The recent study published in the Journal of Cosmetic Dermatology documents four individuals who developed bumps and swellings in the eye area as a result of the treatment - none of which disappeared completely without surgical intervention before the end of the study period.
Polylactic acid is a biodegradable absorbable powder that has been used for over twenty years as an ingredient in the absorbable sutures, screws and pins used in medical surgery.
Injections of PLA to the face have become popular in correcting the facial lipoatrophy (the breakdown of fat beneath the skin) sometimes experienced by HIV patients undergoing antiretroviral therapy.
In recent years injections of PLA have become popular for the treatment of wrinkles and expression lines, being marketed under the name New-Fill in the UK and Asutralia.
'PLA acts as a stimulant to fibroblasts, inducing synthesis of new collagen, which produces the cosmetic result' the report explains.
After injection PLA begins to biodegrade, primarily being hydrolysed into monomers or oligomers which are then subjected to phagocytosis by macrophages.
The first two clinical trials of PLA for cosmetic use were performed in the late 1990s and focused on 115 women.
The results suggested that the treatment was generally well tolerated and delivered long lasting positive results.
However two women on these first trials experienced adverse effects to the test injection and subsequently withdrew from the trial.
The recent study focuses on four women who have had adverse reactions to the injections, including bumps and swellings around the test site and, in one patient, a foreign-body granuloma reaction.
A foreign-body granuloma formation is one of the reactions that can occur after the use of foreign substances in tissue augmentation, having been linked to the use of silicon among other cosmetics injections.
This suggests that although PLA has previously been thought to be inert it may still lead to granulomatous type reactions which worryingly can often be permanent.
The report writes that 'in all four of our case studies, excluding one case where the nodules were surgically excised, the nodules were still present two years after their initial treatment despite the use of corticosteroids in two of the four cases.'
This leads the team to conclude that the product may warrant further studies before it can be considered a safe and reliable product, along with suggesting that a cautionary warning regarding these complications would be prudent.
This study comes at a time when the popularity of cosmetic fillers is at a record high, with a survey by BioForm medical conducted in early 2007 suggesting that 22 million US women over the age of 35 are wither willing to use or considering using such treatment.