Navigation Links
Drug Used to Prevent HIV Transmission from Mother to Child Damages DNA

HIV transmission from mother to child can occur in utero, during labor or from breastfeeding. If left untreated, approximately 25 percent of newborns// exposed to the virus from their infected mothers will become infected themselves and potentially develop AIDS. Fortunately, antiretroviral drug combinations, which typically include AZT (zidovudine), a nucleoside reverse transcriptase inhibitor (NRTI), have reduced the rate of transmission from mother to child to less than 2 percent in infants who are not breast fed.

NRTIs work by inhibiting the viral reverse transcriptase and by incorporating into the viral DNA and terminating nascent strands, thus preventing the virus from duplicating. However, previous research has shown that NRTIs also incorporate into the DNA of host cells, causing damage that could have long-term health consequences for those exposed to the drugs.

Two new animal studies have examined the cancer-causing effects of transplacental exposure to AZT in mice and rats and found increased rates of tumors and tumors with gene changes that frequently occur in human cancer. In addition, two human studies are the first to observe the induction of mutations and large scale chromosomal damage in red blood cells of newborns exposed to NRTIs in utero.

Researchers led by Dale M. Walker of Experimental Pathology Laboratories in Herndon, VA, administered AZT in varying doses to female mice and rats during the last 7 days of gestation and examined the tissue of their offspring two years later. They found clear evidence of an AZT-induced increase in the incidence of hemangiosarcoma (cancer originating in cells that line the blood vessels) in male mice and mononuclear cell leukemia in female rats.

There was also some evidence of increased liver cancer and reproductive tumors. "Although the implications of these findings for the long-term health of human children exposed tranplacentally to AZT are uncertain, the possib ility of increased cancer risk for a subset of these children in mid and late adulthood appears highly plausible," the authors state. The carcinogenic effects of AZT were further demonstrated by a study on mice led by Hue-Hua Hong of the National Institute of Environmental Health Sciences in Research Triangle Park, NC. This study found mutations in the K-ras and p53 cancer genes that are often mutated in human lung tumors. The development of lung cancer in these mice suggests that the incorporation of AZT or its metabolites into DNA, oxidative stress, and genomic instability may be the contributing factors to the pattern of mutations observed in the study, according to the authors. They conclude, "The cumulative mutagenesis data suggest that infants exposed transplacentally to AZT may be at increased risk for cancer as they age."

In the first of the two human studies, researchers led by Patricia A. Escobar of the University of Pittsburgh, in Pittsburgh, PA, measured DNA damage caused by AZT in the blood of newborns. They found increased frequencies of glycophorin A mutations in the red blood cells of newborns who had been exposed to AZT plus lamivudine (another type of NRTI) in utero, and these changes persisted for the most part through one year of age. The researchers note that although the combination of the two NRTIs is more effective at preventing transmission of HIV from mother to fetus, it is also more genotoxic than AZT alone. They conclude that "there is a need for careful monitoring of the future health of children who received peripartum AZT-based therapies, the development of new safer NRTIs, and the identification of antimutagenic drugs that will mitigate the side effects of NRTI-based highly active antiretroviral therapy."

In the second study involving humans, researchers led by Kristine L. Witt of the National Institute of Environmental Health Sciences in Research Triangle Park, NC measured the frequency of immature red blood c ells (reticulocytes; RET) containing micronuclei (MN), indicators of chromosomal damage, in blood samples of HIV-infected women and their infants exposed to antiretroviral drugs during pregnancy. Most, but not all, of the prenatal treatment regimens in this study included AZT. At birth, the researchers observed ten-fold increases in the frequencies of micronucleated reticulocytes (MN-RET) in the women and infants whose prenatal drug regimen included AZT. No increases were detected in the women and infants who did not receive prenatal AZT. The frequency of MN-RET in the AZT-exposed newborns decreased over the first 6 months of life to levels seen in nonexposed infants. These findings imply a strong potential for AZT-induced genetic damage in the developing fetus. The authors state "We are concerned about the long-term health implications for these infants because the MN increases noted in this study add to the growing body of evidence that ZDV [AZT] readily induces genetic damage," The authors conclude by emphasizing that they do not advocate eliminating the use of AZT in the treatment of HIV because it is highly effective in preventing mother to child transmission of the virus. However they recommend long-term monitoring of AZT-exposed infants who are HIV uninfected.


Related medicine news :

1. Lose stomach for Life....Preventive removal of stomach saves the risk of cancer
2. Prevention is better than cure
3. Prevention of cataracts
4. Medications to Prevent Relapse to Cocaine Use
5. Estrogen Does Not Prevent Recurrent Strokes
6. Over-The-Counter Drugs May Prevent Alzheimers
7. Aspirin and Warfarin Are Equally Effective for Stroke Prevention
8. Alcoholism Drug Fails To Prevent Drinking Relapses
9. Preventing mental decline in the aged
10. Preventing white coat hypertension
11. Simple Stroke Prevention is Best
Post Your Comments:

(Date:11/25/2015)... ... November 25, 2015 , ... Additional breast cancers found with ... according to a study published online in the journal Radiology. Researchers said that ... necessitate a change in treatment. , Breast MRI is the most sensitive technique ...
(Date:11/25/2015)... ... November 25, 2015 , ... Finnleo, a leader in the traditional and far-infrared ... traditional and far-infrared saunas. , For traditional saunas, Finnleo is offering ... sauna wood, and Finnleo uses only European Grade A Nordic White Spruce from sustainably ...
(Date:11/25/2015)... ... November 25, 2015 , ... Dr. John Pierce, Medical Director ... about hair loss treatment with the Capillus272™ Pro laser therapy cap. FDA cleared for ... and fuller hair, without the need for surgery, prescription pills, or topical foams. ...
(Date:11/25/2015)... ... ... For the first time, Vitalalert is donating half of its earnings to ... between the two groups began in 2014 with Vitalalert pledging a portion of every ... founded in 1954 and is an international Christian-based health organization whose mission is to ...
(Date:11/25/2015)... ... November 25, 2015 , ... Dental professionals who would ... OH , are invited to attend Dr. Mark Iacobelli’s Advanced Implant Mentoring (AIM) CE ... Cleveland, OH. , As the co-founders of Advanced Implant Mentoring (AIM), Dr. Iacobelli ...
Breaking Medicine News(10 mins):
(Date:11/25/2015)... 2015 Endo International plc (NASDAQ: ENDP ) ... President and CEO, will discuss corporate updates at the 27 ... New York on Wednesday, December 2, 2015 at ... Investor Relations, and then the link to the event. Participants ... time to visit the site and download any streaming media ...
(Date:11/25/2015)... November 25, 2015 --> ... blood glucose devices was valued at $11,171.1 million in ... CAGR of 5.7% during 2015 - 2022. The global ... increasing prevalence of diabetes. In addition, the increase in ... also contributing to the growth of the market. Furthermore, ...
(Date:11/25/2015)... 25, 2015  Mindray Medical International ... MR ), a leading developer, manufacturer ... today announced that it will hold ... shareholders at the Company,s Hong Kong office (FLAT/RM ... Edward West Road, Mongkok KL, Hong Kong) ...
Breaking Medicine Technology: