Thiazolidinediones (TZDs) enhance insulin secretory response via GPR40 and adenylate cyclase (AC)

Recent Glycemia Is a Major Determinant of β-Cell Function in Type 2 Diabetes Mellitus

BACKGRUOUND

Progressive deterioration of β-cell function is a characteristic of type 2 diabetes mellitus (T2DM). We aimed to investigate the relative contributions of clinical factors to β-cell function in T2DM.

METHODS

In a T2DM cohort of 470 adults (disease duration 0 to 41 years), β-cell function was estimated using insulinogenic index (IGI), disposition index (DI), oral disposition index (DIO), and homeostasis model assessment of β-cell function (HOMA-B) derived from a 75 g oral glucose tolerance test (OGTT). The relative contributions of age, sex, disease duration, body mass index, glycosylated hemoglobin (HbA1c) levels (at the time of the OGTT), area under the curve of HbA1c over time (HbA1c AUC), coefficient of variation in HbA1c (HbA1c CV), and antidiabetic agents use were compared by standardized regression coefficients. Longitudinal analyses of these indices were also performed.

RESULTS

IGI, DI, DIO, and HOMA-B declined over time (P<0.001 for all). Notably, HbA1c was the most significant factor affecting IGI, DI, DIO, and HOMA-B in the multivariable regression analysis. Compared with HbA1c ≥9%, DI was 1.9-, 2.5-, 3.7-, and 5.5-fold higher in HbA1c of 8%-<9%, 7%-<8%, 6%-<7%, and <6%, respectively, after adjusting for confounding factors (P<0.001). Conversely, β-cell function was not affected by the type or duration of antidiabetic agents, HbA1c AUC, or HbA1c CV. The trajectories of the IGI, DI, DIO, and HOMA-B mirrored those of HbA1c.

CONCLUSION

β-Cell function declines over time; however, it is flexible, being largely affected by recent glycemia in T2DM.

Thiazolidinediones are Partially Effective Bitter Blockers

PURPOSE

The bad bitter taste of some medicines is a barrier to overcoming noncompliance with medication use, especially life-saving drugs given to children and the elderly. Here, we evaluated a new class of bitter blockers (thiazolidinediones, TZDs).

METHODS

In this study, 2 TZDs were tested, rosiglitazone (ROSI) and a simpler form of TZD, using a high-potency sweetener as a positive control (neohesperidin dihydrochalcone, NHDC). We tested bitter-blocking effects using the bitter drugs tenofovir alafenamide fumarate (TAF), a treatment for HIV and hepatitis B infection, and praziquantel (PRAZ), a treatment for schistosomiasis, by conducting taste testing with 2 separate taste panels: a general panel (N = 97, 20-23 years, 82.5% female, all Eastern European) and a genetically informative panel (N = 158, including 68 twin pairs, 18-82 years, 76% female, 87% European ancestry). Participants rated the bitterness intensity of the solutions on a 100-point generalized visual analog scale.

FINDINGS

Person-to-person differences in drug bitterness were striking; TAF and PRAZ were weakly or not bitter for some people but moderately to highly bitter for others. Participants in both taste panels rated the bitter drugs TAF and PRAZ as less bitter on average when mixed with NHDC than when sampled alone. ROSI partially suppressed the bitterness of TAF and PRAZ, but effectiveness differed between the 2 panels: bitterness was significantly reduced for PRAZ but not TAF in the general panel and for TAF but not PRAZ in the genetically informative panel. ROSI was a more effective blocker than the other TZD.

IMPLICATIONS

These results suggest that TZDs are partially effective bitter blockers and the suppression efficacy differs from drug to drug, from person to person, and from panel to panel, suggesting other TZDs should be designed and tested with more drugs and on diverse populations to define which ones work best with which drugs and for whom. The discovery of bitter receptor blockers can improve compliance with medication use.

Thiazolidinediones are partially effective bitter blockers

Purpose

The bad bitter taste of some medicines is a barrier to overcoming non-compliance with medication use, especially life-saving drugs given to children and the elderly. Here we evaluated a new class of bitter blockers (thiazolidinediones; TZDs).

Methods

In this study, two TZDs were tested, rosiglitazone (ROSI) and a simpler form of TZD, using a high-potency sweetener as a positive control (neohesperidin dihydrochalcone, NHDC). We tested bitter-blocking effects using the bitter drugs tenofovir alafenamide fumarate (TAF), a treatment for HIV and hepatitis B infection, and praziquantel (PRAZ), a treatment for schistosomiasis, by conducting taste testing with two separate taste panels: a general panel (N=97, 20-23 yrs, 82.5% female, all Eastern European) and a genetically informative panel (N=158, including 68 twin pairs, 18-82 yrs, 76% female, 87% European ancestry). Participants rated the bitterness intensity of the solutions on a 100-point generalized visual analog scale.

Findings

Participants in both taste panels rated the bitter drugs TAF and PRAZ as less bitter on average when mixed with NHDC than when sampled alone. ROSI partially suppressed the bitterness of TAF and PRAZ, but effectiveness differed between the two panels: bitterness was significantly reduced for PRAZ but not TAF in the general panel and for TAF but not PRAZ in the genetically informative panel. ROSI was a more effective blocker than the other TZD.

Implications

These results suggest that TZDs are partially effective bitter blockers, suggesting other TZDs should be designed and tested with more drugs and on diverse populations to define which ones work best with which drugs and for whom. The discovery of bitter receptor blockers can improve compliance with medication use.