Chinese herbal medicines containing aristolochic acids and their derivatives (collectively known as AAs) are widely implicated in hepatocellular carcinoma (HCC) in Taiwan and throughout Asia, a new study shows.
တရုတ္ရိုးရာ ေရွးနည္း ကု ထံုးေတြမွာ aristolochic acids အေပါင္ း အပါေတြ ပါေနလို့
အသည္ကင္ဆာ အတြက္ ပို မို သက္ေရာက္ေစတယ္ ျဖစ္ေစတယ္
AA is a natural compound found in Aristolochia and Asarum plant species commonly used in herbal medicine.
AA has been linked to multiple cancers as well as kidney failure.
Taiwan banned some AA-containing herbal remedies in 2003, and China has restricted use of some AA-containing herbs in traditional medicine. The US Food and Drug Administration has issued warnings regarding consumption of AA-containing products.
ကင္ဆာလညး္ျဖစ္သလို ေက်ာက္ကပ္လညး္ ပ်က္ဆီးတယ္တဲ့
As for the mechanism of AA-induced mutagenesis, "animal studies indicate that AA is absorbed quickly from the alimentary tract into the blood, and eventually the highest concentrations are found in the liver and the kidneys,"
aristolochic acids ကို အူလမ္းေၾကာင္း မွ စုတ္ယူျပီး ေသြးကေန တဆင့္ အသည္းတို့ ေက်ာက္ကပ္တို့မွာ စုစည္းမွ ုမ်ားလာ
Dr Rozen told Medscape Medical News. "After enzymatic bioactivation, AA covalently binds to purines. Some of these are repaired by the cell's innate DNA repair mechanism, but the ones that are not repaired lead almost exclusively to adenine-to-thymine mutations.
aristolochic acids သည္ purinesနဲ့ covalently binds တယ္ DNA repair mechanism ကို အဟန့္ အတားျဖစ္ေစျပီး
adenine-to-thymine mutations ေတြကို ျဖစ္ေစတယ္
We hypothesize that some of these mutations then inactivate genes that prevent cancer or activate genes that promote cancer.
အဲလို မွားယြင္းတဲ့ ေပါင္းဖက္ ၿခင္းေတြကို ျဖစ္ေစျပီး ကင္ဆာမျဖစ္ေအာင္ ကာကြယ္တဲ့ gene က ျမံ ု့ သြားျပီး ကင္ဆာျဖစ္ေစမယ့္ genes ကို တိုးမ်ားလာေစ
These mutations then are 'hits' in the usual multi-hit model of cancer development," he added.
usual multi-hit model of cancer development အဲ့ေတာ ကင္ဆာက ပို မို ၾကီးထြားလာ
Herb Tied to 'Remarkable' Number of Liver Cancers in Asia
Chinese herbal medicines containing aristolochic acids and their derivatives (collectively known as AAs) are widely implicated in hepatocellular carcinoma(HCC) in Taiwan and throughout Asia, a new study shows.
Mutational analysis of 98 HCCs from two hospitals in Taiwan revealed the distinctive mutational signature of AA exposure in more than three quarters (78%) of cases, "accounting for most of the nonsilent mutations in known cancer driver genes," the study team found.
"This study shows that AA is involved in a remarkable proportion of liver cancers in Asia," lead researcher Steven G. Rozen, PhD, director, Center for Computational Biology, and professor, Cancer and Stem Cell Biology Program, Duke-NUS Graduate Medical School in Singapore, told Medscape Medical News.
The researchers also searched for the AA signature in 1400 HCCs from diverse geographic regions. Consistent with AA exposure through known herbal medicines, 47% of HCCs in Chinese patients showed the signature, albeit with lower mutation loads than seen in Taiwan.
AA exposure is geographically widespread.
They also found the AA signature in 29% of HCCs from Southeast Asia, in 13% from Korea, and in 2.7% from Japan, as well as in 4.8% and 1.7% of HCCs from North America and Europe, respectively, excluding one US hospital where 22% of 87 HCCs from patients of Asian ethnicity had the signature. "Thus, AA exposure is geographically widespread," they conclude.
The researchers also observe that in the United States, sale of herbs containing AAs is unregulated, provided such products are correctly labeled and that no health claims are made about them. In addition, "Plants known to contain high concentrations of aristolochic acids are easily available on the internet," the investigators write.
AA is a natural compound found in Aristolochia and Asarum plant species commonly used in herbal medicine. AA has been linked to multiple cancers as well as kidney failure. Taiwan banned some AA-containing herbal remedies in 2003, and China has restricted use of some AA-containing herbs in traditional medicine. The US Food and Drug Administration has issued warnings regarding consumption of AA-containing products.
Despite the Taiwan ban on AA in 2003, Dr Rozen's team found no significant difference in the prevalence of the AA signature or in the numbers of AA signature mutations in HCCs diagnosed before and after 2003.
It is possible that the fact that the incidence of AA-associated HCCs has not declined represents a delaying effect following reductions in AA exposure, akin to what has been seen for tobacco-related lung cancer. Ongoing exposure to AA-containing herbal remedies is another possible explanation, they say.
As for the mechanism of AA-induced mutagenesis, "animal studies indicate that AA is absorbed quickly from the alimentary tract into the blood, and eventually the highest concentrations are found in the liver and the kidneys," Dr Rozen told Medscape Medical News. "After enzymatic bioactivation, AA covalently binds to purines. Some of these are repaired by the cell's innate DNA repair mechanism, but the ones that are not repaired lead almost exclusively to adenine-to-thymine mutations. We hypothesize that some of these mutations then inactivate genes that prevent cancer or activate genes that promote cancer. These mutations then are 'hits' in the usual multi-hit model of cancer development," he added.
https://www.medscape.com/viewarticle/887575
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