The present invention generally relates to the treatment of 
uremic toxins in vivo using uremic 
toxin-treating enzymes, and / or cells capable of producing uremic 
toxin-treating enzymes or otherwise reacting with 
uremic toxins. Non-limiting examples of cases where the treatment of 
uremic toxins is desired include renal 
disease or dysfunction, 
gout, subjects receiving 
chemotherapy, or the like. In one aspect, the treatment includes an oral delivery composition able to reduce the 
blood concentration of one or more non-
protein nitrogen compounds 
in vivo. The composition, in some cases, may comprise one, two, or more uremic 
toxin-treating enzymes, such as 
urease, uricase or 
creatininase. The oral delivery composition may be able to deliver the uremic toxin-treating enzymes, substantially undigested, to the intestines, where the enzymes can interact with uremic toxins transported to the intestines from the bloodstream. In another aspect, the treatment includes an oral delivery composition comprising a 
cell able to reduce the concentration of one or more uremic toxins 
in vivo. In some cases, the 
cell may be designed to overexpress one, two, or more uremic toxin-treating enzymes, such as 
urease, uricase or 
creatininase, for example, by transfecting the 
cell with a corresponding 
gene. In some embodiments, a species able to react with or otherwise sequester by-products of the uremic toxin-treating 
enzyme reactions may be included with the oral delivery composition. For example, if the by-product is 
ammonium, the species may be a 
sorbent able to adsorb 
ammonium, an 
enzyme able to react with the 
ammonium, or the like.