Evaluation of HIV protease and nucleoside reverse transcriptase inhibitors on proliferation, necrosis, apoptosis in intestinal epithelial cells and electrolyte and water transport and epithelial barrier function in mice.
BACKGROUND
Protease inhibitors (PI's) and reverse transcriptase drugs are important components of highly active antiretroviral therapy (HAART) for treating human acquired immunodeficiency syndrome (AIDS). Long-term clinical therapeutic efficacy and treatment compliance of these agents have been limited by undesirable side-effects, such as diarrhea. This study aims to investigate the effects of selected antiretroviral agents on intestinal histopathology and function in vivo and on cell proliferation and death in vitro.


METHODS
Selected antiretroviral drugs were given orally over 7 days, to Swiss mice, as follows: 100 mg/kg of nelfinavir (NFV), indinavir (IDV), didanosine (DDI) or 50 mg/kg of zidovudine (AZT). Intestinal permeability measured by lactulose and mannitol assays; net water and electrolyte transport, in perfused intestinal segments; and small intestinal morphology and cell apoptosis were assessed in treated and control mice. In vitro cell proliferation was evaluated using the WST-1 reagent and apoptosis and necrosis by flow cytometry analysis.


RESULTS
NFV, IDV, AZT and DDI caused significant reductions in duodenal and in jejunal villus length (p < 0.05). IDV and AZT increased crypt depth in the duodenum and AZT increased crypt depth in the jejunum. NFV, AZT and DDI significantly decreased ileal crypt depth. All selected antiretroviral drugs significantly increased net water secretion and electrolyte secretion, except for DDI, which did not alter water or chloride secretion. Additionally, only NFV significantly increased mannitol and lactulose absorption. NFV and IDV caused a significant reduction in cell proliferation in vitro at both 24 h and 48 h. DDI and AZT did not alter cell proliferation. There was a significant increase in apoptosis rates in IEC-6 cells after 24 h with 70 ug/mL of NFV (control: 4.7% vs NFV: 22%) while IDV, AZT and DDI did not show any significant changes in apoptosis compared to the control group. In jejunal sections, IDV and NFV significantly increased the number of TUNEL positive cells.


CONCLUSIONS
The PI's, NFV and IDV, increased cell apoptosis in vivo, water and electrolyte secretion and intestinal permeability and decreased villus length and cell proliferation. NFV was the only drug tested that increased cell apoptosis in vitro. The nucleoside reverse transcriptase inhibitors, AZT and DDI, did not affect cell apoptosis or proliferation. These findings may partly explain the intestinal side-effects associated with PI's.
Braga Neto
Manuel B
MB
Institute of Biomedicine and Clinical Research Unit-University Hospital, Federal University of Ceará, Fortaleza, Brazil.
Aguiar
Carolina V
CV
Maciel
Jamilly G
JG
Oliveira
Bruna M C
BM
Sevilleja
Jesus E
JE
Oriá
Reinaldo B
RB
Brito
Gerly A C
GA
Warren
Cirle A
CA
Guerrant
Richard L
RL
Lima
Aldo A M
AA
D000818:Animals; D044966:Anti-Retroviral Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D001835:Body Weight / Q000187:drug effects; D002463:Cell Membrane Permeability / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects*; D016049:Didanosine / Q000494:pharmacology; D017320:HIV Protease Inhibitors / Q000494:pharmacology*; D019469:Indinavir / Q000494:pharmacology; D007408:Intestinal Absorption / Q000187:drug effects*; D007413:Intestinal Mucosa / Q000187:drug effects / Q000473:pathology* / Q000502:physiology; D008297:Male; D051379:Mice; D023421:Models, Animal; D009336:Necrosis; D019888:Nelfinavir / Q000494:pharmacology; D018894:Reverse Transcriptase Inhibitors / Q000494:pharmacology*; D015996:Survival Rate; D014882:Water-Electrolyte Balance / Q000187:drug effects*; D015215:Zidovudine / Q000494:pharmacology
D044966:Anti-Retroviral Agents; D017320:HIV Protease Inhibitors; D018894:Reverse Transcriptase Inhibitors; D015215:Zidovudine; D019469:Indinavir; D019888:Nelfinavir; D016049:Didanosine