Hepatic porphyrins and urinary prophyrins and prophyrin precursors in liver cirrhosis

Urinary Porphyrin Excretion in Hepatitis C Infection

“…In a small series of patients (n = 8) with chronic liver diseases and porphyrinuria we did find a distinctly reduced fecal porphyrin excretion (median coproporphyrin 3 µg/g dried stool, interquartile range 2-7 µg/g, compared to controls 3-24 µg/g; median percentage of isomer I of total coproporphyrins 66 %, interquartile range 59 %-71 %, compared to controls 66 %-74 %). Mechanisms that might lead to increased porphyrin synthesis in liver diseases are (i) increased heme turnover to meet higher cytochrome requirements or by non-specific induction of aminolevulinic acid synthase or porphobilinogen deaminase (31,32), (ii) ineffective heme synthesis, possibly by decreased ferrochelatase activity or uroporphyrinogen decarboxylase deficiency (33,34) leading to precursor accumulation (heme precursor underutilisation), (iii) increased irreversible oxidation of porphyrinogens by oxidative stress, (iv) a decreased activity of heme oxigenase. Porphyrins, with the exception of protoporphyrin, are notably byproducts that have escaped from the biosynthetic pathway by irreversible oxidation of the corresponding porphyrinogens; oxidised porphyrins are thought to interfere with several enzymes in the metabolic pathway of heme (35).…”

Porfiria cutânea tardia

“…49 The analysis of urinary porphyrin excretion and of hepatic porphyrin concentration in alcoholics with chronic liver disease suggests that the biochemical changes consistent with Urod deficiency are more frequent than the diagnosis of PCT. 50 Chronic alcoholism leads to suppression of erythropoiesis and increases dietary iron absorption. 51 Alcohol induces cytochrome P450 isoenzyme causing the consumption of the hepatic heme and affecting ALA-synthetase expression, increasing Urogen generation and overloading Urod, inhibited or genetically altered, promoting the enzyme deficit manifestation.…”

Koproporphyrin [Biomonitoring Methods in German language, 1978b]

“…Erhöhte Exkretion von Koproporphyrin ist nicht pathognomonisch für eine Bleivergiftung. Sie kommt bei verschiedenen Formen der Anaemie, besonders bei der hämolytischen Anaemie, vor, ferner bei Ikterus verschiedener Genese, bei einigen Infektionskrankheiten, bei anderen Intoxikationen, wie mit Quecksilber und Wismut, bei einigen Porphyrien und sogar nach Alkoholabusus [9,19,11]. Andererseits sind aber auch Fälle beschrieben worden, bei denen stark bleiex-…”