using the Prevenar-13 vaccine. Twenty-four healthy male volunteers were vaccinated with Prevenar-13, either three times, twice or once in a double-blind, placebo-controlled, randomized single... Show moreusing the Prevenar-13 vaccine. Twenty-four healthy male volunteers were vaccinated with Prevenar-13, either three times, twice or once in a double-blind, placebo-controlled, randomized single center clinical study. Anti-pneumococcal wall, oxLDL and phosphorycholine antibody levels were measured at a fixed serum dilution, as well as circulating lipid levels over the course of 68 weeks. A significant increase in anti-oxLDL IgG and IgM was seen in the group receiving two doses six months apart compared to the placebo. However, these differences were not observed in the groups receiving a single dose, two doses one month apart, or three doses. This study shows that vaccination with Prevenar-13 does not result in robust anti-oxLDL IgM levels in humans. Further research would be required to test alternative pneumococcal-based vaccines, vaccination regimens or study populations, such as cardiovascular disease patients. Show less
Diabetes mellitus type 2 (DM) is a major risk factor for developing active tuberculosis (TB) disease, yet the causal mechanisms driving this association remain largely elusive. As the incidence of... Show moreDiabetes mellitus type 2 (DM) is a major risk factor for developing active tuberculosis (TB) disease, yet the causal mechanisms driving this association remain largely elusive. As the incidence of DM is rising, especially in TB endemic countries, it is important to identify the relevant immunological and metabolic processes that underlie TB-DM comorbidity, because such insights will facilitate optimal treatment, diagnosis and prevention. In this thesis, we have started to unravel key factors underlying the association between TBand DM using two approaches. Firstly, we identified and analyzed human macrophage subsets and studied the interactions between these human cells and a major pathogen, Mycobacterium tuberculosis (Mtb), and the specific metabolic changes involved using well-controlled in vitro systems. Next, we employed metabolomics to determine the impact of concurrent TB-DM on circulating metabolites in patient cohorts ex vivo. In this thesis we present evidence derived from in vitro experiments and from ex vivo observational data which collectively suggest a pathogenic role of atherogenic lipid species during TB development. Show less
Ascone, G.; Ceglie, I. di; Walgreen, B.; Sloetjes, A.W.; Lindhout, E.; Bot, I.; ... ; Lent, P.L.E.M. van 2020
Rheumatoid arthritis (RA) is a chronic inflammatory disease, characterized by severe joint inflammation and bone destruction as the result of increased numbers and activity of osteoclasts. RA is... Show moreRheumatoid arthritis (RA) is a chronic inflammatory disease, characterized by severe joint inflammation and bone destruction as the result of increased numbers and activity of osteoclasts. RA is often associated with metabolic syndrome, whereby elevated levels of LDL are oxidized into oxLDL, which might affect osteoclastogenesis. In this study, we induced antigen-induced arthritis (AIA) in Apoe(-/-) mice, which spontaneously develop high LDL levels, to investigate the effects of high LDL/oxLDL levels on osteoclast differentiation and bone destruction. Whereas basal levels of bone resorption were comparable between naive WT and Apoe(-/-) mice, induction of AIA resulted in a significant reduction of bone destruction in Apoe(-/-) mice as compared to WT controls. In line with that, the TRAP(+) area on the cortical bone was significantly decreased. The absence of Apoe did affect neither the numbers of CD11b(+) Ly6C(high) and CD11b(-)/Ly6C(high)osteoclast precursors (OCPs) in the BM of naive mice nor their in vitro osteoclastogenic potential as indicated by comparable mRNA expression of osteoclast markers. Addition of oxLDL, but not LDL, to pre-osteoclasts from day 3 and mature osteoclasts from day 6 of osteoclastogenesis strongly reduced the number of TRAP(+) osteoclasts and their resorptive capacity. This coincided with a decreased expression of various osteoclast markers. Interestingly, oxLDL significantly lowered the expression of osteoclast-associated receptor (Oscar) and the DNAX adaptor protein-12 encoding gene Tyrobp, which regulate the immunoreceptor tyrosine-based activation motif (ITAM) co-stimulation pathway that is strongly involved in osteoclastogenesis. Collectively, our findings suggest that under inflammatory conditions in the joint, high LDL levels lessen bone destruction during AIA, probably by formation of oxLDL that inhibits osteoclast formation and activity through modulation of the ITAM-signaling. Show less
Ascone, G.; Di Ceglie, I.; Walgreen, B.; Sloetjes, A.W.; Lindhout, E.; Bot, I.; ... ; Lent, P.L.E.M. van 2019
Rheumatoid arthritis (RA) is a chronic inflammatory disease, characterized by severe joint inflammation andbone destruction as the result of increased numbers and activity of osteoclasts. RA is... Show moreRheumatoid arthritis (RA) is a chronic inflammatory disease, characterized by severe joint inflammation andbone destruction as the result of increased numbers and activity of osteoclasts. RA is often associated withmetabolic syndrome, whereby elevated levels of LDL are oxidized into oxLDL, which might affect osteoclastogenesis.In this study, we induced antigen-induced arthritis (AIA) in Apoe−/− mice, which spontaneously develophigh LDL levels, to investigate the effects of high LDL/oxLDL levels on osteoclast differentiation and bonedestruction. Whereas basal levels of bone resorption were comparable between naive WT and Apoe−/− mice,induction of AIA resulted in a significant reduction of bone destruction in Apoe−/− mice as compared to WTcontrols. In line with that, the TRAP+ area on the cortical bone was significantly decreased. The absence of Apoedid affect neither the numbers of CD11b+Ly6Chigh and CD11b−/Ly6Chigh osteoclast precursors (OCPs) in the BMof naïve mice nor their in vitro osteoclastogenic potential as indicated by comparable mRNA expression ofosteoclast markers. Addition of oxLDL, but not LDL, to pre-osteoclasts from day 3 and mature osteoclasts fromday 6 of osteoclastogenesis strongly reduced the number of TRAP+ osteoclasts and their resorptive capacity. Thiscoincided with a decreased expression of various osteoclast markers. Interestingly, oxLDL significantly loweredthe expression of osteoclast-associated receptor (Oscar) and the DNAX adaptor protein-12 encoding gene Tyrobp,which regulate the immunoreceptor tyrosine-based activation motif (ITAM) co-stimulation pathway that isstrongly involved in osteoclastogenesis. Collectively, our findings suggest that under inflammatory conditions inthe joint, high LDL levels lessen bone destruction during AIA, probably by formation of oxLDL that inhibitsosteoclast formation and activity through modulation of the ITAM-signaling. Show less
Ren, B.; Kampen, E.E.M. van; Berkel, T.J.C. van; Cruickshank, S.M.; Eck, M. van 2017
Background and aimsArginase1 (Arg1), an M2 macrophage marker, plays a critical role in a number of immunological functions in macrophages, which are the main cell type facilitating atherosclerotic... Show moreBackground and aimsArginase1 (Arg1), an M2 macrophage marker, plays a critical role in a number of immunological functions in macrophages, which are the main cell type facilitating atherosclerotic lesion development. Arg1 uses the substrate l-arginine to create l-ornithine, a precursor molecule required for collagen formation and vascular smooth muscle cell differentiation. By reducing l-arginine availability, Arg1 limits the production of nitric oxide (NO), a pro-atherogenic factor in macrophages. In endothelial cells, conversely, NO is strongly anti-atherogenic. However, until now, the role of Arg1 in atherosclerosis is largely unknown. The aim of this study is to specifically investigate the effect of Arg1 deletion in hematopoietic cells on atherosclerosis susceptibility.MethodsLdlr KO mice were transplanted with Arg1flox/flox;Tie2-Cre (Arg1 KO) bone marrow (BM) or wildtype (WT) BM. After 8 weeks of recovery on chow diet, recipients mice were fed a Western-Type Diet (WTD) for 10 weeks to induce atherosclerosis.ResultsAfter 10-week WTD challenge, blood leukocyte counts were decreased by 25% (p < 0.001), and spleen leukocytes were decreased by 35% (p = 0.05) in Ldlr KO mice transplanted with Arg1 KO BM compared to mice transplanted with WT BM. The decrease in leukocytes was due to lower B lymphocyte counts. However, oxLDL-specific antibodies were increased in plasma of Ldlr KO mice transplanted with Arg1 KO BM compared to WT BM transplanted controls, whereas oxLDL-specific IgM was not affected. On the other hand, peritoneal foam cells in Arg1 KO BM recipients were increased 3-fold (p < 0.001) compared to WT BM recipients. No change in blood cholesterol was found. Despite changes in leukocyte counts and macrophage foam cell formation, we did not observe differences in atherosclerotic plaque size or plaque macrophage content in the aortic root. Surprisingly, there was also no difference in plaque collagen content, indicating that absence of macrophage Arg1 function does not reduce plaque stability.ConclusionsDeletion of Arg1 in hematopoietic cells adversely affects blood leukocyte counts and increases foam cell formation. However, no effects on atherosclerosis could be demonstrated, indicating that hematopoietic Arg1 function is not a decisive factor in atherosclerotic plaque formation. Show less
Ren, B.; Kampen, E.E.M. van; Berkel, T.J.C. van; Cruickshank, S.M.; Eck, M. van 2017
Background and aimsArginase1 (Arg1), an M2 macrophage marker, plays a critical role in a number of immunological functions in macrophages, which are the main cell type facilitating atherosclerotic... Show moreBackground and aimsArginase1 (Arg1), an M2 macrophage marker, plays a critical role in a number of immunological functions in macrophages, which are the main cell type facilitating atherosclerotic lesion development. Arg1 uses the substrate l-arginine to create l-ornithine, a precursor molecule required for collagen formation and vascular smooth muscle cell differentiation. By reducing l-arginine availability, Arg1 limits the production of nitric oxide (NO), a pro-atherogenic factor in macrophages. In endothelial cells, conversely, NO is strongly anti-atherogenic. However, until now, the role of Arg1 in atherosclerosis is largely unknown. The aim of this study is to specifically investigate the effect of Arg1 deletion in hematopoietic cells on atherosclerosis susceptibility.MethodsLdlr KO mice were transplanted with Arg1flox/flox;Tie2-Cre (Arg1 KO) bone marrow (BM) or wildtype (WT) BM. After 8 weeks of recovery on chow diet, recipients mice were fed a Western-Type Diet (WTD) for 10 weeks to induce atherosclerosis.ResultsAfter 10-week WTD challenge, blood leukocyte counts were decreased by 25% (p p = 0.05) in Ldlr KO mice transplanted with Arg1 KO BM compared to mice transplanted with WT BM. The decrease in leukocytes was due to lower B lymphocyte counts. However, oxLDL-specific antibodies were increased in plasma of Ldlr KO mice transplanted with Arg1 KO BM compared to WT BM transplanted controls, whereas oxLDL-specific IgM was not affected. On the other hand, peritoneal foam cells in Arg1 KO BM recipients were increased 3-fold (p ConclusionsDeletion of Arg1 in hematopoietic cells adversely affects blood leukocyte counts and increases foam cell formation. However, no effects on atherosclerosis could be demonstrated, indicating that hematopoietic Arg1 function is not a decisive factor in atherosclerotic plaque formation. Show less
Ren, B.; Kampen, E.E.M. van; Berkel, T.J.C. van; Cruickshank, S.M.; Eck, M. van 2017
Background and aimsArginase1 (Arg1), an M2 macrophage marker, plays a critical role in a number of immunological functions in macrophages, which are the main cell type facilitating atherosclerotic... Show moreBackground and aimsArginase1 (Arg1), an M2 macrophage marker, plays a critical role in a number of immunological functions in macrophages, which are the main cell type facilitating atherosclerotic lesion development. Arg1 uses the substrate l-arginine to create l-ornithine, a precursor molecule required for collagen formation and vascular smooth muscle cell differentiation. By reducing l-arginine availability, Arg1 limits the production of nitric oxide (NO), a pro-atherogenic factor in macrophages. In endothelial cells, conversely, NO is strongly anti-atherogenic. However, until now, the role of Arg1 in atherosclerosis is largely unknown. The aim of this study is to specifically investigate the effect of Arg1 deletion in hematopoietic cells on atherosclerosis susceptibility.MethodsLdlr KO mice were transplanted with Arg1flox/flox;Tie2-Cre (Arg1 KO) bone marrow (BM) or wildtype (WT) BM. After 8 weeks of recovery on chow diet, recipients mice were fed a Western-Type Diet (WTD) for 10 weeks to induce atherosclerosis.ResultsAfter 10-week WTD challenge, blood leukocyte counts were decreased by 25% (p p = 0.05) in Ldlr KO mice transplanted with Arg1 KO BM compared to mice transplanted with WT BM. The decrease in leukocytes was due to lower B lymphocyte counts. However, oxLDL-specific antibodies were increased in plasma of Ldlr KO mice transplanted with Arg1 KO BM compared to WT BM transplanted controls, whereas oxLDL-specific IgM was not affected. On the other hand, peritoneal foam cells in Arg1 KO BM recipients were increased 3-fold (p ConclusionsDeletion of Arg1 in hematopoietic cells adversely affects blood leukocyte counts and increases foam cell formation. However, no effects on atherosclerosis could be demonstrated, indicating that hematopoietic Arg1 function is not a decisive factor in atherosclerotic plaque formation. Show less
Ren, B.; Kampen, E.E.M. van; Berkel, T.J.C. van; Cruickshank, S.M.; Eck, M. van 2017
Background and aimsArginase1 (Arg1), an M2 macrophage marker, plays a critical role in a number of immunological functions in macrophages, which are the main cell type facilitating atherosclerotic... Show moreBackground and aimsArginase1 (Arg1), an M2 macrophage marker, plays a critical role in a number of immunological functions in macrophages, which are the main cell type facilitating atherosclerotic lesion development. Arg1 uses the substrate l-arginine to create l-ornithine, a precursor molecule required for collagen formation and vascular smooth muscle cell differentiation. By reducing l-arginine availability, Arg1 limits the production of nitric oxide (NO), a pro-atherogenic factor in macrophages. In endothelial cells, conversely, NO is strongly anti-atherogenic. However, until now, the role of Arg1 in atherosclerosis is largely unknown. The aim of this study is to specifically investigate the effect of Arg1 deletion in hematopoietic cells on atherosclerosis susceptibility.MethodsLdlr KO mice were transplanted with Arg1flox/flox;Tie2-Cre (Arg1 KO) bone marrow (BM) or wildtype (WT) BM. After 8 weeks of recovery on chow diet, recipients mice were fed a Western-Type Diet (WTD) for 10 weeks to induce atherosclerosis.ResultsAfter 10-week WTD challenge, blood leukocyte counts were decreased by 25% (p p = 0.05) in Ldlr KO mice transplanted with Arg1 KO BM compared to mice transplanted with WT BM. The decrease in leukocytes was due to lower B lymphocyte counts. However, oxLDL-specific antibodies were increased in plasma of Ldlr KO mice transplanted with Arg1 KO BM compared to WT BM transplanted controls, whereas oxLDL-specific IgM was not affected. On the other hand, peritoneal foam cells in Arg1 KO BM recipients were increased 3-fold (p ConclusionsDeletion of Arg1 in hematopoietic cells adversely affects blood leukocyte counts and increases foam cell formation. However, no effects on atherosclerosis could be demonstrated, indicating that hematopoietic Arg1 function is not a decisive factor in atherosclerotic plaque formation. Show less
Ren, B.; Kampen, E.E.M. van; Berkel, T.J.C. van; Cruickshank, S.M.; Eck, M. van 2017
Background and aimsArginase1 (Arg1), an M2 macrophage marker, plays a critical role in a number of immunological functions in macrophages, which are the main cell type facilitating atherosclerotic... Show moreBackground and aimsArginase1 (Arg1), an M2 macrophage marker, plays a critical role in a number of immunological functions in macrophages, which are the main cell type facilitating atherosclerotic lesion development. Arg1 uses the substrate l-arginine to create l-ornithine, a precursor molecule required for collagen formation and vascular smooth muscle cell differentiation. By reducing l-arginine availability, Arg1 limits the production of nitric oxide (NO), a pro-atherogenic factor in macrophages. In endothelial cells, conversely, NO is strongly anti-atherogenic. However, until now, the role of Arg1 in atherosclerosis is largely unknown. The aim of this study is to specifically investigate the effect of Arg1 deletion in hematopoietic cells on atherosclerosis susceptibility.MethodsLdlr KO mice were transplanted with Arg1flox/flox;Tie2-Cre (Arg1 KO) bone marrow (BM) or wildtype (WT) BM. After 8 weeks of recovery on chow diet, recipients mice were fed a Western-Type Diet (WTD) for 10 weeks to induce atherosclerosis.ResultsAfter 10-week WTD challenge, blood leukocyte counts were decreased by 25% (p p = 0.05) in Ldlr KO mice transplanted with Arg1 KO BM compared to mice transplanted with WT BM. The decrease in leukocytes was due to lower B lymphocyte counts. However, oxLDL-specific antibodies were increased in plasma of Ldlr KO mice transplanted with Arg1 KO BM compared to WT BM transplanted controls, whereas oxLDL-specific IgM was not affected. On the other hand, peritoneal foam cells in Arg1 KO BM recipients were increased 3-fold (p ConclusionsDeletion of Arg1 in hematopoietic cells adversely affects blood leukocyte counts and increases foam cell formation. However, no effects on atherosclerosis could be demonstrated, indicating that hematopoietic Arg1 function is not a decisive factor in atherosclerotic plaque formation. Show less
