Does lactose support Muller cell protein expression patterns in the absence of the retinal pigment epithelium?
In RPE-deprived retinas supplemented with lactose, Muller cells were morphologically normal. The proper photoreceptor outer segment morphogenesis observed under these conditions was uniquely associated with normal levels of glutamine synthetase expression. The exact significance of this finding with respect to photoreceptor outer segment morphogenesis is unknown. We suggest that glutamine synthetase may be a marker of Muller cell metabolic or structural integrity that may reflect the enhanced ability of these cells, in the presence of lactose, to support photoreceptor outer segment morphogenesis.
  This meta-analysis suggested that smoking, family history of PBC and UTI were strongly associated with PBC in a white population by systematic review of five existing studies, and the association remains to be validated in other populations.