown. It is possible that microglial precursors use combinations of adhesion molecules on cerebral endothelium to gain entry into the developing CNS. In the present study, we have shown the distribution of microglia within human fetal cerebral cortex between 16 and 22 weeks of gestation using RCA-1 lectin histochemistry. We have also demonstrated dual anti-macrophage antibody labelling of these cells in conjunction with adhesion molecules ICAM-1, ICAM-2 and PECAM on cerebral endothelium throughout this period. We conclude that fetal microglia usually occur at highly vascularised sites within the developing human fetal brain and are more specifically associated with the expression of ICAM-2 on cerebral endothelium.

Lewy bodies are located preferentially in limbic areas in diffuse Lewy body disease.

Lewy bodies (LBs)are found throughout the brain stem, limbic and neocortical areas in Parkinson's disease. Lewy bodies are also associated in these areas with dementia and the substrate of 'dementia with Lewy bodies' is thought to include Lewy body pathology in limbic and neocortical areas with or without Alzheimer-type changes. In order to determine whether dementia with Lewy bodies is characterised primarily by cortical or limbic LB pathology, we have measured the density of Lewy bodies, neuritic plaques and neurofibrillary tangles in 12 neocortical, limbic and brain stem sites in 10 patients who were pathologically diagnosed with diffuse Lewy body disease (DLBD) (64.7 +/- 2.7 years). The mean LB density in limbic areas (3.00 +/- 0.61/mm2) was significantly greater than that of neocortical areas (1.13 +/- 0.22/mm2, P < 0.001). The greatest density of LBs was found in the amygdala (4.1 +/- 0.7/mm2) and the lowest in the occipital cortex (0.3 +/- 0.1/mm2). In limbic areas, LB formation positively correlated with neuritic plaque formation (r = 0.51, P < 0.01) but not with neurofibrillary tangle densities. These data indicate that dementia with Lewy bodies is characterised primarily by limbic, and secondly by neocortical, LB pathology. It remains to be determined why limbic areas are selectively vulnerable to LB pathology in dementia with Lewy bodies.