This paper begins with an extensive review of previous research on the degradation of non-
protein nitrogen compounds for improved
therapy of
renal failure. During the 1970s, Malchesky established that naturally occurring strains of microorganisms were highly effective for the in vitro degradation of
urea and other compounds found in urine, and that these bacteria could be conditioned with selected media to enhance growth and degradation efficiency. A few years later, Setala introduced the concept of oral delivery of lyophilized bacteria, harvested from soil, to uremic patients, for degradation of non-
protein nitrogen compounds. In the 1990s, Chang proposed delivery of encapsulated genetically modified bacteria for removal of uremic
waste products in vitro and in vivo. Recently, our group has pursued the idea of orally delivering formulated combinations of
enzymes or modified bacteria. A new study is also described, which characterizes the capacity of a single
alginate microcapsule containing a mixture of genetically modified cells and
enzyme to degrade
urea,
uric acid and
creatinine. The combination capsules were found to be effective in vitro and in vivo in a rodent model of chemically-induced
renal failure. Reduction of
urea concentration in vivo required co-administration of a
cation exchange resin to adsorb
ammonia. Increased investigative effort is warranted for these approaches which offer significant potential as an adjunct to conventional forms of dialysis.