Serum Indicators Of Bile Acid Metabolism In Diabetic Patients –Are They Potential Risk Factor For Senile Nuclear Cataract?

The aim of this study was to quantify serum indicators of bile acid metabolism in diabetic patients with nuclear cataract. Inclusion criteria were age ≥ 45 years, diabetes and hyperlipidemia. Exclusion criteria were age <45 years, other type of cataract (traumatic, uveitic, presenile) and inherited disorders of bile acid metabolism. The study was conducted from 1^st January 2021. until 1^st  January 2022.  at the Department of Ophthalmology, University Hospital Centre Osijek.

This case-control study included 150 patients divided into three groups. The first group consisted of patients with diabetes and senile nuclear cataract, second group consisted of patients with diabetes, hyperlipidemia and senile nuclear cataract and third group was control group (diabetics without cataract). All participants underwent thorough ophthalmological examination and data on their ophthalmological history were collected.

The grade of opacity of the lens was determined during slit lamp examination according to LOCS III (Lens Opacity Classification System III) and grading was conducted by two specialists of ophthalmology. The participants from first two groups were those already scheduled for the cataract surgery, while the control group consisted of diabetic patients regularly scheduled for ophthalmological examination. All measurments of bile acid serum levels were conducted at Department for Laboratory Diagnostics, University Hospital Centre Osijek on Clinical Chemistry Analyzer AU680 (Beckam Coulter, USA). The Randox 5th Generation Bile Acids assay was used to quantify total bile acid serum levels.

The control group consisted of 50 participants, 27 males and 23 females with an average age of  61,94 ± 10,41 years. The first group consisted of 51 participants, 26 males and 25 females with an average age of  71,02 ± 7,51 years, while the second group consisted of 49 participants, 17 males and 32 females with an average age of 73,29 ± 7,29 years. Kruskal–Wallis one-way analysis of variance (p= 0,02979) confirmed statistically significant difference in bile acid distribution between the groups. The mean  value of bile acids in the control group was 4,46 µmol/l (SD 1,75), in the first group 6,38 µmol/l  (SD 4,87) and the second group 4,87 µmol/l (SD 2,07).

The serum bile acid level was significantly higher in the first group of patients (p= 0,02979), while the presence of hyperlipidemia in patients with cataract reduced the serum bile acids values. Bile acids are produced in the human lens from the oxidation of cholesterol, and their level is decreasing with aging, presumably due to oxidative changes of cholesterol. Previous studies have shown that bile acids play a role in a protection of the chaperon activity of α-crystalline. The results indicate that bile acids are a risk factor for cataract development independent of serum cholesterol levels, a finding not yet described in literature.