Correlation Between the Levels of Air Pollution With the Hyperplasia of Goblet Cells in Human Conjunctiva During the Last 7 Years in the Metropolitan Area of Buenos Aires, Argentina

Abstract

 

Purpose:

 

This retrospective study was designed to evaluate the correlation between air pollution with the hyperplasia of conjunctival goblet cells (GC) in patients with ocular discomfort in the metropolitan area of Buenos Aires (MABA).

 

Methods:

 

We analyzed the impression cytology of 8,377 patients with symptoms of ocular discomfort, together with on-road mobile emissions of particulate matter (PM) and nitrogen oxides (NOx) in MABA between 2000 to 2006. Nelson classification was used and we considered more than 300 GC in 10 high power fields (HPF) with 400X magnification as hyperplasia of GC. The PM and NOx annual emissions were computed by means of the 2006 MABA on-road mobile emission inventory, taking into consideration the fleet evolution through time as well as the incorporation of new vehicle technologieans. Locally-measured emission factors as well as those presented by the European COPERT III methodology were employed.

 

Results:

 

The levels of PM and NOx on-road mobile emissions in MABA increased significantly during the last seven years, PM: 3.4 to 4.0 gigagrams (Gg) and NOx: 64 to 76 Gg. In impression cytology samples, GC hyperplasia was also increased significantly between 5.75% to 18%.  

 

Conclusions:

 

The results suggest that the exposure to PM and NO_x on-road mobile emissions induced a dose dependent GC conjunctival hyperplasia. These findings suggest that this event is an adaptive response of the conjunctival epithelium to chronic environmental injury. Nevertheless, this adaptation is not enough to inhibit the symptoms of ocular irritation.

 

Keywords: clinical (human) or epidemiologic studies: risk factor assessment • ocular irritants • conjunctiva