Different effects of statins on induction of diabetes mellitus: an experimental study

Abstract

Background: To determine the effect of different statins on the induction of diabetes mellitus.

Materials and methods: Four statins (atorvastatin, pravastatin, rosuvastatin, and pitavastatin) were used. Cytotoxicity, insulin secretion, glucose-stimulated insulin secretion, and G0/G1 phase cell cycle arrest were investigated in human pancreas islet β cells, and glucose uptake and signaling were studied in human skeletal muscle cells (HSkMCs).

Results: Human pancreas islet β cells treated with 100 nM atorvastatin, pravastatin, rosuvastatin, and pitavastatin had reduced cell viability (32.12%, 41.09%, 33.96%, and 29.19%, respectively) compared to controls. Such cytotoxic effect was significantly attenuated by decreasing the dose to 10 and 1 nM, ranged from 1.46% to 17.28%. Cells treated with 100 nM atorvastatin, pravastatin, rosuvastatin, and pitavastatin had a reduction in the rate of insulin secretion rate by 34.07%, 30.06%, 26.78%, and 19.22%, respectively. The inhibitory effect was slightly attenuated by decreasing the dose to 10 and 1 nM, ranging from 10.84% to 29.60%. Insulin secretion stimulated by a high concentration of glucose (28 mmol/L) was significantly higher than a physiologic concentration of glucose (5.6 mmol/L) in all treatment groups. The glucose uptake rates at a concentration of 100 nM were as follows: atorvastatin (58.76%) < pravastatin (60.21%) < rosuvastatin (72.54%) < pitavastatin (89.96%). We also found that atorvastatin and pravastatin decreased glucose transporter (GLUT)-2 expression and induced p-p38 MAPK levels in human pancreas islet β cells. Atorvastatin, pravastatin, and rosuvastatin inhibited GLUT-4, p-AKT, p-GSK-3β, and p-p38 MAPK levels in HSkMCs.

Conclusion: Statins similar but different degree of effects on pancreas islet β cells damage and induce insulin resistance in HSkMC.

Keywords: glucose; human pancreas islet β cell; human skeletal muscle cells; insulin; statins.

Figure 1

The relative cell viability (%) after 24 hours of different concentrations of four statin treatments. Notes: *P<0.05 and ***P<0.001 vs control group. ^{^}P<0.05 and ^{^^}P<0.01 between indicated groups.

Figure 2

The insulin secretion stimulation index high glucose stimulation/physiologic glucose stimulation ratio after 24 hours of different concentrations of four statin treatments. Notes: *P<0.05 and **P<0.01 vs control group.

Figure 3

DNA histograms after 24 hours of different concentrations of four statin treatments. Notes: (A–C) Atorvastatin (1, 10, and 100 µM, respectively), (D–F) pravastatin (1, 10, and 100 µM, respectively), (G–I) rosuvastatin (1, 10, and 100 µM, respectively), (J–L) pitavastatin (1, 10, and 100 µM, respectively), and (M) control.

Figure 4

Cell cycle distribution after 24 hours of different concentrations of four statin treatments. Note: *P<0.05 vs control group.

Figure 5

Decrease in glucose uptake in human skeletal muscle cells after 48 hours of different concentrations of four statin treatments. Notes: *P<0.05 and **P<0.01 vs control group. ^{^}P<0.05 between indicated groups.

Figure 6

Western blotting in human pancreas islet β cells after 24 hours of different concentrations of four statin treatments. Notes: (A and B) GLUT-2, (C and D) PKA, (E and F) p-p38 MAPK. *P<0.05 and **P<0.01 vs control group. Abbreviations: GLUT-2, glucose transporter 2; GAPDH, glyceraldehyde 3-phosphate dehydrogenase.

Figure 7

Western blotting in human skeletal muscle cells after 48 hours of different concentrations of four statin treatments. Notes: (A and B) GLUT-4, (C and D) AKT, (E and F) p-AKT, (G and H) GSK-3β, (I and J) p-GSK-3β, (K and L) p38 MAPK, (M and N) p-p38 MAPK. *P<0.05, **P<0.01, and ***P<0.001 vs control group. Abbreviations: GLUT-4, glucose transporter 4; GAPDH, glyceraldehyde 3-phosphate dehydrogenase.

Figure 7

Western blotting in human skeletal muscle cells after 48 hours of different concentrations of four statin treatments. Notes: (A and B) GLUT-4, (C and D) AKT, (E and F) p-AKT, (G and H) GSK-3β, (I and J) p-GSK-3β, (K and L) p38 MAPK, (M and N) p-p38 MAPK. *P<0.05, **P<0.01, and ***P<0.001 vs control group. Abbreviations: GLUT-4, glucose transporter 4; GAPDH, glyceraldehyde 3-phosphate dehydrogenase.

Figure 8

Altered human pancreas islet β cells and HSkMCs phenotype normalized after MAPK and AKT inhibitor treatment. Notes: (A) Human pancreas islet β cells survival, (B) insulin secretion stimulation index high glucose stimulation/physiologic glucose stimulation ratio of human pancreas islet β cells, (C) HSkMCs glucose uptake, and (D) p-AKT and p-p38 MAP signaling of HSkMCs. **P<0.01 and ***P<0.001 vs control group. Abbreviations: HSkMC, human skeletal muscle cell; OD, optical density; ns, not significant.

Figure 9

The relative rate insulin secretion (%) after 24 hours of different concentrations of four statin treatments. Notes: **P<0.01 and ***P<0.001 vs control group. ^{^}P<0.05 and ^{^^}P<0.01 between indicated groups.