pyrimidinones and Kidney-Diseases

In the current era of HIV treatment, the toxicity profiles of antiretroviral drugs have increasingly emerged as a basis for selecting initial antiretroviral regimens as well as a reason for switching therapy in treatment-experienced patients. In this respect, an intensive research effort involving clinical research as well as basic science research over the past six years, has focused on the cluster of metabolic and body composition abnormalities that have come to be termed the 'lipodystrophy syndrome'. These data have now provided a clear and clinically relevant understanding of the individual profiles of drugs within the nucleoside analogue reverse transcriptase inhibitor , HIV protease inhibitor and non-nucleoside analogue reverse transcriptase inhibitor drug classes, and have provided a rational basis for assessing and monitoring these adverse effects in clinical practice. In this review, current and emerging drug toxicities are considered with an emphasis on lipodystrophy complications.

Topics: Adenine; Alkynes; Anti-Retroviral Agents; Antiretroviral Therapy, Highly Active; Benzoxazines; Cardiovascular Diseases; Cyclopropanes; Drug Monitoring; Drug Therapy, Combination; HIV Infections; HIV-Associated Lipodystrophy Syndrome; Humans; Kidney Diseases; Lopinavir; Metabolic Syndrome; Nevirapine; Organophosphonates; Oxazines; Pyrimidinones; Risk Factors; Tenofovir

This study evaluates the effect of renal impairment on the pharmacokinetics of telbivudine. Thirty-six subjects were assigned, on the basis of creatinine clearance (CL(CR)), to 1 of 5 renal function groups with 6 to 8 subjects per group: normal renal function; mild, moderate, or severe renal impairment; or end-stage renal disease [ESRD] requiring hemodialysis. Subjects received a single oral dose of telbivudine at 600 mg (normal function and mild impairment), 400 mg (moderate impairment), or 200 mg (severe impairment and ESRD); plasma and/or urine samples were collected over a 48-h period for pharmacokinetic analyses. Telbivudine was well tolerated by all subjects. The pharmacokinetics of 600 mg of telbivudine were comparable for subjects with mild renal impairment and normal renal function. Likewise, for subjects with moderate to severe impairment, including ESRD, reduced doses from 200 to 400 mg produced plasma exposure similar to that for subjects with normal renal function. These results indicate that the pharmacokinetics of telbivudine were dependent on renal function, especially for subjects with moderate to severe renal impairment or ESRD. Apparent total plasma clearance, renal clearance (CL(R)), and urinary excretion of telbivudine decreased as renal function deteriorated. A linear relationship was established between CL(R) and CL(CR). In ESRD subjects, a routine 3.5- to 4-h hemodialysis session removed telbivudine from plasma at an extraction ratio of approximately 45%, representing a approximately 23% reduction in total exposure. These results suggest that while no adjustment of the telbivudine dose appears necessary for subjects with mild renal impairment, dose adjustment is warranted for those with moderate to severe renal impairment or ESRD in order to achieve optimal plasma exposure.

Topics: Adolescent; Adult; Aged; Female; Humans; Kidney Diseases; Kidney Failure, Chronic; Kidney Function Tests; Male; Metabolic Clearance Rate; Middle Aged; Nucleosides; Pyrimidinones; Telbivudine; Thymidine

To investigate the effects of age and renal and hepatic impairment on the pharmacokinetics, tolerability and safety of sildenafil (single 50-mg oral dose) and its major circulating N-desmethyl metabolite, UK-103,320.. Three open-label, parallel-group studies were conducted. The first study compared sildenafil pharmacokinetics, safety and toleration in 15 healthy young male subjects (mean age 30 years; range 19--45 years) to 15 healthy elderly male subjects (mean age 70 years; range 65--81 years). The second study included eight male volunteers with normal renal function and 16 male volunteers with varying degrees of renal impairment as assessed by measurement of creatinine clearance (CLcr). The third study included 12 male volunteers with normal hepatic function and 12 male volunteers with chronic stable hepatic cirrhosis (Child-Pugh A and B). For all three studies, blood and urine samples were collected predose and at specified intervals up to 48 h postdose for assays of sildenafil and UK-103,320, and measurements of protein binding.. Significant differences in Cmax and AUC were observed between the young and the elderly subjects for both the parent drug and the metabolite. In the elderly, AUC values were approximately twice as high and Cmax values 60--70% higher than those for young men, while t1/2 values were approximately 1 h longer for sildenafil and 2 h longer for UK-103,320. Due to a significantly smaller unbound fraction of drug in the elderly, free drug concentrations were only approximately 40% higher in the elderly group compared to the young group. In the renal impairment study, significant correlations with CLcr were demonstrated for sildenafil oral clearance (CL/F) and Cmax and UK-103,320 Cmax and AUC. Pairwise comparisons between subjects with normal renal function and those with severe renal impairment (CLcr<30 ml min-1) supported these findings, showing significant increases in Cmax and AUC for both the parent drug and the metabolite in the severely impaired subjects. The hepatic impairment study demonstrated that the pharmacokinetics of sildenafil were altered in subjects with chronic stable cirrhosis, as shown by a 46% reduction in CL/F and a 47% increase in Cmax compared with subjects with normal hepatic function, suggesting a reduction in first-pass metabolism as well as systemic clearance. The increase in systemic exposure for UK-103,320 was approximately twice that seen for the parent drug. In all three studies, sildenafil was well tolerated, most adverse events were mild and no subjects discontinued treatment.. Sildenafil pharmacokinetics were affected by age and by renal and hepatic impairment, suggesting that a lower starting dose of 25 mg should be considered for patients with severely compromised renal or hepatic function.

Topics: Administration, Oral; Adult; Age Factors; Aged; Aged, 80 and over; Area Under Curve; Humans; Kidney; Kidney Diseases; Liver; Liver Diseases; Male; Metabolic Clearance Rate; Middle Aged; Phosphodiesterase Inhibitors; Piperazines; Purines; Pyrimidinones; Sildenafil Citrate; Sulfones

Transforming growth factor β (TGF-β) is the key cytokine involved in causing fibrosis through cross-talk with major profibrotic pathways. However, inhibition of TGF-β to prevent fibrosis would also abrogate its anti-inflammatory and wound-healing effects. β-catenin is a common co-factor in most TGF-β signaling pathways. β-catenin binds to T-cell factor (TCF) to activate profibrotic genes and binds to Forkhead box O (Foxo) to promote cell survival under oxidative stress. Using a proximity ligation assay in human kidney biopsies, we found that β-catenin/Foxo interactions were higher in kidney with little fibrosis, whereas β-catenin/TCF interactions were upregulated in the kidney of patients with fibrosis. We hypothesised that β-catenin/Foxo is protective against kidney fibrosis. We found that Foxo1 protected against rhTGF-β1-induced profibrotic protein expression using a CRISPR/cas9 knockout of Foxo1 or TCF1 in murine kidney tubular epithelial C1.1 cells. Co-administration of TGF-β with a small molecule inhibitor of β-catenin/TCF (ICG-001), protected against kidney fibrosis in unilateral ureteral obstruction. Collectively, our human, animal and in vitro findings suggest β-catenin/Foxo as a therapeutic target in kidney fibrosis.

Topics: Animals; beta Catenin; Bridged Bicyclo Compounds, Heterocyclic; Cell Line; Disease Models, Animal; Fibrosis; Forkhead Box Protein O1; Gene Knockout Techniques; Hepatocyte Nuclear Factor 1-alpha; Humans; Kidney; Kidney Diseases; Male; Mice; Pyrimidinones; Signal Transduction; Transforming Growth Factor beta1

Because fibrotic kidneys exhibit aberrant activation of β-catenin signaling, this pathway may be a potential target for antifibrotic therapy. In this study, we examined the effects of β-catenin activation on tubular epithelial-mesenchymal transition (EMT) in vitro and evaluated the therapeutic efficacy of the peptidomimetic small molecule ICG-001, which specifically disrupts β-catenin-mediated gene transcription, in obstructive nephropathy. In vitro, ectopic expression of stabilized β-catenin in tubular epithelial (HKC-8) cells suppressed E-cadherin and induced Snail1, fibronectin, and plasminogen activator inhibitor-1 (PAI-1) expression. ICG-001 suppressed β-catenin-driven gene transcription in a dose-dependent manner and abolished TGF-β1-induced expression of Snail1, PAI-1, collagen I, fibronectin, and α-smooth muscle actin (α-SMA). This antifibrotic effect of ICG-001 did not involve disruption of Smad signaling. In the unilateral ureteral obstruction model, ICG-001 ameliorated renal interstitial fibrosis and suppressed renal expression of fibronectin, collagen I, collagen III, α-SMA, PAI-1, fibroblast-specific protein-1, Snail1, and Snail2. Late administration of ICG-001 also effectively attenuated fibrotic lesions in obstructive nephropathy. In conclusion, inhibiting β-catenin signaling may be an effective approach to the treatment of fibrotic kidney diseases.

Topics: beta Catenin; Bridged Bicyclo Compounds, Heterocyclic; Cell Line; CREB-Binding Protein; Epithelial-Mesenchymal Transition; Gene Expression Regulation; Humans; Kidney Diseases; Pyrimidinones; Smad Proteins; Transforming Growth Factor beta1

Kidney fibrosis, a typical characteristic of chronic renal disease, is associated with tubular epithelial cell apoptosis. The results of our recent studies have shown that Omi/HtrA2 (Omi), a proapoptotic mitochondrial serine protease, performs a crucial function in renal tubular epithelial apoptotic cell death in animal models of acute kidney injury, including cisplatin toxicity and ischemia-reperfusion insult. However, the role of Omi in tubulointerstitial disease-associated fibrosis in the kidney remains to be clearly defined. We evaluated the potential function and molecular mechanism of Omi in ureteral obstruction-induced kidney epithelial cell apoptosis and fibrosis. The mice were subjected to unilateral ureteral obstruction (UUO) via the ligation of the left ureter near the renal pelvis. UUO increased the protein level of Omi in the cytosolic fraction of the kidney, with a concomitant reduction in the mitochondrial fraction. UUO reduced the X-linked inhibitor of apoptosis protein (XIAP), a substrate of Omi, and pro-caspase-3, whereas it increased cleaved poly(ADP-ribose) polymerase (cleaved PARP) and the number of terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL)-positive cells. When mice were treated with ucf-101, an inhibitor of the proteolytic activity of Omi (6.19 microg/day ip), on a daily basis beginning 2 days before UUO and continuing until the end of the experiment, the Omi inhibitor protected XIAP cleavage after UUO and reduced the increment of PARP cleavage and the numbers of TUNEL-positive cells. Furthermore, the Omi inhibitor significantly attenuated UUO-induced increases in fibrotic characteristics in the kidney, including the atrophy and dilation of tubules, expansion of the interstitium, and increases in the expression of collagens, alpha-smooth muscle actin, and fibronectin. In conclusion, Omi/HtrA2 is associated with apoptotic signaling pathways in tubular epithelial cells activated by unilateral ureteral obstruction, thereby resulting in kidney fibrosis.

Topics: Actins; Animals; Apoptosis; Caspase 3; Disease Models, Animal; Epithelial Cells; Fibrosis; High-Temperature Requirement A Serine Peptidase 2; In Situ Nick-End Labeling; Kidney Diseases; Kidney Tubules; Male; Mice; Mice, Inbred BALB C; Mitochondria; Mitochondrial Proteins; Poly(ADP-ribose) Polymerases; Protease Inhibitors; Pyrimidinones; Serine Endopeptidases; Signal Transduction; Thiones; Time Factors; Ureteral Obstruction; X-Linked Inhibitor of Apoptosis Protein

Telbivudine is a new nucleoside analog indicated for the treatment of chronic hepatitis B infection. A population pharmacokinetic model was developed based on data pooled from 16 early phase studies in 363 healthy participants and patients. Telbivudine was administered as single and/or multiple doses of 25 to 1800 mg daily for up to 28 days. A 2-compartment model with first-order input and lag time provided the best fit to the data. A final model was built with identified covariates, including creatinine clearance on plasma clearance, dose and race on bioavailability fraction, and body weight on central volume of distribution. The final model was applied to simulate steady-state exposure for patients with impaired renal function for various dosing regimens. Results from these simulation analyses support that in patients with moderate to severe renal impairment or end-stage renal disease, reduced daily doses of telbivudine could be an alternative to interval adjustment to achieve exposure comparable to patients with normal renal function or mild renal impairment treated with the full clinical dose.

Topics: Adult; Aged; Antiviral Agents; Biological Availability; Female; Humans; Kidney Diseases; Male; Middle Aged; Models, Biological; Nucleosides; Pyrimidinones; Telbivudine; Thymidine

Tenofovir-related tubule damage characterized by Fanconi syndrome, renal insufficiency and nephrogenic diabetes insipidus has been reported in the adult HIV-infected population. To our knowledge there has been no reported case of such complications in the pediatric population. We report the case of a 12-year-old perinatally HIV-infected African-American girl who developed nephrogenic diabetes insipidus, renal insufficiency and Fanconi-like syndrome while taking tenofovir (Viread) in combination with lopinavir-ritonavir (Kaletra) and didanosine (Videx).

Topics: Adenine; Anti-HIV Agents; Child; Diabetes Insipidus, Nephrogenic; Didanosine; Drug Therapy, Combination; Fanconi Syndrome; Female; HIV; HIV Infections; HIV Protease Inhibitors; Humans; Kidney; Kidney Diseases; Lopinavir; Organophosphonates; Pregnancy; Pregnancy Complications; Pyrimidinones; Ritonavir; Tenofovir

Topics: Adult; Antiretroviral Therapy, Highly Active; Chemical and Drug Induced Liver Injury; Drug Hypersensitivity; Exanthema; Female; HIV Infections; HIV Protease Inhibitors; Humans; Kidney Diseases; Lopinavir; Myelopoiesis; Pyrimidinones

Current treatment strategies need to be planned carefully, because there is an inadequate supply of new types of drugs available to treat people who have failed previous therapies. It is important to fully use existing therapies so as not to limit future options. Drugs in development include: ABT-378, a protease inhibitor from Abbott Laboratories; tipranavir (PNU-140690), a protease inhibitor by Pharmacia & Upjohn; and S-1153, a non-nucleoside reverse transcriptase inhibitor from Agouron Pharmaceuticals. All were effective and well-tolerated in recent trials. A warning was issued for adefovir, a nucleoside reverse transcriptase inhibitor, regarding the development of kidney toxicity for people taking the drug more than 20 weeks. Information on expanded access programs for abacavir, adefovir, amprenavir, and efavirenz is provided.

Topics: Adenine; Alkynes; Anti-HIV Agents; Benzoxazines; Carbamates; CD4 Lymphocyte Count; Clinical Trials as Topic; Cyclopropanes; Dideoxynucleosides; Drug Therapy, Combination; Drugs, Investigational; Furans; HIV Infections; HIV Protease Inhibitors; Humans; Imidazoles; Kidney Diseases; Lopinavir; Oxazines; Pyridines; Pyrimidinones; Reverse Transcriptase Inhibitors; Sulfonamides; Viral Load