Colestilan

Hyperphosphatemia is a potentially life altering condition in end-stage renal disease patients who are on regular hemodialysis that can lead to cardiovascular calcification, metabolic bone disease and secondary hyperparathyroidism. Bile acid sequestrants are anion exchange resins bind to bile acids and phosphate in the intestine resulting in preventing intestinal absorption of dietary phosphate, interruption of bile acid homeostasis and reduction in low-density lipoprotein cholesterol levels. Cholestyramine is chosen for study in hemodialysis patients based on the effectiveness and safety of bile acid sequestrants such colestilan and colestipol in the treatment of hyperphosphatemia and hypercholesterolemia in hemodialysis patients. A prospective, interventional, randomized, double blinded, placebo-controlled two arm study was carried out to assess the efficacy of oral cholestyramine on reduction of serum phosphate level in adult hemodialysis patients. 76 eligible patients were randomly assigned to either a drug group or a placebo group for the 2-month study period. The protocol was approved by the institutional review board of the faculty of pharmacy Ain Shams University Ethical committee and has been registered on ClinicalTrials.gov: NCT05577507. Over the 2-month treatment period, patients in cholestyramine group showed a significant decline in serum phosphorus levels versus placebo group (4.6 mg/dl vs. 6.6 mg/dl; p < 0.001) and serum calcium-phosphorus product (40 mg²/dl² vs. 59.8 mg²/dl²; p < 0.001). Median serum triglyceride and low-density lipoprotein cholesterol levels had decreased significantly versus baseline values in the cholestyramine group. Cholestyramine used with phosphate binders effectively lowers phosphorus levels, improves the lipid profile, and has mild adverse effects.

Diarrhoea is one of the most serious complications in hereditary ATTR (ATTRv) amyloidosis. However, its precise pathomechanism remains unknown. The present study investigated the involvement of bile acid in diarrhoea along with the therapeutic effect of colestimide, a bile acid sequestrant, in ATTRv amyloidosis.

We prospectively enrolled 19 ATTRv amyloidosis patients (9 with refractory diarrhoea and 10 without diarrhoea) and 20 healthy individuals for measurements of serum 7a-hydroxy-4-cholesten-3-one (C4) levels. The patients with diarrhoea were then treated with oral colestimide (1.5 g twice daily) for 28 days. The frequency of diarrhoea and C4 level were evaluated before and after colestimide treatment.

Mean serum C4 level was significantly higher in ATTRv patients with diarrhoea (62.3 ng/mL) than in ATTRv patients without diarrhoea (24.0 ng/mL, p = 0.03). Colestimide treatment significantly decreased mean diarrhoea frequency (pre-treatment period: 9.1 times/week, colestimide treatment period, 6.6 times/week, p = 0.04) and increased mean C4 level (before treatment: 66.2 ng/mL, after treatment: 187.1 ng/mL, p = 0.02).

Bile acid status was significantly associated with diarrhoea in ATTRv amyloidosis. Colestimide and other bile acid sequestrants may reduce diarrhoea frequency in afflicted patients.