Nrf2 and Cigarette Smoke ---A Possible Link to B12 Deficiency.......?

Cigarette smoke has been demonstrated to induce a number of Nrf2 protective genes.If transcobalamine is important as a carrier for B12 and is upregulated by Nrf2 does this possibly suggest that Nrf-/- may make one more susceptible to conditions where B12 is needed as a metabolic cofactor? One might ask, for what other conditions might Nrf2 elevate expression of transcobalamine? Also, this may lead one to suggest there may be an important role for B12, in addition to that of free radical scavenger and as a vitamin since it so important for neural health. Could the loss of this function increase the damage to the CNS such as in dopaminergic neurons from toxic bioaccumulations of metabolic products. For instance, would this aggravate metabolic disruptions from homocysteine or ammonia?  

Rangasamy (2004). Genetic ablation of nrf2 enhances susceptibility to cigarette smoke - induced emphysema in mice. 114:1248-1259. Table 2....http://www.citeulike.org/user/HEIRS/article/6637967