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  1. Article ; Online: Endothelial Cell Identity, Heterogeneity and Plasticity in the Kidney.

    Ballermann, Barbara J

    Journal of the American Society of Nephrology : JASN

    2019  Volume 31, Issue 1, Page(s) 1–2

    MeSH term(s) Endothelial Cells ; Endothelium ; Kidney ; Sequence Analysis, RNA ; Water Deprivation
    Language English
    Publishing date 2019-12-09
    Publishing country United States
    Document type Editorial ; Research Support, Non-U.S. Gov't ; Comment
    ZDB-ID 1085942-1
    ISSN 1533-3450 ; 1046-6673
    ISSN (online) 1533-3450
    ISSN 1046-6673
    DOI 10.1681/ASN.2019111179
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: The Glomerular Endothelium Restricts Albumin Filtration.

    Ballermann, Barbara J / Nyström, Jenny / Haraldsson, Börje

    Frontiers in medicine

    2021  Volume 8, Page(s) 766689

    Abstract: Inflammatory activation and/or dysfunction of the glomerular endothelium triggers proteinuria in many systemic and localized vascular disorders. Among them are the thrombotic microangiopathies, many forms of glomerulonephritis, and acute inflammatory ... ...

    Abstract Inflammatory activation and/or dysfunction of the glomerular endothelium triggers proteinuria in many systemic and localized vascular disorders. Among them are the thrombotic microangiopathies, many forms of glomerulonephritis, and acute inflammatory episodes like sepsis and COVID-19 illness. Another example is the chronic endothelial dysfunction that develops in cardiovascular disease and in metabolic disorders like diabetes. While the glomerular endothelium is a porous sieve that filters prodigious amounts of water and small solutes, it also bars the bulk of albumin and large plasma proteins from passing into the glomerular filtrate. This endothelial barrier function is ascribed predominantly to the endothelial glycocalyx with its endothelial surface layer, that together form a relatively thick, mucinous coat composed of glycosaminoglycans, proteoglycans, glycolipids, sialomucins and other glycoproteins, as well as secreted and circulating proteins. The glycocalyx/endothelial surface layer not only covers the glomerular endothelium; it extends into the endothelial fenestrae. Some glycocalyx components span or are attached to the apical endothelial cell plasma membrane and form the formal glycocalyx. Other components, including small proteoglycans and circulating proteins like albumin and orosomucoid, form the endothelial surface layer and are bound to the glycocalyx due to weak intermolecular interactions. Indeed, bound plasma albumin is a major constituent of the endothelial surface layer and contributes to its barrier function. A role for glomerular endothelial cells in the barrier of the glomerular capillary wall to protein filtration has been demonstrated by many elegant studies. However, it can only be fully understood in the context of other components, including the glomerular basement membrane, the podocytes and reabsorption of proteins by tubule epithelial cells. Discovery of the precise mechanisms that lead to glycocalyx/endothelial surface layer disruption within glomerular capillaries will hopefully lead to pharmacological interventions that specifically target this important structure.
    Language English
    Publishing date 2021-11-29
    Publishing country Switzerland
    Document type Journal Article ; Review
    ZDB-ID 2775999-4
    ISSN 2296-858X
    ISSN 2296-858X
    DOI 10.3389/fmed.2021.766689
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: The Glomerular Endothelium Restricts Albumin Filtration

    Barbara J. Ballermann / Jenny Nyström / Börje Haraldsson

    Frontiers in Medicine, Vol

    2021  Volume 8

    Abstract: Inflammatory activation and/or dysfunction of the glomerular endothelium triggers proteinuria in many systemic and localized vascular disorders. Among them are the thrombotic microangiopathies, many forms of glomerulonephritis, and acute inflammatory ... ...

    Abstract Inflammatory activation and/or dysfunction of the glomerular endothelium triggers proteinuria in many systemic and localized vascular disorders. Among them are the thrombotic microangiopathies, many forms of glomerulonephritis, and acute inflammatory episodes like sepsis and COVID-19 illness. Another example is the chronic endothelial dysfunction that develops in cardiovascular disease and in metabolic disorders like diabetes. While the glomerular endothelium is a porous sieve that filters prodigious amounts of water and small solutes, it also bars the bulk of albumin and large plasma proteins from passing into the glomerular filtrate. This endothelial barrier function is ascribed predominantly to the endothelial glycocalyx with its endothelial surface layer, that together form a relatively thick, mucinous coat composed of glycosaminoglycans, proteoglycans, glycolipids, sialomucins and other glycoproteins, as well as secreted and circulating proteins. The glycocalyx/endothelial surface layer not only covers the glomerular endothelium; it extends into the endothelial fenestrae. Some glycocalyx components span or are attached to the apical endothelial cell plasma membrane and form the formal glycocalyx. Other components, including small proteoglycans and circulating proteins like albumin and orosomucoid, form the endothelial surface layer and are bound to the glycocalyx due to weak intermolecular interactions. Indeed, bound plasma albumin is a major constituent of the endothelial surface layer and contributes to its barrier function. A role for glomerular endothelial cells in the barrier of the glomerular capillary wall to protein filtration has been demonstrated by many elegant studies. However, it can only be fully understood in the context of other components, including the glomerular basement membrane, the podocytes and reabsorption of proteins by tubule epithelial cells. Discovery of the precise mechanisms that lead to glycocalyx/endothelial surface layer disruption within glomerular capillaries will ...
    Keywords endothelial surface layer ; endothelial dysfunction ; fenestrae ; glycocalyx ; hyaluronan ; permselectivity ; Medicine (General) ; R5-920
    Subject code 570
    Language English
    Publishing date 2021-11-01T00:00:00Z
    Publisher Frontiers Media S.A.
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article ; Online: Dependence of renal microvessel density on angiotensin II: only in the fetus?

    Ballermann, Barbara J

    Journal of the American Society of Nephrology : JASN

    2010  Volume 21, Issue 3, Page(s) 386–388

    MeSH term(s) Angiotensin II/metabolism ; Female ; Fetus/physiology ; Humans ; Kidney/blood supply ; Kidney/embryology ; Kidney/metabolism ; Microcirculation/physiology ; Pregnancy ; Receptor, Angiotensin, Type 1/metabolism ; Signal Transduction/physiology
    Chemical Substances Receptor, Angiotensin, Type 1 ; Angiotensin II (11128-99-7)
    Language English
    Publishing date 2010-02-18
    Publishing country United States
    Document type Comment ; Editorial ; Research Support, Non-U.S. Gov't
    ZDB-ID 1085942-1
    ISSN 1533-3450 ; 1046-6673
    ISSN (online) 1533-3450
    ISSN 1046-6673
    DOI 10.1681/ASN.2010010069
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article: Tipping the balance from angiogenesis to fibrosis in CKD.

    Ballermann, Barbara J / Obeidat, Marya

    Kidney international supplements

    2015  Volume 4, Issue 1, Page(s) 45–52

    Abstract: Chronic progressive renal fibrosis leads to end-stage renal failure many patients with chronic kidney disease (CKD). Loss of the rich peritubular capillary network is a prominent feature, and seems independent of the specific underlying disease. The ... ...

    Abstract Chronic progressive renal fibrosis leads to end-stage renal failure many patients with chronic kidney disease (CKD). Loss of the rich peritubular capillary network is a prominent feature, and seems independent of the specific underlying disease. The mechanisms that contribute to peritubular capillary regression include the loss of glomerular perfusion, as flow-dependent shear forces are required to provide the survival signal for endothelial cells. Also, reduced endothelial cell survival signals from sclerotic glomeruli and atrophic or injured tubule epithelial cells contribute to peritubular capillary regression. In response to direct tubular epithelial cell injury, and the inflammatory reaction that ensues, capillary pericytes dissociate from their blood vessels, also reducing endothelial cell survival. In addition, direct inflammatory injury of capillary endothelial cells, for instance in chronic allograft nephropathy, also contributes to capillary dropout. Chronic tissue hypoxia, which ensues from the rarefaction of the peritubular capillary network, can generate both an angiogenic and a fibrogenic response. However, in CKD, the balance is strongly tipped toward fibrogenesis. Understanding the underlying mechanisms for failed angiogenesis in CKD and harnessing endothelial-specific survival and pro-angiogenic mechanisms for therapy should be our goal if we are to reduce the disease burden from CKD.
    Language English
    Publishing date 2015-07-31
    Publishing country United States
    Document type Review ; Journal Article
    ZDB-ID 193442-9
    ISSN 2157-1716 ; 2157-1724 ; 0098-6577
    ISSN (online) 2157-1716
    ISSN 2157-1724 ; 0098-6577
    DOI 10.1038/kisup.2014.9
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: An In Vitro Kinase Assay to Assess Rac1 Phosphorylation by ERK.

    Brandwein, Daniel / Tong, Junfeng / Li, Laiji / Ballermann, Barbara / Wang, Zhixiang

    Methods in molecular biology (Clifton, N.J.)

    2018  Volume 1821, Page(s) 131–140

    Abstract: Recent findings suggest that phosphorylation might further contribute to the tight regulation of Rho GTPases. Interestingly, sequence analysis of Rac1 shows that T108 within ... ...

    Abstract Recent findings suggest that phosphorylation might further contribute to the tight regulation of Rho GTPases. Interestingly, sequence analysis of Rac1 shows that T108 within the
    MeSH term(s) Adenosine Triphosphate/chemistry ; Amino Acid Motifs ; Extracellular Signal-Regulated MAP Kinases/chemistry ; Extracellular Signal-Regulated MAP Kinases/genetics ; Extracellular Signal-Regulated MAP Kinases/metabolism ; Humans ; Isotope Labeling/methods ; Phosphorylation ; Recombinant Fusion Proteins/chemistry ; Recombinant Fusion Proteins/genetics ; Recombinant Fusion Proteins/metabolism ; rac1 GTP-Binding Protein/chemistry ; rac1 GTP-Binding Protein/genetics ; rac1 GTP-Binding Protein/metabolism
    Chemical Substances RAC1 protein, human ; Recombinant Fusion Proteins ; Adenosine Triphosphate (8L70Q75FXE) ; Extracellular Signal-Regulated MAP Kinases (EC 2.7.11.24) ; rac1 GTP-Binding Protein (EC 3.6.5.2)
    Language English
    Publishing date 2018-07-31
    Publishing country United States
    Document type Journal Article
    ISSN 1940-6029
    ISSN (online) 1940-6029
    DOI 10.1007/978-1-4939-8612-5_9
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: Contribution of the endothelium to the glomerular permselectivity barrier in health and disease.

    Ballermann, Barbara J

    Nephron. Physiology

    2007  Volume 106, Issue 2, Page(s) p19–25

    Abstract: Background: The endothelium that lines glomerular capillaries shares many properties with endothelial cells in general, but unlike most endothelial cells, it is extremely flat and densely perforated by transendothelial cell pores, the fenestrae. Until ... ...

    Abstract Background: The endothelium that lines glomerular capillaries shares many properties with endothelial cells in general, but unlike most endothelial cells, it is extremely flat and densely perforated by transendothelial cell pores, the fenestrae. Until recently, it was believed that the fenestrae allow free passage of large proteins, and that the glomerular endothelium contributes little to the permselectivity of the glomerular capillary wall.
    Methods: Key studies addressing the nature of the glomerular capillary endothelium and its contribution to glomerular permselectivity were reviewed.
    Results: Glomerular endothelial cell flattening and fenestrae formation requires signals from differentiated podocytes, and from the glomerular basement membrane. Deletion of VEGF-A from podocytes prevents flattening and fenestration of glomerular endothelium. Application of VEGF-A to endothelial cells in vivo stimulates fenestrae formation, and neutralization of VEGF-A by soluble VEGF receptor 1 (sFlt-1) or anti-VEGF antibodies results in loss of glomerular fenestrae, and proteinuria. Neutralizing TGF-beta1 antibodies, deletion of laminin alpha3 in mice or laminin beta3 in humans cause similar defects. The glomerular endotheliosis lesion of pre-eclampsia is due to the placenta-derived inhibitors sFlt-1 and sEndoglin, which block the VEGF-A/VEGF receptor and TGF-beta/endoglin signaling, respectively, causing the loss of glomerular endothelial cell fenestrae, cell swelling and proteinuria. The glomerular endothelium is covered by a glycocalyx that extends into the fenestrae and by a more loosely associated endothelial cell surface layer of glycoproteins. Mathematical analyses of functional permselectivity studies have concluded that the glomerular endothelial cell glycocalyx and its associated surface layer account for the retention of up to 95% of proteins within the circulation. Furthermore, the fenestrae are critical for the maintenance of the high hydraulic conductivity of the glomerular capillary wall, and their loss results in a reduction in the glomerular filtration rate.
    Conclusions: Loss of GFR and proteinuria can result from glomerular endothelial cell injury.
    MeSH term(s) Endothelium/physiopathology ; Female ; Humans ; Kidney Glomerulus/physiopathology ; Pre-Eclampsia/physiopathology ; Pregnancy ; Proteinuria/physiopathology ; Vascular Endothelial Growth Factor A/metabolism
    Chemical Substances Vascular Endothelial Growth Factor A
    Language English
    Publishing date 2007
    Publishing country Switzerland
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Review
    ZDB-ID 207121-6
    ISSN 1660-2137 ; 1423-0186 ; 2235-3186 ; 1660-8151 ; 0028-2766
    ISSN (online) 1660-2137 ; 1423-0186 ; 2235-3186
    ISSN 1660-8151 ; 0028-2766
    DOI 10.1159/000101796
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article: Glomerular endothelial cell differentiation.

    Ballermann, Barbara J

    Kidney international

    2005  Volume 67, Issue 5, Page(s) 1668–1671

    Abstract: Background: Glomerular endothelial cells differ from most other endothelial cells in that they are extraordinarily flattened and highly fenestrated. In this differentiated form, they allow formation of glomerular ultrafiltrate at a prodigious rate.: ... ...

    Abstract Background: Glomerular endothelial cells differ from most other endothelial cells in that they are extraordinarily flattened and highly fenestrated. In this differentiated form, they allow formation of glomerular ultrafiltrate at a prodigious rate.
    Methods: Molecular processes that dictate the development and differentiation of glomerular endothelium are reviewed.
    Results: During glomerular development, angioblasts already present in the metanephric blastema well before any organized angiogenic sprouts invade the capillary cleft of developing nephrons at the comma and S-shape stages in response to chemotactic and guiding cues from primitive podocytes. The angioblasts then undergo homotypic aggregation into precapillary cords as yet devoid of a lumen. Lumen development then proceeds through the loss of superfluous endothelial cells by apoptosis as well as flattening of the remaining viable endothelial cells. The final step, fenestration, is critically dependent on appropriate stimuli, most notably vascular endothelial growth factor A (VEGF-A), from differentiated podocytes. Current evidence suggests that the fenestrae of fully differentiated glomerular endothelium can be lost within hours if the VEGF-A stimulus is removed, and that the glomerular endotheliosis, loss of glomerular filtration rate (GFR) and proteinuria observed in preeclampsia are due to the circulating inhibitor of VEGF-A, soluble VEGF receptor 1 (VEGFR-1).
    Conclusion: Differentiation of the glomerular endothelium is highly dependent on podocyte-derived stimuli and their loss leads to the derangements of glomerular function in preeclampsia.
    MeSH term(s) Animals ; Apoptosis ; Cell Differentiation ; Endothelium, Vascular/cytology ; Endothelium, Vascular/embryology ; Endothelium, Vascular/metabolism ; Female ; Humans ; Kidney Glomerulus/blood supply ; Kidney Glomerulus/embryology ; Kidney Glomerulus/metabolism ; Mice ; Pre-Eclampsia/etiology ; Pre-Eclampsia/metabolism ; Pre-Eclampsia/pathology ; Pregnancy ; Vascular Endothelial Growth Factor A/genetics ; Vascular Endothelial Growth Factor A/metabolism ; Vascular Endothelial Growth Factor Receptor-1/metabolism
    Chemical Substances Vascular Endothelial Growth Factor A ; vascular endothelial growth factor A, mouse ; Vascular Endothelial Growth Factor Receptor-1 (EC 2.7.10.1)
    Language English
    Publishing date 2005-05
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Review
    ZDB-ID 120573-0
    ISSN 1523-1755 ; 0085-2538
    ISSN (online) 1523-1755
    ISSN 0085-2538
    DOI 10.1111/j.1523-1755.2005.00260.x
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: TIMAP promotes angiogenesis by suppressing PTEN-mediated Akt inhibition in human glomerular endothelial cells.

    Obeidat, Marya / Li, Laiji / Ballermann, Barbara J

    American journal of physiology. Renal physiology

    2014  Volume 307, Issue 5, Page(s) F623–33

    Abstract: The function of TIMAP, an endothelial cell (EC)-predominant protein phosphatase 1-regulatory subunit, is poorly understood. We explored the potential role of TIMAP in the Akt-dependent regulation of glomerular EC proliferation, survival, and in vitro ... ...

    Abstract The function of TIMAP, an endothelial cell (EC)-predominant protein phosphatase 1-regulatory subunit, is poorly understood. We explored the potential role of TIMAP in the Akt-dependent regulation of glomerular EC proliferation, survival, and in vitro angiogenesis. To deplete TIMAP, the EC were transfected with TIMAP-specific or nonspecific small interfering (si) RNA. The rate of electrical impedance development across subconfluent EC monolayers, a measure of the time-dependent increase in EC number, was 93 ± 2% lower in TIMAP-depleted than in control EC. This effect on cell proliferation was associated with reduced DNA synthesis and increased apoptosis: TIMAP silencing reduced 5-ethynyl-2'-deoxyuridine incorporation by 38 ± 2% during the exponential phase of EC proliferation, and cleaved caspase 3 as well as caspase 3 activity increased in TIMAP-depleted relative to control cells. Furthermore, TIMAP depletion inhibited the formation of angiogenic sprouts by glomerular EC in three-dimensional culture. TIMAP depletion strongly diminished growth factor-stimulated Akt phosphorylation without altering ERK1/2 phosphorylation, suggesting a specific effect on the PI3K/Akt/PTEN pathway. Endogenous TIMAP and PTEN colocalized in EC and coimmunoprecipitated from EC lysates. The inhibitory PTEN phosphorylation on S370 was significantly reduced in TIMAP-depleted compared with control EC, while phosphorylation of PTEN on the S380/T382/T383 cluster remained unchanged. Finally, the PTEN inhibitor bpV(phen) fully reversed the suppressive effect of TIMAP depletion on Akt phosphorylation. The data indicate that in growing EC, TIMAP is necessary for Akt-dependent EC proliferation, survival, and angiogenic sprout formation and that this effect of TIMAP is mediated by inhibition of the tumor suppressor PTEN.
    MeSH term(s) Apoptosis/physiology ; Cell Proliferation/physiology ; Cell Survival/physiology ; Cells, Cultured ; Endothelial Cells/cytology ; Endothelial Cells/physiology ; Humans ; In Vitro Techniques ; Kidney Glomerulus/cytology ; Kidney Glomerulus/physiology ; Membrane Proteins/physiology ; Neovascularization, Physiologic/physiology ; PTEN Phosphohydrolase/antagonists & inhibitors ; PTEN Phosphohydrolase/physiology ; Phosphatidylinositol 3-Kinases/physiology ; Phosphorylation/physiology ; Proto-Oncogene Proteins c-akt/antagonists & inhibitors ; Proto-Oncogene Proteins c-akt/physiology
    Chemical Substances Membrane Proteins ; PPP1R16B protein, human ; Phosphatidylinositol 3-Kinases (EC 2.7.1.-) ; Proto-Oncogene Proteins c-akt (EC 2.7.11.1) ; PTEN Phosphohydrolase (EC 3.1.3.67) ; PTEN protein, human (EC 3.1.3.67)
    Language English
    Publishing date 2014-09-01
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 603837-2
    ISSN 1522-1466 ; 0363-6127
    ISSN (online) 1522-1466
    ISSN 0363-6127
    DOI 10.1152/ajprenal.00070.2014
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article: Adding Endothelium to Artificial Vascular Grafts.

    Ballermann, Barbara J.

    News in physiological sciences : an international journal of physiology produced jointly by the International Union of Physiological Sciences and the American Physiological Society

    2001  Volume 13, Page(s) 154

    Language English
    Publishing date 2001-05-25
    Publishing country United States
    Document type Journal Article
    ZDB-ID 632842-8
    ISSN 1522-161X ; 0886-1714
    ISSN (online) 1522-161X
    ISSN 0886-1714
    DOI 10.1152/physiologyonline.1998.13.3.154
    Database MEDical Literature Analysis and Retrieval System OnLINE

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