Heme metabolism enzymes are dynamically expressed during Xenopus embryonic development

As the key component of many hemoproteins (heme-containing proteins), heme is involved in a broad range of biological processes. Enzymes required for heme biosynthesis and degradation pathways are evolutionarily conserved. While heme metabolism has been studied extensively, the expression of heme metabolism enzymes during development has not been described. Here, we report that all heme biosynthases and two heme oxygenases, which initiate heme degradation, are dynamically expressed during Xenopus embryonic development. All heme synthases, with the exception of aminolevulinic acid synthase 2, are maternally expressed. At neurula stage, heme synthases are expressed in the developing neural tissue and in migrating neural crest cells. At the swimming tadpole stage, expression of heme synthases can be detected in multiple lineages, including eyes, neural crest cells, developing central nervous system, ventral blood island, pronephron, and pronephric tubule. Similar to heme synthases, heme oxygenases are expressed maternally. Zygotic expression of heme oxygenases is mainly restricted to the developing neural and neural crest lineages. Unlike heme synthases, heme oxygenases are not expressed in the ventral blood island and are expressed at a very low level in the pronephron and pronephric tubule. This indicates that heme metabolism may play important roles during development.

Porfiria aguda: reporte de caso y revisión de tema / Porfiria aguda. reporte de caso e revisão de tema / Acute porphyria: case report and review

Las porfirias agudas comprenden un grupo de desórdenes genéticos en la síntesis del grupo heme que pueden comprometer la vida del paciente y cuyas manifestaciones son similares a las de otras condiciones médicas. La falta de reconocimiento clínico y la demora en el diagnóstico retarda en ocasiones el inicio del tratamiento específico, incrementando así la morbimortalidad. El diagnóstico se puede confirmar rápidamente demostrando niveles elevados de porfirinas totales en sangre y en orina y de porfobilinógeno y de ácido delta-aminolevulínico en la orina. La terapia con hemina intravenosa iniciada tan pronto como sea posible es el tratamiento más efectivo y los factores desencadenantes se deben identificar y minimizar al máximo. Un diagnóstico temprano y un completo y adecuado tratamiento mejoran el pronóstico y previenen el desarrollo de complicaciones. En este reporte de caso se muestran las manifestaciones clínicas típicas de una porfiria aguda en una mujer joven a la que se le hizo un rápido diagnóstico, pero que falleció sin recibir tratamiento por la falta de disponibilidad del medicamento en el país...

The acute porphyries include a group of genetic disorders in the heme biosynthesis, that cause neurovisceral manifestations that mimic many medical conditions, psychiatric illnesses and sometimes, it even compromises the patients life. The lack of clinical recognition and delay in diagnosis, often retard the specific treatment and follow an increase in the morbimortality. The diagnosis can be quickly confirmed when demonstrating levels markedly high of porphobylinogen, and delta-aminolevulínic acid in urine and total porphyirines in blood and urine. The therapy with intravenous Hemine started as soon as possible is the most effective treatment. The trigger factors should be identified and minimized. An early diagnosis and appropriate treatment thoroughly improves its prognosis and prevents the development of further complications. In this case report we show the typical manifestations of acute porphyria in a young woman, in which case the diagnosis was not delayed, the problem was the attainment of the specific treatment which was not available in Colombia and the patient died without treatment...

As porfiarias agudas compreendem um grupo de desordens genéticas na síntese do grupo heme que podem comprometer a vida do paciente e cujas manifestações são similares às de outras condições médicas. A falta de reconhecimento clínico e a demora no diagnóstico retarda em ocasiões o início do tratamento específico, incrementando assim a morbi mortalidade. O diagnostico se pode confirmar rapidamente demonstrando níveis elevados de porfirinas totais em sangue e na urina e de porfobilinógeno e de ácido aminolevulínico na urina. A terapia com hemina intravenosa iniciada tão cedo como seja possível é o tratamento mais efetivo e os fatores desencadeantes se devem identificar e minimizar ao máximo. Um diagnóstico cedo e um completo e adequado tratamento melhoram o prognóstico e prevem o desenvolvimento de complicações. Neste reporte de caso mostram-se as manifestações clínicas típicas de uma porfiria aguda numa mulher jovem à que se lhe fez um rápido diagnóstico, mas que faleceu sem receber tratamento pela falta de disponibilidade do medicamento no país...

The decrease in uroporphyrinogen decarboxylase activity induced by ethanol predisposes rats to the development of porphyria and accelerates xenobiotic-triggered porphyria, regardless of hepatic damage

We evaluated the porphyrinogenic ability of ethanol (20 percent in drinking water) per se, its effect on the development of sporadic porphyria cutanea tarda induced by hexachlorobenzene in female Wistar rats (170-190 g, N = 8/group), and the relationship with hepatic damage. Twenty-five percent of the animals receiving ethanol increased up to 14-, 25-, and 4.5-fold the urinary excretion of delta-aminolevulinate, porphobilinogen, and porphyrins, respectively. Ethanol exacerbated the precursor excretions elicited by hexachlorobenzene. Hepatic porphyrin levels increased by hexachlorobenzene treatment, while this parameter only increased (up to 90-fold) in some of the animals that received ethanol alone. Ethanol reduced the activities of uroporphyrinogen decarboxylase, delta-aminolevulinate dehydrase and ferrochelatase. In the ethanol group, many of the animals showed a 30 percent decrease in uroporphyrinogen activity; in the ethanol + hexachlorobenzene group, this decrease occurred before the one caused by hexachlorobenzene alone. Ethanol exacerbated the effects of hexachlorobenzene, among others, on the rate-limiting enzyme delta-aminolevulinate synthetase. The plasma activities of enzymes that are markers of hepatic damage were similar in all drug-treated groups. These results indicate that 1) ethanol exacerbates the biochemical manifestation of sporadic hexachlorobenzene-induced porphyria cutanea tarda; 2) ethanol per se affects several enzymatic and excretion parameters of the heme metabolic pathway; 3) since not all the animals were affected to the same extent, ethanol seems to be a porphyrinogenic agent only when there is a predisposition, and 4) hepatic damage showed no correlation with the development of porphyria cutanea tarda