Causal effect of porphyria biomarkers on alcohol-related hepatocellular carcinoma through Mendelian Randomization

PURPOSE

According to some cohort studies, an association exists between acute intermittent porphyria (AIP) and liver cancer. However, establishing a definitive causal relationship between porphyria and hepatocellular carcinoma (HCC) remains challenging. Prexisting studies regarding porphyria biomarkers and alcohol-related hepatocellular carcinoma (AR-HCC) make possible an entry point. In this study, we aimed to investigate the causal relationships between biomarkers of two types of porphyria, AIP and congenital erythropoietic porphyria (CEP), and AR-HCC.

METHODS

Single-nucleotide polymorphisms (SNPs) associated with porphobilinogen deaminase (PBGD) and uroporphyrinogen-III synthase (UROS), along with outcome data on AR-HCC, were extracted from public genome-wide association studies (GWAS). The GWAS data were then used to explore the potential causal relationships via a two-sample Mendelian randomization (MR) analysis. The effect estimates were calculated using the random-effect inverse-variance-weighted (IVW) method. Additionally, the Cochrane's Q test, MR-Egger test, and leave-one-out analysis were conducted to detect heterogeneity and pleiotropy in the MR results.

RESULTS

Using the IVW method as the primary causal effects model in the MR analyses, we found that both PBGD (effect estimate = 1.51; 95% CI, from 1.08 to 2.11, p = 0.016) and UROS (effect estimate = 1.53; 95% CI, from 1.08 to 2.18, p = 0.018) have a significant causal effect on AR-HCC.

CONCLUSION

Our findings revealed a causal effect of both PBGD and UROS on AR-HCC, suggesting that both AIP and CEP have a causal association with AR-HCC.

Experimentally produced porphyria in animals

The chemical findings of Schmid & Schwartz (1952) in experimental porphyria of rabbits induced by sedormid have been confirmed. Since sedormid is hypnotic, a group of related drugs has been tested to find one which might produce the chemical picture in animals without hypnosis. Such a drug is allyl- iso propyl-acetamide (A.I.A.). In this investigation, the constant chemical structure affecting porphyrin metabolism was found to be CH 2 =CH—CH 2 —CH R —CO—NH—. Some rabbits excrete large amounts of porphobilinogen and uroporphyrin when given either sedormid or A.I.A., others produce little. It is suggested that the cause of this difference is related to a variability of the individual rabbit liver to deal effectively with those drugs. Rabbits, intoxicated with either drug, became constipated, had poor appetite and lost weight. They did not become paralyzed, nor show any change in systolic blood pressure or in their haematological values. Two fowls, one also given a barbiturate, and nine rats wore intoxicated with allyl- iso propyl-acetamide. Although these animals excreted relatively high levels of porphobilinogen and porphyrins, they did not develop paralysis. The experimentally induced porphyria in animals is compared with hum an acute porphyria. The effects are described of reticulo-endothelial blockade, splenectomy and barbiturate administration on porphyria induced experimentally in rabbits. Experimental porphyria appears to be due to an overproduction of porphyrins, rather than to an under-utilization of porphyrin pigments. An atypical porphobilinogen reaction is described. It is present in the early stage of drug intoxication in rabbits and has also been noted in human acute porphyria at low levels of porphobilinogen excretion.