Medical Device Daily Washington Editor

Some of the more forward-looking work at any conference is found in the pages of abstracts that populate conference handouts. At last week's annual conference of the American Society for Laser Medicine and Surgery (ASLMS; Wausau, Wisconsin), several abstracts gave some insight as to where device makers may be focusing their efforts in the years and decades to come.

One abstract dealt with the use of carbon nanohorns, a construct that upon close inspection more closely resembles a thimble than a horn. According to the abstract presented by a team led by Jon Whitney, a PhD candidate at Virginia Polytechnic Institute (Blacksburg, Virginia), laser therapy for cancer "could be greatly enhanced through integration of dual photothermal and photochemical sensitizing agents in the form of single-walled carbon nanohorns." The team's work hints that this configuration of carbon atoms does a nice job of absorbing energy at wavelengths near infrared and then expel heat as a result.

However, when the team inserted endohedral fullerenes, which are vaguely spheroidal and can house additional carbon particles, they boosted the thermal value of the particle, thus killing off more cancer cells. Another potential element of usefulness of the fullerene-containing nanohorn is the tendency of the combination to induce the formation of reactive oxygen species under laser light, which could kill off additional cancer cells by oxidation.

The researchers established the effect of these structures by inserting lutetium and gadolinium inside the fullerenes and measuring the absorption of laser energy in the range of 200-1,200 nanometers with a photospectrometer. The team measured the impact of the procedure on cancer cells by measuring levels of heat shock proteins (HSPs), which are known to promote the proliferation of cancers. The team at Virginia Tech is not the only group interested in HSPs, however. One of the more commonly examined heat shock proteins, HSP90, is named in 26 trials listed at clinicaltrials.gov.

Dosing model for 'nano' cancer therapy

It's all good and well to say you can zap cancer cells, but dosing is the big question after that, and that question was taken up by two researchers at Virginia Tech, Saugata Sarkar, PhD and Marissa Nichole Rylander, PhD. In their abstract, they remind the reader that "non-specific heating of target tissue" can damage nearby healthy tissue during laser treatment for cancer, but the HSP is also a consideration. If the treatment does not stimulate sufficient levels of heat, these proteins can be stimulated rather than fried, hence actually helping to spread the cancer in those immediate areas.

In their effort to develop a treatment planning model for laser therapy using multi-walled nanotubes, the pair devised a computational model that would "predict the temperature, injury and HSP expression distribution" in the treated areas, with provisions made for the accidental induction of greater HSP production due to insufficient heating. Thanks to magnetic resonance imaging, Rylander and Sarkar were able to validate their computational model, which is designed to establish not only the optimal size and shape of the nanotube, but also the distribution and concentration of nanotubes necessary to achieve the optimal therapeutic response. The algorithm is also written to provide accurate numbers on the pulse duration, wavelength, and power of the laser. With such a tool in hand, physicians could quickly establish how to "maximize tumor destruction and minimize tumor recurrence through precise control of thermal injury and HSP production."

Laser light to beat cholesterol?

It's the stuff of science fiction: stand in front of a beam of light and lower your cholesterol. This is not precisely what one of the presenters at ASLMS suggested, but his presentation and abstract hinted at exactly that.

Ryan Maloney, medical director of Erchonia Medical (McKinney, Texas) presented very preliminary findings at ASLMS that suggest that low-level laser radiation can interrupt the process by which cholesterol forms inside the cell, hence cutting short the accumulation of lipids that do so much damage to the circulatory system and help rack up huge healthcare costs. The non-controlled pilot study enrolled 20 volunteers between the ages of 18 and 65 to establish whether Erchonia's LipoLaser could do more than just accelerate the melting away of excess pounds. According to the abstract, the treatment regime, consisting of three episodes a week for two weeks, resulted in an overall reduction in serum cholesterol of between 1 and 31 milligrams per deciliter of blood in 75% of patients (15), with the average falling at 16.1 milligrams. Of equal significance in the eyes of some cardiologists is that triglycerides also dropped in 60% of the participants who saw a drop in cholesterol.

As is known, not all cholesterol is a problem, and the abstract states that 93% (or 14 of the 15) saw a fall-off in levels of low-density lipoprotein (LDL), "with 47% (7) revealing a reduction in LDL levels without experiencing a reduction in HDL," or high-density lipoprotein levels. Maloney reported that the company will shortly commence with a randomized, placebo-controlled trial later this year.

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