We all do it (empty our bladder that is), many times, every day. But we often take for granted the impact of losing bladder function on everyday life. Unfortunately, due to tissue problems and complications with infections, bladder transplants are not considered appropriate in treating bladder incontinence. This means that there is now a real drive for scientists to use lab-grown bladder cells that can be used not only to study the bladder in detail for potential treatments, but also, one day, used to grow person-specific tissues to repair and replace faulty bladders.
One exciting development in this field is growing cells in 3D. But what exactly do we mean by this? Conventionally, to study how tissues and organs work, scientists grow the cells they want to study in a single layer on a plastic dish. However, growing these cells in 3D rather than 2D, mimics how they exist in the body, which is a distinct advantage when looking to paint an accurate picture of how these cells behave in real life and how best to treat them. It also means that scientists have better control of the experiment, examining exactly what they want, how they want.
Hot on the heels of recent developments in lab-grown bladder tissue, a group led by Stephane Bolduc at Laval University in Quebec have refined the 3D cell-growing technique. Their method uses bladder cells grown on a collagen layer (which is the main structural component in our body) submerged in a urine-supplemented growth liquid. Impressively, including urine in the growth liquid means that the experiment resembles (even more closely) the real-life environment of the bladder.
Bolduc and his team successfully showed that this technique could transform bladder cells to grow into bladder tissue, by testing positive for key markers of bladder formation. They visualised their newly grown 3D cells using transmission electron microscopy – a form of microscopy that uses electrons rather than light, which allows greater and more accurate resolution than can be seen with conventional microscopes. The scientists observed a protein known as Cldn4 which is important for the formation of water tight ‘tight junctions’ between cells, which is a vital property of the cells in the urinary tract.
Uroplakin is an important factor used to measure bladder tissue quality. In the bladder, uroplakin forms a membrane which is important in stretching and contracting the bladder as it fills and empties daily. In their newly grown cells, the team observed ‘fusiform vesicles’ (which are important for the movement of uroplakin) as well as uroplakin-containing membranes similar to those found in real bladder tissue. This was another important confirmation that they were in fact growing life-like bladder cells.
This technique marks a significant development in the field of tissue engineering and has important implications for stem-cell therapy, whereby the hope is that a patient’s own cells could be used to grow person-specific bladder cells and deliver a personalised approach in treating bladder disorders.
Harder: Although relatively complicated, this urine-submerged method means that these lab-grown cells are reminiscent of real bladder tissues, which can be assessed to study mechanisms of bladder development.
Better: Urine makes biologically active molecules, which can be used by surrounding cells for their needs and growth.
Faster: This bladder model provides lab-grown bladder tissues in about two weeks, which could be used as an alternative to animal studies in drug testing.
Stronger: The hope is that this technology will provide stronger tissue that could eventually be used as graftable bladder patches for restorative surgery.