Limits...
Effects of photobleaching on selected advanced glycation end products in the human lens.

Holm T, Raghavan CT, Nahomi R, Nagaraj RH, Kessel L - BMC Res Notes (2015)

Bottom Line: Transmission increased and AGE-related fluorescence decreased significantly after photobleaching but no changes were observed in the concentration of the measured AGEs.We found a significant effect of the photobleaching treatment on lens optical parameters but we could not associate the optical findings to a change in the concentration of the AGEs we measured.The biochemical nature of the photochemical reactions associated with photobleaching remains to be elucidated.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, Glostrup Hospital, Ringvej 57, 2600, Glostrup, Denmark. holm03@gmail.com.

ABSTRACT

Background: Cataract is the leading cause of blindness, especially in the developing world. To ease access to treatment, we have proposed that cataract could be treated non-invasively by photobleaching of the chemically modified proteins responsible for cataract formation. The present study was aimed at examining the optical and biochemical effects of the proposed treatment.

Methods: Human donor lenses were photobleaced using a 445 nm cw laser. Lens optical quality was assessed before and after photobleaching by light transmission and scattering. The concentration of the advanced glycation end products (AGEs) pentosidine, argpyrimidine, carboxymethyllysine, hydroimidazolone was measured.

Results: Transmission increased and AGE-related fluorescence decreased significantly after photobleaching but no changes were observed in the concentration of the measured AGEs.

Conclusions: We found a significant effect of the photobleaching treatment on lens optical parameters but we could not associate the optical findings to a change in the concentration of the AGEs we measured. This finding suggests that other AGEs were responsible for the observed photobleaching of the human lens after laser treatment. The biochemical nature of the photochemical reactions associated with photobleaching remains to be elucidated.

Show MeSH

Related in: MedlinePlus

Box plot (lower 25 percentile, median and upper 75 percentile) of fluorescence measurements in control lenses and lenses treated with photobleaching. Fluorescence was measured for argpyrimidine and pentosidine-like AGEs (λem/λex 335/385 nm) and for other AGEs (λem/λex 370/440 nm).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC4302587&req=5

Fig4: Box plot (lower 25 percentile, median and upper 75 percentile) of fluorescence measurements in control lenses and lenses treated with photobleaching. Fluorescence was measured for argpyrimidine and pentosidine-like AGEs (λem/λex 335/385 nm) and for other AGEs (λem/λex 370/440 nm).

Mentions: In addition, we measured the fluorescence intensity of argpyrimidine and pentosidine-like AGEs as the emission peak at 385 nm after excitation at 335 nm and the fluorescence intensity of other AGEs was measured at the fluorescence peak at 440 nm after excitation at 370 nm in 7 lens pairs, see Figure 4. Fluorescence was on average 25.9% ± 22.3% (mean ± SD) lower after photobleaching at λem/λex 335/385 nm and it was 32.3% ± 20.8% (mean ± SD) lower at λem/λex 370/440 nm. The difference was significant for both λem/λex 370/440 nm and λem/λex 335/385 nm (p = 0.02, signed rank sum test).Figure 4


Effects of photobleaching on selected advanced glycation end products in the human lens.

Holm T, Raghavan CT, Nahomi R, Nagaraj RH, Kessel L - BMC Res Notes (2015)

Box plot (lower 25 percentile, median and upper 75 percentile) of fluorescence measurements in control lenses and lenses treated with photobleaching. Fluorescence was measured for argpyrimidine and pentosidine-like AGEs (λem/λex 335/385 nm) and for other AGEs (λem/λex 370/440 nm).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4302587&req=5

Fig4: Box plot (lower 25 percentile, median and upper 75 percentile) of fluorescence measurements in control lenses and lenses treated with photobleaching. Fluorescence was measured for argpyrimidine and pentosidine-like AGEs (λem/λex 335/385 nm) and for other AGEs (λem/λex 370/440 nm).
Mentions: In addition, we measured the fluorescence intensity of argpyrimidine and pentosidine-like AGEs as the emission peak at 385 nm after excitation at 335 nm and the fluorescence intensity of other AGEs was measured at the fluorescence peak at 440 nm after excitation at 370 nm in 7 lens pairs, see Figure 4. Fluorescence was on average 25.9% ± 22.3% (mean ± SD) lower after photobleaching at λem/λex 335/385 nm and it was 32.3% ± 20.8% (mean ± SD) lower at λem/λex 370/440 nm. The difference was significant for both λem/λex 370/440 nm and λem/λex 335/385 nm (p = 0.02, signed rank sum test).Figure 4

Bottom Line: Transmission increased and AGE-related fluorescence decreased significantly after photobleaching but no changes were observed in the concentration of the measured AGEs.We found a significant effect of the photobleaching treatment on lens optical parameters but we could not associate the optical findings to a change in the concentration of the AGEs we measured.The biochemical nature of the photochemical reactions associated with photobleaching remains to be elucidated.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, Glostrup Hospital, Ringvej 57, 2600, Glostrup, Denmark. holm03@gmail.com.

ABSTRACT

Background: Cataract is the leading cause of blindness, especially in the developing world. To ease access to treatment, we have proposed that cataract could be treated non-invasively by photobleaching of the chemically modified proteins responsible for cataract formation. The present study was aimed at examining the optical and biochemical effects of the proposed treatment.

Methods: Human donor lenses were photobleaced using a 445 nm cw laser. Lens optical quality was assessed before and after photobleaching by light transmission and scattering. The concentration of the advanced glycation end products (AGEs) pentosidine, argpyrimidine, carboxymethyllysine, hydroimidazolone was measured.

Results: Transmission increased and AGE-related fluorescence decreased significantly after photobleaching but no changes were observed in the concentration of the measured AGEs.

Conclusions: We found a significant effect of the photobleaching treatment on lens optical parameters but we could not associate the optical findings to a change in the concentration of the AGEs we measured. This finding suggests that other AGEs were responsible for the observed photobleaching of the human lens after laser treatment. The biochemical nature of the photochemical reactions associated with photobleaching remains to be elucidated.

Show MeSH
Related in: MedlinePlus