Posted on July 19, 2022
As expected, brand new kidney approval off cephalexin is greatly diminished at the low amount (step one mg/kg), in addition to approval proportion was less than unity (0
It’s got come reported that term regarding Oct2 and you may Oat1, which is present on basolateral membrane layer out-of tubular epithelial structure, are decreased into the an excellent hyperuricenic design received of the 10-day serving regarding oxonic acidic and you can uric acid from inside the rats . In today’s study, i concentrated specifically to the Mate1, an organic cation transporter at the renal tubular apical membrane layer. It has started stated that Mate1 expression is reduced from inside the a rat kidney failure design generated by adenine government having 4 weeks . In the current model, on the other hand, renal failure try lightweight at the most, because the conveyed because of the unimportant transform regarding inulin clearance and you may minimal raise regarding BUN ( Table 1 ). Additionally the expose model might be considerably better to look at the newest certain results of hyperuricemia.
Rather, on hyperuricemic rats, the new plasma amount and renal approval away from creatinine, a clinically put biomarker regarding kidney form, had been notably increased and you may reduced, correspondingly ( Fig 3C and you can 3F ). At the same time, brand new renal clearance proportion of creatinine in order to inulin try diminished off step one.62 to 1.09 about hyperuricemic mice ( Desk dos ). Which observance would be said when it comes to reduced tubular hormonal via Oct2 and you can/otherwise Mate1 transporters, but not because of the a decrease away from GFR, because the analysis was indeed corrected to possess inulin approval. Habu Y et al., stated that a reduction in Oct2 proteins phrase in the hyperurecemic rats contributed to a reduction in the latest buildup of monium and you may cimetidine, into the renal incisions . Considering it report, the fresh new paid off Oct2 mRNA profile decreased creatinine uptake from the blood on tubular cells. It is 
a prospective system of your own reduced amount of renal Oct2-mediated creatinine clearance found in hyperuricemic rats. On the other hand, most recent investigation displayed the reduced total of Mate1 necessary protein phrase most likely contributed to the newest reduced amount of creatinine excretion on the tubular tissues into the lumen. The new buildup off creatinine for the kidney would be as a result of the reduction of Mate1 proteins expression. From all of these efficiency, it is highly signifies that the brand new reduced total of Mate1 term was one of the main factors behind the fresh new decrease in renal creatinine approval found in hyperuricemic rats, along with the reduced amount of Oct2 term.
Metformin is secreted into the urine via e manner as creatinine [22, 25]. Plasma concentration and renal clearance of metformin in the hyperuricemic rats showed no statistically significant change ( Fig 3A and 3D ). On the other hand, accumulation of metformin in the kidney tissue (Kp, kidney) increased significantly from 16.6 to 90.3 ( Table 2 ). The renal clearance of metformin is considered to be a blood flow rate-limited in our study (rat blood flow 23 mL/min/kg ) as well as reported in mice , which indicates that the contribution of Oct2 to metformin elimination from the blood was negligible. Since Mate1 is a key transporter which excretes metformin from the tubular cells into the lumen, it is reasonable that decreased Mate1 expression would affect kidney tissue accumulation, but not the apparent plasma profile of metformin in rats. As metformin and creatinine are substrates of Oct1/2 as well as Mate1 in kidney, the elevated endogenous creatinine may affect pharmacokinetics of metformin. However, the renal clearance of metformin is considered to be a blood flow rate-limited, which means apparently less affected by transporter-mediated interaction. Therefore, the renal clearance of metformin is considered to be unlikely affected by creatinine via competition on Oct1/2 transporters in kidney.
Brand new results you to definitely reabsorption are widespread at lowest dosage, it is perhaps not effective at new highest serving, might be said regarding saturation out of Pept-mediated reabsorption out of cephalexin
Cephalexin is taken up into kidney tissues via transporters such as Oat1 and secreted via Mate1 [23, 24, 35]. In addition, it is reabsorbed via peptide transporters Pept1 and Pept2 (Slc15a2) [36–38]. The observed changes in plasma concentration, kidney tissue accumulation and renal clearance of cephalexin could be well explained by the changes of these transporters. Urinary recovery of cephalexin was significantly delayed or decreased in the hyperuricemic rats ( Fig 3E ). Since cephalexin is reabsorbed via Pept transporters, it was considered that the reabsorption efficiency is increased due to the decreased tubular intra-lumen concentration of cephalexin. To confirm this, we evaluated the dose dependence of cephalexin disposition by decreasing the dose to 1 mg/kg from 10 mg/kg in control rats ( Fig 4 ). 34), whereas it was higher than unity (1.44) at the high dose (10 mg/kg, Table 3 ). Therefore, the decrease of renal clearance ratio to less than unity in hyperuricemia is considered to be due to more efficient reabsorption as a consequence of the decreased tubular concentration of cephalexin resulting from the lower Mate1 expression. When the same mechanism is assumed, the clearance ratio probably remains to be less than 1, along with a decrease in renal clearance and an increase in Kp,renal through decreasing Oat1 and Mate1 activities in hyperuricemic rats at 1 mg/kg. This mechanism may account predominantly for the substantial change in renal handling of cephalexin in hyperuricemic rats, even though the Pept1 and Pept2 mRNA levels in the hyperuricemic rats were lower than in control rats ( Fig 2 ).