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The most advanced, freshly isolated in vitro kidney proximal tubule cell (PTC) model for nephrotoxicity assays

Kidney proximal tubule cell model for safety/efficacy and transporter studies

Newcells Biotech offers a comprehensive platform for in vitro renal studies from transporter studies, DDI to nephrotoxicity.


A unique primary proximal tubule cell model derived from fresh kidney tissue with high renal transporter expression levels.

aProximate proximal tubule cell (PTC) model.
aProximate proximal tubule cell (PTC) model. Schematic diagram of aProximate PTCs showing the expression of all key renal transporters (left) and the formation of tight junctions as shown by ZO-1 tight junction protein labelling (bottom right).


aProximate™ PTCs are primary cells derived from fresh human kidney tissue. They are grown on Transwells® and express the functional properties of a polarised cell layer with tight junctions.

In contrast to other models, aProximate™ PTCs retain high expression of the key renal transporters involved in drug handling including Megalin and Cubilin. Studies with aProximate™ give you a detailed mechanistic understanding of how drugs are transported and eliminated through the kidney. The model can be used to carryout drug-drug interaction studies to inform clinical trial design.


Key Features
  • Functional properties of polarised cell layer with tight junctions
  • Expressed Megalin and Cubilin
  • Available in multiple species (rat, dog, monkey, human)
  • Fast and reliable Nephrotoxicity service
Available Analytical Readouts
  • Flux and net transport measurements
  • Measurement of intracellular drug and metabolite concentrations
  • Identification of transporter-mediated drug-drug interactions
  • Early renal damage biomarkers
  • Cell viability

Speak to a Kidney Expert

aProximate™ Model Highlights

Accelerate your lead compound selection by understanding their mode of action in kidney tissue


Fully differentiated and polarised kidney proximal tubule cells


High level of expression of all key renal transporters


High predictivity of in vivo and clinical outcomes

Related reading

Model formats

  • 24-well Transwells (static and flow)
  • 96-well Transwells (static and flow)
  • Assay-ready plates for shipment (Human, 24-well & 96-well)

Cell Types

  • aProximate™ - primary kidney proximal tubule cells


  • Human
  • Mouse
  • Rat
  • Dog
  • Non-human primate (NHP)

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About Newcells Biotech

Newcells Biotech provides clients with validated in vitro tools to understand how drugs interact with tissues. We enable the generation of robust and informative data to support critical decisions during any stage of drug-development.

We believe that improving the in vitro models available to drug discovery and development scientists is a key method for increasing the efficiency of in-vitro to in-vivo translation and ultimately to delivering new therapies to patients.

By applying our expertise in iPSCs, primary tissues, a deep understanding of cellular physiology and organoid technology, we have built validated models and assays that have proven to be predictive of how drugs interact with tissues and organs.

Office reception

Young innovative company located in Newcastle upon Tyne, in the Northeast of England


A microscope image of a nephron model
ZO-1 Immunocytochemistry staining of PTCs (red) and Hoescht nuclear staining.
A graph showing different levels of creatine uptake
Functional validation of aProximate™ assay-ready plates for transporter assays Functional validation studies for transcellular flux and uptake of creatinine revealed preferential basolateral-to-apical (JBA) creatinine transport, indicative of normal physiological function. A JBA uptake ratio >1.5 indicates that the cells are functional.

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