Biomedical subjects

M Kouwenhoven

Publications and source records attributed to M Kouwenhoven.

At least 19 recordsLinked to original sources

PubMed2005

Dendritic cells in the cerebrospinal fluid and peripheral nerves in Guillain-Barré syndrome and chronic inflammatory demyelinating polyradiculoneuropathy.

The role of antigen-presenting cells (APC) involved in induction of T and B cell mediated autoaggressive immunity in Guillain-Barre syndrome (GBS) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is poorly understood. We studied the numbers and phenotype of dendritic cells (DC) in blood and cerebrospinal fluid (CSF) over the course of GBS and CIDP before and after immunomodulatory treatment. Four out of seven GBS patients examined prior to treatment with high-dose intravenous immunoglobulins (IvIg) had elevated numbers of CD123(+) plasmacytoid DC in the CSF, while both GBS and CIDP patients examined prior to treatment had elevated numbers of CD11c(+) myeloid DC in the CSF, as compared to patients with noninflammatory neurological diseases (OND). The percentages of blood DC expressing the cell surface marker CD1a, co-stimulatory molecules CD80 and CD86, adhesion molecule CD54, and chemokine receptors CCR1, CCR2, CCR5, and CXCR4 were not affected in GBS or CIDP. The immunohistochemistry of sural nerve biopsies revealed CD11c(+)CD83(-)CD14(-)CD16(-) immature myeloid DC at low numbers, mostly in the perineurium, without difference between CIDP patients and controls. In contrast, the numbers of CD11c(+)CD14(+)/CD16(+) macrophages were higher within the endoneurium in CIDP patients compared with the controls. The recruitment of DC to CSF in GBS and CIDP may be important in capturing antigens released from inflamed spinal nerve roots into CSF and in transferring these antigens from CSF to local lymph nodes, where naive T and B cells may be activated.

Antigens, CD↗

PubMed2003

Multiple sclerosis: a study of chemokine receptors and regulatory T cells in relation to MRI variables.

Magnetic resonance imaging (MRI) remains the most valuable tool for monitoring disease activity and progression in patients with multiple sclerosis (MS), a chronic demyelinating disease of the central nervous system (CNS) with presumably autoimmune etiology. Chemokine receptors have been implicated in MS as key molecules directing inflammatory cells into the CNS. Regulatory (CD4+CD25+) T cells (Tr cells) are important in suppressing autoimmunity, and their absolute or functional deficit could be expected in MS. In the present study, venous blood was obtained from MS patients concurrent with MRI examination of the brain, and expression of chemokine receptors CCR1, CCR2, CCR5, CXCR3 and CXCR4 by CD4 T cells and monocytes, proportions of Tr cells, as well as expression of CD45RO, CD95, CTLA-4, HLA-DR and interleukin (IL)-10 by Tr cells and non-Tr (CD25-) CD4 T cells was analyzed by flow cytometry. Surface expression of CXCR3 by CD4 T cells was downregulated in the group of patients with high lesion load (LL) on T2-weighted images and gadolinium (Gd)-enhancing lesions on T1-weighted images, compared to the group with high LL and no Gd-enhancing lesions, and to the group with low LL, suggesting internalization of CXCR3 due to the release of its chemokine ligand (IP-10/CXCL10) from active MS lesions. Proportions of Tr cells amongst all CD4 T cells, and expression of IL-10 by Tr cells were increased in the patients with high LL and Gd-enhancing lesions. These results suggest that there is correlation between MRI parameters, chemokine receptor expression and the status of circulating Tr cells in MS, but further studies need to discriminate between pathogenetically relevant and bystander phenomena.

Adult↗

PubMed2002

Non-T(H)1 cytokines are augmented systematically early in Guillain-Barré syndrome.

The T(H)1 vs non-T(H)1 cytokine balance in Guillain-Barré syndrome (GBS) is unknown. Using enzyme-linked immunospot (ELISPOT) assays, we observed elevated numbers of interleukin (IL)-6 and IL-10-secreting blood mononuclear cells (BMNC) during the acute phase in untreated patients, and low levels of tumor necrosis factor alpha-secreting BMNC in the recovery phase of GBS. Numbers of IL-12p70-secreting BMNC were not affected over the course of GBS. The non-T(H)1 cytokine profile observed early in GBS may explain the self-limited clinical course associated with GBS.

Acute Disease↗

PubMed2002

Elevated expression of CCR5 by myeloid (CD11c+) blood dendritic cells in multiple sclerosis and acute optic neuritis.

Myeloid and plasmacytoid dendritic cells (DC) are present in cerebrospinal fluid (CSF) in non-inflammatory neurological diseases (NIND) and elevated in clinically definite multiple sclerosis (MS) and in early MS - acute monosymptomatic optic neuritis (ON). Here, we show that expression of CCR5, a chemokine receptor for regulated on activation, normal T cell expressed and secreted (RANTES) and macrophage inflammatory protein (MIP)-1alpha/beta, is elevated on blood myeloid (CD11c+) DC in MS and ON compared to non-inflammatory controls. In contrast, expression of CXCR4, a receptor for stromal cell-derived factor (SDF)-1alpha, is similar in all groups. Blood myeloid DC from MS patients respond chemotactically to RANTES and MIP-1beta, which are expessed in MS lesions. In active MS and ON, expression of CCR5 by myeloid DC in blood correlates with numbers of these cells in CSF. Thus, elevation of CCR5 may contribute to recruitment of myeloid DC to CSF in MS and ON. Recruitment of plasmacytoid DC to CSF appears to be CCR5-independent.

Acute Disease↗

PubMed2002

Cytokines in multiple sclerosis: methodological aspects and pathogenic implications.

Multiple sclerosis (MS) is one of the leading causes of disability among young adults of Caucasian origin. One hundred and fifty years after the first description of the disease, the cause of MS remains unknown. Ironically, the few hypotheses concerning MS pathogenesis that are valid today were first proposed over a hundred years ago. However, equipped with the advanced technology of molecular biology and imaging systems, we are at present progressively uncovering dues to understanding the pathogenesis of the disease. It is dearly evident that aberrant immune responses occur in MS, and it is likely that the spectrum of cytokines produced decisively influences disease outcome. The detrimental consequences of IFN-gamma and the beneficial effects of IFN-beta treatment in MS support this hypothesis. However, there are still major gaps in our knowledge of the involvement of cytokines in MS. Numerous studies have addressed the question of cytokine levels in MS, often with conflicting results; elevated, normal and decreased levels of almost all cytokines have been reported. This scenario most probably reflects methodological dilemmas as well as the complex biology of cytokines. Here we focus on possible reasons for the discrepancies of results reported on cytokines in MS and summarize findings obtained in particular by the application of enzyme-linked immunospot (ELISPOT) assays to cytokine studies in MS.

Antibody Formation↗

PubMed2001

IL-12/IL-12R system in multiple sclerosis.

IL-12/IL-12 receptor (IL-12R) system orchestrates the Th1 pathway of the immune system by maintaining one of the major bridges between innate and adaptive immune responses. Here, we studied both sides of this system in patients with multiple sclerosis (MS) and in controls. MS patients displayed elevated IL-12Rbeta1 and IL-12Rbeta2 expression on PHA-activated T cells compared to healthy subjects. Higher percentages of IL-12Rbeta1 and IL-12Rbeta2 positive T cells in cerebrospinal fluid (CSF) compared to blood were observed both in MS and other neurological diseases (OND). In contrast, numbers of IL-12 secreting blood mononuclear cells (MNC) were similar in MS and controls. The functional importance of high IL-12Rbeta2 in MS was underlined by the finding that IL-12 stimulated IFN-gamma production and proliferation of PHA-activated T cells correlated with levels of IL-12Rbeta2 expression. Our data indicates a dysregulation of the IL-12/IL-12R system in MS. It is suggested that even in the absence of increased IL-12 levels, the net effect of IL-12 might be augmented in MS by elevated expression of its receptor.

Adult↗

PubMed2001

Monocytes in multiple sclerosis: phenotype and cytokine profile.

Multiple sclerosis (MS) is an inflammatory demyelinating disease characterised by immune abnormalities in the central nervous system (CNS) as well as systemically. Activated, blood-borne monocytes are abundant in MS lesions, the properties of circulating monocytes are incompletely known. To delineate phenotype and levels of cytokine secreting monocytes in MS patients' blood, ELISPOT assays were used for detection and enumeration of monocytes secreting the cytokines IL-6, IL-12, TNF-alpha and IL-10. In parallel, the expression by monocytes of co-stimulatory molecules (CD40, CD80, CD86), major histocompatibility complex molecules (HLA-ABC, HLA-DR) and Fcgamma receptors (CD16, CD64) was examined by flow cytometry. Levels of blood monocytes secreting IL-6 and IL-12 were higher in patients with untreated MS and other neurological diseases (OND) compared to healthy controls, while levels of monocytes secreting TNF-alpha and IL-10 did not differ between groups. MS patients' blood monocytes also displayed elevated mean fluorescence intensity for the co-stimulatory molecule CD86, and MS patients with longer disease duration (>10 years) and higher disease severity (EDSS >3) had higher percentages of CD80 expressing monocytes compared to patients with short duration or lower severity. In conclusion, monocyte aberrations occur in MS and may change over the disease course.

Adult↗

PubMed2001

Functional cardiac MR imaging with steady-state free precession (SSFP) significantly improves endocardial border delineation without contrast agents.

Contrast between blood and myocardium in standard turbo gradient echo MR techniques (TFE) used routinely in clinical practice is mainly caused by unsaturated inflowing blood. Steady-state free precession (SSFP) has excellent contrast even in the absence of inflow effects. In 45 subjects cardiac cine loops in two long axis projections were acquired using TFE and compared with SSFP. A visual score (range 0 worst - 3 best) was assigned for endocardial border delineation for six myocardial segments in two long axis views. Endocardial border delineation score for TFE was 1.3 +/- 0.3 per segment and 2.4 +/- 0.3 for SSFP (P < 0.0001). Signal intensity blood/signal intensity myocardium was 1.5 +/- 0.4 at enddiastole and 1.4 +/- 0.3 at systole for TFE and 3.5 +/- 1.1 and 3.2 +/- 1.3 for SSFP, respectively (P < 0.0001). SSFP increases contrast between blood and myocardium more than twofold, resulting in an improved endocardial border definition. This may reduce variability for the determination of cardiac volumes and ejection fraction.

Adult↗

PubMed2001

Systemic immune response in whiplash injury and ankle sprain: elevated IL-6 and IL-10.

Whiplash injury and whiplash-associated disorders (WAD) are significant problems of modern society. Numerous attempts have been made to characterize the nature of whiplash injury. Whether the immune system is involved during the disease process is not known. In a prospective study, using enzyme-linked immunospot (ELISPOT) assays, we examined numbers of blood mononuclear cells (MNC) secreting pro- (IFN-gamma, TNF-alpha, IL-6) and anti-inflammatory (IL-10) cytokines in patients with WAD and, for reference, patients with ankle sprain and multiple sclerosis and healthy subjects. An immune response reflected by elevated numbers of TNF-alpha- and IL-10-secreting blood MNC was observed in patients with WAD examined within 3 days compared to 14 days after the whiplash injury. The patients with WAD examined within 3 days after the injury had also higher numbers of IL-6 and IL-10 secreting blood MNC compared to healthy subjects. The alterations of cytokine profiles observed in WAD were also observed in patients with ankle sprain when examined within 3 days after trauma. In contrast, there were no differences for cytokine profiles between patients with WAD examined 14 days after the whiplash injury and healthy subjects. Relatively minor trauma like WAD and ankle sprain are associated with a systemic dysregulation in numbers of cells secreting pro- as well as anti-inflammatory cytokines.

Adolescent↗

PubMed2001

Multiple sclerosis: elevated expression of matrix metalloproteinases in blood monocytes.

Multiple sclerosis (MS) is an inflammatory, demyelinating disease of the central nervous system (CNS) characterized by blood-brain barrier (BBB) breakdown. Disruptions of BBB continuity result in an influx of activated T cells and monocytes, and could contribute to lesion formation in the CNS. Matrix metalloproteinases (MMP) are enzymes implicated in BBB disruption, and in degradation of extracellular matrix proteins and myelin components. An imbalance in levels of MMP and tissue inhibitors of MMP (TIMP) has been implicated in the pathogenesis of MS. Since monocytes form a major cell population in acute MS lesions and may facilitate their entrance into the CNS by secretion of MMP, knowledge on MMP expression by blood monocytes could be useful to improve our understanding of the pathogenesis of MS. In the present study, we examined the expression of MMP-1, -3, -7, -9, -14 and TIMP-1 mRNA by blood monocytes in patients with MS using in situ hybridization. Levels of MMP-1, -3, -7, -9 and of TIMP-1 mRNA expressing monocytes were elevated in MS compared to controls, while those of MMP-14 did not differ. We therefore conclude that MS is associated with elevated levels of MMP and TIMP expressing blood monocytes that may contribute to MS pathogenesis.

Female↗

PubMed2001

Chemokines and their receptors in whiplash injury: elevated RANTES and CCR-5.

The human sufferings and socioeconomic burden due to whip-lash-associated disorders (WAD) are obvious but the pathogenesis of WAD is obscure. The possible involvement of the immune system during the disease process in WAD is not known. Effector molecules including chemokines and their receptors could play a role in WAD. In a prospective study using flow cytometry, we examined percentages of blood mononuclear cells (MNC) expressing the chemokines RANTES, MCP-1, MIP-1alpha, MIP-1beta, and IL-8, the chemokine receptor CCR-5, the T cell activation marker CD25, and the T cell chemoattractant IL-16 in patients with WAD and, for reference, in healthy controls. Higher percentages of RANTES-expressing blood MNC and T cells were observed in patients with WAD examined within 3 days compared to 14 days after the whiplash injury and, likewise, compared with healthy controls. The patients with WAD examined within 3 days after the accident also had higher percentages of CCR-5-expressing blood MNC, T cells, and CD45RO+ T cells compared to healthy controls. In contrast, there were no differences for any of these variables between patients with WAD examined 14 days after injury and healthy controls. In conclusion, WAD is associated with a systemic but transient dysregulation in percentages of RANTES and CCR-5 expressing MNC and T cells.

Adult↗

PubMed2001

Matrix metalloproteinase and cytokine profiles in monocytes over the course of stroke.

Stroke is a common cause of death and disability in our society. Stroke is associated with changes in immune responses within the central nervous system as well as systemically. The cells contributing to such changes as well as the factors contributing to formation of the inflammatory infiltrate observed in stroke remain to be clarified. In this study, blood monocytes and corresponding mononuclear cells (MNC) were separated and examined in parallel within 4 days and 1-3 months after onset of ischemic stroke. Numbers of TNF-alpha-, IL-12-, IL-6-, and IL-10-secreting cells and of cells expressing mRNA for matrix metalloproteinase (MMP)-1, -2, -7, -9 and tissue inhibitor of MMP (TIMP)-1 were studied. The TNF-alpha-, IL-12-, and IL-6-secreting monocytes and MNC were elevated during the acute phase compared to healthy controls. Such differences were not observed when stroke patients were examined during convalescence. The IL-10-secreting monocytes did not change over the course of stroke. Levels of monocytes expressing MMP-1, MMP-7 and TIMP-1 mRNA were elevated in the acute phase of stroke patients compared to convalescence and healthy controls, as were levels of MMP-1, -2, -7, -9 and TIMP-1 mRNA expressing blood MNC. The MMP-2 and -9 activity as measured by zymography also was higher in MNC supernatants in the acute phase of stroke compared to convalescence. The high levels of proinflammatory cytokines and MMPs in blood monocytes and MNC further demonstrate the presence of systemic aberrations in the acute phase of stroke. Such changes may contribute to the influx of blood-borne cells into the ischemic lesions during the acute phase of stroke.

Aged↗

PubMed2001

Enzyme-linked immunospot assays provide a sensitive tool for detection of cytokine secretion by monocytes.

Blood monocytes as well as tissue-differentiated macrophages play a pivotal role in controlling immune reactions. Monocytes regulate the extent, nature, and duration of immune responses by secretion of cytokines. Interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-alpha), IL-10, and IL-12 are of particular interest, since IL-12 shifts the immune response towards a Th1 type, facilitating the production of, e.g., TNF-alpha and IL-6, while IL-10 counteracts Th1 responses and promotes the production of Th2-related cytokines such as IL-4. A tight regulation of these four cytokines keeps the balance and decides whether Th1 or Th2 will predominate in immune reactions. Enzyme-linked immunospot (ELISPOT) assays are among the most-sensitive and -specific methods available for cytokine research. They permit ex vivo identification of individual cells actively secreting cytokines. In the present study we prepared monocytes from healthy subjects' blood and adapted ELISPOT assays to define optimal conditions to detect and enumerate monocytes secreting IL-6, TNF-alpha, IL-10, and IL-12. The optimal time for monocyte incubation was 24 h, and optimal monocyte numbers (in cells per well) were 2,000 for IL-6, 1,000 for TNF-alpha, 50,000 for IL-10, and 100,000 for enumeration of IL-12 secreting monocytes. Among healthy subjects, 10% +/- 5% of the monocytes secreted IL-6, 12% +/- 12% secreted TNF-alpha, 0.1% +/- 0.1% secreted IL-10, and 0.2% +/- 0.3% secreted IL-12 (values are means +/- standard deviations). In conclusion, ELISPOT assays constitute a valuable tool to enumerate monocytes secreting IL-6, TNF-alpha, IL-10, and IL-12 and probably to enumerate monocytes secreting other cytokines and proteins.

Adult↗

PubMed2001

Dendritic cells derived from patients with multiple sclerosis show high CD1a and low CD86 expression.

Dendritic cells (DC) are important antigen presenting cells (APC) and play a major role in initiating and orchestrating immune responses by priming T cells. Little is known about involvement of DC in multiple sclerosis (MS), where auto-aggressive T cells against myelin autoantigens are considered to contribute to inflammation and demyelination in the central nervous system. In this study, we compared phenotype and cytokine secretion of DC from patients with MS, other neurological diseases (OND) and healthy subjects. DC were generated from blood adherent mononuclear cells (MNC) by culture for 7 days with granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4). The yield and morphology of DC were similar in MS patients and controls. In both, the DC phenotype was that of immature myeloid lineage, comprising CD1a+ and CD11c+. The proportion of CD1a+ DC, being important for presentation of lipid antigens to T cells, was higher in MS patients compared to controls. The proportion of CD86+ DC, a co-stimulatory molecule that is assumed to promote Th2 differentiation, was low in MS. Low proportions of CD86+ DC were only observed in untreated MS patients but not in patients treated with IFN-beta. Production of IL-10 and IL-12 p40 by DC did not differ in MS patients and controls. These findings indicate that alterations of functionally important surface molecules on DC are associated with MS.

Adult↗

PubMed2000

Multiple sclerosis: pro- and anti-inflammatory cytokines and metalloproteinases are affected differentially by treatment with IFN-beta.

Interferon-beta (IFN-beta) has a beneficial influence on the course of multiple sclerosis (MS) and has become standard treatment of this disease, though its mechanisms of action are incompletely understood. This study examines the effect of IFN-beta treatment on the cytokines IL-6, TNF-alpha, IFN-gamma and IL-10; the metalloproteinases MMP-3, -7 and -9 and the tissue inhibitor of metalloproteinase-1 (TIMP-1). IFN-beta treatment resulted in decreased numbers of mononuclear cells (MNC) secreting IL-6 and TNF-alpha and expressing mRNA of MMP-3 and MMP-9 compared to pretreatment levels. On the contrary, numbers of IL-10 secreting MNC and TIMP-1 mRNA expressing were augmented during IFN-beta therapy. Whether the down-regulatory effects on pro-inflammatory and upregulatory effects on anti-inflammatory molecules are a direct result of IFN-beta on the immune system or secondary to clinical stabilization of MS pathology induced by IFN-beta remains to be evaluated.

Cells, Cultured↗

PubMed2000

IL-12 elispot assays to detect and enumerate IL-12 secreting cells.

The cytokine IL-12 promotes Th(1)type immune responses and plays a key role in immune regulation. The complex nature of IL-12 hampered its detection without use of stimulants that might give less relevant information. To detect circulating IL-12 p40, we developed enzyme-linked immunospot (ELISPOT) assays that allow enumeration of IL-12 p40 secreting cells without prior in vitro stimulation of the cells. In parallel, intracellular staining of IL-12 p40 by flow cytometry was performed to compare the two methods. IL-12 p40 secreting cells were detected in healthy subjects at a mean number of 103+/-155 per 10(5)blood mononuclear cells (MNC). Numbers of IL-12 p40 secreting blood MNC correlated with IL-12 p40 positive blood MNC detected by flow cytometry. Bacterial endotoxins and the inflammatory cytokines TNF-alpha and IFN-gamma control IL-12 production by antigen presenting cells. Utilizing IL-12 p40 ELISPOT assays, we could confirm occurrence of elevated numbers of IL-12 p40 secreting blood MNC after stimulation with TNF-alpha, IFN-gamma, LPS, LPS+TNF-alpha or LPS+IFN-gamma, compared to cultures without stimulant. Due to its central role in inflammation and autoimmunity, IL-12 is an attractive target for immunotherapy. IL-12 p40 ELISPOT assays represent a sensitive, specific and reliable tool for investigating the role of IL-12 in both health and disease.

Adult↗

PubMed2000

Renal artery blood flow: quantification with breath-hold or respiratory triggered phase-contrast MR imaging.

The aim of this study was to evaluate the validity and reproducibility of breath-hold and respiratory triggered phase-contrast (PC) MR imaging techniques in the measurement of renal artery blood flow. In 12 healthy subjects cardiac-gated PC flow measurements were obtained in the renal arteries using a breath-hold and a respiratory-triggered technique. The flow measurements were repeated in each renal artery separately. Comparison between the sum of flow measurements in the renal arteries and the difference in aortic flow measurements above and below the renal arteries served as an internal control. The flow measurements showed a good reproducibility both with the breath-hold (r=0.92, p < 0.0001) and with the respiratory-triggered (r = 0.91, p < 0.0001) technique. The validity of both methods was good and there was no statistically significant difference. Reproducible quantitative measurements of renal artery blood flow are possible with respiratory controlled, cardiac-gated, PC MR imaging.

Adult↗

PubMed2000

Dealing with the subvoxel vessel position relative to the reconstruction voxel grid in 2D MR quantitative flow measurements.

A method is introduced that quantifies the error in 2D MR Quantitative Flow measurements induced by the position of the vessel relative to the reconstruction voxel grid, called the subvoxel vessel position. In this method, the vessel area and the volume flow rate are determined for all possible subvoxel vessel positions resulting in a mean value with standard deviation. Since the subvoxel vessel position in standard MR image reconstruction is completely arbitrary, the standard deviation can be considered as a measure of its random error contribution. Simulation studies and in vivo measurements show that our method can be used to quantify and subsequently eliminate this random error. It is further quantitatively shown that, for low noise levels, Fourier interpolation to a higher reconstruction matrix also decreases the random error. We conclude that the precision of a 2D MR Quantitative Flow measurement is improved either by using our method or by reconstruction to a higher matrix.

Aorta↗