Are the Protean Effects of Pentoxifylline in the Therapy of Diabetes and Its Complications Still Relevant?

LncRNA SNHG7/miR-181b-5p/TLR4 Activates Inflammation And Promotes Pyroptosis Through NF-κB Signaling in Diabetic Nephropathy

MiR-181b-5p plays a critical role in the pyroptosis and injury of kidney tubular cells in diabetic kidney disease (DKD). The long noncoding RNA (lncRNA) small nucleolar RNA hostgene 7 (SNHG7) has been shown to bind to and inhibit the function of miR-181b-5p. However, the precise role of SNHG7 in DKD remains unclear. To address this, the current study measured the expression levels of SNHG7, miR-181b-5p, and Toll-like receptor 4 (TLR4) using RT-qPCR analysis of renal biopsies from both normal individuals and patients with DKD. An in vitro DKD model was subsequently established by exposing HK-2 cells to high glucose (HG). In both DKD tissues and HG-stimulated HK-2 cells, SNHG7 and TLR4 levels were significantly elevated, while miR-181b-5p levels were markedly reduced. Knockdown of SNHG7 resulted in multiple beneficial effects: it effectively attenuated high glucose-induced lactate dehydrogenase (LDH) leakage, restored cell viability, inhibited the production of inflammatory cytokines tumor necrosis factor alpha (TNF-α), interleukin 18 (IL-18), and interleukin 1β (IL-1β), and suppressed the activation of the nucleotide-binding oligomerization domain (NOD)-like receptor pyrin domain containing 3 (NLRP3)/acysteinyl aspartate-specific proteinase 1 (caspase-1)/gasdermin D (GSDMD) pathway. Mechanistically, SNHG7 functions as a molecular sponge for miR-181b-5p, while miR-181b-5p directly targets TLR4, collectively regulating nuclear factor-kappaB (NF-κB) pathway activation. Moreover, inhibition of miR-181b-5p or up-regulation of TLR4 reversed the protective effects of SNHG7 knockdown. Additionally, co-transfection of a TLR4 over-expression vector with a miR-181b-5p mimic counteracted the effects of miR-181b-5p overexpression on cell viability, LDH leakage, and the expression of inflammatory factors and pyroptosis-related molecules. In summary, SNHG7 acts as a molecular sponge for miR-181b-5p, promoting inflammation and pyroptosis in DKD, which in turn regulates TLR4 expression and the NF-κB signaling pathway.

Evaluation of pharmacokinetics and relative bioavailability of pentoxifylline and its metabolite in beagle dogs following different formulations

A single-oral-dose, two-period cross-over study with a 5-day washout period under fed condition was conducted in six beagle dogs to explore the pharmacokinetic characteristics and relative bioavailability between sustained-release (SR) tablets and enteric-coated (EC) tablets of pentoxifylline (PTX) and its metabolite. The results showed that M5 exhibited the highest exposure level, while M1 demonstrated the lowest in both the SR and EC tablet groups. For PTX and M1, T1/2 were 0.42 and 0.55 h, with tmax of 1.83 and 1.83 h, respectively, in the SR tablet group; in the EC tablet group, T1/2 were 0.38 and 0.47 h, respectively. However, a significantly prolonged absorption process was noted, with tmax values of 5.06 and 5.78 h. In contrast, M5 exhibited distinct pharmacokinetic differences compared to PTX and M1. For the SR tablet group, T1/2 and tmax were recorded at 2.03 and 3.08 h, respectively. In the EC tablet group, T1/2 and tmax were 1.67 and 5.78 h, respectively. With regard to the geometric least squares mean (LSM) of AUC and Cmax for SR tablets and EC tablets, the ratios of SR/EC of PTX, M1 and M5 were 67.62% (90% CI, 50.49%-90.55%), 78.18% (90% CI, 54.15%-112.88%), and 119.11% (90% CI, 99.62%-142.41%), respectively, for AUC(0-t). The ratios were 67.62% (90% CI, 50.50%-90.55%), 78.36% (90% CI, 54.48%-112.72%), and 119.39% (90% CI, 100.03%-142.50%) for AUC(0-∞) and 54.36% (90% CI, 36.63%-80.67%), 58.80% (90% CI, 40.84%-84.66%), and 100.51% (90% CI, 89.50%-112.88%) for Cmax, respectively. The AUC ratio predictions of bioconversion results indicated that there was no significant difference in the bioconversion of M1 between the SR tablets and EC tablets, with conversion rates of 0.37 and 0.36, respectively. In contrast, the conversion rate of M5 demonstrated a significant difference (p < 0.05) between the SR tablets and EC tablets, with the ratio of 3.09 and 1.91, respectively. Furthermore, the EC tablet group demonstrated notable inter-individual differences and irregular drug absorption, following meals. Consequently, the SR tablets appeared to provide a more stable and controllable therapeutic effect in beagle dogs.

The potential for improved outcomes in the prevention and therapy of diabetic kidney disease through 'stacking' of drugs from different classes

Aggressive therapy of diabetic kidney disease (DKD) can not only slow the progression of DKD to renal failure but, if utilized at an early enough stage of DKD, can also stabilize and/or reverse the decline in renal function. The currently recognized standard of therapy for DKD is blockade of the renin-angiotensin system with angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs). However, unless utilized at a very early stage, monotherapy with these drugs in DKD will only prevent or slow the progression of DKD and will neither stabilize nor reverse the progression of DKD to renal decompensation. Recently, the addition of a sodium-glucose cotransporter-2 inhibitor and/or a mineralocorticoid receptor blocker to ACE inhibitors or ARBs has been clearly shown to further decelerate the decline in renal function. The use of glucagon-like peptide-1 (GLP-1) agonists shown promise in decelerating the progression of DKD. Other drugs that may aid in the deceleration the progression of DKD are dipeptidyl peptidase-4 inhibitors, pentoxifylline, statins, and vasodilating beta blockers. Therefore, aggressive therapy with combinations of these drugs (stacking) should improve the preservation of renal function in DKD.

The effect of a methylxanthine vasodilator: pentoxifylline on the treatment of diabetic nephropathy-a meta-analysis

This meta-analysis aimed to comprehensively evaluate the efficacy and safety of pentoxifylline (PTF) in the treatment of diabetic nephropathy (DN) and to offer fresh perspectives and evidence-based references for this condition. Meta-analysis. Relevant randomized controlled trials (RCTs) were searched from PubMed, Embase, Cochrane Library, China Knowledge Network (CNKI), Wanfang, and China Biomedical Literature Database. All trials were screened for compliance with the inclusion and exclusion criteria, and relevant data were extracted after quality evaluation. Eighteen studies with a total of 1280 patients were finally included. Compared to the control group, high sensitivity C-reactive protein (hsCRP) was improved (MD = - 0.23. 95% CI = [- 0.41, - 0.05], P = 0.01); urinary albumin excretion (UAE) rate was reduced (MD = - 16.50, 95% CI = [- 18.87, - 14.13], P<0.00001); the change of serum creatinine (Scr) from baseline was reduced (MD = - 0.05, 95%CI = [- 0.08, - 0.01], P = 0.009); fasting plasma glucose (FPG) was decreased (MD = - 5.66, 95% CI = [- 9.79, - 1.53], P = 0.007); and the improvement of glomerular filtration rate (eGFR) from baseline was increased (MD = 4.38, 95% CI = [3.28, 5.48], P<0.00001) in the treatment group. No significant difference was observed between the two groups concerning systolic blood pressure, diastolic blood pressure, total cholesterol, and triglycerides. And in terms of safety, the use of PTF was relatively safe with some self-limiting adverse events. FPG was decreased by PTF more effectively, but there was no effect of PTF on glycated hemoglobin (HbA1c). PTF could improve hsCRP, decrease UAE and Scr, and raise eGFR in the treatment of DN.

Pentoxifylline inhibits phosgene-induced lung injury via improving hypoxia

Inhalation of high concentrations of phosgene often causes pulmonary edema, which obstructs the airway and causes tissue hypoxia. There is currently no specific antidote. This study was performed to investigate the effect behind pentoxifylline (PTX) treatment for phosgene-induced lung injury in rat models. Rats were exposed to phosgene. The protein levels of hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF), and occludin proteins in lung tissue were determined. The effect of both prophylactic and therapeutic administration of PTX (50 mg/kg and 100 mg/kg) was evaluated. The lung permeability index and HIF-1α protein level increased, the arterial blood oxygenation index (PaO2/FIO2 ratio) and occludin protein level decreased significantly 6 h after phosgene exposure (P < 0.05). PTX exerted protective effects by HIF-1α-VEGF-occludin signaling pathway to some extent. Moreover, prophylactic, but not therapeutic administration of PTX (100 mg/kg), exhibited a significant protective effect. Pretreatment with PTX protected against phosgene-induced lung injury, possibly by inhibiting differential expression of HIF-1α, VEGF, and occludin.

Outcomes of a Pharmacological Protocol with Pentoxifylline and Tocopherol for the Management of Medication-Related Osteonecrosis of the Jaws (MRONJ): A Randomized Study on 202 Osteoporosis Patients

Medication-related osteonecrosis of the jaws (MRONJ) is a challenging situation in clinics. Previous studies have shown that pentoxifylline combined with tocopherol proved to be beneficial in patients with osteoradionecrosis, due to their antioxidant and antifibrotic properties. The aim of this randomized study was to evaluate the effect of pentoxifylline and tocopherol in patients that had developed MRONJ after tooth extractions. The study population consisted of 202 Stage I MRONJ female patients with an average age of 66.4 ± 8.3 years, who were divided into two groups. The test group (n = 108) received a pharmacological protocol with pentoxifylline and tocopherol (2 months pre-operatively and 6 months post-operatively). The control group (n = 94) had sequestrectomy operations without any pharmacological preparation. The main outcomes were clinical healing of the mucosa after 1 month, and clinical and radiographic healing of the bone lesion at 6 months. In the test group all patients had mucosal healing and there was only one relapse within 6 months. In the control group, in 17% of the patients the mucosa did not heal, 71% of the patients relapsed within two months, and 7% developed infectious complications (such as abscess or phlegmon). After 6 months, the control group patients with persisting issues were prescribed pentoxifylline and tocopherol, as in the test group. At a subsequent follow-up, all those patients healed completely. Patients were monitored for a period of 7.8 ± 0.3 years, during which no relapse or additional problems were reported. As a conclusion, pentoxifylline and tocopherol protocol seems to be beneficial in the management of MRONJ patients.

Perfluorooctane sulfonate-induced oxidative stress contributes to pancreatic β-cell apoptosis by inhibiting cyclic adenosine monophosphate pathway: Prevention by pentoxifylline

Endocrine-disrupting chemical perfluorooctane sulfonate (PFOS) acute exposure stimulates insulin secretion from pancreatic β-cells. However, chronic exposure to PFOS on pancreatic β-cells, its role in insulin secretion, and the underlying mechanisms have not been studied. We used rat insulinoma INS-1 and human 1.1b4 islet cells to investigate the chronic effects of PFOS on glucose-stimulated insulin secretion and toxicity implicated in the downregulation of β-cell functionality. Chronic exposure of INS-1 cells or human pancreatic 1.1b4 β-cells to PFOS stimulated the small G-protein RAC1-guanosine triphosphate-dependent nicotinamide adenine dinucleotide phosphate oxidase (NOX2/gp91phox) subunit expression and activation. Upregulated NOX2/gp91phox activation led to elevated reactive oxygen species (ROS) production with a decrease in the cyclic adenosine monophosphate/protein kinase A (cAMP/PKA) pathway in both cell types. Inhibition of cAMP/PKA signaling induces β-cell mitochondrial dysfunction and endoplasmic stress via the loss of PDX1-SERCA2B and glucose-stimulated insulin release. Inhibiting RAC1-NOX2/gp91phox activation or elevating cAMP by pentoxifylline, a Food and Drug Administration-approved phosphodiesterase inhibitor, significantly reduced PFOS-induced ROS production and restored insulin secretory function of pancreatic β-cells. Enhanced secretory function in pentoxifylline-treated cells was associated with increased stability of PDX1-SERCA2B protein levels. Intriguingly, inhibition of cAMP/PKA signaling impaired pentoxifylline-induced insulin secretion caused by the activation of ROS production and mitochondrial dysfunction. Overall, our findings show that PFOS has a new and first-ever direct chronic effect on pancreatic β-cell failure through increased RAC1-NOX2/gp91phox activation and pentoxifylline-induced cAMP/PKA signaling, which inhibits PFOS-mediated mitochondrial dysfunction.

DRONet: effectiveness-driven drug repositioning framework using network embedding and ranking learning

As one of the most vital methods in drug development, drug repositioning emphasizes further analysis and research of approved drugs based on the existing large amount of clinical and experimental data to identify new indications of drugs. However, the existing drug repositioning methods didn't achieve enough prediction performance, and these methods do not consider the effectiveness information of drugs, which make it difficult to obtain reliable and valuable results. In this study, we proposed a drug repositioning framework termed DRONet, which make full use of effectiveness comparative relationships (ECR) among drugs as prior information by combining network embedding and ranking learning. We utilized network embedding methods to learn the deep features of drugs from a heterogeneous drug-disease network, and constructed a high-quality drug-indication data set including effectiveness-based drug contrast relationships. The embedding features and ECR of drugs are combined effectively through a designed ranking learning model to prioritize candidate drugs. Comprehensive experiments show that DRONet has higher prediction accuracy (improving 87.4% on Hit@1 and 37.9% on mean reciprocal rank) than state of the art. The case analysis also demonstrates high reliability of predicted results, which has potential to guide clinical drug development.

Repurposing drugs for highly prevalent diseases: pentoxifylline, an old drug and a new opportunity for diabetic kidney disease

Diabetic kidney disease is one of the most frequent complications in patients with diabetes and constitutes a major cause of end-stage kidney disease. The prevalence of diabetic kidney disease continues to increase as a result of the growing epidemic of diabetes and obesity. Therefore, there is mounting urgency to design and optimize novel strategies and drugs that delay the progression of this pathology and contain this trend. The new approaches should go beyond the current therapy focussed on the control of traditional risk factors such as hyperglycaemia and hypertension. In this scenario, drug repurposing constitutes an economic and feasible approach based on the discovery of useful activities for old drugs. Pentoxifylline is a nonselective phosphodiesterase inhibitor currently indicated for peripheral artery disease. Clinical trials and meta-analyses have shown renoprotection secondary to anti-inflammatory and antifibrotic effects in diabetic patients treated with this old known drug, which makes pentoxifylline a candidate for repurposing in diabetic kidney disease.

Combine and Conquer: With Type 2 Diabetes Polypharmacy Is Essential Not Only to Achieve Glycemic Control but Also to Treat the Comorbidities and Stabilize or Slow the Advancement of Diabetic Nephropathy

The concept of polypharmacy in the type 2 diabetic patient is both historic and redundant. A combination of three or more medications usually at doses which are less than those utilized for monotherapy is efficacious not only in the therapy of hyperglycemia but also in the therapy of the comorbidities of hypertension and hyperlipidemia. In addition, multiple medications are now accepted as being necessary to reduce albuminuria and decelerate the decline in renal function in the patient with diabetic nephropathy.