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zondag 26 augustus 2012

Chlamydia pneumonia is more than an energy parasite

The pathogenesis of Systemic Chlamydial Infections: Theoretical Considerations of Host Cell Energy Depletion and its metabolic consequences

Chlamydiae are prokaryocytes that
develop in eukaryotic cells and utilize
part of the host cell metabolism.

electron microscopic studies have shown
that replicating chlamydiae are always
found in close proximity to mitochondria.
Therefore, it has been suggested
that chlamydiae behave in the reverse
manner of mitochondria in that mitochondria
import ADP from the host cell
cytoplasm and export ATP, while
chlamydiae import ATP and export ADT.
Depletion of host cell energy by the
intracellular infection with Chlamydia
species might cause additional energyrelated
complications. As fewer electrons
are available to move through the
electron transport chain of the host cell
mitochondrial matrix membrane, the
citric acid cycle produces more succinyl-
CoA which. in turn, promotes increased
synthesis of d-ALA. The net result is an
increased amount of heme precursors
and heme porphyrins. The presence of
porphyrins in the mitochondrial matrix
may damage the cell as these molecules
are unstable and form free radicals.
The clinical result of the intracellular
and extracellular accumulation of porphyrins,
if extensive, could be an tissue/
organ specific secondary porphyria
which might produce the classical manifestations
of porphyria including neuropsychiatric
symptoms and signs. As
the chlamydial-infected host cells lyse,
as can happen in the normal life cycle
of Chlamydia, the intracellular porphyrins
are released and result in porphyria