Functional protective role for mucin glycosylated repetitive domains

Mucins carry out a number of protective roles, some of which are more easily studied than others. One mucin function is believed to be the protection of the mucosal epithelium against acidic and proteolytic damage in the stomach and intestines. In the present work, a portion of stomach mucin tandem repeat sequence (Muc6) was joined to the catalytic domain of a reporter enzyme [human milk cholesterol esterase (CE)] to determine whether the former can protect the latter protein from damage. This Muc6 domain replaced a unique series of glycosylated C-terminal repeats normally present in CE. The chimeric protein (CE/Muc6) was expressed in two different cell lines and its properties compared to recombinant full-length CE and a truncated version of CE which contained only the catalytic domain (CE/trunc). Results showed that both CE and CE/Muc6 were resistant to denaturation by acid and to proteolysis by pepsin at low pH values or by pancreatic proteases compared to CE/trunc. Thus, a stomach Muc6 domain is sufficient to confer stability on the CE catalytic domain, demonstrating a protective effect by a glycosylated mucin sequence

rhBSSL Improves Growth and LCPUFA Absorption in Preterm Infants Fed Formula or Pasteurized Breast Milk

OBJECTIVES: Preterm infants often experience suboptimal growth, which can affect organ development. The aim of this study was to improve growth by treatment with bile salt–stimulated lipase (BSSL), naturally present in breast milk, but lost after pasteurization, and absent in formula. METHODS: Two clinical trials were performed with a predefined analysis of combined data to investigate the effects of recombinant human BSSL (rhBSSL) treatment on growth velocity and fat absorption in preterm infants. The studies were randomized and double-blinded comparing 7-day treatment with rhBSSL and placebo, administered in pasteurized breast milk or formula, using a crossover design. RESULTS: Sixty-three infants were evaluated for safety. At randomization, the mean (standard deviation) weight was 1467 (193) g and mean postmenstrual age was 32.6 (0.5) weeks. Sixty and 46 infants were evaluated for growth velocity and fat absorption, respectively. rhBSSL treatment significantly improved mean growth velocity by 2.93 g · kg(−1) · day(−1) (P < 0.001) compared with placebo (mean 16.86 vs 13.93 g · kg(−1) · day(−1)) and significantly decreased the risk of suboptimal growth (<15 g · kg(−1) · day(−1)) (30% vs 52%, P = 0.004). rhBSSL significantly increased absorption of the long-chain polyunsaturated fatty acids, docosahexaenoic acid, and arachidonic acid by 5.76% (P = 0.013) and 8.55% (P = 0.001), respectively, but had no significant effect on total fat absorption. The adverse-event profile was similar to placebo. CONCLUSIONS: In preterm infants fed pasteurized breast milk or formula, 1 week of treatment with rhBSSL was well tolerated and significantly improved growth and long-chain polyunsaturated fatty acid absorption compared to placebo. This publication presents the first data regarding the use of rhBSSL in preterms and the results have led to further clinical studies