The photopharmacology symposium in Vic lays the foundations for the future application of drugs regulated by light in humans

The leading international figures in the photopharmacology field met last Thursday and Friday in Vic, at the second international symposium to be held on this emerging branch of science, which uses light to control the activity of medication. Around 130 people from universities and research centres in 15 different countries participated in the event, which was jointly organised by the University of Vic - Central University of Catalonia (UVic-UCC), the Institute for Bioengineering of Catalonia (IBEC) - Barcelona Institute of Science and Technology and the Institute for Advanced Chemistry of Catalonia - Spanish National Research Council (IQAC-CSIC).

The symposium was a meeting and debating forum for leading researchers and international figures in photopharmacology, where the main new ideas in the discipline were presented. In more specific terms, it focused on the innovative diagnostic tools and therapies based on light that are currently being developed and on the technologies that are emerging in this field, ranging from drugs to optoelectronic devices.

Microsystems implantable in the body

One of the lectures that made the biggest impression on those attending was given by Jae-Wong Jeong, from the Korea Advanced Institute of Science and Technology. In his presentation, he discussed the progress he has made in designing microsystems that can be implanted in the human body and regulated by Bluetooth, which enable precise control of the localised release of a drug, and of the amount of light that is needed to activate it. Jeong showed how this microsystem, which can be implanted in subcutaneous tissue because of its small size, has already been successfully tested in animal trials.

An example of the device's applications is in the treatment of chronic pain, as the exact dose can be adjusted to meet the patient's needs at all times, minimising the drug's side effects. The application of photopharmacology in the treatment of chronic pain was also discussed by Cyril Goudet, of the Institute of Genomic Fonctionelle (IGF), who is working on controlling pain based on the identification and treatment of only the brain receptors involved in its transmission by means of photopharmacology.

Treatments to cure blindness

Other studies discussed during the symposium were those involving breakthroughs in treating blindness using photosensitive drugs. One of the researchers in this field is Michael Telias, at the University of California Berkeley, who explained how this pathology has already been reversed in animals with the implantation of photosensitive molecules in the retina. These molecules act as artificial light sensors, and with the neurons that survive the retinal degeneration process, they reactivate the biological process, meaning that sight can be restored. Another speaker covering this field was Dirk Trauner of New York University, who is developing compounds with pharmacological activity that is regulated reversibly with light, or in other words, which are activated and deactivated like a switch, which is why they are known as photoswitches. These compounds are the drugs used as a molecular prosthesis in the treatment of blindness.

Photopharmacology against cancer

Other topics covered at the symposium included the treatment of cancer with photopharmacology. This field was covered in the lecture by Edith C. Glazer, of the University of Kentucky, who uses light for the controlled release of drugs that act only in the specific area where the tumour is located. This subject was also discussed by Romain Quidant, an ICREA research professor at the Institute of Photonic Sciences (ICFO), who is working on the development of nanoparticles that heat up locally with light, and which in oncology can use this heat to attack and destroy tumour cells. Other pathologies which are being studied in this area include diabetes and Alzheimer's disease.

Creating synergies and cooperation between centres and researchers

With this symposium, the organisers aim to foster synergies and cooperation between centres and researchers, and establish a debate to delineate problems, define solutions, align strategies and consider future developments. To that end, they also aimed to make the debate a wide-ranging one, including points of view from professionals from areas of influence within photopharmacology, such as doctors, representatives of industrial sectors linked to light (photonics, spectroscopy and optics), molecular therapy (the pharmaceutical industry, biotechnology and medical chemistry) and medical devices.

One of the talks was by Vasilis Ntziachristos, from the Technische Universität in Munich, who presented a molecular image system used in diagnostic and clinical applications, in both biological tissues and living organisms. This system combines the interaction of light and ultrasound to obtain very high definition molecular images in real time. Kristian Berg, of the University of Oslo, also discussed the current situation of photodynamic therapy, a medical technology that uses a combination of photoactivated molecules and light to induce controlled cell death. This therapy is currently being applied in the treatment of various tumours and in the controlled elimination of microorganisms. 

The symposium included twenty lectures, three blocks of short presentations and two poster sessions. The opening ceremony on Thursday morning was chaired by the rector of the UVic-UCC, Joan Masnou, and the member of the organising and research committee of the IQAC, Amadeu Llebaria.

An expanding discipline

The event in Vic followed on from the first photopharmacology symposium, which took place at the Medical Centre of the University of Groningen (in the Netherlands) in February 2017, and was organised by the research teams of Wiktor Szymanski and Ben Feringa, who also participated in this second event. At the event that took place in Vic, Ben Feringa, who received the Nobel Prize in Chemistry in 2016 for the design and synthesis of molecular machines, summarised the applications of light in molecular control and its various applications. Among other areas, he mentioned controlling nanostructures for the release of drugs, the use of molecular motors, antibiotics activated by light, systems for regulating the activity of biological molecules such as nucleic acids and proteins, and the new smart materials that can acquire properties based on the characteristics of light.

What is photopharmacology?
Photopharmacology is based on administering photosensitive compounds as drugs, which are only activated and take effect in combination with light. This specific characteristic provides a high level of control over the administration of medications and therapies, since it means that the specific point of the body where it is applied and the duration of the application can be decided. This precision and location means that as a technique, photopharmacological treatments are not invasive, and can achieve optimum results with minimal secondary effects.

Although its history dates back to the 1960s, photopharmacology has primarily developed over the last ten years. During this period, a significant critical mass of researchers has been created in research centres and universities around the world that focus on the field from various perspectives. It is a multifaceted science, which includes biology, pharmacology, physics, chemistry, engineering and medicine. Its applications are also extremely wide-ranging: it may be therapeutically useful in a wide variety of medical fields, within which neurosciences and cardiology are particularly important. Some applications that are being studied could also provide substantial improvements in pathologies such as diabetes and chronic pain. Photopharmacology can also be used as a research tool, and can be combined with other technologies, such as materials nanotechnology.