Phycocyanin stimulates ulcerative colitis healing via selective activation of cannabinoid receptor-2, intestinal mucosal healing, Treg accumulation, and p38MAPK/MK2 signaling inhibition.

Ulcerative colitis (UC) is a chronic inflammatory condition that until this date, lacks curative treatments. Previously, synthetic selective CB2 receptor (CB2R) agonists demonstrated effective preclinical anti-inflammatory activities in UC. Phycocyanin (PC), photosynthetic assistant protein isolated from Microcystis aeruginosa Kützing blue green algae, has multiple pharmacological effects, however, it's effect against UC remains unexplored. Our study aimed at investigating the therapeutic effectiveness of PC against UC, and correlating its mechanisms with CB2R agonistic activities. In silico; PC showed structural similarity with endocannabinoid receptors' ligand "Δ9-tetrahydrocannabinol", target prediction studies suggested high affinity for G-coupled protein family-receptors, and molecular docking affirmed preferable affinity towards CB2R vs CB1R. In LPS-exposed-Caco-2 cell line; PC demonstrated comparable interaction with CB2R, and downregulation of CB2R, p38 and MK2 gene expressions with reference agonist "6d", and exhibited preferred selectivity towards CB2R over CB1R. In DSS-induced mice; PC-treatment ameliorated DSS-induced colon shortening, elevated disease activity index, and colonic pathological alterations. PC showed effective CB2R activation through potent anti-inflammatory activities, Treg-cell accumulation, suppression in p38MAPK/MK2 signaling, and tight junction barrier restoration as indicated by ultrastructural examinations, elevated ZO-1 and occludin protein expressions, and Ki67 immunohistochemical expression in colonic tissues. Additionally, PC alleviated intestinal dysbiosis via downregulating LPS/TLR4/NF-κB signaling and gut microbiota maintenance. Notably, PC-protective activities were abolished when co-administered with SR144528 (selective CB2 antagonist) except for gut microbiota maintenance, which was independent from CB2R activation. Our findings provide evidence of PC effectiveness against UC through acting as CB2R agonist, thus expanding its possible therapeutic application against other inflammatory diseases.

Development of fluorinated and methoxylated benzothiazole derivatives as highly potent and selective cannabinoid CB2 receptor ligands.

The upregulation of the CB2 receptors in neuroinflammation and cancer and their potential visualization with PET (positron emission tomography) could provide a valuable diagnostic and therapy-monitoring tool in such disorders. However, the availability of reliable CB2-selective imaging probes is still lacking in clinical practice. We have recently identified a benzothiazole-2-ylidine amide hit (6a) as a highly potent CB2 ligand. With the aim of enhancing its CB2 over CB1 selectivity and introducing structural sites suitable for radiolabeling, we herein describe the development of fluorinated and methoxylated benzothiazole derivatives endowed with extremely high CB2 binding affinity and an exclusive selectivity to the CB2 receptor. Compounds 14, 15, 18, 19, 21, 24 and 25 displayed subnanomolar CB2Ki values (ranging from 0.16 nM to 0.68 nM) and interestingly, all of the synthesized compounds completely lacked affinity at the CB1 receptor (Ki > 10,000 nM for all compounds), indicating their remarkably high CB2 over CB1 selectivity factors. The fluorinated analogs, 15 and 21, were evaluated for their in vitro metabolic stability in mouse and human liver microsomes (MLM and HLM). Both 15 and 21 displayed an exceptionally high stability (98% and 91% intact compounds, respectively) after 60 min incubation with MLM. Contrastingly, a 5- and 2.8-fold lower stability was demonstrated for compounds 15 and 21, respectively, upon incubation with HLM for 60 min. Taken together, our data present extremely potent and selective CB2 ligands as credible leads that can be further exploited for 18F- or 11C-radiolabeling and utilization as PET tracers.

Transplantation in the era of the Covid-19 pandemic: How should transplant patients and programs be handled?

Due to the Covid-19 pandemic caused by SARS-CoV-2, transplant programs worldwide have been severely impacted with dwindling numbers of transplantations performed and a complete halt in several areas. In this review we examine whether SARS-CoV-2 infection presents differently in transplant recipients, whom and how we should test, how susceptible the transplant population is to overt infection and describe the range of outcomes. From retrieved published reports on SARS-CoV-2infections in 389solid organ transplant recipients reported in the literature, the overall mortality rate was 16.7% (n = 65); however for those with mild or moderate Covid-19 disease this was 2.9% and 2.3% respectively; conversely, for those with severe infection the mortality rate was 52.2%.We then address questions regarding halting transplantation programs during this pandemic, whether all human tissues being considered for transplantation are capable of transmitting the infection, and if we should alter immunosuppressive medications during the pandemic.

Benzofuran and pyrrole derivatives as cannabinoid receptor modulators with in vivo efficacy against ulcerative colitis.

Aim: Highlighting the need for effective therapies for the treatment of ulcerative colitis, novel series of potential CB2 modulators (benzofuran and pyrrole carboxamides) were developed and tested for their functional activities on CB1/CB2 receptors. Results: In the benzofuran series, the cannabinoid (CB) receptor selectivity and the functional profile were dependent on the nature of the amide substituent and the position of the methoxy group, meanwhile the pyrrole derivatives, displayed an exclusive selectivity to the CB2 receptor and a functionality that is controlled by the nature of the pyrrole nitrogen substituent. Conclusion: Remarkably, we succeeded to develop potent and selective pyrrole-based CB2 receptor agonists, represented by compound 25a, which also demonstrated an exquisite anti-inflammatory effect in a dextran sodium sulfate-induced colitis model in mice.

Micro RNA-192 Is Negatively Associated With Cardiovascular Events Among Wait-Listed Potential Kidney Transplant Recipients on Hemodialysis Over a 5-year Follow-up Period.

BACKGROUND: Patients with chronic renal disease are susceptible to accelerated vascular calcification and cardiovascular morbidity and mortality. Micro RNAs (miRNAs) have been linked to the pathogenesis of cardiovascular diseases in the general population. AIM: This study was carried out to evaluate the link between miRNA 192 and vascular calcification, pre-existing as well as newly occurring major adverse cardiovascular events, and mortality among hemodialysis patients who are also considered to be potential kidney transplant recipients. METHODS: We screened 64 potential transplant recipients on hemodialysis at our university hospital. Pre-existing overt cardiovascular disease was recorded; new adverse cardiovascular events and all causes of death over an observational period of 5 years were prospectively followed. Vascular calcification was measured in the aorta using computerized tomography scans, and micro RNA 192 was measured. RESULTS: The final study population included 55 patients followed for 63 months. Micro RNA 192 was significantly lower in patients who had preexisting cardiovascular disease (P = .015) as well and in all patients who had experienced any event by the end of the observational period (P = .012). A multiregression analysis model including micro RNA, age, dialysis vintage, intradialytic hypotension, vascular calcification, diabetes, systolic blood pressure, and smoking found the only independently correlating factor to cardiovascular events in this model to be micro RNA (ß = -0.286, P = .05). CONCLUSIONS: MiRNA 192 levels are significantly lower among patients experiencing cardiovascular events while on hemodialysis awaiting kidney transplantation.

Structure-activity relationships of thiazole and benzothiazole derivatives as selective cannabinoid CB2 agonists with in vivo anti-inflammatory properties.

The strong therapeutic potential of CB2 receptor agonists for use as anti-inflammatory agents that lack psychiatric side effects has attracted substantial interest. We herein describe the rational design and synthesis of novel thiazole and benzothiazole derivatives and the evaluation of their binding affinity and functional activity on CB1 and CB2 receptors. The series with the general formula N-(3-pentylbenzo [d]thiazol-2(3H)-ylidene) carboxamide (compounds 6a-6d) exhibited the highest affinity and selectivity towards CB2 receptors with Kis in the picomolar or low nanomolar range, and selectivity indices (Ki hCB1/Ki hCB2) reaching up to 429 fold. Notably, these compounds also demonstrated an agonistic functional activity in cellular assays with EC50s in the low nanomolar range. More interestingly, compound 6d, the 3-(trifluoromethyl)benzamide derivative, exhibited remarkable protection against DSS-induced acute colitis in mice model.

VKORC1 gene (vitamin K epoxide reductase) polymorphisms are associated with cardiovascular disease in chronic kidney disease patients on hemodialysis.

Vitamin K is necessary for the carboxylation of clotting factors and matrix Gla protein (MGP). Vitamin K epoxide reductase (VKOR) is the enzyme responsible for recirculation of Vitamin K increasing its tissue availability. Polymorphisms of VKOR may alter the function of MGP, thereby influencing vascular calcification. We conducted this study to investigate the relationship of VKORC1 gene single nucleotide polymorphisms (SNP's) to vascular calcification and clinically overt cardiovascular disease in chronic kidney disease (CKD) patients on hemodialysis (HD). The study included 54 CKD patients on HD. We excluded those with diabetes or on anticoagulant therapy. Vascular calcifications were measured using computerized tomography scans and roentgenograms. Prevalent clinically overt cardiovascular disease was reported based on the evidence of documented preexisting major cardiovascular events. Genotype detection for the gene VKORC1 C1173T and G-1639A polymorphisms was carried out by polymerase chain reaction. We found a significant association between C1173T polymorphisms and vascular calcification (odds ratio [OR] = 43, P = 0.001). The mutant T allele was also linked with higher odds of vascular calcification (OR = 8.880, 95% confidence interval [CI] = 3.1-25.4, P = 0.001) and clinically overt cardiovascular disease (OR = 4.7, 95% CI = 1.5-14.7, P = 0.005). VKORC1 G-1639A polymorphisms were not associated with vascular calcification and had lower prevalence of clinically overt cardiovascular disease (OR = 0.07, 95% CI = 0.01-0.4, P = 0.001). In patients with CKD on HD, we found that VKORC1 gene polymorphisms did have an association with prevalent cardiovascular calcification and clinically overt cardiovascular disease, C1173T polymorphisms with higher risk for disease, and G-1639A with lower risk.

Comparing different calcification scores to detect outcomes in chronic kidney disease patients with vascular calcification.

BACKGROUND: There is no consensus on the most appropriate technique to diagnose vascular calcification in chronic kidney disease. This is primarily because of the absence of direct comparisons of predictive values of the various calcification scores, especially outside the coronary vascular beds, to detect clinical outcomes. METHODS: We included 93 haemodialysis patients and performed 6 vascular calcification scores: two scores utilised simple X-rays of abdominal aorta and peripheral vessels. CT scans of the thoracic, upper abdominal and lower abdominal aorta were performed to calculate the aortic calcification index and CT of the pelvis for calcification of iliac vessels. Patients were followed for 63months (mean 46.8months) for first major cardiovascular events and mortality. RESULTS: Nineteen cardiovascular events and 28 deaths occurred. Calcification was detected more sensitively in central and peripheral beds using CT scans compared to X-rays (p<0.001). CT scans detected calcification more frequently in distal than proximal vascular beds (p<0.001). Calcification of the pelvic vessels and lower abdominal aorta were most predictive of events including pre-existing cardiovascular disease O.R. 6.5 (95% C.I. 2-22; p=0.001) and O.R. 3 (95% C.I. 1.1-9; p=0.035); new major cardiovascular events H.R. 4.2 (95% C.I. 1.5-11; p=0.006) and H.R. 2 (95% C.I. 0.8-5.3; p=0.1) as well as mortality H.R. 2.8 (95% C.I. 1.3-6; p=0.01) and H.R. 2.2 (95% C.I. 1.04-5; p=0.04) respectively. CONCLUSIONS: CT based techniques are more sensitive than plain X-rays at detecting peripheral and aortic vascular calcifications. Distal CT scans of the aorta and pelvic vessels have the highest predictive value for cardiovascular events and mortality.

Discovery of novel Tetrahydrobenzo[b]thiophene and pyrrole based scaffolds as potent and selective CB2 receptor ligands: The structural elements controlling binding affinity, selectivity and functionality.

CB2-based therapeutics show strong potential in the treatment of diverse diseases such as inflammation, multiple sclerosis, pain, immune-related disorders, osteoporosis and cancer, without eliciting the typical neurobehavioral side effects of CB1 ligands. For this reason, research activities are currently directed towards the development of CB2 selective ligands. Herein, the synthesis of novel heterocyclic-based CB2 selective compounds is reported. A set of 2,5-dialkyl-1-phenyl-1H-pyrrole-3-carboxamides, 5-subtituted-2-(acylamino)/(2-sulphonylamino)-thiophene-3-carboxylates and 2-(acylamino)/(2-sulphonylamino)-tetrahydrobenzo[b]thiophene-3-carboxylates were synthesized. Biological results revealed compounds with remarkably high CB2 binding affinity and CB2/CB1 subtype selectivity. Compound 19a and 19b from the pyrrole series exhibited the highest CB2 receptor affinity (Ki = 7.59 and 6.15 nM, respectively), as well as the highest CB2/CB1 subtype selectivity (∼70 and ∼200-fold, respectively). In addition, compound 6b from the tetrahydrobenzo[b]thiophene series presented the most potent and selective CB2 ligand in this series (Ki = 2.15 nM and CB2 subtype selectivity of almost 500-fold over CB1). Compound 6b showed a full agonism, while compounds 19a and 19b acted as inverse agonists when tested in an adenylate cyclase assay. The present findings thus pave the way to the design and optimization of heterocyclic-based scaffolds with lipophilic carboxamide and/or retroamide substituent that can be exploited as potential CB2 receptor activity modulators.

Complementary and Alternative Medicine Use Among Patients With Chronic Kidney Disease and Kidney Transplant Recipients.

OBJECTIVE: To explore and compare complementary and alternative medicine (CAM) practice among subsets of patients with chronic kidney disease (CKD) and renal allograft recipients. DESIGN: Cross-sectional survey questionnaire. SETTING: Three outpatient nephrology clinics and dialysis centers in Egypt. SUBJECTS: A total of 1005 subjects were included in the study (560 predialyis patients with CKD 3-4, 245 patients on hemodialysis, and 200 transplant recipients). INTERVENTION: Face to face interview with CKD patients. The survey inquired about epidemiological data, types, sources, and patterns of CAM used as well as the effect of CAM use on the patients' interaction with modern medicine and clinical caregivers. MAIN OUTCOME MEASURE: (1) Prevalence and types of CAM used by CKD patients; (2) Associations and correlates of CAM use including epidemiological features, impact of CAM use on adherence to conventional treatment and interaction of the users with modern medical systems; (3) Differences in CAM practice between subsets of CKD patients viz. hemodialysis patients, CKD 3-4, and transplant recipients. RESULTS: Overall, 522 patients (52%) were using CAM (64% of predialyis patients, 33% of dialysis patients, and 40.5% of transplant recipients, P < .001). Herbal and natural products were the most commonly used type of CAM (78%), followed by mind and body procedures (21.6%). CAM users were more likely to be males (odds ratio [OR] 1.4; 95% confidence interval [CI] 1.1-1.6); employed (OR 1.6; 95% CI 1.2-2); urban residents (OR 1.3; 95% CI 1.2-1.5); have higher income (OR 2.6; 95% CI 2-3.6); and higher education (OR 1.6; 95% CI 1.2-2). Seventy nine percent of CAM users did not report their practices to their caregivers mainly because they were not asked; however, transplant recipients were more likely to report P < .02. Compliance to medical treatment was affected in 4.2% of users. Thirty natural products were identified as well as 4 body and mind procedures. The most commonly used herbs were Nigella sativa, Hibiscus sabdariffa, and Cymbopogon proximus. Potentially harmful CAM included intake of licorice and vinegar. CONCLUSIONS: Use of traditional medicine is highly prevalent among CKD patients. Some of these practices are potentially harmful and may affect patient compliance to modern medicine. Physicians commonly ignore to inquire about these practices, which frequently reflect patient frustration with modern medicine efficacy and/or price.

Fasting during the month of Ramadan among patients with chronic kidney disease: renal and cardiovascular outcomes.

BACKGROUND: Fasting during the month of Ramadan is a religious obligation for Muslims who represent 20% of the world population. This study explores the safety of fasting for a whole month among patients with chronic kidney disease (CKD) with the possible risk of dehydration and hyperviscosity leading to deterioration of kidney functions and vascular thrombosis. METHODS: We followed CKD patients with stable kidney function who chose to fast during the month of Ramadan. A group of nonfasting CKD patients served as controls. Serum creatinine was recorded at the beginning of the month, after 1 week of fasting, at the end of the month and 3 months later. Patients were followed for major adverse cardiovascular events (MACE). RESULTS: A total of 131 CKD patients were recruited and included in two groups: fasting and nonfasting (mean baseline estimated glomerular filtration rate 27.7, SD 13 and 21.5, SD 11.8 mL/min/1.73 m2, respectively). A rise of serum creatinine was noted during fasting in 60.4% of patients by Day 7 and was associated with intake of renin angiotensin aldosterone system antagonists [relative risk (RR) 2, P = 0.002]. Adverse cardiovascular events were observed in six patients in the fasting cohort and were associated with a rise of serum creatinine after 1 week of fasting (P = 0.009) and the presence of pre-existing cardiovascular disease (RR 15, P = 0.001); the latter association was confirmed by logistic regression analysis. Only one event was recorded in the nonfasting group, P = 0.036. CONCLUSIONS: MACE occurred more frequently among fasting CKD patients with pre-existing cardiovascular disease and were predicted by an early rise of serum creatinine.

The Association between Fibroblast Growth Factor-23 and Vascular Calcification Is Mitigated by Inflammation Markers.

BACKGROUND: Fibroblast growth factor-23 (FGF-23) has been linked to vascular calcification, ventricular hypertrophy and mortality in chronic kidney disease (CKD), although these links may not be direct and independent. Similar grave outcomes are associated with inflammation and oxidative stress in CKD. Recently, accumulating evidence has linked components of phosphate homeostasis to inflammation and oxidative stress. The interaction between the triad of inflammation, FGF-23 and cardiovascular outcomes is underinvestigated. METHODS: We studied 65 patients with stage 5 CKD on hemodialysis. Serum levels of FGF-23, high-sensitivity C-reactive protein (hsCRP), endogenous soluble receptor of advanced glycation end products (esRAGE), advanced oxidation protein products (AOPP), parathormone, lipids, calcium and phosphorous were measured. The aortic calcification index (ACI) was determined using non-contrast CT scans of the abdominal aorta. RESULTS: FGF-23 was elevated (mean: 4,681 pg/ml, SD: 3,906) and correlated with hsCRP, esRAGE, AOPP, dialysis vintage and phosphorus in univariate analysis. In multiple regression analysis, hsCRP, AOPP and phosphorus but not esRAGE were all significantly correlated to FGF-23 (R2 = 0.7, p < 0.001). In univariate analysis, ACI correlated with hsCRP, esRAGE, FGF-23, dialysis vintage, systolic blood pressure (BP) and serum cholesterol. In multiple regression analysis not including inflammation markers, ACI was associated with FGF-23. However, inclusion of inflammation markers in another multiple regression analyses showed that ACI correlated with hsCRP, BP, dialysis vintage and esRAGE but not with FGF-23 (R2 = 0.65, p < 0.001). CONCLUSION: FGF-23 is strongly correlated to various markers of inflammation and oxidative stress in hemodialysis patients. The association between FGF-23 and vascular calcification was mitigated when corrected for inflammation markers.

Endogenous soluble receptor of advanced glycation end-products (esRAGE) is negatively associated with vascular calcification in non-diabetic hemodialysis patients.

BACKGROUND: Advanced glycation end-products (AGE) accumulate in CKD and may predispose to cardiovascular disease by inducing inflammatory and oxidant stress in the vascular endothelium. Soluble forms of the receptor for AGE (RAGE) may be protective against these effects by binding AGE in the soluble phase. Accumulating evidence suggests a protective role of soluble RAGE against vascular calcification. This study investigates the association between endogenous soluble RAGE (esRAGE) and vascular calcification in hemodialysis patients. METHODS: We studied 65 non-diabetic hemodialysis patients, on 3 × 4 h dialysis schedule, and 19 controls. Serum levels of esRAGE, hsCRP, parathormone, lipids, calcium, and phosphorus were measured. Aortic calcification index (ACI) was measured using non-contrast CT of the abdominal aorta. RESULTS: Aortic calcification was detected in 64 out of 65 hemodialysis patients. Levels of esRAGE were lower in hemodialysis patients (278 pg/ml, SD 101.1) than in controls (443 ± 109 pg/ml; P = 0.001). ACI correlated negatively in stepwise multivariate analysis with esRAGE (P = 0.002) and positively with hsCRP (<0.0001), systolic blood pressure (P < 0.0001) and dialysis vintage (P = 0.05); R (2) = 0.65. CONCLUSION: Levels of esRAGE were low among hemodialysis patients and correlated negatively with ACI.

Synthesis, binding studies and molecular modeling of novel cannabinoid receptor ligands.

In the present work, we report upon the design, synthesis and biological evaluation of new anandamide derivatives obtained by modifications of the fatty acyl chain and/or of the ethanolamide 'tail'. The compounds are of the general formula: 6-(substituted-phenyl)/naphthyl-4-oxohex-5-enoic acid N-substituted amide and 7-naphthyl-5-oxohept-6-enoicacid N-substituted amide. The novel compounds had been evaluated for their binding affinity to CB1/CB2 cannabinoid receptors, binding studies showed that some of the newly developed compounds have measurable affinity and selectivity for the CB2 receptor. Compounds XI and XVIII showed the highest binding affinity for CB2 receptor. None of the compounds exhibited inhibitory activity towards anandamide hydrolysis, thus arguing in favor of their enzymatic stability. The structure-activity relationship has been extensively studied through a tailor-made homological model using constrained docking in addition to pharmacophore analysis, both feature and field based.

Fibroblast growth factor-23 (FGF-23) is independently correlated to aortic calcification in haemodialysis patients.

BACKGROUND: Vascular calcification has detrimental consequences on chronic kidney disease (CKD) patients, yet its pathogenesis is not fully understood. Fibroblast growth factor-23 (FGF-23) is involved in the regulation of mineral metabolism which may in turn affect vascular calcification. Data on the relationship between FGF-23 and peripheral vascular calcification, using conventional radiographs, are conflicting, and less is known about its relation to aortic calcification. We conducted this study to investigate the relationship between FGF-23 and aortic calcification in a standard haemodialysis setting. METHODS: The study included 65 haemodialysis patients (46 prevalent and 19 incident) on a three times 4-h dialysis schedule as well as 15 controls. Those with diabetes, oral anticoagulation or parathyroidectomy were excluded. Intact FGF-23, parathormone, lipids, calcium and phosphorus were measured. Aortic calcification index (ACI) was assessed by a non-contrast computerized tomography (CT) of the abdominal aorta. RESULTS: FGF-23 levels were higher among haemodialysis patients (4681.3 +/- 3906.1 pg/mL) compared to controls (98.2 +/- 51.9 pg/mL), P = 0.005. ACI was higher in haemodialysis patients (14.1 +/- 12) than controls (3.2 +/- 3.6), P = 0.009. FGF-23 (P < 0.0001) and systolic blood pressure (BP) (P < 0.0001) were independently related to ACI in stepwise multiple regression analysis of pooled analysis of haemodialysis patients, R(2) = 0.476; in subgroup analysis, the independent factors relating to ACI among prevalent dialysis patients were systolic BP (P < 0.0001), FGF-23 (P = 0.002) and age (P = 0.012), R(2)=0.48; whereas in incident patients, only FGF-23 was associated with ACI (P = 0.007), R(2) = 0.37. CONCLUSIONS: In haemodialysis patients, FGF-23 and ACI were significantly increased, and FGF-23 was independently associated with aortic calcification.