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Anthony de Ronde

Publications and source records attributed to Anthony de Ronde.

8 recordsLinked to original sources
PubMed2005

Infection with HIV-1 induces a decrease in mtDNA.

Cross-sectional studies have suggested that infection with human immunodeficiency virus (HIV) type 1 could reduce the mitochondrial DNA (mtDNA) content of blood cells. We investigated mtDNA content in peripheral blood mononuclear cells (PBMCs) obtained from 36 antiretroviral therapy-naive documented HIV-1 seroconverters, before and after seroconversion. mtDNA content statistically significantly decreased 1 year after seroconversion and showed a nonsignificant decrease during the subsequent 4 years. These findings confirm that infection with HIV-1 may, itself, reduce mtDNA content, at least within PBMCs. This could have implications for the subsequent development of mitochondrial toxicities associated with the use of nucleoside analogue reverse-transcriptase inhibitors.

Acquired Immunodeficiency Syndrome↗
PubMed2005

Aggressive HIV-1?

New York City health officials announced on February 11, 2005 that a patient rapidly developed full-blown AIDS shortly after being diagnosed with a rare, drug-resistant strain of HIV-1. The New York City Department of Health issued an alert to all hospitals and doctors and a press conference was held to announce the emergence of an aggressive HIV-1 strain that may be difficult to treat and that appears to trigger rapid progression to AIDS. Is the panic justified?

Acquired Immunodeficiency Syndrome↗
PubMed2005

Increased multinucleoside drug resistance and decreased replicative capacity of a human immunodeficiency virus type 1 variant with an 8-amino-Acid insert in the reverse transcriptase.

Resistance to antiretroviral drugs is generally conferred by specific amino acid substitutions, rather than insertions or deletions, in reverse transcriptase (RT) of human immunodeficiency virus type 1 (HIV-1). The exception to these findings is the amino acid insertions found in the beta3-beta4 loop of the RT enzyme in response to treatment with nucleoside reverse transcriptase inhibitors. This insert consists most commonly of two amino acids, but we describe in detail the evolution of a variant with an 8-amino-acid (aa) insert in a patient treated with zidovudine (ZDV) and 2'-3'-dideoxycytidine (ddC). The 24-nucleotide insert is a partial duplication of local sequences but also contains a sequence segment of unknown origin. Extensive sequence analysis of longitudinal patient samples indicated that the HIV-1 population prior to the start of therapy contained not the wild-type amino acid 215T in RT but a mixture with 215D and 215C. Treatment with ZDV and subsequent ZDV-ddC combination therapy resulted in the evolution of an HIV-1 variant with a typical ZDV resistance genotype (41L, 44D, 67N, 69D, 210W, 215Y), which was slowly replaced by the insert-containing variant (41L, 44D, insert at position 69, 70R, 210W, 215Y). The latter variant demonstrated increased resistance to a wide range of drugs, indicating that the 8-aa insert augments nucleoside analogue resistance. The gain in drug resistance of the insert variant came at the expense of a reduction in replication capacity when assayed in the absence of drugs. We compared these data with the resistance and replication properties of 133 insert-containing sequences of different individuals present in the ViroLogic database and found that the size and actual sequence of the insert at position 69 influence the level of resistance to nucleoside analogues.

Adult↗
PubMed2004

Changes in mitochondrial DNA copy number in blood cells from HIV-infected patients undergoing antiretroviral therapy.

Mitochondrial DNA (mtDNA) copy number was measured in peripheral blood mononuclear cells (PBMCs) from 69 individuals using a real-time NASBA quantitative assay. Patients with HIV infection harbored significantly lower mtDNA copy number in PBMC than HIV-negative controls. Besides, subjects on stavudine-containing regimens showed significantly lower median mtDNA amounts than HIV-positive patients receiving other antiretroviral drugs, and this was associated with higher lactate levels. Thus, either HIV infection itself or treatment with stavudine-containing regimens might induce mtDNA depletion and related metabolic disturbances as hyperlactatemia.

Anti-HIV Agents↗
PubMed2004

Prevalence of lipoatrophy and mitochondrial DNA content of blood and subcutaneous fat in HIV-1-infected patients randomly allocated to zidovudine- or stavudine-based therapy.

INTRODUCTION: Mitochondrial toxicity resulting from mitochondrial DNA (mtDNA) depletion is suggested to be involved in the pathogenesis of lipodystrophy. METHODS: We cross-sectionally assessed lipodystrophy both clinically and radiographically in patients who, 4 years before, had been enrolled in a randomized comparative trial of stavudine- or zidovudine-based therapy. mtDNA content was measured in peripheral blood mononuclear cells (PBMCs) and subcutaneous adipose tissue from the thigh and back. RESULTS: Twenty-eight of the 45 patients enrolled in the original trial were included. Despite comparable exposure to stavudine or zidovudine (51 and 50 months, respectively), lipoatrophy prevalence by intent-to-treat analysis was significantly greater in stavudine recipients (82 vs 9%, P=0.0001). Likewise, those allocated to stavudine had significantly less peripheral fat. In an analysis restricted to patients who had remained on randomly allocated nucleoside reverse transcriptase inhibitors (NRTIs), mtDNA in PBMCs decreased after the start of treatment in both groups (P<0.0001) (-73% for stavudine and -67% for zidovudine, P=0.11), resulting in significantly lower levels in patients with lipoatrophy (P=0.007). The mtDNA content in subcutaneous adipose tissue from the thigh, but not from the back, was significantly lower in patients allocated to stavudine compared to zidovudine (P=0.01). mtDNA in adipose tissue from either location did not differ significantly between those with or without lipoatrophy. DISCUSSION: This study objectively confirms that regimens containing stavudine are associated with a greater risk of lipoatrophy than those containing zidovudine. mtDNA in PBMCs markedly declined with both treatments and was lowest in patients with lipoatrophy. The lack of difference in mtDNA in adipose tissue from patients with as opposed to without lipoatrophy may have been masked by a relative preponderance of stromal and vascular tissue in the subcutaneous tissue samples from these patients, combined with compensatory mitochondrial proliferation in remaining adipocytes. However, our findings may also suggest that the different risk of lipoatrophy observed between NRTIs cannot solely be explained by differences in mtDNA depletion directly at the level of peripheral adipose tissue.

Adipose Tissue↗
PubMed2003

Assessment of precision and concordance of quantitative mitochondrial DNA assays: a collaborative international quality assurance study.

BACKGROUND: A number of international research groups have developed DNA quantitation assays in order to investigate the role of mitochondrial DNA depletion in anti-retroviral therapy-induced toxicities. OBJECTIVES: A collaborative study was undertaken to evaluate intra-assay precision and between laboratory concordance of measurements of mitochondrial DNA quantity, as a component of a comprehensive quality assurance project. STUDY DESIGN: Four laboratories were asked to measure and report mitochondrial DNA and nuclear DNA genome copy number, as well as mitochondrial DNA copy number/cell, for 17 coded aliquots of DNA derived from serial dilutions of pooled DNA from a lymphoblastoid cell line. Samples included masked replicates and five standards. All samples had similar mitochondrial DNA/nuclear DNA ratios. Precision within laboratories was assessed by determining the coefficient of variation of replicates. Concordance between laboratories was assessed by determining the average coefficient of variation of the mean replicate values for each sample. The effect of standardising the assay for these three measurements was also assessed for laboratories A, B and C. RESULTS: Measurements of mitochondrial DNA and nuclear DNA content for replicate samples varied by an average of less than 6% (based on log(10) values, 72% non-logged values), and measurements of mitochondrial DNA/cell for replicates varied by less than 12% (based on log(10) values, 32% non-logged values), with no improvement of precision after standardisation. Standardisation did significantly improve the concordance of results for measurements of mitochondrial DNA content and mitochondrial DNA/cell. Non-standardised measurements of mitochondrial DNA content for the same sample set varied by 19% between laboratories (based on log(10) values, 96% non-logged values), and after standardisation results varied by less than 3% (based on log(10) values, 54% non-logged values). There was no significant improvement for concordance of measures of nuclear DNA content after standardisation, with results varying by 4.56% between laboratories (based on log(10) values, 45% non-logged values) before standardisation, and by 2.49% (based on log(10) values, 50% non-logged values) after standardisation. Derived values of mitochondrial DNA/cell varied between laboratories by an average of 91% (non-logged, 56% log(10) values) before and by 56% (non-logged, 13% log(10) values) after standardisation. CONCLUSION: All assays demonstrated good precision. The use of common standards is an important step in improving the comparability of data between laboratories.

Cell Line↗
PubMed2002

Efficient human immunodeficiency virus replication requires a fine-tuned level of transcription.

Transcription represents a crucial step in the life cycle of human immunodeficiency virus (HIV) and is highly regulated. Here we show that the strength of the viral long terminal repeat (LTR) promoter is optimized for efficient replication. Artificially increasing the rate of LTR-driven transcription was strongly detrimental for viral fitness, and HIV was able to regain replication capacity by selecting for variants with a weaker LTR. Strikingly, the strength of the evolved promoter was equivalent to that of the wild-type LTR.

Cell Line↗