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Peroxisomes and peroxisomal enzymes in the human fetal small intestine
1Laboratoire de Biologie Cellulaire du Développement, Faculté des Sciences, Université de Nancy I, Vandoeuvre-les-Nancy, France.
Insights
Peroxisomes and their enzymes develop in the human fetal intestine from 11 weeks gestation. Enzyme activity increases, with distinct peroxisome shapes appearing as development progresses.
Area of Science:
- Gastroenterology
- Cell Biology
- Developmental Biology
Background:
- Peroxisomes are vital organelles involved in metabolic processes.
- Their role and development in the human fetal intestine are not fully understood.
Purpose of the Study:
- To investigate the appearance, morphology, and enzyme expression of peroxisomes in the developing human fetal intestine.
- To establish the developmental timeline of peroxisomal enzymes during gestation.
Main Methods:
- Ultrastructural cytochemistry to visualize peroxisome morphology.
- Biochemical assays to measure enzyme activities (catalase, fatty acylCoA oxidase, D-amino acid oxidase, L-alpha-hydroxyacid oxidase).
Main Results:
- Rare, circular peroxisomes observed from 11 weeks gestation, increasing in number from 16 weeks.
- Two peroxisome types identified: round/oval and elongated/tailed.
- Intestinal catalase and fatty acylCoA oxidase activities increased steadily from 11 weeks gestation.
- Other peroxisomal oxidase activities appeared later in fetal development.
Conclusions:
- This study details the morphological and enzymatic development of peroxisomes in the human fetal intestine.
- It establishes the temporal patterns of peroxisome biogenesis and enzyme expression during human fetal development.
Abstract:
The appearance and development of peroxisomes and the expression of their enzymes in the human fetal intestine have been investigated between 11 and 22 weeks of gestation. In the youngest samples (11-16 weeks of age), cytochemistry at the ultrastructural level revealed the presence of rare, mostly circular peroxisomes. From 16 weeks of gestation onwards, an increase was noted in the number of peroxisomes. Two peroxisomal types were distinguished: round to oval forms and elongated and/or tailed organelles. Biochemical assays revealed that total and specific intestinal catalase activities increased gradually between 11 and 20 weeks of gestation. The activity of fatty acylCoA oxidase, the first enzyme of the peroxisomal beta-oxidation system, was detectable as early as 11 weeks of gestation. Thereafter, total and specific activities of the enzyme increased steadily. Activities of other peroxisomal oxidases (D-amino acid oxidase, L-alpha-hydroxyacid oxidase) appeared more slowly in the fetal intestine during the period studied. This investigation establishes the presence and the morphological changes that occur in intestinal peroxisomes during human fetal development as well as the developmental patterns of associated enzymes.