Chronic relapsing experimental allergic encephalomyelitis. Correlation of circulating lymphocyte fluctuations with disease activity in suppressed and unsuppressed animals

Stem Cell Therapy for Neurogenic Bladder Dysfunction in Rodent Models: A Systematic Review

PURPOSE

Neurogenic bladder dysfunction (NGB) has an impact on the quality of life, which made it an important research subject in preclinical studies. The present review investigates the effect of stem cell (SC) therapy on bladder functional recovery after the onset of spinal cord injury (SCI), multiple sclerosis (MS), Parkinson disease (PD), and stroke in rodent models.

METHODS

All experiments evaluated the regenerative potential of SC on the management of NGB in rodent models up to June 2019, were included. From 1,189 relevant publications, 20 studies met our inclusion criteria of which 15 were conducted on SCI, 2 on PD, 2 on stroke, and 1 on MS in the rodent models. We conducted a meta-analysis on SCI experiments and for other neurological diseases, detailed urodynamic findings were reported.

RESULTS

The common SC sources used for therapeutical purposes were neural progenitor cells, bone marrow mesenchymal SCs, human amniotic fluid SCs, and human umbilical cord blood SCs. There was a significant improvement of micturition pressure in both contusion and transaction SCI models 4 and 8 weeks post-SC transplantation. Residual urine volume, micturition volume, and bladder capacity were improved 28 days after SC transplantation only in the transaction model of SCI. Nonvoiding contraction recovered only in 56 days post-cell transplantation in the contusion model.

CONCLUSION

Partial bladder recovery has been evident after SC therapy in SCI models. Due to limitations in the number of studies in other neurological diseases, additional studies are necessary to confirm the detailed mechanism for bladder recovery.

Mouse models of multiple sclerosis: experimental autoimmune encephalomyelitis and Theiler's virus-induced demyelinating disease

Experimental autoimmune encephalomyelitis (EAE) and Theiler's Murine Encephalitis Virus-Induced Demyelinating Disease (TMEV-IDD) are two clinically relevant murine models of multiple sclerosis (MS). Like MS, both are characterized by mononuclear cell infiltration into the CNS and demyelination. EAE is induced by either the administration of myelin protein or peptide in adjuvant or by the adoptive transfer of encephalitogenic T cell blasts into naïve recipients. The relative merits of each of these protocols are compared. Depending on the type of question being asked, different mouse strains and peptides are used. Different disease courses are observed with different strains and different peptides in active EAE. These variations are also addressed. Additionally, issues relevant to clinical grading of EAE in mice are discussed. In addition to EAE induction, useful references for other disease indicators such as DTH, in vitro proliferation, and immunohistochemistry are provided. TMEV-IDD is a useful model for understanding the possible viral etiology of MS. This section provides detailed information on the preparation of viral stocks and subsequent intracerebral infection of mice. Additionally, virus plaque assay and clinical disease assessment are discussed. Recently, recombinant TMEV strains have been created for the study of molecular mimicry which incorporate various 30 amino acid myelin epitopes within the leader region of TMEV.

Adenosine deaminase and 5'nucleotidase activities in peripheral blood T cells of multiple sclerosis patients

Multiple sclerosis (MS) is one of the most common causes of neurological disability in young and middle-aged adults and is thought to be mediated by autoreactive T cells. Activities of adenosine deaminase (ADA) and 5'(nucleotidase (5'NT), which are involved in the differentiation and maturation of the lymphoid system, were measured in peripheral blood T cells from 21 MS patients and in 23 age and sex matched healthy controls to determine whether an association existed between these enzyme abnormalities and cellular immune functions. ADA and 5'NT activities were found significantly decreased in MS patients (P < .001 and P < .01 respectively) when compared with controls. Low levels of ADA and 5'NT activities were found irrespective of whether patients had relapsing-remitting or chronic progressive MS. These findings suggest that low levels of these enzyme activities in T cells may be related to the persistent abnormalities in T cell function in the clinical course of MS.

Experimental autoimmune encephalomyelitis: antigen-induced inhibition of biochemical and immunohistological alterations

A comprehensive biochemical, immunological, and histological study was undertaken during suppression of experimental autoimmune encephalomyelitis (EAE) induced by antigen-specific inhibition of the immune response. Pretreatment of Wistar rats by intraperitoneal administration of low doses of saline-soluble bovine myelin or myelin basic protein (MBP) but not with ovalbumin suppresses the appearance of the clinical symptoms of EAE induced by sensitization with bovine myelin in complete Freund's adjuvant. Analysis of the central nervous system (CNS) of animals pretreated with MBP or whole myelin shows inhibition of the diminution of MBP and 2',3'-cyclic nucleotide 3'-phosphohydrolase (CNPase) activity observed in the EAE animals or in rats pretreated with ovalbumin. With respect to the CNS lipid content, these suppressive treatments abolish the increase in esterified cholesterol and partially revert the diminution in the content of cerebrosides and total cholesterol characteristic of the acute stage of the disease. Concomitantly, meningeal and parenchymal infiltration with mononuclear cells and deposits of immunoglobulins in the infiltrated regions as well as in spinal cord motor neurons were reduced. Analysis of the humoral response to myelin antigens shows that all EAE as well as treated animals developed antibodies to MBP and other myelin proteins. However, a higher incidence and level of these antibodies was observed in nontreated EAE animals and MBP- and ovalbumin-treated rats, while rats treated with total bovine myelin showed a highly reduced humoral response. The present results indicate that intraperitoneal treatment with soluble forms of myelin antigens, concomitant with the suppression of the clinical symptoms of the disease, markedly reduces the biochemical and histological alterations occurring in EAE animals and produces changes in the autoimmune humoral response.

Experimental allergic encephalomyelitis in cynomolgus monkeys. Quantitation of T cell responses in peripheral blood

Chronic relapsing-remitting experimental allergic encephalomyelitis (EAE) was induced in cynomolgus monkeys by a single immunization with a homogenate of human brain white matter (BH) in adjuvant. Proliferative T lymphocyte responses to BH, to myelin basic protein (MBP), but not to proteolipid protein, were detected in peripheral blood mononuclear cells (PBMC) of all animals and persisted until their death or, in surviving animals, for greater than 10 mo postimmunization. Responses of higher magnitude tended to be associated with fatal, compared with nonfatal, episodes of clinical EAE. The frequency of MBP-reactive T cells in PBMC of animals with acute EAE was quantitated with a soft agar colony system; the ratio of T cells that proliferated specifically to MBP was estimated at between 5 and 20 per 10(6) PBMC. A similar frequency of peptide-specific T cells was estimated from PBMC of monkeys immunized with a synthetic 14-mer peptide corresponding to a region near the carboxy terminus of MBP. Thus, autoantigen-reactive T cells can be detected in the circulation throughout the course of chronic EAE, are predictive of disease severity, and occur at a frequency similar to that estimated to be present in humans with multiple sclerosis.

Suppression of experimental allergic encephalomyelitis by the encephalitogenic peptide, in solution or bound to liposomes

We have investigated the ability of liposome-bound encephalitogenic peptide to suppress experimental allergic encephalomyelitis (EAE) in the guinea pig. EAE was induced by challenge with the encephalitogenic peptide, residues 113-122 of human myelin basic protein (MBP) in complete Freund's adjuvant. The peptide was acylated with stearic acid in order to anchor it to the lipid bilayer. The liposomal-bound peptide effectively suppressed clinical signs of EAE at relatively low doses, when given subcutaneously or intraperitoneally without incomplete Freund's adjuvant, several days after challenge. In vitro proliferation of lymphocytes from treated, protected animals in response to the peptide was greatly decreased but that to the purified protein derivative of tuberculin antigen was not, indicating an antigen-specific effect. However, histological signs of EAE were not reduced. The free peptide in solution was somewhat less effective when given intraperitoneally but was as or nearly as effective as liposome-bound peptide when given subcutaneously. Binding to liposomes may decrease the rate of clearance or degradation of the peptide when given intraperitoneally.

Plasma immunoglobulin responses and disease severity in chronic relapsing experimental allergic encephalomyelitis

Plasma IgG, IgA and IgM responses in various stages of chronic relapsing experimental allergic encephalomyelitis (CR-EAE) were investigated by ELISA and rocket immunoelectrophoresis. Autoantibody levels were elevated in acute EAE but immunoglobulin responses were maximal in chronic disease. Plasma IgG and IgA specific for the whole cord, myelin and MBP correlated closely with the clinical signs of post-acute disease; in age-matched groups, levels were lower in animals in remission or with no further disease than in those in relapse or with a stable chronic disease course. Sequential sampling revealed a significant increase in neuroantigen-specific IgG (with MBP as the dominant autoantigen) during the onset of a relapse. Lipid-specific antibody levels were raised throughout CR-EAE but constituted only a small proportion of the total response against neural antigens. Determination of total immunoglobulin concentrations suggested a general suppression of IgG responses in guinea pigs in remission. The strong correlations found between antibody levels and the severity of chronic disease provide further evidence that antibody-mediated mechanisms can play a major role in the pathogenesis of CR-EAE.

In vivo depletion of Lyt-2 cells fails to alter acute and relapsing EAE

The cellular mechanisms of recovery and relapses in experimental allergic encephalomyelitis (EAE) are not known. In order to determine the role of the suppressor/cytotoxic T lymphocytes (Lyt-2+) in EAE we studied the effect of in vivo depletion of this subset using monoclonal antibodies. Intraperitoneal injection of 1 mg of monoclonal antibody 2.43 resulted in rapid depletion of Lyt-2+ cells from lymph node, spleen and blood. Depletion of this subset had no effect on the kinetics of development, severity, and duration of acute EAE. Furthermore, following recovery from acute EAE administration of 2.43 did not result in development of relapses that were different in onset or severity from control animals. These results suggest that T cells of the Lyt-2 phenotype do not play a significant role in the immunoregulation of EAE.

Lymphocytic activation in peripheral blood and cerebrospinal fluid during the course of chronic relapsing experimental allergic encephalomyelitis

A monoclonal antibody against the human interleukin-2 receptor (anti-Tac) has been found to cross-react with an antigen on the surface of guinea pig leucocytes. Cells marking with anti-Tac and with an anti-pan T cell monoclonal antibody have been quantitated in the peripheral blood and cerebrospinal fluid (CSF) of guinea pigs with chronic relapsing experimental allergic encephalomyelitis (CR-EAE). T cells account for about 90% of peripheral blood leucocytes in all animals whilst in the CSF, T cells are the major contributor only when there is a pleocytosis. The proportion of T cells marking with anti-Tac, a measure of T cell activation, in blood and CSF of control animals is 12%, rising to 23% in blood in the post-acute phase of the disease. However, a fall in the blood Tac/T ratio to 13% occurs during the first 10 days of relapse with a subsequent rise to 30-35%. This change is related to the time after onset of relapse irrespective of the subsequent course of the disease. From first relapse onwards CSF lymphocytes show a greater level of activation than lymphocytes from paired peripheral blood samples but the proportion of Tac+ cells in CSF does not increase with increasing CSF pleocytosis. The data is consistent with migration of activated T cells from blood to CSF at the onset of relapse.

Activated T-cells and macrophages in the cerebrospinal fluid and the spinal meningeal exudate in chronic relapsing experimental allergic encephalomyelitis

An analysis has been made of the cell types which mark with monoclonal antibodies against T cells, macrophages and the IL-2 receptor (anti-Tac) in the blood, cerebrospinal fluid (CSF) and spinal meningeal exudates taken from guinea pigs in the relapse and remission stages of chronic relapsing experimental allergic encephalomyelitis (CR-EAE). Whilst the T-cell and macrophage content of blood remained unchanged throughout the course of CR-EAE, T cells accounted for the majority of the CSF pleocytosis associated with relapsing disease but both T cells and macrophages populated the meningeal exudate in substantial numbers. Activated T cells (Tac+) rose in number in blood only after the onset of relapse but formed a far higher proportion of the CSF pleocytosis or meningeal exudate than in paired blood samples. Meningeal exudate cells from Freund's adjuvant-inoculated, but not uninoculated animals, also showed an increase in Tac+ cell levels. In addition, the meningeal exudate contained a substantial number of cells which did not label with anti-T or anti-macrophage antibodies and which did not vary in absolute numbers throughout the course of disease.

Chronic relapsing experimental autoimmune encephalomyelitis. Transient presence in blood of lymphocytes sensitised to encephalitogen at onset of inflammatory relapses

Juvenile guinea pigs were immunised with homologous spinal cord and monitored daily over a 6-month period for neurological signs of chronic relapsing experimental autoimmune encephalomyelitis (CREAE). At various times animals were killed, numbers of leucocytes in their cerebrospinal fluid (CSF) quantified, and in vitro proliferative responses of blood lymphocytes to myelin basic protein (MBP) and its encephalitogenic nonapeptide (NP) determined. After recovering from initial acute clinical signs, animals suffered at least two major spontaneous relapses separated by remission periods of 4-5 weeks mean duration. In the early chronic phase, 5-12 weeks post-immunisation (pi), 63% of the animals recovered fully from relapses, whereas relatively irreversible neurological deficits predominated in the late chronic phase. During the acute and chronic phases, there was a highly significant correlation between clinical severity and CSF pleocytosis only in animals killed within 24 h of onset of a clinical exacerbation associated with more than 100 leucocytes/microliter of CSF. Guinea pigs with this degree of CSF pleocytosis were defined as suffering an inflammatory relapse. Blood lymphocytes responsive to MBP and NP were detected only in animals killed at the onset of clinical signs of either the acute or an inflammatory relapse. This dynamic relationship suggests that migration of encephalitogen-responsive lymphocytes via the blood to the central nervous system could produce certain relapses in CREAE. However, the relative paucity of CSF leucocytes in most animals killed during relapses between 15-26 weeks pi suggests that other factors may elicit neurological exacerbations in the late chronic phase.

Relapsing experimental allergic encephalomyelitis. An autoimmune model of multiple sclerosis

R-EAE is a valuable model for human MS. Table 2 outlines the similarities between R-EAE and MS. The clinical course and pathologic changes seen in this model accurately reflect the pattern of MS. The immunologic changes seen in animals with R-EAE also are similar to those seen in MS. Therefore, the clinicopathologic features of MS can be duplicated with a purely autoimmune model. Although this is of considerable pathogenic significance in understanding MS, we do not know what the inciting event is in MS that would be the equivalent of immunizing an animal with neural antigen. Despite this, R-EAE has and should continue to provide experimental data of considerable importance to an understanding of the mechanisms involved in the evolution of inflammatory demyelination. Other important models of MS utilize viral-induced demyelination. Although the clinical picture of most of the chronic demyelinating viral infections does not show as clear a relapsing or remitting pattern as seen in R-EAE, viral etiologies better fit the epidemiology of MS [16]. Several studies have demonstrated development of an acute EAE-like disease with sensitization to neural antigens following viral infection [12, 30, 56]. Thus, one can hypothesize an initial viral illness causing sensitization of the host to a neural antigen (?MBP) with a subsequent immunopathogenic course similar to that seen in R-EAE. Whether this will in fact be the case remains unproven as yet. Our understanding of the immunopathogenic mechanisms underlying inflammatory demyelination has been enlarged through studies of R-EAE. It is now clear that the minimal myelin antigen necessary for production of the disease is MBP, although this may differ in some species. The relapsing nature of this disorder is mediated in part through lymphocytes, as demonstrated in transfer studies, and thus does not require persistent antigenic depots. There is a genetic susceptibility to development of the CNS autoimmune state, and we speculate that an as yet unidentified perturbation of the host immune system allows for the occurrence of relapsing disease (Table 3).

Suppression of chronic-relapsing experimental allergic encephalomyelitis in strain-13 guinea pigs by administration of liposome-associated myelin basic protein

Juvenile strain-13 guinea pigs were challenged with isologous spinal cord in CFA. After recovery from the first EAE episode the animals were treated with guinea pig MBP inserted into liposomes, with cytochrome-c-liposomes, with MBP in saline or with MBP in IFA. Guinea pigs treated with MBP-liposomes showed a striking reduction in clinical signs and in the number and intensity of relapses. They displayed virtually no demyelinating lesions, and had comparatively little parenchymal inflammation in the spinal cord. Early T rosette levels showed an inverse correlation with the severity of histological lesions in the spinal cord but correlation with the clinical status at the time of rosette assay was less well defined.

Lymphocyte subpopulations in the blood and cerebrospinal fluid of multiple sclerosis patients in active disease

Lymphocyte subpopulations (total T cells, active T cells and B cells) were simultaneously analyzed in peripheral blood and CSF of MS patients. All patients were in active disease, 3 to 4 weeks after first signs of disease activation appeared. Per cent levels and absolute numbers of examined lymphocyte subpopulations in the blood of MS patients were significantly lower than in healthy controls. In MS, the level of active T lymphocytes was lower in CSF than in peripheral blood. The results support our earlier observations relating to the role of active T lymphocytes in the clinical course of disease.

Chronic relapsing experimental allergic encephalomyelitis: its value as an experimental model for multiple sclerosis

Comparison of the pathohistology of chronic relapsing experimental allergic encephalomyelitis (CR-EAE) and multiple sclerosis (MS) reveals a close similarity. Thus, CR-EAE appears to be a valuable model for the study of pathogenetic factors leading to the formation of MS lesions, although the induction of the disease may be different (active sensitization with CNS antigens and adjuvant in CR-EAE versus unknown etiology in MS). CR-EAE furthermore mimicks the pathohistological patterns of other related human inflammatory demyelinating diseases (i.e., acute perivenous leukoencephalomyelitis and acute hemorrhagic leukoencephalomyelitis). The expression of an acute, predominantly inflammatory versus chronic inflammatory demyelinating disease in this model depends upon the time interval between sensitization and sampling of the animals. Recent evidence is discussed that a cooperation between cellular and humoral immune mechanisms, directed against multiple CNS antigens, is responsible for the formation of large demyelinated plaques in EAE and MS.

Neuroimmunology in multiple sclerosis

A review of latest immunological interpretations regarding the pathogenesis of Multiple the Sclerosis. Data on a new immunoenzymatic method for the identification of blood lymphocyte populations are presented together with preliminary results relating to an immunogenetic correlation between primary affective disorders and Multiple Sclerosis.

Antigen-induced suppression of mitogen responses and resistance to experimental autoimmune encephalomyelitis

Random-bred Hartley and inbred Strain 2 and Strain 13 guinea pigs were inoculated for acute experimental autoimmune encephalomyelitis (EAE). Sixty-six percent (69/103) of the Hartleys developed signs of EAE while the remaining 34% (34/103) were resistant. No Strain 2 and all Strain 13 guinea pigs developed EAE. Histologic examination of nervous tissue revealed that susceptible Hartleys and Strain 13 and Strain 2 animals had lesions characteristic of EAE. Tissue from resistant Hartleys showed fewer and less severe changes. Lymphocyte-transformation assays with EAE-inducing and noninducing antigens and T-cell mitogens revealed three different sets of responses in vitro: (i) lymphocytes from all animals responded to mitogens; (ii) lymphocytes from susceptible animals responded to EAE-inducing antigens; and (iii) lymphocytes from resistant Hartleys were suppressed from responding to the mitogens solely by EAE-inducing antigens. Plasmas from all EAE-sensitized animals had equivalent anti-myelin basic proteins (MBP) antibody titers and skin tests of EAE-inoculated Hartleys were all positive for MBP sensitization. Therefore, resistance and reduced histologic changes characteristic of EAE correlated with a disease-specific antigen-induced suppression of lymphocyte responses to T-cell mitogens. This suggests that clinical resistance to EAE in Hartley guinea pigs is mediated by an immunologic suppressor mechanism.

Chronic relapsing experimental allergic encephalomyelitis: cerebrospinal fluid cytology and a comparison with meningeal and spinal cord pathology

Cerebrospinal fluid (CSF) was taken from strain 13 guinea pigs in various stages of chronic relapsing experimental allergic encephalomyelitis, the spinal cords removed for histological examination and meningeal stretch preparations made. CSF cells were counted and characterized by morphological studies, anti-IgG and alpha-naphthyl acetate esterase (ANAE) staining. Approximately 65% of normal CSF lymphocytes were ANAE positive and 10% stained with anti-IgG. No polymorphonuclear leucocytes were seen. Five out of eight relapsing animals had raised cell counts (up to 152/microliters) as did three animals in remission. There was no change in the proportion of various types of CSF cells where increased numbers were recorded. Infiltrating cells in spinal cord sections and meningeal preparations were similarly characterized and the results compared with CSF cells findings. Animals in relapse which had, in addition, macroscopically visible cord plaques showed the most severe infiltrative changes in spinal cord tissue and in the meninges. There were differences between the proportion of various types of CSF cells and meningeal infiltrate cells on ANAE staining reaction. In general there were far more lymphocyte-type cells in the CSF but more monocyte-type cells in meningeal infiltrates.

Experimental allergic encephalomyelitis. Early T cells and TG cells are separate subpopulations

To investigate whether previously described fluctuations in circulating early T cell levels reflected a change in suppressor activity, early T cell and TG cell values were determined in guinea pigs with acute and chronic experimental allergic encephalomyelitis (EAE) and normals. It was found that while both subpopulations showed similar changes in EAE, particularly decreases during periods of clinical worsening, changes in the two subpopulations were not always synchronous. Also, similar levels of TG cells could be found both in isolated early and isolated late (total) T cells. These two lines of evidence indicate that early T cells and TG cells are heterologous populations and that early T cells do not reflect suppressor activity, findings in accord with a similar, recent study on multiple sclerosis.

Chronic relapsing experimental autoimmune encephalomyelitis. treatment with combinations of myelin components promotes clinical and structural recovery

Preliminary results are presented on the treatment of Strain 13 guinea pigs with chronic relapsing experimental autoimmune (allergic) encephalomyelitis (EAE) induced by a single sensitisation with whole spinal cord. Animals were treated at different stages of the disease with injection containing either myelin basic protein (MBP) alone in incomplete Freund's adjuvant (IFA), or MBP in combination with a lipid hapten of myelin, galactocerebroside (GC) in IFA. The rationale for this treatment stemmed from previous work which suggested that MBP was responsible for T cell sensitisation in EAE and that GC was important in producing demyelinating antibodies and that both myelin components were needed in the induction of disease. Although treatment with MBP alone caused some initial stabilisation of the disease process, subsequent relapses occurred in all animals. However, in animals given MBP and GC together, either early or late in the course of the disease, marked clinical improvement has been noted with little or no development of relapses over an observation period of more than one year post-treatment. In addition, evidence of extensive remyelination and oligodendroglial proliferation in CNS lesions has been found in MBP-GC-treated animals suggesting that this therapy might be beneficial for CNS repair and relevant to multiple sclerosis.

Antibodies-restricted heterogeneity in serum and cerebrospinal fluid of chronic relapsing experimental allergic encephalomyelitis

An animal model which might help to study multiple sclerosis has long been sought. With chronic relapsing experimental allergic encephalitis (EAE), the search seems to have brought hope and evidence of comparable pathology whether concerned with clinical or neuropathological results, but no study of the cerebrospinal fluid (CSF) electrophoretic pattern has been made so far. A new sensitive method enables to study the CSF proteins: unconcentrated CSF proteins after agar gel electrophoresis are stained with silver reagents. The silver technique allows to follow the evolution of the inflammatory reaction in chronic relapsing EAE as well as in the acute form of EAE. This technique provides an additional approach to the study of EAE and an argument in favor of chronic relapsing EAE in guinea pigs as a model for multiple sclerosis.

Encephalitis induced in rabbits by staphylococcal lipoteichoic acid

Rabbits were immunized with staphylococcal lipoteichoic acid (LTA) in Freund's adjuvant. After four injections (six weeks) the rabbits showed decreased activity and unsteadiness of the head. Two weeks after the sixth injection (ten weeks), two of five rabbits developed clinical signs of encephalitis with nystagmus, ataxia, general weakness, decreased activity, and dragging of the hind legs. The other three animals showed only mild symptoms. Neuropathological examination showed inflammatory infiltrates containing small lymphocytes and some plasma cells in the leptomeninges and within the perivascular spaces of the brain.

Experimental allergic encephalomyelitis. Frequent sampling of blood alters disease course

Previous studies have shown that Strain 13 guinea pigs sensitised for experimental allergic encephalomyelitis (EAE) as adults usually develop an acute, fatal form of disease while animals inoculated as juveniles usually display a chronic relapsing form. The present study reports that following repeated short-interval blood sampling by cardiac puncture for the estimation of lymphocyte populations, some adult Strain 13 guinea pigs sensitised for acute EAE unexpectedly survived and developed chronic EAE, while a group of juveniles sensitised for chronic EAE and bled under the same conditions, developed a more severe, acute form of EAE. It is suggested that this reversal of disease course was related to the depletion of circulating factors.