Erythropoietin alters the pharmacokinetics of organic anions mainly eliminated by the kidney in rats.

Erythropoietin (EPO) is a cytokine originally used for its effects on the hematopoietic system, and is widely prescribed around the world. In the present study, the effects of EPO administration on p-aminohippurate (PAH, a prototype organic anion) pharmacokinetics and on the renal expression of PAH transporters were evaluated. Male Wistar rats were treated with EPO or saline (control group). After 42 h, PAH was administered, and plasma samples were obtained at different time points to determine PAH levels. PAH levels in renal tissue and urine were also assessed. The renal expression of PAH transporters was evaluated by Western blotting. EPO-treated rats showed an increase in PAH systemic clearance, in its elimination rate constant, and in urinary PAH levels, while PAH in renal tissue was decreased. Moreover, EPO administration increased the expression of the transporters of the organic anions evaluated. The EPO-induced increase in PAH clearance is accounted for by the increase in its renal secretion mediated by the organic anion transporters. The goal of this study is to add important information to the wide knowledge gap that exists regarding drug-drug interactions. Owing to the global use of EPO, these results are useful in terms of translation into clinical practice.

Prevalence of potentially inappropriate medications in older adults in Argentina using Beers criteria and the IFAsPIAM List.

Background Medications in which the risk of adverse events exceeds the expectations of clinical benefits are called potentially inappropriate medications (PIMs). To identify the use of PIMs in elderly patients, the most commonly used tool are the Beers criteria, developed for the population of the United States. Recently, a consensus panel of Argentine experts developed the first Latin American tool, called the IFAsPIAM List. Objective The present study aimed to identify PIM prescriptions in elderly outpatients, to estimate the prevalence of PIMs, and to evaluate their possible relation with polypharmacy and gender and age of the patients. Also, we aimed to compare the results obtained by using the Beers criteria and the IFAsPIAM List. Setting Ten community pharmacies of Rosario, Santa Fe, Argentina. Methods A cross-sectional observational study was conducted between February and September 2015. Data were acquired from 56,952 prescriptions prescribed to 2231 patients aged 65 years old or older. To detect the use of PIMs, we used two tools: the Beers criteria and the IFAsPIAM List. Main outcome measure The prevalence of PIM use according to the Beers criteria and the IFAsPIAM List. Results The monthly average of medications dispensed per patient was 4.35 ± 2.18 and 42.27% of the patients presented major polypharmacy. The prevalence of PIMs was 72.75% according to the Beers criteria and 71.13% according to the IFAsPIAM List (Kappa coefficient k = 0.72), and was significantly higher in patients with major polypharmacy, older than 75 years old, and females. The most frequent PIMs prescribed were anxiolytics, analgesics and antipsychotics. Conclusions The IFAsPIAM List is an effective tool to evaluate the prescription of PIMs in the elderly. The results showed a high prevalence of PIMs with a multicausal origin and directly associated with polypharmacy. As clarified by the authors of the IFAsPIAM List, the criteria specified in the list do not substitute the clinical evaluation of each patient.

Experimental bio-artificial liver: Importance of the architectural design on ammonia detoxification performance.

AIM: To determine the influence of the construction design over the biological component's performance in an experimental bio-artificial liver (BAL) device. METHODS: Two BAL models for liver microorgans (LMOs) were constructed. First, we constructed a cylindrical BAL and tested it without the biological component to establish its correct functioning. Samples of blood and biological compartment (BC) fluid were taken after 0, 60, and 120 min of perfusion. Osmolality, hematocrit, ammonia and glucose concentrations, lactate dehydrogenase (LDH) release (as a LMO viability parameter), and oxygen consumption and ammonia metabolizing capacity (as LMO functionality parameters) were determined. CPSI and OTC gene expression and function were measured. The second BAL, a "flat bottom" model, was constructed using a 25 cm2 culture flask while maintaining all other components between the models. The BC of both BALs had the same capacity (approximately 50 cm3) and both were manipulated with the same perfusion system. The performances of the two BALs were compared to show the influence of architecture. RESULTS: The cylindrical BAL showed a good exchange of fluids and metabolites between blood and the BC, reflected by the matching of osmolalities, and glucose and ammonia concentration ratios after 120 min of perfusion. No hemoconcentration was detected, the hematocrit levels remained stable during the whole study, and the minimal percentage of hemolysis (0.65% ± 0.10%) observed was due to the action of the peristaltic pump. When LMOs were used as biological component of this BAL they showed similar values to the ones obtained in a Normothermic Reoxygenation System (NRS) for almost all the parameters assayed. After 120 min, the results obtained were: LDH release (%): 14.7 ± 3.1 in the BAL and 15.5 ± 3.2 in the NRS (n = 6); oxygen consumption (µmol/min·g wet tissue): 1.16 ± 0.21 in the BAL and 0.84 ± 0.15 in the NRS (n = 6); relative expression of Cps1 and Otc: 0.63 ± 0.12 and 0.67 ± 0.20, respectively, in the BAL, and 0.86 ± 0.10 and 0.82 ± 0.07, respectively, in the NRS (n = 3); enzymatic activity of CPSI and OTC (U/g wet tissue): 3.03 ± 0.86 and 222.0 ± 23.5, respectively, in the BAL, and 3.12 ± 0.73 and 228.8 ± 32.8, respectively, in the NRS (n = 3). In spite of these similarities, LMOs as a biological component of the cylindrical BAL were not able to detoxify ammonia at a significant level (not detected vs 35.1% ± 7.0% of the initial 1 mM NH4 + dose in NRS, n = 6). Therefore, we built a second BAL with an entirely different design that offers a flat base BC. When LMOs were placed in this "flat bottom" device they were able to detoxify 49.3% ± 8.8% of the initial ammonia overload after 120 min of perfusion (n = 6), with a detoxification capacity of 13.2 ± 2.2 µmol/g wet tissue. CONCLUSION: In this work, we demonstrate the importance of adapting the BAL architecture to the biological component characteristics to obtain an adequate BAL performance.

Potentially Inappropriate Medications in Elderly Ambulatory Patients: A Comparative Study between a Primary Health Care Center and a Community Pharmacy.

OBJECTIVE: This study aims to compare, both qualitatively and quantitatively, the medication dispensed to elderly patients in a primary health care center (PHC) and a community pharmacy (CP) in Argentina and to identify the prescription of potentially inappropriate medications (PIMs). METHODS: A cross-sectional observational study. Data were acquired from 886 prescriptions in the PHC and 2368 in the CP between February and April 2015. Dispensed medications were coded according to the Anatomical, Therapeutic, and Chemical (ATC) classification system. The frequency of prescriptions for each of them was determined. The number and monthly average of drugs dispensed were calculated for each patient. The use of PIMs was identified using Beers Criteria. RESULTS: In both institutions, the means of medications dispensed per individual and month were similar: 3.69 ± 1.93 in the PHC and 3.46 ± 2.18 in the CP. Most of the medications corresponded to cardiovascular system agents. In the CP, 111 prescriptions (4.69%) dispensed to 51 patients (19.39%) were identified as PIMs. In the PHC, 72 prescriptions (8.13%) dispensed to 27 patients (28.42%) were identified as PIMs. In patients with major polymedication the possibility of consuming these drugs was 2.55 times higher in the CP and 2.60 times higher in the PHC. The percentage of PIM prescriptions was significantly higher in the PHC, although the percentage of patients receiving them did not differ significantly. CONCLUSIONS: The prevalence of PIMs found in this population is relevant enough to implement measures that address the problem in an integral way, to improve the quality of prescriptions and the health outcomes of patients.

Assessment of polypharmacy in elderly patients by using data from dispensed medications in community pharmacies: analysis of results by using different methods of estimation.

Background Estimating the prevalence of polypharmacy is essential for the evaluation of public health. Many different methodologies are used to determine the number of drugs used by a patient. Objective To analyse and compare three different methods (simultaneous, cumulative and continuous medication) to determine the number of drugs used by a patient, to estimate the prevalence of polypharmacy and to evaluate the possible association between polypharmacy and the gender and age of patients. Method Cross-sectional observational study carried out between April and September 2015. Data were acquired from prescriptions corresponding to 3972 patients aged 65 years old or older in ten community pharmacies in Argentina. Results The prevalence of polypharmacy varied significantly according to the method used. Major polypharmacy (use of five or more drugs) was detected in 20.5-47.1% of the patients. The association between gender, age and polypharmacy was statistically significant only when using the continuous medication method. The prevalence of minor polypharmacy (use of two to four drugs) was similar with the three methods. Conclusion These results contribute to deciding which is the best method to determine polypharmacy according to the objective of future studies and considering the advantages and disadvantages of each of them.

Impact of the induced organic anion transporter 1 (Oat1) renal expression by furosemide on the pharmacokinetics of organic anions.

AIM: Furosemide is a loop diuretic. Different authors demonstrated that continuous administration of furosemide modulates the expression of organic anion transporters. This study was undertaken to simultaneously evaluate the effects of furosemide pretreatment on organic anion transporter 1 (Oat1) and multidrug resistance protein 2 (Mrp2) renal expressions, on p-aminohippurate (PAH) pharmacokinetics and on renal and urinary PAH levels in rats. METHODS: Male Wistar rats were treated with furosemide (6 mg/100 g body weight per day, subcutaneously, 4 days) (treated group) or saline (control group). On the fifth day, PAH was administered as a bolus infusion in the femoral vein, and plasma samples were obtained from femoral artery at different time points. PAH levels in renal tissue and urine were also assessed. Renal Oat1 and Mrp2 expressions were evaluated by western blotting. RESULTS: Furosemide pretreatment increased both the expression of Oat1 and Mrp2. PAH plasma concentrations decreased following a biexponential function. The furosemide-treated group showed higher PAH plasma levels, a lower systemic clearance and elimination rate constant from the peripheral compartment, indicating that PAH renal elimination was decreased. PAH levels in renal tissue were significantly elevated and in urine appeared to be significantly lower as compared with control animals. CONCLUSIONS: Furosemide pretreatment caused a significant decrease of PAH renal elimination, despite Oat1 and Mrp2 augmented renal expression. The goal of the present study is the addition of important information in the wide gap of knowledge that exists about drug-drug interactions. Because of furosemide worldwide use, the data obtained are interesting and useful in terms of translation to clinical practice.

Performance of cold-preserved rat liver Microorgans as the biological component of a simplified prototype model of bioartificial liver.

AIM: To develop a simplified bioartificial liver (BAL) device prototype, suitable to use freshly and preserved liver Microorgans (LMOs) as biological component. METHODS: The system consists of 140 capillary fibers through which goat blood is pumped. The evolution of hematocrit, plasma and extra-fiber fluid osmolality was evaluated without any biological component, to characterize the prototype. LMOs were cut and cold stored 48 h in BG35 and ViaSpan® solutions. Fresh LMOs were used as controls. After preservation, LMOs were loaded into the BAL and an ammonia overload was added. To assess LMOs viability and functionality, samples were taken to determine lactate dehydrogenase (LDH) release and ammonia detoxification capacity. RESULTS: The concentrations of ammonia and glucose, and the fluids osmolalities were matched after the first hour of perfusion, showing a proper exchange between blood and the biological compartment in the minibioreactor. After 120 min of perfusion, LMOs cold preserved in BG35 and ViaSpan® were able to detoxify 52.9% ± 6.5% and 53.6% ± 6.0%, respectively, of the initial ammonia overload. No significant differences were found with Controls (49.3% ± 8.8%, P < 0.05). LDH release was 6.0% ± 2.3% for control LMOs, and 6.2% ± 1.7% and 14.3% ± 1.1% for BG35 and ViaSpan® cold preserved LMOs, respectively (n = 6, P < 0.05). CONCLUSION: This prototype relied on a simple design and excellent performance. It's a practical tool to evaluate the detoxification ability of LMOs subjected to different preservation protocols.

Estudio de prevalencia de medicación potencialmente inapropiadas en adultos mayores / Prevalence study of potentially inappropriate medication in older adults

INTRODUCCIÓN La población adulta mayor es un grupo de riesgo asociado con la pluripatología, con la polifarmacia y mayor riesgo de efectos adversos. La medicación potencialmente inapropiada (PIM) es aquella en la que el riesgo de eventos adversos es superior a los beneficios clínicos. Existen diferentes métodos para medir prescripciones PIMs, los más utilizados son Criterios de Beers; de STOPP y el Indice de Medicación Apropiada (MAI). OBJETIVO Evaluar la prevalencia de prescripciones PIM en una población de adultos mayores que reciben su medicación en centros de atención primaria de la salud de Rosario. MATERIAL Y MÉTODOS Estudio retrospectivo observacional de corte transversal de 106 pacientes mayores de 65 años de una muestra aleatoria de seis centros de salud. RESULTADOS Se analizaron 492 prescripciones, encontrándose una prevalencia de PIM de 35.85% según Beers, 45.28% según STOPP y 76.00% con el índice MAI. Solo se halló asociación estadísticamente significativa entre prescripciones PIM y polimedicación mayor con los criterios STOPP. Las PIMs más frecuentemente observadas correspondieron a los grupos farmacológicos de los antiulcerosos, AINES, glibenclamida, benzodiacepinas y antipsicóticos. A través del índice MAI, los pacientes con PIM presentaron para cada uno de los criterios diferentes prevalencias, siendo las más frecuentes; el uso de medicamento inapropiado por la edad o no tenían diagnóstico 76.00%, interacciones fármaco-fármaco; 44.00% interacciones fármacos-enfermedad 24.00% y las duplicaciones innecesarias 4.00%., se encontró que el 76% fueron interacciones fármaco-fármaco, 44% fármaco-enfermedad y hubo un 4% de duplicaciones innecesarias. DISCUSIÓN Los resultados obtenidos muestran una alta prevalencia de PIM utilizando todos los criterios y están en concordancia a la escasa literatura nacional. De los criterios explícitos los de STOPP mostraron una mejor adaptación para ser utilizados en la estimación de PIM en nuestra población

Cold storage of liver microorgans in ViaSpan and BG35 solutions: study of ammonia metabolism during normothermic reoxygenation.

INTRODUCTION: This work focuses on ammonia metabolism of Liver Microorgans (LMOs) after cold preservation in a normothermic reoxygenation system (NRS). We have previously reported the development of a novel preservation solution, Bes-Gluconate-PEG 35 kDa (BG35) that showed the same efficacy as ViaSpan to protect LMOs against cold preservation injury. The objective of this work was to study mRNA levels and activities of two key Urea Cycle enzymes, Carbamyl Phosphate Synthetase I (CPSI) and Ornithine Transcarbamylase (OTC), after preservation of LMOs in BG35 and ViaSpan and the ability of these tissue slices to detoxify an ammonia overload in a NRS model. MATERIAL AND METHODS: After 48 h of cold storage (0°C in BG35 or ViaSpan) LMOs were rewarmed in KHR containing an ammonium chloride overload (1 mM). We determined ammonium detoxification capacity (ADC), urea synthesis and enzyme activities and relative mRNA levels for CPSI and OTC. RESULTS: At the end of reoxygenation LMOs cold preserved in BG35 have ADC and urea synthesis similar to controls. ViaSpan group demonstrated a lower capacity to detoxify ammonia and to synthesize urea than fresh LMOs during the whole reoxygenation period which correlated with the lower mRNA levels and activities for CPSI and OTC observed for this group. CONCLUSION: We demonstrate that our preservation conditions (48 hours, BG35 solution, anoxia, 0ºC) did not affect ammonia metabolism of cold preserved LMOs maintaining the physiological and biochemical liver functions tested, which allows their future use as biological component of a BAL system.

Hypothermic preservation of rat liver microorgans (LMOs) in bes-gluconate solution. Protective effects of polyethyleneglycol (PEG) on total water content and functional viability.

We have reported of an alternative solution to preserve hepatocytes that have three key components: gluconate, sucrose and an aminosulfonic acid (BGS solution). In order to extend the use of this solution to organs as the liver, we evaluate the effect of the addition of PEG of 8, 20 and 35 kDa to BG Solution on the total water content and functional viability of rat liver microorgans (LMOs). LMOs were preserved (48 h 0 ºC) in the following solutions: ViaSpan(®); BGS; BG plus 4% PEG 8000 (BG8); BG plus 4% PEG 20.000 (BG20) and BG plus 4% PEG 35.000 (BG35). LDH Release and Total Water Content showed a marked increase in LMOs preserved in BGS. This indicates that, in the absence of PEG, the tissue showed important cell membrane integrity deterioration and was incapable of regulating cell volume. After the preservation period, all groups were reoxygenated (120 min, 37 ºC, KHR) and Total Water Content, Glycogen Content and Oxygen Consumption were determined. After 120 min LMOs preserved in BG35 showed values of Oxygen Consumption similar to controls. On the other hand, LMOs preserved in BG8, BG20 and ViaSpan(®) showed oxygen consumption rates and glycogen content significantly smaller than controls. In conclusion, BG35 was the most effective preservation solution to protect LMOs against cold preservation injury due to ischemia and reoxygenation. It is a good alternative to ViaSpan(®) because of its higher buffer capacity, its best indexes of respiration activity and for being considerably less expensive.

A novel BES-gluconate-sucrose (BGS) solution for cold storage of isolated hepatocytes.

We have used hepatocyte suspensions to study how hypothermic storage in a modified University of Wisconsin (mUW) solution affects liver cell metabolism and cell membrane properties. At present the UW solution is the gold standard of organ preservation. However it contains several ingredients which either are expensive or cannot easily be obtained worldwide. The aim of the present study was the development of a novel preservation solution for rat hepatocytes effective and comparable with the mUW, with enhanced buffer capacity and less expensive. In particular, we investigated the effects of the buffering agent BES, a derivate of aminosulfonic acid, on liver cells metabolism during cold storage and rewarming. In the development of this novel preservation solution we have included three key components: gluconate as impermeant anion, sucrose to give additional osmotic support and the aminosulfonic acid BES for its buffer capacity. Our results shown that BGS solution was equally effective to mUW to protect rat hepatocytes against cold preservation injury due to ischemia and reoxigenation. Also, BGS solution is a good alternative with its high buffer capacity, best indices of respiration activity and it is considerably less expensive than the mUW solution. The use of this solution for the storage of isolated hepatocytes may facilitate hepatocyte research in situations in which the more complex and expensive mUW solution is not available since the cost of one liter of BGS is about 1/3 that an equal volume of mUW solution.