Biliverdin (from the Latin for green bile) is a green tetrapyrrolic bilepigment, and is a product of hemecatabolism.[1][2] It is the pigment responsible for a greenish color sometimes seen in bruises.[2]
Biliverdin is seen briefly in some bruises as a green color. In bruises, its breakdown into bilirubin leads to a yellowish color.[2]
Role in disease
Biliverdin has been found in excess in the blood of humans suffering from hepatic diseases. Jaundice is caused by the accumulation of biliverdin or bilirubin (or both) in the circulatory system and tissues.[1] Jaundiced skin and sclera (whites of the eyes) are characteristic of liver failure.
Role in treatment of disease
While typically regarded as a mere waste product of heme breakdown, evidence that suggests that biliverdin – and other bile pigments – has a physiological role in humans has been mounting.[4][5]
Bile pigments such as biliverdin possess significant anti-mutagenic and antioxidant properties and therefore, may fulfil a useful physiological function.[5] Biliverdin and bilirubin have been shown to be potent scavengers of hydroperoxyl radicals.[4][5] They have also been shown to inhibit the effects of polycyclic aromatic hydrocarbons, heterocyclic amines, and oxidants – all of which are mutagens. Some studies have found that people with higher concentration levels of bilirubin and biliverdin in their bodies have a lower frequency of cancer and cardiovascular disease.[4] It has been suggested that biliverdin – as well as many other tetrapyrrolic pigments – may function as an HIV-1 protease inhibitor[6] as well as having beneficial effects in asthma[5] though further research is needed to confirm these results. There are currently no practical implications for using biliverdin in the treatment of any disease.
In non-human animals
Biliverdin is an important pigment component in avian egg shells, especially blue and green shells. Blue egg shells have a significantly higher concentration of biliverdin than brown egg shells.[7]
Research has shown that the biliverdin of egg shells is produced from the shell gland, rather than from the breakdown of erythrocytes in the blood stream,[citation needed] although there is no evidence that the sources of the material are neither tetrapyrroles nor free haem from the blood plasma.[clarification needed][citation needed]
Along with its presence in avian egg shells, other studies have also shown that biliverdin is present in the blue-green blood of many marine fish, the blood of tobacco hornworm, the wings of moth and butterfly, the serum and eggs of frogs, and the placenta of dogs.[8] With dogs this can lead, in extremely rare cases, to the birth of puppies with green fur; however, the green color fades out soon after birth.[9] In the garfish (Belone belone) and related species, the bones are bright green because of biliverdin.[citation needed] The green coloration of many grasshoppers and lepidopteran larvae is also due to biliverdin.[10]
Biliverdin is also present in the green blood, muscles, bones, and mucosal lining of skinks of the genus Prasinohaema, found in New Guinea. It is uncertain whether this presence of biliverdin is an ecological or physiological adaptation of any kind. It has been suggested that accumulation of biliverdin might deter harmful infection by Plasmodiummalaria parasites, although no statistically significant correlation has been established.[11] The Cambodian frog, Chiromantis samkosensis, also exhibits this characteristic along with turquoise bones.[12]
In fluorescence imaging
Fluorescent proteins visualize the cell cycle progression. IFP2.0-hGem(1/110) fluorescence is shown in green and highlights the S/G2/M phases. smURFP-hCdtI(30/120) fluorescence is shown in red and highlights the G0/G1 phases.
In a complex with reengineered bacterial phytochrome, biliverdin has been employed as an IR-emitting chromophore for in vivo imaging.[13][14] In contrast to fluorescent proteins which form their chromophore through posttranslational modifications of the polypeptide chain, phytochromes bind an external ligand (in this case, biliverdin), and successful imaging of the first bacteriophytochrome-based probe required addition of the exogenous biliverdin.[13] Recent studies demonstrated that bacteriophytochrome-based fluorescent proteins with high affinity to biliverdin can be imaged in vivo utilizing endogenous ligand only and, thus, with the same ease as the conventional fluorescent proteins.[14] Advent of the second and further generations of the biliverdin-binding bacteriophytochrome-based probes should broaden the possibilities for the non-invasive in vivo imaging.
^Seyfried, H; Klicpera, M; Leithner, C; Penner, E (1976). "Bilirubin metabolism (author's transl)". Wiener Klinische Wochenschrift. 88 (15): 477–82. PMID793184.
^ abcBulmer, A. C.; Ried, K.; Blanchfield, J. T.; Wagner, K. H. (2008). "The anti-mutagenic properties of bile pigments". Mutation Research. 658 (1–2): 28–41. doi:10.1016/j.mrrev.2007.05.001. PMID17602853.
^Halepas, Steven; Hamchand, Randy; Lindeyer, Samuel E. D.; Brückner, Christian (2017). "Isolation of Biliverdin IXα, as its Dimethyl Ester, from Emu Eggshells". Journal of Chemical Education. 94 (10): 1533–1537. Bibcode:2017JChEd..94.1533H. doi:10.1021/acs.jchemed.7b00449.
^Fang, LS; Bada, JL (1990). "The blue-green blood plasma of marine fish". Comparative Biochemistry and Physiology B. 97 (1): 37–45. doi:10.1016/0305-0491(90)90174-R. PMID2253479.
^Lee Grismer, L.; Thy, Neang; Chav, Thou; Holden, Jeremy (2007). "A New Species of Chiromantis Peters 1854 (Anura: Rhacophoridae) from Phnom Samkos in the Northwestern Cardamom Mountains, Cambodia". Herpetologica. 63 (3): 392–400. doi:10.1655/0018-0831(2007)63[392:ANSOCP]2.0.CO;2. S2CID84472376.
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