Impression cytology implicates cell autophagy in aqueous deficiency dry eye

Figures & data

Table 1 Baseline patient characteristics

n of eyes	56
Age	69.0±12.4
Range	36–89
TBUT	7.7±3.4 seconds
Schirmer	8.8±7.1 mm
OSDI	16.2±13.4

Note: Data are presented as mean ± standard deviation.

Abbreviations: OSDI, ocular surface disease index; TBUT, tear film break-up time.

Figure 1 Confocal images of conjunctival epithelium stained with LC3.

Notes: Blue represents DAPI-stained nuclei and red represents the antibody for LC3. Overlap of blue and red indicates normal conjunctiva with nuclear translocation of LC3. (A) Impression cytology sample with minimal nuclear translocation of LC3. This indicates a high degree of autophagy. (B) Impression cytology sample with significant nuclear translocation of LC3. This indicates a normal conjunctival epithelium. Magnification ×60.
Abbreviation: LC3, microtubule-associated protein light chain 3.

Table 2 Patient characteristics stratified based on LC3 status

Characteristics	LC3≥1.0	LC3<1.0	P-value
n of eyes	38	18
Age, years	67.9±13.2	71.2±10.2	0.34
Range	36–89	57–86
TBUT (seconds)	7.5±3.7	8.2±2.7	0.48
Schirmer (mm)	10.1±8.0	6.0±3.5	<0.05
OSDI	14.2±13.7	20.6±11.9	0.095

Notes: Data are presented as mean ± standard deviation. LC3 equal or greater than 1 indicates a preponderance of LC3 in the nucleus suggestive of a healthy ocular surface. The findings from patients with a healthy occular surface according to LC3 status are in the first column. A ratio of less than one indicated that more LC3 was in the cytoplasm and hence there was a higher degree of autophagic cellular stress. Those patients’ characteristics are in the second column.

Abbreviations: LC3, microtubule-associated protein light chain 3; OSDI, ocular surface disease index; TBUT, tear film break-up time.

Figure 2 Significantly higher Schirmer scores were obtained in samples with LC3 ratios ≥1.0 (P<0.05).

Notes: The asterisk denotes a significant difference in the two Schirmer scores. Analysis was done using one-way ANOVA followed by Tukey’s multiple comparisons test. The sample size for eyes with LC3 ratio ≥1.0 is 38; the sample size for eyes with LC3 ratio <1.0 is 18.
Abbreviations: ANOVA, analysis of variance; LC3, microtubule-associated protein light chain 3.

Table 3 Pearson’s correlation coefficients

r	Schirmer	LC3 ratio	Age	TBUT	OSDI
Schirmer	–	0.41	0.11	0.12	0.11
LC3 ratio	0.41	–	−0.14	−0.15	−0.06
Age	0.11	−0.14	–	0.10	−0.24
TBUT	0.12	−0.15	0.10	–	−0.05
OSDI	0.11	−0.06	−0.24	−0.05	–

Note: ‘–’ indicates not applicable.

Abbreviations: LC3, microtubule-associated protein light chain 3; OSDI, ocular surface disease index; TBUT, tear film break-up time.