Getting it right and getting it wrong

By Jan Tunér


In mid-2014 a LPT study by Arany et al. experienced considerable international publicity. The leading Swedish morning paper Dagens Nyheter presented the study over two full pages, see below:

This was good news, LPT studies are rarely covered in the news. But getting things right about LPT seems to be almost as easy as getting it wrong. However, before we plunge into that matter, here is an abstract of the study:

Rapid advancements in the field of stem cell biology have led to many current efforts to exploit stem cells as therapeutic agents in regenerative medicine. However, current ex vivo cell manipulations common to most regenerative approaches create a variety of technical and regulatory hurdles to their clinical translation, and even simpler approaches that use exogenous factors to differentiate tissue-resident stem cells carry significant off-target side effects. We show that non-ionizing, low-power laser (LPL) treatment can instead be used as a minimally invasive tool to activate an endogenous latent growth factor complex, transforming growth factor-β1 (TGF-β1) that subsequently differentiates host stem cells to promote tissue regeneration. LPL treatment induced reactive oxygen species (ROS) in a dose-dependent manner, which, in turn, activated latent TGF-β1 (LTGF-β1) via a specific methionine residue (at position 253 on LAP). Laser-activated TGF-β1 was capable of differentiating human dental stem cells in vitro. Further, an in vivo pulp capping model in rat teeth demonstrated significant increase in dentin regeneration after LPL treatment. These in vivo effects were abrogated in TGF-β receptor II (TGF-βRII) conditional knockout (DSPP(Cre)TGF-βRII(fl/fl)) mice or when wild-type mice were given a TGF-βRI inhibitor. These findings indicate a pivotal role for TGF-β in mediating LPL-induced dental tissue regeneration. More broadly, this work outlines a mechanistic basis for harnessing resident stem cells with a light-activated endogenous cue for clinical regenerative applications.

Now back to Dagens Nyheter. It is not easy for a journalist to present science in a style that is easy to understand for the average reader and, at the same time, correct in the details. Unfortunately the scientific editor contacted the wrong person. She called the Karolinska Institute in Stockholm and landed at the department of periodontology. This department has a PhD in laser dentistry with five published studies (Talat Qadri). But the person on the phone was obviously unaware of this and gladly answered to the questions. She thought the study was very good but it would take time before it could be applied in dentistry. “We do not make holes into the pulp” as in the study. Don’t we? There are things like accidental pulpal lesions in adults and intentional removal of the coronary pulp in deciduous teeth. In these cases dentists perform “pulp capping” with a dressing. So we do make “holes”, although not always intentionally. The aims of the pulp capping is to create a new dentin barrier – exactly what the Arany study did, but with better outcome thanks to the laser. The interviewed dentist also believed that it would take time before dentist would use therapeutic lasers. Well, they are already doing it!

So here we have a negative description of the usefulness of the results in the study. And all wrong. It is not easy to be a journalist–such a person has to get a fair insight into many fields–and especially a scientific journalist. But it didn’t end with an unfortunate selection of a dentist to be interviewed. The headline of the article in Dagens Nyheter reads: “Laser makes teeth repair themselves”. Well, laser does not; cavities still have to be drilled and filled. So it is an overstatement. But the laser can save teeth with deep cavities and teeth with exposed vital pulp.

Later on Praveen Arany was also interviewed in the journal of the Swedish Dental Association (Tandläkartidningen). This article was much better, to say the least.

What can we learn from this story? Well, first of all I would like to know how the authors managed to obtain such great publicity. A very good study, indeed, but these come in the hundreds every week and editors are picky. And then we can learn that whenever you read an article in the news and you are an expert in the field, you are bound to be disappointed. Journalism is hectic. And trying to get it right afterwards is of no use. I know! However, the mere fact that LPT is featured is good. We have to be grateful, still. And grateful to Praveen Arany and his team for creating great advances in laser phototherapy. Praveen is the current president of the North American Association for Light Therapy, here caught at NAALT2009. The lady is Hyunjung Kim from Korea.