Inhibition effect of curcumin on TNF-α and MMP-13 expression induced by advanced glycation end products in chondrocytes

Does Chronic Pancreatitis in Growing Pigs Lead to Articular Cartilage Degradation and Alterations in Subchondral Bone?

Chronic pancreatitis (CP), a progressive inflammatory disease, poses diagnostic challenges due to its initially asymptomatic nature. While CP's impact on exocrine and endocrine functions is well-recognized, its potential influence on other body systems, particularly in young individuals, remains underexplored. This study investigates the hypothesis that CP in growing pigs leads to alterations in articular cartilage and subchondral bone, potentially contributing to osteoarthritis (OA) development. Utilizing a pig model of cerulein-induced CP, we examined the structural and compositional changes in subchondral bone, articular cartilage, and synovial fluid. Histological analyses, including Picrosirius Red and Safranin-O staining, were employed alongside immuno-histochemistry and Western blotting techniques. Our findings reveal significant changes in the subchondral bone, including reduced bone volume and alterations in collagen fiber composition. Articular cartilage in CP pigs exhibited decreased proteoglycan content and alterations in key proteins such as MMP-13 and TGF-β1, indicative of early cartilage degradation. These changes suggest a link between CP and musculoskeletal alterations, underscoring the need for further research into CP's systemic effects. Our study provides foundational insights into the relationship between CP and skeletal health, potentially guiding future pediatric healthcare strategies for early CP diagnosis and management.

Precision Cut Lung Slices as a Preclinical Model for Non-Small Cell Lung Cancer Chemoprevention

Lung cancer chemoprevention is critical to addressing cancer burden in high-risk populations. Chemoprevention clinical trials rely on data from preclinical models; however, in vivo studies have high financial, technical, and staffing requirements. Precision cut lung slices (PCLS) provide an ex vivo model that maintains the structure and function of native tissues. This model can be used for mechanistic investigations and drug screenings and reduces the number of animals and time required to test hypotheses compared with in vivo studies. We tested the use of PCLS for chemoprevention studies, demonstrating recapitulation of in vivo models. Treatment of PCLS with the PPARγ agonizing chemoprevention agent iloprost produced similar effects on gene expression and downstream signaling as in vivo models. This occurred in both wild-type tissue and Frizzled 9 knockout tissue, a transmembrane receptor required for iloprost's preventive activity. We explored new areas of iloprost mechanisms by measuring immune and inflammation markers in PCLS tissue and media, and immune cell presence with immunofluorescence. To demonstrate the potential for drug screening, we treated PCLS with additional lung cancer chemoprevention agents and confirmed activity markers in culture. PCLS offers an intermediate step for chemoprevention research between in vitro and in vivo models that can facilitate drug screening prior to in vivo studies and support mechanistic studies with more relevant tissue environments and functions than in vitro models.

PREVENTION RELEVANCE

PCLS could be a new model for premalignancy and chemoprevention research, and this work evaluates the model with tissue from prevention-relevant genetic and carcinogen exposed in vivo mouse models, in addition to evaluating chemoprevention agents.

Nutraceuticals and COVID-19: A mechanistic approach toward attenuating the disease complications

Nutraceuticals have emerged as potential compounds to attenuate the COVID-19 complications. Precisely, these food additives strengthen the overall COVID treatment and enhance the immunity of a person. Such compounds have been used at a large scale, in almost every household due to their better affordability and easy access. Therefore, current research is focused on developing newer advanced formulations from potential drug candidates including nutraceuticals with desirable properties viz, affordability, ease of availability, ease of administration, stability under room temperature, and potentially longer shelf-lives. As such, various nutraceutical-based products such as compounds could be promising agents for effectively managing COVID-19 symptoms and complications. Most importantly, regular consumption of such nutraceuticals has been shown to boost the immune system and prevent viral infections. Nutraceuticals such as vitamins, amino acids, flavonoids like curcumin, and probiotics have been studied for their role in the prevention of COVID-19 symptoms such as fever, pain, malaise, and dry cough. In this review, we have critically reviewed the potential of various nutraceutical-based therapeutics for the management of COVID-19. We searched the information relevant to our topic from search engines such as PubMed and Scopus using COVID-19, nutraceuticals, probiotics, and vitamins as a keyword. Any scientific literature published in a language other than English was excluded. PRACTICAL APPLICATIONS: Nutraceuticals possess both nutritional values and medicinal properties. They can aid in the prevention and treatment of diseases, as well as promote physical health and the immune system, normalizing body functions, and improving longevity. Recently, nutraceuticals such as probiotics, vitamins, polyunsaturated fatty acids, trace minerals, and medicinal plants have attracted considerable attention and are widely regarded as potential alternatives to current therapeutic options for the effective management of various diseases, including COVID-19.

Phytochemicals as Potential Inhibitors of Advanced Glycation End Products: Health Aspects and Patent Survey

BACKGROUND

The glycation of proteins and lipids synthesizes the advanced glycation end products (AGEs), i.e., substances that irreversibly damage macromolecules present in tissues and organs, which contribute to the impairment of biological functions. For instance, the accumulation of AGEs induces oxidative stress, the inflammatory responses, and consequently the on set/worsening of diseases, including obesity, asthma, cognitive impairment, and cancer. There is a current demand on natural and low-cost sources of anti-AGE agents. As a result, food phytochemicals presented promising results to inhibit glycation and consequently, the formation of AGEs.

OBJECTIVE

Here we describe how the AGEs are present in food via Maillard reaction and in organs via natural aging, as well as the effects of AGEs on the worsening of diseases. Also we described the methods used to detect AGEs in samples, and the current findings on the use of phytochemicals (phenolic compounds, phytosterols, carotenoids, terpenes and vitamins) as natural therapeuticals to inhibit health damages via inhibition of AGEs in vitro and in vivo.

METHODS

This manuscript reviewed publications available in the PubMed and Science Direct databases dated from the last 20 years on the uses of phytochemicals for the inhibition of AGEs. Recent patents on the use of anti-AGEs drugs were reviewed with the use of Google Advanced Patents database.

RESULTS AND DISCUSSION

There is no consensus about which concentration of AGEs in blood serum should not be hazardous to the health of individuals. Food phytochemicals derived from agroindustry wastes, including peanut skins, and the bagasses derived from citrus and grapes are promising anti-AGEs agents via scavenging of free radicals, metal ions, the suppression of metabolic pathways that induces inflammation, the activation of pathways that promote antioxidant defense, and the blocking of AGE connection with the receptor for advanced glycation endproducts (RAGE).

CONCLUSION

Phytochemicals derived from agroindustry are promising anti-AGEs, which can be included to replace synthetic drugs to inhibit AGE formation, and consequently to act as therapeutical strategy to prevent and treat diseases caused by AGEs, including diabetes, ovarian cancer, osteoporosis, and Alzheimer's disease.

Resveratrol and Curcumin Attenuate Ex Vivo Sugar-Induced Cartilage Glycation, Stiffening, Senescence, and Degeneration

OBJECTIVE

Advanced glycation end-product (AGE) accumulation is implicated in osteoarthritis (OA) pathogenesis in aging and diabetic populations. Here, we develop a representative nonenzymatic glycation-induced OA cartilage explant culture model and investigate the effectiveness of resveratrol, curcumin, and eugenol in inhibiting AGEs and the structural and biological hallmarks of cartilage degeneration.

DESIGN

Bovine cartilage explants were treated with AGE-bovine serum albumin, threose, and ribose to determine the optimal conditions that induce physiological levels of AGEs while maintaining chondrocyte viability. AGE crosslinks, tissue stiffness, cell viability, metabolism and senescence, nitrite release and loss of glycosaminoglycans were assessed. Explants were cotreated with resveratrol, curcumin, or eugenol to evaluate their anti-AGE properties. Blind docking analysis was conducted to estimate binding energies of drugs with collagen II.

RESULTS

Treatment with 100 mM ribose significantly increased AGE crosslink formation and tissue stiffness, resulting in reduced chondrocyte metabolism and enhanced senescence. Blind docking analysis revealed stronger binding energies of both resveratrol and curcumin than ribose, with glycation sites along a human collagen II fragment, indicating their increased likelihood of competitively inhibiting ribose activity. Resveratrol and curcumin, but not eugenol, successfully inhibited AGE crosslink formation and its associated downstream biological response.

CONCLUSIONS

We establish a cartilage explant model of OA that recapitulates several aspects of aged human cartilage. We find that resveratrol and curcumin are effective anti-AGE therapeutics with the potential to decelerate age-related and diabetes-induced OA. This in vitro nonenzymatic glycation-induced model provides a tool for screening OA drugs, to simultaneously evaluate AGE-induced biological and mechanical changes.

The benefit of combining curcumin, bromelain and harpagophytum to reduce inflammation in osteoarthritic synovial cells

BACKGROUND

Osteoarthritis (OA) is the most common form of arthritis, affecting millions of people worldwide and characterised by joint pain and inflammation. It is a complex disease involving inflammatory factors and affecting the whole joint, including the synovial membrane. Since drug combination is widely used to treat chronic inflammatory diseases, a similar strategy of designing plant-derived natural products to reduce inflammation in OA joints may be of interest. In this study, we characterised the response of OA synovial cells to lipopolysaccharide (LPS) and investigated the biological action of the combination of curcumin, bromelain and harpagophytum in this original in vitro model of osteoarthritis.

METHODS

Firstly, human synovial cells from OA patients were stimulated with LPS and proteomic analysis was performed. Bioinformatics analyses were performed using Cytoscape App and SkeletalVis databases. Additionally, cells were treated with curcumin, bromelain and harpagophytum alone or with the three vegetal compounds together. The gene expression involved in inflammation, pain or catabolism was determined by RT-PCR. The release of the encoded proteins by these genes and of prostaglandin E2 (PGE2) were also assayed by ELISA.

RESULTS

Proteomic analysis demonstrated that LPS induces the expression of numerous proteins involved in the OA process in human OA synovial cells. In particular, it stimulates inflammation through the production of pro-inflammatory cytokines (Interleukin-6, IL-6), catabolism through an increase of metalloproteases (MMP-1, MMP-3, MMP-13), and the production of pain-mediating neurotrophins (Nerve Growth Factor, NGF). These increases were observed in terms of mRNA levels and protein release. LPS also increases the amount of PGE2, another inflammation and pain mediator. At the doses tested, vegetal extracts had little effect: only curcumin slightly counteracted the effects of LPS on NGF and MMP-13 mRNA, and PGE2, IL-6 and MMP-13 release. In contrast, the combination of curcumin with bromelain and harpagophytum reversed lots of effects of LPS in human OA synovial cells. It significantly reduced the gene expression and/or the release of proteins involved in catabolism (MMP-3 and -13), inflammation (IL-6) and pain (PGE2 and NGF).

CONCLUSION

We have shown that the stimulation of human OA synovial cells with LPS can induce protein changes similar to inflamed OA synovial tissues. In addition, using this model, we demonstrated that the combination of three vegetal compounds, namely curcumin, bromelain and harpagophytum, have anti-inflammatory and anti-catabolic effects in synovial cells and may thus reduce OA progression and related pain.

Role of Advanced Glycation End-Products and Other Ligands for AGE Receptors in Thyroid Cancer Progression

To date, thyroid cancers (TCs) remain a clinical challenge owing to their heterogeneous nature. The etiopathology of TCs is associated not only with genetic mutations or chromosomal rearrangements, but also non-genetic factors, such as oxidative-, nitrosative-, and carbonyl stress-related alterations in tumor environment. These factors, through leading to the activation of intracellular signaling pathways, induce tumor tissue proliferation. Interestingly, the incidence of TCs is often coexistent with various simultaneous mutations. Advanced glycation end-products (AGEs), their precursors and receptors (RAGEs), and other ligands for RAGEs are reported to have significant influence on carcinogenesis and TCs progression, inducing gene mutations, disturbances in histone methylation, and disorders in important carcinogenesis-related pathways, such as PI₃K/AKT/NF-kB, p21/MEK/MPAK, or JAK/STAT, RAS/ERK/p53, which induce synthesis of interleukins, growth factors, and cytokines, thus influencing metastasis, angiogenesis, and cancer proliferation. Precursors of AGE (such as methylglyoxal (MG)) and selected ligands for RAGEs: AS1004, AS1008, and HMGB1 may, in the future, become potential targets for TCs treatment, as low MG concentration is associated with less aggressive anaplastic thyroid cancer, whereas the administration of anti-RAGE antibodies inhibits the progression of papillary thyroid cancer and anaplastic thyroid cancer. This review is aimed at collecting the information on the role of compounds, engaged in glycation process, in the pathogenesis of TCs. Moreover, the utility of these compounds in the diagnosis and treatment of TCs is thoroughly discussed. Understanding the mechanism of action of these compounds on TCs pathogenesis and progression may potentially be the grounds for the development of new treatment strategies, aiming at quality-of-life improvements.

Topical nanocarriers for management of Rheumatoid Arthritis: A review

Rheumatoid arthritis (RA) is a systemic autoimmune disease manifested by chronic joint inflammation leading to severe disability and premature mortality. With a global prevalence of about 0.3%-1% RA is 3-5 times more prevalent in women than in men. There is no known cure for RA; the ultimate goal for treatment of RA is to provide symptomatic relief. The treatment regimen for RA involves frequent drug administration and high doses of NSAIDs such as indomethacin, diclofenac, ibuprofen, celecoxib, etorcoxib. These potent drugs often have off target effects which drastically decreases patient compliance. Moreover, conventional non-steroidal anti-inflammatory have many formulation challenges like low solubility and permeability, poor bioavailability, degradation by gastrointestinal enzymes, food interactions and toxicity. To overcome these barriers, researchers have turned to topical route of drug administration, which has superior patience compliance and they also bypass the first past effect experienced with conventional oral administration. Furthermore, to enhance the permeation of drug through the layers of the skin and reach the site of inflammation, nanosized carriers have been designed such as liposomes, nanoemulsions, niosomes, ethosomes, solid lipid nanoparticles and transferosomes. These drug delivery systems are non-toxic and have high drug encapsulation efficiency and they also provide sustained release of drug. This review discusses the effect of formulation composition on the physiochemical properties of these nanocarriers in terms of particle size, surface charge, drug entrapment and also drug release profile thus providing a landscape of topically used nanoformulations for symptomatic treatment of RA.

Effectiveness of Curcuma longa extract versus placebo for the treatment of knee osteoarthritis: A systematic review and meta-analysis of randomized controlled trials

The aim of this systematic review was to evaluate the efficacy and safety of all types of Curcuma longa extract versus placebo for knee osteoarthritis (OA) treatment. The research was conducted by using the databases of PubMed, Embase, Scopus, and Cochrane Library through April 2021. Randomized controlled trials (RCTs) that compared the effect of Curcuma longa extract with placebo for patients with knee OA were considered eligible. The pooled results were expressed as mean differences or relative risks with 95% confidence intervals. A total of 10 RCTs with 783 patients were eligible for this meta-analysis. The pooled analysis showed that Curcuma longa extract was associated with significantly better pain relief and functional improvement compared with placebo for knee OA. Moreover, the smallest effect sizes of VAS for pain and WOMAC total score exceeded the minimum clinically important differences (MCIDs). Current evidence indicates that, compared with placebo, Curcuma longa extract has more benefit in pain relief and functional improvement for symptomatic knee OA. However, considering the potential heterogeneity in the included studies, more future high-quality RCTs with large sample sizes are necessary to confirm the benefits of Curcuma longa extract on knee OA.

Curcumin and Freshwater Clam Extracts Alleviate the Progression of Osteoarthritis by Reducing Synovial Inflammation and Allowing Cartilage Regeneration

Osteoarthritis (OA) is a common degenerative disorder and is accompanied by numerous pain symptoms. With increased age, individuals develop a chronic inflammatory status, and pro-inflammatory cytokines as well as mediators contribute to the progression of OA. However, no desirable remedies have been completely able to inhibit OA progression or safely provide effective symptomatic relief. Natural component extracts or dietary-derived compounds are widely used for anti-inflammatory diseases. Curcumin and freshwater clam extract (FCE) have been proven as functional foods that are able to regulate immune systems. This study demonstrated that curcumin and FCE had synergistic effects on alleviating the progression of OA by assuaging inflammation and repairing the cartilage within the joints. After consumption of curcumin and FCE, the severity of synovitis was quantified by the infrapatellar fat pad inflammation scoring system and the Osteoarthritis Research Society International (OARSI) scoring system. Significant improvement and articular cartilage regeneration were noted. Moreover, once the inflammation within the joints was reduced, the animals redistributed their body weight on the OA-induced hindlimb. In summary, curcumin and FCE possess desirable anti-inflammatory and repair functions, suggesting their potential as alternative remedies in the management of OA or other inflammatory diseases.

Efficacy of Curcumin Gel on Zinc, Magnesium, Copper, IL-1β, and TNF-α in Chronic Periodontitis Patients

Curcumin exhibits antibacterial, antioxidant, and anti-inflammatory effects and has been suggested as a treatment for inflammatory diseases. The study is aimed at evaluating the effect of curcumin gel on serum levels of micronutrients (zinc, copper, and magnesium) and proinflammatory cytokines (IL-1β and TNF-α) in chronic periodontitis patients. Ninety subjects with an age of 25-54 were included in this study. From the total number, 30 subjects with healthy periodontium (control group) (mean age = 37.30 ± 7.08) were employed for the sole purpose of obtaining the normal mean values of clinical, chemical, and immunological parameters, and 60 with chronic periodontitis (mean age = 36.73 ± 6.22) were divided randomly into 2 groups, of which each group included 30 subjects. Group A received scaling and root planing SRP and curcumin gel injection covered by Coe pack for 7 days, and group B received SRP alone covered by Coe pack. Clinical parameters (plaque index, gingival index, bleeding on probing, pocket depth, and clinical attachment loss measurements) and blood samples were collected before and after 1 month of treatment to measure serum levels of zinc, copper, magnesium, IL-1β, and TNF-α. The results showed significant micronutrient alteration and increase of proinflammatory cytokines in the chronic periodontitis group as compared to healthy control (P ≤ 0.05), and curcumin gel had a significant effect on the reduction of IL-1β, TNF-α, copper, and clinical parameters (P ≤ 0.05) and increase of zinc and magnesium levels after 1 month as compared to baseline (P ≤ 0.05), nearly the same pattern for group B but with nonsignificant differences for Zn (P > 0.05). In conclusion, curcumin gel resulted in a more significant reduction in clinical parameters, inflammatory mediators, and copper and increase of zinc and magnesium levels as compared to SRP alone.

Overview of MMP-13 as a Promising Target for the Treatment of Osteoarthritis

Osteoarthritis (OA) is a common degenerative disease characterized by the destruction of articular cartilage and chronic inflammation of surrounding tissues. Matrix metalloproteinase-13 (MMP-13) is the primary MMP involved in cartilage degradation through its particular ability to cleave type II collagen. Hence, it is an attractive target for the treatment of OA. However, the detailed molecular mechanisms of OA initiation and progression remain elusive, and, currently, there are no interventions available to restore degraded cartilage. This review fully illustrates the involvement of MMP-13 in the initiation and progression of OA through the regulation of MMP-13 activity at the molecular and epigenetic levels, as well as the strategies that have been employed against MMP-13. The aim of this review is to identify MMP-13 as an attractive target for inhibitor development in the treatment of OA.

Are Nutraceuticals Beneficial in Chronic Kidney Disease?

Chronic kidney disease (CKD) is a worldwide health problem in which prevalence is constantly rising. The pathophysiology of CKD is complicated and has not been fully resolved. However, elevated oxidative stress is considered to play a vital role in the development of this disease. CKD is also thought to be an inflammatory disorder in which uremic toxins participate in the development of the inflammatory milieu. A healthy, balanced diet supports the maintenance of a good health status as it helps to reduce the risk of the development of chronic diseases, including chronic kidney disease, diabetes mellitus, and hypertension. Numerous studies have demonstrated that functional molecules and nutrients, including fatty acids and fiber as well as nutraceuticals such as curcumin, steviol glycosides, and resveratrol not only exert beneficial effects on pro-inflammatory and anti-inflammatory pathways but also on gut mucosa. Nutraceuticals have attracted great interest recently due to their potential favorable physiological effects on the human body and their safety. This review presents some nutraceuticals in which consumption could exert a beneficial impact on the development and progression of renal disease as well cardiovascular disease.

Curcumin ameliorates IL-1β-induced apoptosis by activating autophagy and inhibiting the NF-κB signaling pathway in rat primary articular chondrocytes

Articular cartilage damage and chondrocyte apoptosis are common features of rheumatoid arthritis and osteoarthritis. Recently, curcumin has been reported to exhibit protective effects on degeneration in articular cartilage diseases. However, the effects and mechanisms of curcumin on articular chondrocyte injury remain to be elucidated. The aim of the present study is to investigate the chondroprotective mechanisms of curcumin on interleukin-1β (IL-1β)-induced chondrocyte apoptosis in vitro. The results revealed that IL-1β decreased cell viability and induced apoptosis in primary articular chondrocytes. Curcumin pretreatment reduced IL-1β-induced articular chondrocyte apoptosis. In addition, treatment with curcumin increased autophagy in articular chondrocytes and protected against IL-1β-induced apoptosis. The curcumin-mediated protection against IL-1β induced apoptosis was abolished when cells were treated with the autophagy inhibitor 3-methyladenine or transfected with Beclin-1 small interfering RNA. Furthermore, IL-1β stimulation significantly increased the phosphorylation levels of nuclear factor (NF)-κB p65 and glycogen synthase kinase-3β, and decreased the phosphorylation levels of β-catenin in articular chondrocytes, and these alterations to the phosphorylation levels were partly reversed by treatment with curcumin. Dual-luciferase and electrophoretic mobility shift assays demonstrated that IL-1β increased NF-κB p65 promoter activity in chondrocytes, and this was also reversed by curcumin. Pretreatment with the NF-κB inhibitor pyrrolidine dithiocarbamate enhanced the protective effects of curcumin on chondrocyte apoptosis, but Wnt/β-catenin inhibitor, XAV-939, did not exhibit this effect. Molecular docking and dynamic simulation studies results showed that curcumin could bound to RelA (p65) protein. These results indicate that curcumin may suppress IL-1β-induced chondrocyte apoptosis through activating autophagy and restraining NF-κB signaling pathway.

Nutraceutical Activity in Osteoarthritis Biology: A Focus on the Nutrigenomic Role

Osteoarthritis (OA) is a disease associated to age or conditions that precipitate aging of articular cartilage, a post-mitotic tissue that remains functional until the failure of major homeostatic mechanisms. OA severely impacts the national health system costs and patients' quality of life because of pain and disability. It is a whole-joint disease sustained by inflammatory and oxidative signaling pathways and marked epigenetic changes responsible for catabolism of the cartilage extracellular matrix. OA usually progresses until its severity requires joint arthroplasty. To delay this progression and to improve symptoms, a wide range of naturally derived compounds have been proposed and are summarized in this review. Preclinical in vitro and in vivo studies have provided proof of principle that many of these nutraceuticals are able to exert pleiotropic and synergistic effects and effectively counteract OA pathogenesis by exerting both anti-inflammatory and antioxidant activities and by tuning major OA-related signaling pathways. The latter are the basis for the nutrigenomic role played by some of these compounds, given the marked changes in the transcriptome, miRNome, and methylome. Ongoing and future clinical trials will hopefully confirm the disease-modifying ability of these bioactive molecules in OA patients.

Evaluation of the articular cartilage in the knees of rats with induced arthritis treated with curcumin

This study was designed to evaluate the anti-inflammatory effects of a curcumin treatment on the knee of rats with induced osteoarthritis. Fifteen adult rats were used and divided in three groups: the osteoarthritis group (OAG), control group (CG-without induction of osteoarthritis), and curcumin-treated osteoarthritis group (COAG). Osteoarthritis was induced in the right knee of rats in the OAG and COAG by administering an intra-articular injection of 1 mg of zymosan. Fourteen days after induction, 50 mg/kg curcumin was administered by gavage daily for 60 days to the COAG. After the treatment period, rats from all groups were euthanized. Medial femoral condyles were collected for light microscopy and immunohistochemical staining. The expression of SOX-5, IHH, MMP-8, MMP-13, and collagen 2 (Col2) was analyzed. The COAG exhibited an increase in the number of chondrocytes in the surface and middle layers compared with that of the OAG and CG, respectively. The COAG also showed a decrease in the thicknesses of the middle and deep layers compared with those of the OAG, and an increase in Col2 expression was observed in all articular layers (surface, middle, and deep) in the COAG compared with that in the OAG. SOX-5 expression was increased in the surface and deep layers of the COAG compared with those in the OAG and CG. Based on the results of this study, the curcumin treatment appeared to exert a protective effect on cartilage, as it did not result in an increase in cartilage thickness or in MMP-8 and MMP-13 expression but led to increased IHH, Col2, and SOX-5 expression and the number of chondrocytes.

Involvement of TLR4 in the protective effect of intra-articular administration of curcumin on rat experimental osteoarthritis

PURPOSE

In view of the principal role of Toll-like receptor 4 (TLR4) in mediating sterile inflammatory response contributing to osteoarthritis (OA) pathogenesis, we used lipopolysaccharide (LPS), a known TLR4 activator, to clarify whether modulation of TLR4 contributed to the protective actions of intra-articular administration of curcumin in a classical rat OA model surgically induced by anterior cruciate ligament transection (ACLT).

METHODS

The rats underwent ACLT and received 50μl of curcumin at the concentration of 1 mg mL-1 and 10 μg LPS by intra-articular injection once a week for 8 weeks. Morphological changes of the cartilage and synovial tissues were observed. Apoptotic chondrocytes were detected using TUNEL assay. The concentrations of IL-1β and TNF-ɑ in synovial fluid were determined using ELISA kits. The mRNA and protein expression levels of TLR4 and NF-κB p65 were detected by real-time PCR and Western blotting, respectively.

RESULTS

Intra-articular administration of curcumin significantly improved articular cartilage injury, suppressed synovial inflammation and down-regulated the overexpression of TLR4 and its downstream NF-κB caused by LPS-induced TLR4 activation in rat osteoarthritic knees.

CONCLUSION

The data suggested that the inhibition of TLR4 signal might be an important mechanism underlying a protective effect of local curcumin administration on OA.

Evaluation of the efficacy and safety of Capsule Longvida® Optimized Curcumin (solid lipid curcumin particles) in knee osteoarthritis: a pilot clinical study

Purpose: Osteoarthritis is the single most common cause of disability in older adults with an estimated 10% to 15% prevalence in individuals above 60 years. The contemporary medications include nonsteroidal anti-inflammatory drugs acetaminophen, cyclooxygenase-2 inhibitors, and surgical interventions. In view of safety issues regarding their longterm use, necessitating search for effective and safe alternatives, we evaluated Capsule Longvida^® Optimized Curcumin prepared using solid lipid curcumin particles (SLCP) technology in patients with knee osteoarthritis.

Patients and methods: Eligible patients fulfilling American College of Rheumatology Criteria were randomized to SLCP group (400 mg twice daily delivering 80 mg of curcumin per capsule) or Ibuprofen with placebo group (400 mg each once daily) for 90 days. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the Visual Analog Scale (VAS) were used for clinical assessment of knee pain and function. Degree of knee flexion and swelling were also noted. Blood biochemistry included hemogram, blood urea, creatinine, Random blood sugar and inflammatory markers viz. PGE2, TNF α, IL6, IL1β and LTB4 while urine examination included degenerative marker CTX II. The parametric data was analyzed using unpaired t test while non-parametric data was analyzed using Friedman’s test or Mann Whitney t test as applicable. A level of p<0.05 was considered as statistically significant.

Results: Out of 50 recruitments, 25 from the Ibuprofen group and 17 from the SLCP group completed the study with significant improvements in VAS and WOMAC scores indicating comparable efficacy of SLCP in alleviating pain with Ibuprofen. None of the markers displayed significant changes. Except one withdrawal in the study group due to rash and itching, the study drug was found safe.

Conclusions: SLCP in a dose of 160 mg daily was found to be effective and safe in alleviating symptoms in patients suffering from knee osteoarthritis when administered for 90 days.

Therapeutic potential of hyaluronic acid/chitosan nanoparticles for the delivery of curcuminoid in knee osteoarthritis and an in vitro evaluation in chondrocytes

Knee osteoarthritis (OA) is the main cause of leg pain in middle-aged and elderly individuals. Hyaluronic acid (HA), as well as curcuminoid, has been used in the treatment of knee OA. In the present study, HA/chitosan nanoparticles (CNPs) were prepared for the delivery of curcuminoid, in order to investigate whether HA and curcuminoid can act synergistically as a better treatment option. The knee OA model was established by the Hulth method, and a knee OA chondrocyte model was constructed by the co-induction of interleukin-1β and tumor necrosis factor (TNF)-α. The drug loading capacity of HA/CNP for the delivery of curcuminoid was measured by an ultraviolet assay, and the cytotoxicity to chondrocytes was measured by an MTT assay. Collagen II was detected by immunofluorescence, and the expression levels of nuclear factor (NF)-κB and inflammation-related genes in cartilage tissue and chondrocytes were detected. Chondrocyte proliferation was determined by an EdU assay, and chondrocyte apoptosis was determined by flow cytometry. The Mankin pathological score of the Outerbridge classification was obtained. The results demonstrated that the optimum drug loading capacity of HA/CNP for the delivery of curcuminoid was 38.44%, with a good sustained release function. HA/CNP treatment resulted in inhibition of the NF-κB pathway, as well as the expression of matrix metalloproteinase (MMP)-1 and MMP-13, but it increased collagen II expression. HA/CNP for the delivery of curcuminoid significantly decreased the Outerbridge classification and Mankin pathological scores to close to normal until the 4th week. Furthermore, it was also observed that all the effects of HA/CNP on the delivery of curcuminoid were more prominent compared with the effects of HA or curcuminoid treatment individually. Taken together, these findings demonstrated that HA/CNP for the delivery of curcuminoid may suppress inflammation and chondrocyte apoptosis in knee OA via repression of the NF-κB pathway.

Curcumin Prevents Osteoarthritis by Inhibiting the Activation of Inflammasome NLRP3

Curcumin has shown protective potential on osteoarthritis. However, its effect on treatment of osteoarthritis remains elusive so far. This study aimed to determine whether curcumin could ameliorate osteoarthritis in vivo and the underline mechanisms. The mice subjected to destabilization of the medial meniscus (DMM) surgery were administered curcumin. Cartilage integrity was evaluated by immunohistological staining. Expression levels of inflammatory cytokines from mice arthrodial cartilage were detected. THP-1 cells were primed by lipopolysaccharide (LPS)/ATP to induce inflammation, followed by the addition of curcumin. The expression of proinflammatory cytokines was also detected. Moreover, the expression of pro-caspase-1, cleaved caspase-1, and NLRP3 inflammasome was examined. Administration of curcumin significantly reduced osteoarthritis disease progression in DMM model of osteoarthritis. Curcumin suppressed mRNA expression of proinflammatory mediators in arthrodial cartilage of mice subjected to surgery. In LPS- and ATP-induced THP-1 macrophage cells, curcumin significantly suppressed the expression of interleukin 1 beta (IL-1β) and tumor necrosis factor alpha (TNF-α) at both RNA and protein levels. Compared to vehicle-treated controls, curcumin also showed remarkably increased pro-caspase-1 and decreased cleaved caspase-1. This study provides the first evidence that curcumin exerts protection on osteoarthritis by inhibition to the release of inflammasome NLRP3, leading to the downregulation of inflammatory cytokines.

Curcumin protects rabbit articular chondrocytes against sodium nitroprusside-induced apoptosis in vitro

The preventive and therapeutic effects of curcumin on degeneration of articular (joint) cartilage diseases have rarely been investigated. In the present study, the protective effects of curcumin against sodium nitroprusside (SNP)-induced chondrocyte apoptosis were evaluated and the underlying molecular mechanisms were elucidated. Curcumin was used to as a co-treatment with SNP in chondrocytes, and changes occurring in the cells were observed and evaluated. It was shown using a cell counting kit-8 (CCK-8) assay that curcumin protected the viability of chondrocytes against SNP damage. NO (nitric oxide) from SNP could be scavenged by curcumin. Flow cytometry and Hoechst 33342 staining showed that curcumin not only inhibited the cell apoptosis in a concentration-dependent pattern but also ameliorated the SNP-induced nuclear chromatin damage and reduction of the mitochondrial membrane potential in chondrocytes. In SNP-treated chondrocytes, curcumin downregulated the expression of Bax and cleaved caspase-3 but upregulated the expression of Bcl-2, as shown by western blot. Meanwhile, curcumin administration also protected extracellular matrix (ECM) synthesis and prevented its degradation. Taken together, these results support the hypothesis that curcumin exerts its protective effect on chondrocytes against SNP-induced apoptosis, at least partly, via blocking the mitochondrial-dependent apoptotic pathway and maintaining the metabolic balance of ECM. Thus, curcumin may be a potential candidate to be used as a unique biological agent for the prevent and treatment of osteoarthritis (OA).

Nutraceuticals and osteoarthritis pain

Arthritis is a chronic disease of joints. It is highly prevalent, particularly in the elderly, and is commonly associated with pain that interferes with quality of life. Because of its chronic nature, pharmacological approaches to pain relief and joint repair must be safe for long term use, a quality many current therapies lack. Nutraceuticals refer to compounds or materials that can function as nutrition and exert a potential therapeutic effect, including the relief of pain, such as pain related to arthritis, of which osteoarthritis (OA) is the most common form. Of interest, nutraceuticals have recently been shown to have potential in relieving OA pain in human clinical trials. Emerging evidence indicates nutraceuticals may represent promising alternatives for the relief of OA pain. In this paper, we will overview OA pain and the use of nutraceuticals in OA pain management, focusing on those that have been evaluated by clinical trials. Furthermore, we discuss the biologic and pharmacologic actions underlying the nutraceutical effects on pain relief based on the potential active ingredients identified from traditional nutraceuticals in OA pain management and their potential for drug development. The review concludes by sharing our viewpoints that future studies should prioritize elucidating the mechanisms of action of nutraceuticals in OA and developing nutraceuticals that not only relieve OA pain, but also mitigate OA pathology.

Oxidative stress in inflammatory cells of patient with rheumatoid arthritis: clinical efficacy of dietary antioxidants

Rheumatoid arthritis (RA) is an autoimmune disease responsible for significant human morbidity in modern life. However, oxidative stress is one of the key markers for determining pathophysiology of patients with RA. The interaction between cellular immune system and body's endogenous and/or exogenous antigens produce reactive oxygen species (ROS) and reactive nitrogen species (RNS) in autoimmune disease like RA. ROS and RNS include highly toxic superoxide (O₂^-) and peroxynitrite (ONOO^-) radicals, which activate the signaling cascades of inflammatory cells to synthesize pro-inflammatory cytokines and chemokines. Previous studies reported that Th1 cytokines could promote the development of autoimmune disorders like RA, whereas the Th2 cytokines may attenuate the same diseases. An increased awareness of the relationship between food and health led to a tremendous increase of antioxidant research in the last decade. Evaluation of the efficacy of dietary antioxidants is also becoming highly acceptable in RA research. A number of dietary phytomolecules are already established as having antioxidant activity in isolated synovial cellular infiltrate or peripheral blood neutrophils and lymphocytes. This review aims to highlight the oxidative stress in inflammatory cells of patients with RA and to summarize the clinical relevance of dietary antioxidants as a first step in assessing beneficial effect, safety and dose safety ratio in patients with RA.

Natural antioxidant polyphenols on inflammation management: Anti-glycation activity vs metalloproteinases inhibition

The diet polyphenols are a secondary metabolites of plants able to act on inflammation process. Their anti-inflammatory activity is articulated through several mechanisms that are related to their antioxidative and radical scavengers properties. Our work is focused on a novel approach to inflammatory disease management, based on anti-glycative and matrix metalloproteinases (MMPs) inhibition effects, as a connected phenomena. To better understand these correlation, polyphenols Structure-Activity Relationship (SAR) studies were also reported. The antioxidant polyphenols inhibit the AGEs at different levels of the glycation process in the following ways: (1) prevention of Amadori adduct oxidation; (2) trapping reactive dycarbonyl compounds; (3) attenuation of receptor for AGEs (RAGE) expression. Moreover, several flavonoids with radical scavenging property showed also MMPs inhibition interact directly with MMPs or indirectly via radical scavengers and AGEs reduction. The essential polyphenols features involved in these mechanisms are C2-C3 double bond and number and position of hydroxyl, glycosyl and O-methyl groups. These factors induce a change in molecular planarity interfering with the hydrogen bond formation, electron delocalization and metal ion chelation. In particular, C2-C3 double bond improve the antioxidant and MMPs inhibition, while the hydroxylation, glycosylation and methylation induce a positive and negative correlation, respectively.

Serum and knee synovial fluid matrixmetalloproteinase-13 and tumor necrosis factor-alpha levels in patients with late stage osteoarthritis

Objective

To compare the levels of MMP-13 and TNF-α in late stage osteoarthritis, define their predominant pathways and investigate their correlation with McMaster Universities Arthritis Index scores.

Patients and methods

A total of 42 patients (mean age 64 ± 8.8) with grade 3 and grade 4 knee osteoarthritis according to Kellegren- Lawrence criteria and who were scheduled for total knee arthroplasty were enrolled in the study. TNF-alpha and MMP-13 levels were measured preoperatively from venous blood samples and intraoperatively from knee synovial fluid via ELISA. Preoperative and 1 month postoperative knee functions were assessed by McMaster Universities Arthritis Index.

Results

Grade 4 synovial fluid MMP-13 (4.76 ± 5.82) was elevated compared to grade 3 (3.95 ± 4.45) (p = 0.438), whereas grade 3 serum MMP-13 (1.128 ± 0.308) was found elevated compared to grade 4 (1.038 ± 0.204) (p = 0.430). Grade 4 serum TNF-α (0.253 ± 0.277) was elevated compared to grade 3 (0.206 ± 0.219) whereas grade 3 synovial fluid TNF-α (0.129 ± 0.052) was elevated compared to grade 4 (0.118 ± 0.014). Positive correlation was observed between synovial fluid MMP-13 levels and postoperative WOMAC scores. Mean serum TNF-α level (0.226 ± 0.246 pg/ml) was found higher compared to synovial level (0.124 ± 1.59), synovial MMP-13 level (4.31 ± 1.24) was found higher compared to serum level (1.089 ± 1.519).

Conclusion

Despite the systemic increase in TNF-α levels concordant with osteoarthritis grade, MMP-13 levels are elevated via local manner with a significant correlation with WOMAC scores.

Level of evidence

Level IV, Diagnostic study.

The spice for joint inflammation: anti-inflammatory role of curcumin in treating osteoarthritis

Osteoarthritis is a degenerative disease of the joint affecting aging populations worldwide. It has an underlying inflammatory cause, which contributes to the loss of chondrocytes, leading to diminished cartilage layer at the affected joints. Compounds with anti-inflammatory properties are potential treatment agents for osteoarthritis. Curcumin derived from Curcuma species is an anti-inflammatory compound as such. This review aims to summarize the antiosteoarthritic effects of curcumin derived from clinical and preclinical studies. Many clinical trials have been conducted to determine the effectiveness of curcumin in osteoarthritic patients. Extracts of Curcuma species, curcuminoids and enhanced curcumin, were used in these studies. Patients with osteoarthritis showed improvement in pain, physical function, and quality of life after taking curcumin. They also reported reduced concomitant usage of analgesics and side effects during treatment. In vitro studies demonstrated that curcumin could prevent the apoptosis of chondrocytes, suppress the release of proteoglycans and metal metalloproteases and expression of cyclooxygenase, prostaglandin E-2, and inflammatory cytokines in chondrocytes. These were achieved by blocking the activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) system in the chondrocytes, by preventing the activation of nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha, phosphorylation, and translocation of the p65 subunit of NF-κB complexes into the nucleus. In conclusion, curcumin is a potential candidate for the treatment of osteoarthritis. More well-planned randomized control trials and enhanced curcumin formulation are required to justify the use of curcumin in treating osteoarthritis.

Curcumin and tetrahydrocurcumin both prevent osteoarthritis symptoms and decrease the expressions of pro-inflammatory cytokines in estrogen-deficient rats

Background

Menopausal symptoms are associated with inflammation. Curcumin is a well-known anti-inflammatory bioactive compound from turmeric whereas tetrahydrocurcumin (THC) is a major metabolite of curcumin that may have different efficacies. However, they have not been studied for anti-menopausal symptoms and anti-osteoarthritis effects. We compared the efficacies of curcumin and THC for preventing postmenopausal and osteoarthritis symptoms in ovariectomized (OVX) obese rats with monoiodoacetate (MIA) injections into the right knee to generate a similar pathology as osteoarthritis.

Methods

OVX rats were provided a 45 % fat diet containing either (1) 0.4 % curcumin (curcumin), (2) 0.4 % THC, (3) 30 μg/kg body weight 17β-estradiol + 0.4 % dextrin (positive control), (4) 0.4 % dextrin (placebo; control), or (5) 0.4 % dextrin with no MIA injection (normal control) for 4 weeks. At the beginning of the fifth week, OVX rats were given articular injections of MIA or normal-control saline into the right knee and the assigned diets were provided for an additional 3 weeks.

Results

Curcumin and THC had similar efficacies for skin tail temperature in OVX rats whereas THC, but not curcumin, prevented glucose intolerance, which might be involved in exacerbating osteoarthritis. Both protected against osteoarthritis symptoms and pain-related behaviors better than 17β-estradiol treatment in estrogen-deficient rats. Curcumin and THC prevented the deterioration of articular cartilage compared to control. They also maintained lean body mass and lowered fat mass as much as 17β-estradiol treatment. The improvement in osteoarthritis symptoms was associated with decreased gene expressions of matrix metalloproteinase (MMP)3 and MMP13 and tumor necrosis factor-α, interleukin (IL)1β, and IL6 in the articular cartilage.

Conclusions

THC and curcumin are effective for treating postmenopausal and osteoarthritis symptoms in OVX rats with MIA-induced osteoarthritis-like symptoms and may have potential as interventions for menopausal and osteoarthritic symptoms in humans.

Establishment of a rabbit model to study the influence of advanced glycation end products accumulation on osteoarthritis and the protective effect of pioglitazone

OBJECTIVE

To investigate the role of advanced glycation end products (AGEs) in cartilage degeneration in vivo and determine the influence of the peroxisome proliferator-activated receptor-γ (PPARγ) agonist pioglitazone on AGEs-induced osteoarthritis (OA) in a rabbit model.

DESIGN

Thirty-two rabbits were separated into four groups (n = 8 each) and received 500 μL of 123, 350, or 1000 mmol/L D-ribose or Phosphate buffered saline (PBS) solution administered to the right stifle joint via intra-articular injection twice a week. All the rabbits ran 500 m on treadmills every day. Another 16 rabbits were administered 1000 mmol/L D-ribose and divided into 2 groups (n = 8) that received either placebo or pioglitazone administered orally at 20 mg/kg/day. Eight weeks later, cartilage damage was evaluated macroscopically, histologically, and biochemically.

RESULTS

Artificially increasing the AGEs level and exercise load resulted in cartilage damage and dose-dependent downregulation of PPARγ expression. The efficacy of pioglitazone treatment was tested in a rabbit OA model, and a clear chondroprotective effect was revealed by macro- and microscopic assessments.

CONCLUSION

Elevating AGEs in rabbits can accelerate the articular cartilage degradation that occurs with physical exercise, and pioglitazone can reduce the severity of the AGEs-induced OA in a rabbit model.

Adaptive cellular stress pathways as therapeutic targets of dietary phytochemicals: focus on the nervous system

During the past 5 decades, it has been widely promulgated that the chemicals in plants that are good for health act as direct scavengers of free radicals. Here we review evidence that favors a different hypothesis for the health benefits of plant consumption, namely, that some phytochemicals exert disease-preventive and therapeutic actions by engaging one or more adaptive cellular response pathways in cells. The evolutionary basis for the latter mechanism is grounded in the fact that plants produce natural antifeedant/noxious chemicals that discourage insects and other organisms from eating them. However, in the amounts typically consumed by humans, the phytochemicals activate one or more conserved adaptive cellular stress response pathways and thereby enhance the ability of cells to resist injury and disease. Examplesof such pathways include those involving the transcription factors nuclear factor erythroid 2-related factor 2, nuclear factor-κB, hypoxia-inducible factor 1α, peroxisome proliferator-activated receptor γ, and forkhead box subgroup O, as well as the production and action of trophic factors and hormones. Translational research to develop interventions that target these pathways may lead to new classes of therapeutic agents that act by stimulating adaptive stress response pathways to bolster endogenous defenses against tissue injury and disease. Because neurons are particularly sensitive to potentially noxious phytochemicals, we focus on the nervous system but also include findings from other cell types in which actions of phytochemicals on specific signal transduction pathways have been more thoroughly studied.

Efficacy and safety of Curcuma domestica extracts compared with ibuprofen in patients with knee osteoarthritis: a multicenter study

Objective

To determine the efficacy and safety of Curcuma domestica extracts in pain reduction and functional improvement.

Methods

367 primary knee osteoarthritis patients with a pain score of 5 or higher were randomized to receive ibuprofen 1,200 mg/day or C. domestica extracts 1,500 mg/day for 4 weeks. The main outcomes were Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) total, WOMAC pain, WOMAC stiffness, and WOMAC function scores. Adverse events (AEs) were also recorded.

Results

185 and 182 patients were randomly assigned into C. domestica extracts and ibuprofen groups, respectively. The baseline characteristics were no different between groups. The mean of all WOMAC scores at weeks 0, 2, and 4 showed significant improvement when compared with the baseline in both groups. After using the noninferiority test, the mean difference (95% confidence interval) of WOMAC total, WOMAC pain, and WOMAC function scores at week 4 adjusted by values at week 0 of C. domestica extracts were noninferior to those for the ibuprofen group (P=0.010, P=0.018, and P=0.010, respectively), except for the WOMAC stiffness subscale, which showed a trend toward significance (P=0.060). The number of patients who developed AEs was no different between groups. However, the number of events of abdominal pain/discomfort was significantly higher in the ibuprofen group than that in the C. domestica extracts group (P=0.046). Most subjects (96%–97%) were satisfied with the treatment, and two-thirds rated themselves as improved in a global assessment.

Conclusion

C. domestica extracts are as effective as ibuprofen for the treatment of knee osteoarthritis. The side effect profile was similar but with fewer gastrointestinal AE reports in the C. domestica extracts group.

Short-term effects of highly-bioavailable curcumin for treating knee osteoarthritis: a randomized, double-blind, placebo-controlled prospective study

BACKGROUND

We previously developed a surface-controlled water-dispersible form of curcumin and named it Theracurmin(®) (Theracurmin; Theravalues, Tokyo, Japan). The area under the blood concentration-time curve of Theracurmin in humans was 27-fold higher than that of curcumin powder. We determined the clinical effects of orally administered Theracurmin in patients with knee osteoarthritis during 8 weeks of treatment.

METHODS

Fifty patients with knee osteoarthritis of Kellgren-Lawrence grade II or III and who were aged more than 40 years were enrolled in this randomized, double-blind, placebo-controlled, prospective clinical study. Placebo or Theracurmin containing 180 mg/day of curcumin was administered orally every day for 8 weeks. To monitor adverse events, blood biochemistry analyses were performed before and after 8 weeks of each intervention. The patients' knee symptoms were evaluated at 0, 2, 4, 6, and 8 weeks by the Japanese Knee Osteoarthritis Measure, the knee pain visual analog scale (VAS), the knee scoring system of the Japanese Orthopedic Association, and the need for nonsteroidal anti-inflammatory drugs.

RESULTS

At 8 weeks after treatment initiation, knee pain VAS scores were significantly lower in the Theracurmin group than in the placebo group, except in the patients with initial VAS scores of 0.15 or less. Theracurmin lowered the celecoxib dependence significantly more than placebo. No major side effects were observed with Theracurmin treatment.

CONCLUSION

Theracurmin shows modest potential for the treatment of human knee osteoarthritis.

Advanced glycation end-products: a common pathway in diabetes and age-related erectile dysfunction

Reactive derivatives of non-enzymatic glucose-protein condensation reactions integrate a heterogeneous group of irreversible adducts called advanced glycation end-products (AGEs). Numerous studies have investigated the role of the AGEs in cardiovascular system; however, its contribution to erectile dysfunction (ED) that is an early manifestation of cardiovascular disease has been less intensively investigated. This review summarizes the most recent advances concerning AGEs effects in the cavernous tissue of the penis and in ED onset, particularly on diabetes and aging, conditions that not only favor AGEs formation, but also increase risk of developing ED. The specific contribution of AGE on intra- and extracellular deposition of insoluble complexes, interference in activity of endothelial nitric oxide (NO) synthase, NO bioavailability, endothelial-dependent vasodilatation, as well as molecular pathways activated by receptor of AGEs are presented. Finally, the interventional actions that prevent AGEs formation, accumulation or activity in the cavernous tissue and that include nutritional pattern modulation, nutraceuticals, exercise, therapeutic strategies (statins, anti-diabetics, inhibitors of phosphodiesterase-5, anti-hypertensive drugs) and inhibitors of AGEs formation and crosslink breakers, are discussed. From this review, we conclude that despite the experiments conducted in animal models pointing to the AGE/RAGE axis as a potential interventional target with respect to ED associated with diabetes and aging, the clinical data have been very disappointing and, until now, did not provide evidence of benefits of treatments directed to AGE inactivation.