Updates on the treatment of gout, including a review of updated treatment guidelines and use of small molecule therapies for difficult-to-treat gout and gout flares

Proline-derived quinoline formamide compounds as human urate transporter 1 inhibitors with potent uric acid-lowering activities

We report the design and synthesis of a series of proline-derived quinoline formamide compounds as human urate transporter 1 (URAT1) inhibitors via a ligand-based pharmacophore approach. Structure-activity relationship studies reveal that the replacement of the carboxyl group on the polar fragment with trifluoromethanesulfonamide and substituent modification at the 6-position of the quinoline ring greatly improve URAT1 inhibitory activity compared with lesinurad. Compounds 21c, 21e, 24b, 24c, and 23a exhibit potent activities against URAT1 with IC50 values ranging from 0.052 to 0.56 μM. Furthermore, compound 23a displays improved selectivity towards organic anion transporter 1 (OAT1), good microsomal stability, low potential for genotoxicity and no inhibition of the hERG K+ channel. Compounds 21c and 23a, which have superior pharmacokinetic properties, also demonstrate significant uric acid-lowering activities in a mouse model of hyperuricemia. Notably, 21c also exhibits moderate anti-inflammatory activity related to the gout inflammatory pathway. Compounds 21c and 23a with superior druggability are potential candidates for the treatment of hyperuricemia and gout.

Toward targeted treatments for silicosis

PURPOSE OF REVIEW

There has been a rapid increase in silicosis cases, particularly related to artificial stone. The key to management is avoidance of silica exposure. Despite this, many develop progressive disease and there are no routinely recommended treatments. This review provides a summary of the literature pertaining to pharmacological therapies for silicosis and examines the plausibility of success of such treatments given the disease pathogenesis.

RECENT FINDINGS

In-vitro and in-vivo models demonstrate potential efficacy for drugs, which target inflammasomes, cytokines, effector cells, fibrosis, autophagy, and oxidation.

SUMMARY

There is some evidence for potential therapeutic targets in silicosis but limited translation into human studies. Treatment of silicosis likely requires a multimodal approach, and there is considerable cross-talk between pathways; agents that modulate both inflammation, fibrosis, autophagy, and ROS production are likely to be most efficacious.

Non-loading versus loading low-dose colchicine in acute crystal-associated arthritis: A double-blinded randomized controlled study

INTRODUCTION

This study aimed to compare the efficacy of non-loading versus loading low-dose colchicine in patients with acute crystal-associated arthritis.

MATERIALS AND METHODS

All in-patients who were admitted to Chiang Mai University Hospital with non-arthritis disease and developed acute crystal-associated arthritis during admission (within 48 h after arthritis onset) were invited to join this study. The patients were randomized into two groups. Patients in Group I (non-loading group) and Group II (loading group) received colchicine at 1.2 and 2.4 mg in the first 24 h, respectively. The primary outcome was the patients' pain response at 24 h after treatment.

RESULTS

Of 80 patients, 49 were acute gouty arthritis, and 31 acute calcium pyrophosphate (CPP) arthritis. The mean [95% CI] pain score was no different between Groups I and II at the baseline level (6.46[5.72-7.19] vs. 6.654[5.85-7.44], p = .867) and at 24 h (3.13[2.43-3.82] vs. 3.18[2.42-3.93], p = .907). The proportion of patients with ≥50% pain reduction was not different (57.50% vs. 55.00%, p = .822). Sensitivity analysis among patients with a baseline pain score of ≥4 showed the same pattern of response. Mild diarrhea was common and comparable in both groups. Subgroup analysis according to renal function (eGFR < 60 vs. ≥60 mL/min/1.73 m2 ) or type of crystals (acute gouty arthritis vs. acute CPP arthritis) also showed the same pattern of response.

CONCLUSION

Non-loading low-dose colchicine was as effective as loading low-dose colchicine in patients with acute crystal-associated arthritis, regardless of renal function or type of crystals.

Wuling San Based on Network Pharmacology and in vivo Evidence Against Hyperuricemia via Improving Oxidative Stress and Inhibiting Inflammation

Background

Hyperuricemia (HUA) is a major public health issue with a high prevalence worldwide. Wuling San (WLS) is an effective treatment for HUA. However, the active compounds and the related mechanism are unclear. In this study, we aimed to explore the active compounds and the underlying pharmacological mechanisms of WLS against HUA.

Methods

First, a network pharmacology approach was used to detect active compounds of WLS, and potential targets and signaling pathways involved in the treatment of HUA were predicted. Then, a molecular docking strategy was used to predict the affinity between active compounds and key targets. Finally, to verify the prediction, the HUA rat model was established.

Results

49 active compounds with 108 common targets were obtained. Besides, cerevisterol, luteolin, ergosterol peroxide, beta-sitosterol, and sitosterol were identified as key active compounds. In PPI analysis, TNF, IL6, CASP3, PPARG, STAT3, and other 12 core targets were obtained. GO enrichment analysis indicated that WLS was likely to interfere with oxidative stress in the treatment of HUA, and KEGG enrichment analysis indicated multiple inflammation-related signaling pathways possibly involved in the treatment of HUA by WLS, including TNF, and NOD-like receptor, HIF-1, PI3K-Akt, and IL-17 signaling pathways. The results of molecular docking indicated that the active compounds had good binding properties to their key targets. In the validation experiments, WLS significantly reduced the levels of serum uric acid (SUA) and serum malondialdehyde (MDA). Moreover, WLS not only significantly increased the levels of total antioxidant capacity (T-AOC) and superoxide dismutase (SOD), but also inhibited the expression of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6).

Conclusion

In the present study, we demonstrate that WLS has multicomponent, multitarget, and multi-pathway properties in the treatment of HUA. Its potential capability to reduce SUA could be ascribed to oxidative stress improvement and inflammation inhibition.

Computed tomography and magnetic resonance imaging findings in gouty arthritis involving large joints of the upper extremities

BACKGROUND

We aimed to analyze the computed tomography (CT) and magnetic resonance imaging (MRI) findings of gouty arthritis primarily involving the large joints of the upper limbs, signal or density characteristics of the tophi, growth patterns, involvement of the adjacent joints, and differentiation from other lesions occurring in this area and to discuss the causes of misdiagnosis.

METHODS

CT and MRI data were collected from 14 patients with gouty arthritis, primarily involving the shoulder and elbow joints, and their imaging features were analyzed.

RESULTS

All the patiens were ranged from 28-85 years old, and the tophi deposition can be observed on either CT or MRI.The tophi deposition apperas as slightly higher density nodules or masses on CT images,or nodules or masses on MRI with isosignal/hypointensity on T1WI and hyperintensity on T2WI. Five patients showed narrowing of the affected joint space, four had different degrees of bone erosion under the articular surface, eight developed joint effusion, and all showed surrounding soft tissue swelling. The tophi grew around the joint, with anterolateral and posterolateral tophi predominantly in the shoulder joint and dorsal tophi predominantly in the elbow joint on the MRI, with compression and edema of the surrounding soft tissues.

CONCLUSIONS

Gouty arthritis occurs in the large joints of the upper limbs and is characterized by fluid accumulation in the joint capsule and the formation of tophi. These tophi are usually large, with subcutaneous bone resorption and erosion, with or without cartilage destruction. However, extensive edema appeared in the soft tissue around the tophi, but the edema only produced pressure without any obvious signs of soft tissue infiltration, which may be distinguished from the joint tumor. In addition, the gout incidence rate is increased in young patients. Therefore, when the patient has a large joint mass, it is important to confirm whether there is a history of gout.

Study on the compatibility effect and active constituents of Atractylodis Rhizoma in Ermiao Wan against Acute Gouty Arthritis

ETHNOPHARMACOLOGICAL RELEVANCE

Ermiao Wan (EMW), composed of Atractylodis Rhizoma (AR) and Phellodendri Chinensis Cortex (PC), is a classical traditional Chinese medicine prescription having been used to treat the disease named "Tong Feng", which is described as "ache in bones and joints" with the same symptom of modern disease named acute gouty arthritis for many years in TCM clinical practice. Besides, both PC and AR were considered to be effective in anti-inflammatory according to modern pharmacological research.

AIM OF THE STUDY

Present study was undertaken to probe the compatibility rationality between the two herbs PC and AR in EMW and the active constituents of AR against acute gouty arthritis (AGA).

MATERIALS AND METHODS

Rat model of AGA was induced by intra-articular injection of monosodium urate (MSU) crystal suspension, and PC combined with or without different AR extracts were used for AGA treatment. Ankle joint swelling, proinflammatory cytokines in serum and pathological changes of synovium were investigated. Using the developed UHPLC-QQQ-MS method, the plasma concentrations of the primary alkaloids in PC, such as berberine, phellodendrine, magnoflorine, jatrorrhizine, berberrubine, palmatine, and tetrahydropalmatine, in AGA rat were determined, and pharmacokinetics properties were compared following oral administration of PC, PC combined with or without different AR extracts.

RESULTS

PC, PC combined with AR volatile oil (VO) extract or PC combined with whole AR extract significantly attenuated the ankle joint swelling of AGA rats. Besides, the combination of PC and VO extract of AR showed superior efficacy than other groups in ameliorating ankle joint swelling, reducing the IL-6 expression in serum and improving tissue lesions of ankle joints. Furthermore, it turned out that the VO extract of AR increased the blood exposure level of PC related alkaloids than non-volatile oil (NVO) extract of AR, by comparing the pharmacokinetic results of each group.

CONCLUSIONS

The VO components of AR were the key compatible materials to combine with PC in EMW for AGA treatment. Moreover, the enhanced anti-AGA activity of PC after combining with VO extract of AR may attribute to the influence of VO on the pharmacokinetics of PC. This study may provide useful information for elucidating the compatibility effects of AR in EMW against AGA.

Total Saponin of Dioscorea collettii Attenuates MSU Crystal-Induced Inflammation by Inhibiting the Activation of the TLR4/NF-κB Signaling Pathway

BACKGROUND

Rhizomes from Dioscorea collettii are extensively used in traditional medicine for the treatment of arthritic diseases, particularly gouty arthritis (GA). This study aims to investigate whether the total saponin of Dioscorea collettii (TSD) can attenuate monosodium urate (MSU) crystal-induced inflammatory effects by suppressing the activation of the TLR4/NF-κB signaling pathway in vivo and in vitro.

METHODS

Seventy-two male Wistar rats and THP-1 cells were used in this study. Pathological examination was used to examine the ankle joints of rats. The expression levels of TLR4, NF-κB, MyD88, and IL-1β were detected by qRT-PCR, Western blotting, or immunofluorescence.

RESULTS

Compared with those in the normal group, the ankle joints of rats in the model group exhibited significant swelling, synovial tissue hyperplasia, inflammatory cell infiltration, and increased expression of IL-1β protein. The joint swelling degree of rats in the TSD high- and medium-dose groups and the colchicine group was significantly decreased, and the histopathology was obviously improved. TSD and colchicine reduced the levels of IL-1β and TNF-α in synovial fluid. They also decreased the mRNA expression of TLR4, NF-κB, and IL-1β in rat joint synovial tissue and the protein expression of TLR4, MyD88, and NF-κB. NF-κB protein expression in both the cytoplasm and nuclei of THP-1 cells showed the opposite trend. Furthermore, immunofluorescence showed that TSD reduced the nuclear translocation of NF-κBp65 in the model group.

CONCLUSION

TSD exhibits an anti-inflammatory effect in the MSU-induced inflammation model, and the mechanism may be to reduce the production of cytokines by inhibiting the activation of the TLR4/NF-κB signaling pathway.

Rheumatologists' understanding of refractory gout: a questionnaire survey in China

Objective

To explore the understanding of refractory gout in Chinese rheumatologists.

Methods

We conducted an anonymous survey of rheumatologists attending an annual national academic conference on rheumatism.

Results

Of the 910 rheumatologists who completed the questionnaire, 751 (82.5%) had received relevant continuing medical education (CME). Of these, 140 (18.6%) rheumatologists did not select xanthine oxidase inhibitors as the first treatment for patients with chronic tophaceous gout. Of all respondents, 113 (12.4%), 251 (27.6%) and 324 (35.6%) prescribed incorrect maximum doses of allopurinol, febuxostat and benzbromarone, respectively; this tendency was more pronounced in the non-CME group. Most rheumatologists agreed that complications and comorbidities increased the difficulty of gout management and considered the term refractory gout to describe those cases with uncontrolled symptoms, unmet treatment targets or non-shrinkage of tophi after standardized drug treatment. Moreover, 62.8% (472/751) of specialists considered that a diagnosis of refractory gout was appropriate for patients whose lifestyle and compliance failed to improve despite adequate education and regular urate-lowering therapy.

Conclusions

Incorrect and inadequate drug therapy may contribute to some cases of refractory gout, especially in physicians without CME. An emphasis on non-drug therapy and the management of comorbidities and complications may reduce cases of refractory gout.

Optimization of culture medium for Sanghuangporus vaninii and a study on its therapeutic effects on gout

The increasing incidence of gout poses a very challenging management problem. However, the currently available drugs often have various toxic side effects. As a traditional edible and medicinal macrofungus, Sanghuangporus vaninii presents high medical research value. Therefore, to improve fermentation efficiency and identify novel anti-gout drugs, we optimized the culture medium of S. vaninii with lignin and further investigated its anti-gout effects. The results indicated that 0.06 g/L of lignin was most favorable for S. vaninii growth. In the hyperuricemia cell model, we found that S. vaninii could significantly induce the downregulation of xanthine oxidoreductase and the upregulation of hypoxanthine-guanine phosphoribosyltransferase. Furthermore, following oral administration of the extracts, the serum uric acid levels of mice with hyperuricemia were effectively reduced. In a gouty arthritis rat model, S. vaninii also achieved strong suppression of synovial swelling, indicating its anti-inflammatory activity. In addition, the antioxidant assays suggested that S. vaninii shows a strong free radical scavenging capacity and can effectively alleviate cellular oxidative stress. This activity further enhances its anti-inflammatory activity and reduces the incidence of comorbidities. In summary, our results provide the basis for the utilization of S. vaninii to develop anti-gout drugs.

Chinese herbal medicine si-miao-san decoction for acute gouty arthritis: A protocol for systematic review and meta-analysis of randomized controlled trials

BACKGROUND

The prevalence of gout is increasing worldwide, and the symptoms of acute arthritis appearing in gout patients seriously affect the quality of life. The pain and functional limitation caused by acute gouty arthritis (AGA) bring great pain to patients. At present, mainstream drugs have problems such as poor efficacy and side effects. Traditional Chinese medicine has extensive clinical experience in the prevention and treatment of gout, and it also shows clear advantages in the treatment of AGA. Clinical studies have confirmed that si-miao-san decoction (SMSD), a traditional Chinese medicine decoction, can improve the clinical symptoms and signs of AGA patients. Therefore, we will conduct a systematic review to clarify the effectiveness and safety of SMSD for AGA.

METHODS

We will search different database from the built-in to October 2020. The electronic database includes PubMed, Embase, Cochrane Library, Web of Science, CNKI, WanFang, VIP, and CBM. At the same time, we will also search for clinical registration tests and gray literatures. This study only screened clinical randomized controlled trials (RCT) for SMSD for AGA. The 2 researchers independently conducted literature selection, data extraction, and quality assessment. Dichotomous data are represented by relative risk (RR), continuous data are represented by mean difference (MD) or standard mean deviation (SMD), and the final data are fixed effect model (FEM) or random effect model (REM), depending on whether it exists heterogeneity. The main outcomes are clinical efficacy, including pain score, joint function, and degree of swelling. The secondary outcomes include: blood uric acid (BUA), C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR). Finally, a meta-analysis was conducted through Review Manager software version 5.3.

RESULTS

This study will conduct a comprehensive analysis based on the currently released Si-Miao-San data for the treatment of AGA and provide high-quality evidence of clinical efficacy and safety.

CONCLUSION

This systematic review aims to provide new options for SMSD treatment of AGA in terms of its efficacy and safety.

ETHICS AND DISSEMINATION

The review is based solely on a secondary study of published literatures and does not require ethics committee approval. Its conclusion will be disseminated in conference papers, magazines, or peer-reviewed journals.

INPLASY REGISTRATION NUMBER

INPLASY202040163.

Identification of xanthine oxidase inhibitors through hierarchical virtual screening

As a critical enzyme for the uric acid production, xanthine oxidase (XO) has emerged as a primary drug target for antihyperuricemic therapy. A hierarchical virtual screening integrating both ligand-based and structure-based approaches was applied herein to identify potent XO inhibitors. Four compounds, which were previously reported as XO inhibitors, were recognized through the virtual screening protocol, and compound H3, which is distinct from the structures of known XO inhibitors, was identified as a new chemotype inhibitor with IC₅₀ of 2.6 μM. The binding mode of H3 was further investigated by molecular docking and molecular dynamics (MD) simulation. The results suggested the feasibility to discover new chemotypes of XO inhibitors via integrated virtual screening strategies.

CD44 Receptor Mediates Urate Crystal Phagocytosis by Macrophages and Regulates Inflammation in A Murine Peritoneal Model of Acute Gout

Gout is a chronic arthritis caused by the deposition of poorly soluble monosodium urate monohydrate (MSU) crystals in peripheral joints. Resident macrophages initiate inflammation in response to MSU mediated by NF-κB nuclear translocation and NLRP3 inflammasome activation. We investigated the role of CD44, a transmembrane receptor, in mediating MSU phagocytosis by macrophages. We used an antibody that sheds the extracellular domain (ECD) of CD44 to study the role of the receptor and its associated protein phosphatase 2A (PP2A) in macrophage activation. We also studied the significance of CD44 in mediating MSU inflammation in-vivo. Cd44^−/− BMDMs showed reduced MSU phagocytosis, LDH release, IL-1β expression and production compared to Cd44^+/+ BMDMs. Elevated CD44 staining was detected intracellularly and CD44 colocalized with α-tubulin as a result of MSU exposure and ECD-shedding reduced MSU phagocytosis in murine and human macrophages. Anti-CD44 antibody treatment reduced NF-κB p65 subunit nuclear levels, IL-1β expression, pro-IL-1β and IL-8 production in MSU stimulated THP-1 macrophages (p < 0.01). The effect of the antibody was mediated by an enhancement in PP2A activity. CD44 ECD-shedding reduced the conversion of procaspase-1 to active caspase-1, caspase-1 activity and resultant generation of mature IL-1β in macrophages. Neutrophil and monocyte influx and upregulated production of IL-1β was evident in wildtype mice. MSU failed to trigger neutrophil and monocyte recruitment in Cd44^−/− mice and lower IL-1β levels were detected in peritoneal lavages from Cd44^−/− mice (p < 0.01). Anti-CD44 antibody treatment reduced neutrophil and monocyte recruitment and resulted in reduced lavage IL-1β levels in the same model. CD44 plays a biologically significant role in mediating phagocytosis of MSU and downstream inflammation and is a novel target in gout treatment.

Converging Relationships of Obesity and Hyperuricemia with Special Reference to Metabolic Disorders and Plausible Therapeutic Implications

BACKGROUND

Obesity and hyperuricemia mutually influence metabolic syndrome. This study discusses the metabolic relationships between obesity and hyperuricemia in terms of pathophysiology, complications, and treatments.

METHODS

We searched for preclinical or clinical studies on the pathophysiology, complications, and therapy of obesity and hyperuricemia on the PubMed database.

RESULTS

In this systemic review, we summarized our searching results on topics of pathophysiology, complications and therapeutic strategy. In pathophysiology, we firstly introduce genetic variations for obesity, hyperuricemia and their relationships by genetic studies. Secondly, we talk about the epigenetic influences on obesity and hyperuricemia. Thirdly, we describe the central metabolic regulation and the role of hyperuricemia. Then, we refer to the character of adipose tissue inflammation and oxidative stress in the obesity and hyperuricemia. In the last part of this topic, we reviewed the critical links of gut microbiota in the obesity and hyperuricemia. In the following part, we review the pathophysiology of major complications in obesity and hyperuricemia including insulin resistance and type 2 diabetes mellitus, chronic kidney disease, cardiovascular diseases, and cancers. Finally, we recapitulate the therapeutic strategies especially the novel pharmaceutic interventions for obesity and hyperuricemia, which concurrently show the mutual metabolic influences between two diseases.

CONCLUSION

The data reviewed here delineate the metabolic relationships between obesity and hyperuricemia, and provide a comprehensive overview of the therapeutic targets for the management of metabolic syndromes.

Repurposing drugs targeting the P2X7 receptor to limit hyperinflammation and disease during influenza virus infection

Background and Purpose

Severe influenza A virus (IAV) infections are associated with damaging hyperinflammation that can be fatal. There is an urgent need to identify new therapeutic agents to treat severe and pathogenic IAV infections. Repurposing of drugs with an existing and studied pharmacokinetic and safety profile is a highly attractive potential strategy. We have previously demonstrated that the NLRP3 inflammasome plays time‐dependent roles during severe IAV infection with early protective responses and later dysregulation leading to excessive inflammation, contributing to disease severity.

Experimental Approach

We tested two existing drugs, probenecid and AZ11645373, to target P2X7 receptor signalling and dampen NLRP3 inflammasome responses during severe IAV infection. In vitro, the drugs were assessed for their ability to limit NLRP3 inflammasome‐dependent IL‐1β secretion in macrophage cultures. In vivo, their effects were assessed on hyperinflammation and disease during severe IAV infection in C57BL/6 mice.

Key Results

Treatment of macrophages with probenecid or AZ11645373 in vitro diminished NLRP3 inflammasome‐dependent IL‐1β secretion. Intranasal therapeutic treatment of mice displaying severe influenza disease with probenecid or AZ11645373 reduced pro‐inflammatory cytokine production, cellular infiltrates in the lung, and provided protection against disease. Importantly, these drugs could be administered at either early or late stage of disease and provide therapeutic efficacy.

Conclusions and Implications

Our study demonstrates that the anti‐inflammatory drugs probenecid and AZ11645373, which have documented pharmacokinetics and safety profiles in humans, are effective at dampening hyperinflammation and severe influenza disease providing potentially new therapeutic strategies for treating severe or pathogenic IAV infections.

Diagnosis and Treatment of Patellar Tendon Gouty Tophus: A Case Report

The main aim of this case report is to thoroughly describe the steps of diagnosis and treatment in the rare incidence of patellar tendon gouty tophus. The case of a 53-year-old man manual worker who was treated with open excision of the lesion, following failure of extended medical treatment with rheumatological input, is presented. Surgical treatment led to full restoration of the patient's knee function. Open or arthroscopic surgery is a viable option for the unusual case of intratendinous patellar gouty deposition if the patient fails medical management. Medical treatment should still be the mainstay.

Consumption of 100% Tart Cherry Juice Reduces Serum Urate in Overweight and Obese Adults

BACKGROUND

Gout is a frequently occurring, complex rheumatologic form of inflammatory arthritis caused by the accumulation of serum uric acid (sUA) and deposition of uric acid crystals in the joints and tissues of the body. Hyperuricemia is also a significant independent risk factor for all-cause and cardiovascular morbidity and mortality and is associated with hypertension, diabetes, obesity, and osteoarthritis. However, patient adherence to prescribed urate-lowering therapies ranges from 20% to 70%, suggesting that other additional strategies, such as dietary intervention with specific, efficacious foods or beverages, may be necessary to mitigate the risk of arthritis, as well as other comorbidities. Tart cherry juice (TCJ) has been used for decades by some for gout based largely on anecdotal evidence of its efficacy and its antioxidant and anti-inflammatory properties.

OBJECTIVES

We designed this study to test the effect of TCJ on uricemia, lipidemia, glycemia, and inflammation in at-risk overweight and obese humans with a specific hypothesis that TCJ consumption would reduce sUA concentrations.

METHODS

In this randomized, placebo-controlled crossover study, we recruited overweight and obese participants with body mass index (BMI) >25.0 kg/m2 (n = 26, 18 women/8 men, 41 ±11 y; BMI 31.3 ± 6.0; 12 obese, 14 overweight) to consume 240 mL/d (8 oz/d) of either TCJ or placebo beverage, for 4 wk each with a 4-wk intervening washout period followed by 4 wk of the alternate beverage.

RESULTS

TCJ significantly reduced sUA concentration by 19.2% (P < 0.05) and reduced by 19.4% (P = 0.09) and 6.3% (P = 0.08) proinflammatory high-sensitivity C-reactive protein and monocyte chemoattractant protein-1, respectively. The participants in this study displayed risk ratios indicating increased cardiovascular disease risk and insulin resistance but no differences in the pre- and postintervention groups of either placebo or TCJ groups.

CONCLUSION

Collectively, the data suggest that 100% TCJ reduces sUA concentrations, mitigating hyperuricemia associated with gouty arthritis. This trial was registered at clinicaltrials.gov as NCT03636529.

Phospholipidic Colchicinoids as Promising Prodrugs Incorporated into Enzyme-Responsive Liposomes: Chemical, Biophysical, and Enzymological Aspects

Enzyme-responsive liposomes release their cargo in response to pathologically increased levels of enzymes at the target site. We report herein an assembly of phospholipase A2-responsive liposomes based on colchicinoid lipid prodrugs incorporated into lipid bilayer of the nanosized vesicles. The liposomes were constructed to addresses two important issues: (i) the lipid prodrugs were designed to fit the structure of the enzyme binding site; and (ii) the concept of lateral pressure profile was used to design lipid prodrugs that introduce almost no distortions into the lipid bilayer packing, thus ensuring that corresponding liposomes are stable. The colchicinoid agents exhibit antiproliferative activity in subnanomolar range of concentrations.