Usui et al. [91] found that nitrate/nitrite levels, TNF-α levels and levels of asymmetric dimethylarginine (ADMA, the endogenous NO synthase inhibitor) were elevated in HF patients vs. normal controls; within the HF group, nitrate/nitrite was positively correlated with ADMA levels and negatively correlated with ejection fraction. This evidence concerns the gene TNF and hydrops fetalis.