Renin-angiotensin system inhibitors combined with cisplatin exacerbate cisplatin-induced nephrotoxicity in mice

Abstract

Introduction: We previously reported that the concomitant use of enalapril and telmisartan exacerbates the risk of cisplatin (CDDP)-induced acute renal dysfunction compared to other antihypertensive drugs in mice. Thus, in the current study, we investigated the risk of developing chronic kidney disease following repeated concomitant use of CDDP and antihypertensive drugs.

Materials and methods: Male BALB/c mice were divided into 12 groups: (1) Control group (untreated), (2) CDDP group (7 mg/kg, CDDP), (3) AML group (5 mg/kg, amlodipine), (4) ENA group (2.5 mg/kg, enalapril), (5) TEL group (10 mg/kg, telmisartan), (6) LOS group (10 mg/kg, losartan), (7) CDDP+AML group (5 mg/mL, AML), (8) CDDP+ENA group (2.5 mg/kg, ENA), (9) CDDP+LowENA group (1.25 mg/kg, ENA), (10) CDDP+TEL group (10 mg/kg, TEL), (11) CDDP+LowTEL group (5 mg/kg, TEL), and (12) CDDP+LOS group (10 mg/kg, LOS). CDDP was administered intraperitoneally four times every 7 days, and each antihypertensive drug was administered orally from day 3 before CDDP administration until day 24 (six times a week). The degree of renal damage was assessed. The nephrotoxicity of each individual was evaluated by measuring serum creatinine and blood urea nitrogen levels. The degrees of renal fibrosis and epithelial-mesenchymal transition were also examined in kidney tissue sections.

Results and discussion: The results suggest that combinatorial treatment of CDDP and renin-angiotensin system inhibitors, particularly ENA and TEL, may exacerbate CDDP-induced nephrotoxicity. This study clearly demonstrates the need for large-scale clinical studies to construct treatment regimens that do not interfere with the therapeutic intensity of CDDP.

Keywords: Cisplatin; Fibrosis; Nephrotoxicity; Renin-angiotensin system inhibitor.

Fig. 1

Influence of different drug regimens on renal functions. BALB/c mice (6 weeks old, male) were divided into the control group (n = 5, untreated), CDDP group (n = 5, CDDP: 7 mg/kg, i.p.), AML group (n = 5, AML: 5 mg/kg), CDDP+AML group (n = 5, AML: 5 mg/kg), ENA group (n = 5, ENA: 2.5 mg/kg), CDDP+ENA group (n = 10, ENA: 2.5 mg/kg), LOS group (n = 5, LOS: 10 mg/kg), CDDP+LOS group (n = 5, LOS: 10 mg/kg), TEL group (n = 5, TEL: 10 mg/kg), and CDDP+TEL group (n = 8, TEL: 10 mg/kg). CDDP was administered intraperitoneally four times every 7 days (days 0, day 7, day 14, and day 21), with day 0 being the first day of administration. Serum samples were collected on days −3, 0, 7, 14, 21, and 25. (a) Creatinine (CRE) and (b) blood urea nitrogen (BUN) levels were measured in each individual, and the mean plus standard deviation (SD) was calculated. Statistically significant differences were analyzed using the Steel–Dwass test, and P < 0.05 was considered statistically significant (*).

Fig. 2

Influence of CDDP combined with ENA or TEL on mouse survival. BALB/c mice (6-week-old, male) were divided into the control group (n = 5, untreated), CDDP group (n = 5, CDDP: 7 mg/kg, i.p.), ENA group (n = 5, ENA: 2.5 mg/kg), CDDP+ENA group (n = 10, ENA: 2.5 mg/kg), CDDP+Low ENA group (n = 5, ENA: 1.25 mg/kg), TEL group (n = 5, TEL:10 m,g/kg), CDDP+TEL group (n = 8, TEL:10 mg/kg), and CDDP+Low TEL group (n = 5, TEL:2.5 mg/kg). The first dose of CDDP was administered intraperitoneally on day 0, and drugs were administered intraperitoneally four times in seven days (days 0, 7, 14, and 21). Each antihypertensive drug was administered orally (6 times per week) from 3 days before CDDP administration (day −3) until day 24. (a) The survival rates of the control, CDDP, ENA, CDDP+ENA, and CDDP+Low ENA groups on day 25 were calculated. (b) The survival rates on day 25 were calculated for the control, TEL, CDDP, CDDP+TEL, and CDDP+Low TEL groups. Statistically significant differences were analyzed using the log-rank test, and P < 0.05 was considered statistically significant (*).

Fig. 3

Changes in blood urea nitrogen (BUN), systolic blood pressure (sBP), and serum albumin (ALB) levels in groups administered with ENA and TEL. BALB/c mice (6-week-old, male) were divided into CDDP+ENA (n = 10, ENA: 2.5 mg/kg), CDDP+Low ENA (n = 5, ENA: 1.25 mg/kg), CDDP+TEL (n = 8, TEL: 10 mg/kg), and CDDP+Low TEL groups (n = 5, TEL: 5 mg/kg). CDDP was administered intraperitoneally four times every 7 days (days 0, 7, 14 and 21), with day 0 being the first day of CDDP administration. Each antihypertensive drug was administered orally (6 times per week) from 3 days before CDDP administration (day −3) until day 24. The BUN, sBP, and ALB values of animals in each group that (a) died or (b) survived to the end of observation period are shown.

Fig. 4

Influence of the concomitant use of CDDP and antihypertensive drugs or low-dose antihypertensive drugs on renal functions. BALB/c mice (6-week-old, male) were divided into the control (n = 5, untreated), CDDP (n = 5, CDDP: 7 mg/kg, i.p.), ENA (n = 5, ENA: 2.5 mg/kg), CDDP+ENA (n = 10, ENA: 2.5 mg/kg), CDDP+Low ENA (n = 5, ENA: 1.25 mg/kg), TEL (n = 5, TEL:10 mg/kg), CDDP+TEL (n = 8, TEL:10 mg/kg), and CDDP+Low TEL groups (n = 5, TEL:2.5 mg/kg). The first dose of CDDP was administered intraperitoneally on day 0 for a total of four times in seven days (days 0, 7, 14, and 21). Serum samples were collected on days −3, 0, 7, 14, 21, and 25. (a) CRE and (b) BUN levels were measured in each group, and the mean plus SD was calculated. Statistically significant differences were analyzed using the Steel–Dwass test, and P < 0.05 was considered statistically significant (*).

Fig. 5

Influence of CDDP in combination with antihypertensive drugs or low-dose antihypertensive drugs on renal fibrosis and epithelial-mesenchymal transition. BALB/c mice (6-week-old, male) were divided into the control (n = 5, untreated), CDDP (n = 5, CDDP: 7 mg/kg, i.p.), AML (n = 5, AML: 5 mg/kg), CDDP+AML (n = 5, AML: 5 mg/kg), LOS (n = 5, LOS: 10 mg/kg), CDDP+LOS (n = 5, LOS: 10 mg/kg), ENA (n = 5, ENA: 2.5 mg/kg), CDDP+ENA (n = 10, ENA: 2.5 mg/kg), CDDP+Low ENA (n = 5, ENA: 1.25 mg/kg), TEL (n = 5, TEL:10 mg/kg), CDDP+TEL (n = 8, TEL: 10 mg/kg), and CDDP+Low TEL groups (n = 5, TEL: 5 mg/kg). CDDP was administered intraperitoneally four times every 7 days (days 0, 7, 14, and 21) with day 0 being the first day of administration. Each antihypertensive drug was administered orally (6 times per week) from 3 days before CDDP administration (day −3) until day 24. (a) Paraffin sections were prepared from kidneys collected on day 25, and Masson trichrome staining was performed. (b) The ratio of fibrosis area to renal interstitial area in each group was calculated. (c) Another section was immunostained with an anti-α-SMA antibody. (d) Stained areas of α-SMA were extracted from stained images, and the ratio of stained areas of α-SMA to renal interstitial area in each group was calculated. The results of this study were analyzed in individuals who survived until the end of the observation period (day 25). The sections were examined under a microscope at a magnification of x400. Statistically significant differences were analyzed using the Steel–Dwass test, and P < 0.05 was considered statistically significant (*).

Fig. 6

Correlation between the renal fibrosis area ratio and renal function markers or stained area of α-SMA. BALB/c mice (6-week-old, male) were divided into CDDP+ENA (n = 10, ENA: 2.5 mg/kg), CDDP+Low ENA (n = 6, ENA: 1.25 mg/kg), CDDP+TEL (n = 8, TEL: 10 mg/kg), and CDDP+Low TEL groups (n = 5, TEL: 5 mg/kg). CDDP was administered intraperitoneally four times every 7 days (days 0, 7, 14 and 21) with day 0 being the first day of administration. Each antihypertensive drug was administered orally (6 times per week) from 3 days before CDDP administration (day −3) until day 24. The percentage of renal fibrosis area on day 25 was calculated and correlated with (a) CRE levels, (b) BUN levels, or (c) stained area of α-SMA on day 25. Statistical significance of the correlations was expressed as Spearman's rank correlation coefficient (r), where P < 0.05 was considered statistically significant. The results of this analysis were based on individuals who survived until the end of the observation period. CDDP+ENA, CDDP+Low ENA, CDDP+TEL, and CDDP+Low TEL groups are indicated by ○, ▲, and △, respectively.