Pioglitazone Alters the Proteomes of Normal Bladder Epithelial Cells but Shows No Tumorigenic Effects

Therapeutic potential of ginsenoside compound K in managing tenocyte apoptosis and extracellular matrix damage in diabetic tendinopathy

The prevalence of tendinopathy in patients with diabetes is well documented. Despite efforts to improve diabetes management, there is a lack of research on therapeutic agents targeting the core features of tendinopathy, namely, tenocyte apoptosis and extracellular matrix (ECM) damage. In this study, we investigated the potential of ginsenoside compound K (CK), known for its antidiabetic properties, to mitigate tenocyte apoptosis, inflammation, oxidative stress, and the metalloproteinase (MMP) system under hyperglycemic conditions. Our research also aimed to unravel the molecular mechanism underlying the effects of CK. The assessment of apoptosis involved observing intracellular chromatin condensation and measuring caspase 3 activity. To gauge oxidative stress, we examined cellular ROS levels and hydrogen peroxide and malondialdehyde concentrations. Western blotting was employed to determine the expression of various proteins. Our findings indicate that CK treatment effectively countered high glucose-induced apoptosis, inflammation, and oxidative stress in cultured tenocytes. Furthermore, CK normalized the expression of MMP-9, MMP-13, and TIMP-1. Notably, CK treatment boosted the expression of PPARγ and antioxidant enzymes. We conducted small interfering (si) RNA experiments targeting PPARγ, revealing its role in mediating CK's effects on tendinopathy features in hyperglycemic tenocytes. In conclusion, these in vitro results offer valuable insights into the potential therapeutic role of CK in managing tendinopathy among individuals with diabetes. By addressing crucial aspects of tendinopathy, CK presents itself as a promising avenue for future research and treatment development in this domain.

Pioglitazone, Bladder Cancer and the Presumption of Innocence

BACKGROUND

Thiazolidinediones are potent exogenous agonists of PPAR-γ, which augment the effects of insulin to its cellular targets and mainly at the level of adipose tissue. Pioglitazone, the main thiazolidinedione in clinical practice, has shown cardiovascular and renal benefits in patients with type 2 diabetes, durable reduction of glycated hemoglobulin levels, important improvements of several components of the metabolic syndrome and beneficial effects of non-alcoholic fatty liver disease.

OBJECTIVE

Despite all of its established advantages, the controversy for an increased risk of developing bladder cancer, combined with the advent of newer drug classes that achieved major cardiorenal effects have significantly limited its use spreading a persistent shadow of doubt for its future role.

METHODS

Pubmed, Google and Scope databases have been thoroughly searched and relevant studies were selected.

RESULTS

This paper explores thoroughly both in vitro and in vivo (animal models and humans) studies that investigated the possible association of pioglitazone with bladder cancer.

CONCLUSION

Currently the association of pioglitazone with bladder cancer cannot be based on solid evidence. This evidence cannot justify its low clinical administration, especially in the present era of individualised treatment strategies. Definite clarification of this issue is imperative and urgently anticipated from future high quality and rigorous pharmacoepidemiologic research, keeping in mind its unique mechanism of action and its significant pleiotropic effects.

Metformin and Sildenafil Attenuate Inflammation and Suppress Apoptosis After Ischemia/Reperfusion Injury in Rat Urinary Bladder

Purpose

Although metformin and sildenafil can protect various organs against ischemia/reperfusion (I/R) injury, their effects and mechanisms of action in bladder I/R injury remain unknown. This study investigated the effects and mechanisms of action of metformin and sildenafil against bladder I/R insult in rats.

Methods

One hundred male Sprague-Dawley rats were randomly divided into five groups each of twenty rats: a sham-operated group, a bladder I/R group, and bladder I/R groups treated with metformin, sildenafil, or both agents. Ischemia was induced by clamping the bilateral common iliac arteries with atraumatic vascular clamps for 2 hours, followed by reperfusion for 7 days. During this period, rats were injected once daily with 4 mg/kg metformin and/or 1 mg/kg sildenafil.

Results

The increased malondialdehyde (MDA) levels and myeloperoxidase (MPO) activities and the decreased superoxide dismutase (SOD) activities induced by I/R injury were reduced by treatment with metformin and/or sildenafil. The I/R group had significantly higher JNK, p38 MAPK, Bax, caspase-3, and NF-κB levels, and lower ERK and Bcl-2 levels in the bladder than the sham-operated group; these changes were significantly ameliorated by metformin and/or sildenafil treatment. No differences in the levels of these markers were observed between rats co-administered metformin and sildenafil and those treated with either agent alone.

Conclusions

Metformin and sildenafil protected rat bladder against I/R injury. This effect may be due to the inhibition of ROS production through MAPKs, Bax, and Bcl-2 activation, and the restoration of inflammation through NF-κB inhibition. However, the combination of metformin and sildenafil was no more effective than either agent alone.

Increased DNA strand breaks and neoplastic transformation in human bladder cells treated with pioglitazone

Pioglitazone (PIO), an oral hypoglycemic agent, is used in the treatment of type 2 diabetes. Some studies have suggested that an increased risk of bladder cancer with PIO exposure, while the others reported there is no such relationship. Therefore, it is doubtful whether PIO can increase the risk of bladder cancer. The effects of PIO on DNA damage and/or transformation of human bladder cells are not fully known. We investigated the effects of PIO on cytotoxicity, DNA single and double strand breaks and repair and neoplastic transformation in human bladder cells (hTU1) treated with 10, 20, and 40 μM PIO for 24, 48 and 72 hr. PIO decreased cell viability in a concentration-dependent manner. Increased levels of comet parameters showed that PIO and its metabolites can significantly induce DNA double strand breaks at all concentrations tested. PIO also significantly induced the formation of phosphorylated H2AX and p53 binding protein 1 foci. DNA damage was not repaired in a 24 hr recovery period. PIO can also induce malignant transformation of human bladder cells exhibiting loss of contact inhibition and anchorage independent growth. This is the first study to indicate that PIO can induce DNA damage and malignant transformation, reduce or alter the DNA repair capacity in human bladder cells. From these results, we suggest that patients with diabetes treated with PIO may have an increased risk of bladder cancer.