Surface markers are key for identifying and differentiating endothelial cells from other cell types. Endothelial markers are widely used for endothelial cell characterization in both research and clinical settings. These markers help distinguish between different cell types and are essential in cell biology for studying vascular biology.
Gene expression profiles of endothelial cells are often analyzed to identify differentially expressed markers under various conditions. Signaling pathway mechanisms regulate the expression and function of these markers. Expressed endothelial markers are critical for identifying endothelial cells in tissue samples. Clinically, these markers are important for diagnosing and studying vascular diseases, cardiovascular diseases, and endothelial dysfunction. In contemporary clinical practice, numerous clinical studies utilize endothelial cell markers for research and therapeutic purposes.

We’ve put together a list of the most widely used endothelial cell markers and their localization based on recent research. For each marker, you’ll find our recommended antibodies with the applications they have been tested in,  making it quicker and easier for you to choose the best tools for your experiment.

VE-cadherin

VE-cadherin, also known as CDH5, is a well-used surface marker to identify endothelial cells. It helps maintain cell-cell adhesion and vascular integrity, so it is a good marker to use in blood vessel biology studies. Researchers use VE-cadherin to distinguish endothelial cells from other cell types in vitro and in vivo.
This marker is commonly used in immunostaining, flow cytometry, and lineage tracing. Its expression is restricted to vascular endothelial cells, helping to increase the specificity of cell identification in complex tissue environments. CDH5 is also used in studies of endothelial function, angiogenesis, and vascular remodelling¹.

Figure 1. Immunocytochemistry/ Immunofluorescence - Anti-VE Cadherin antibody - Intercellular Junction Marker (ab33168)

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Claudin-5

CLDN5, or claudin-5, is a transmembrane protein used as a marker for endothelial cells, especially in blood–brain barrier and vascular integrity studies. It is a component of tight junctions, where it regulates paracellular permeability between endothelial cells².
Researchers use CLDN5 to study endothelial cell behavior in different tissues, including the brain, retina, and kidneys. It is enriched in microvascular endothelial cells, so it’s useful to distinguish these cells in a complex tissue environment. CLDN5 is also relevant in inflammation, neurovascular disorders, and metabolic diseases, where changes in its expression reflect changes in barrier function.
In experimental models, CLDN5 is analyzed by immunostaining and gene expression profiling. Its consistent presence in vascular endothelium makes it useful for both basic and translational research on vascular health and disease.

Figure 2. Immunohistochemistry (Formalin/PFA-fixed paraffin-embedded sections) - Anti-Claudin 5 antibody [EPR7583] (ab131259)

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PECAM1

PECAM1 (CD31) is a transmembrane glycoprotein used to identify endothelial cells in research and clinical settings. It’s part of the immunoglobulin superfamily and is mainly found at cell-cell junctions in vascular endothelium³.
This marker is involved in cell adhesion, leukocyte transmigration, and vascular development. PECAM1 is used in immunohistochemistry and flow cytometry to detect endothelial cells in tissue samples or cultured systems. It’s also found in platelets and some immune cells, so you need to consider that when designing your experiment.
PECAM1’s consistent localization at endothelial junctions makes it useful for studying vascular remodeling, inflammation, and angiogenesis. It’s also being explored in mechanobiology, where it may interact with other proteins to sense and respond to shear stress.
This marker is still helpful for many vascular biology applications.

Figure 3. Multiplex immunohistochemistry - Anti-CD31 antibody [EPR17259] (ab182981)

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SLC2A1

SLC2A1 (GLUT1) is a facilitative glucose transporter studied in endothelial biology. It’s used as a marker to identify endothelial cells, especially in high metabolic demand tissues like brain and retina. SLC2A1 transports glucose across the endothelial barrier to support energy supply and barrier function⁴.
In vascular research, SLC2A1 is often looked at in the context of blood-brain barrier integrity and endothelial metabolism. Its expression is regulated by metabolic and hemodynamic cues and can be altered in conditions like inflammation, hypoxia, and atherosclerosis. Researchers use SLC2A1 in immunostaining and gene expression studies to assess endothelial cell identity and function.
SLC2A1 is also being looked at in studies of endothelial adaptation to shear stress and metabolic stress, where its role in glycolysis and barrier maintenance is of interest. This marker is still supporting research into vascular health and disease.

Figure 4. Immunohistochemistry (Formalin/PFA-fixed paraffin-embedded sections) - Anti-Glucose Transporter GLUT1 antibody [EPR3915] (ab15730)

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Von Willebrand factor (VWF)

VWF (von Willebrand factor) is a glycoprotein used as a marker to identify endothelial cells, especially in vascular biology and hemostasis studies. It’s synthesized and stored in endothelial cells and released in response to various stimuli, such as inflammation and vascular injury⁵.
Researchers use VWF to measure endothelial activation and dysfunction. It is involved in platelet adhesion and blood clotting, so it’s relevant to thrombosis, bleeding disorders, and cardiovascular disease. VWF is detected by immunostaining or ELISA in both cultured cells and tissue samples.
Expression can vary depending on the vascular bed and physiological context, which adds complexity to its interpretation in experimental models. VWF is also being explored in endothelial responses to oxidative stress and systemic inflammation, including in emerging areas like COVID-19-related vascular complications.
This marker is used in many endothelial health studies.

Figure 5. Immunohistochemistry (Formalin/PFA-fixed paraffin-embedded sections) - Anti-Von Willebrand Factor antibody [EPR12011] (ab174290)

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References

1. Vestweber, D. VE-cadherin: the major endothelial adhesion molecule controlling cellular junctions and blood vessel formation.  Arterioscler. Thromb. Vasc. Biol.   28, 223–232 (2008).

2. Hashimoto, Y., Greene, C., Munnich, A.  et al.  The CLDN5 gene at the blood–brain barrier in health and disease.  Fluids Barriers CNS   20, 22 (2023).

3. Lertkiatmongkol, P.  et al.  Endothelial functions of platelet/endothelial cell adhesion molecule-1 (CD31).  Curr. Opin. Hematol.   23, 253–259 (2016).

4. Tang, M.  et al.  An early endothelial cell-specific requirement for Glut1 is revealed in Glut1 deficiency syndrome model mice.  JCI Insight   6, e145789 (2021).

5. Zanetta, L.  et al.  Expression of von Willebrand factor, an endothelial cell marker, is up-regulated by angiogenesis factors: a potential method for objective assessment of tumor angiogenesis.  Int. J. Cancer   85, 281–288 (2000).