Mutations in the promoter region of methionine transporter gene metM (Rv3253c) confer para-aminosalicylic acid (PAS) resistance in Mycobacterium tuberculosis.

Tuberculosis (TB) is a significant global public health threat. Despite the long-standing use of para-aminosalicylic acid (PAS) as a second-line anti-TB drug, its resistance mechanism remains unclear. In this study, we isolated 90 mutants of PAS-resistant Mycobacterium tuberculosis (MTB) H37Ra in 7H11 solid medium and performed whole-genome sequencing, gene overexpression, transcription level comparison and amino acid level determination in MTB, and promoter activity by ß-galactosidase assays in Mycobacterium smegmatis to elucidate the mechanism of PAS resistance. Herein, we found that 47 of 90 (52.2%) PAS-resistant mutants had nine different mutations in the intergenic region of metM (Rv3253c) and Rv3254. Beta-galactosidase assays confirmed that mutations increased promoter activity only for metM but not Rv3254. Interestingly, overexpression of MetM or its M. smegmatis homolog (MSMEI_1796) either by its promoter in metM's direction or by exogenous expression in MTB induced PAS resistance in a methionine-dependent manner. Therefore, drug susceptibility results for the metM promoter mutants can be misleading when using standard 7H10 or 7H9 medium, which lacks methionine. At the metabolism level, PAS treatment led to higher intracellular methionine levels in the mutants than the wild type, antagonizing PAS and conferring resistance. Furthermore, 12 different mutations in the metM promoter were identified in clinical MTB strains. In summary, we found a novel mechanism of PAS resistance in MTB. Mutations in the metM (Rv3253c) promoter upregulate metM transcription and elevate intracellular methionine, which antagonize PAS. Our findings shed new light on the mechanism of PAS resistance in MTB and highlight issues with the current PAS susceptibility culture medium.IMPORTANCEAlthough para-aminosalicylic acid (PAS) has been used to treat TB for more than 70 years, the understanding of PAS resistance mechanisms is still vague, living gaps in our ability to predict resistance and apply PAS effectively in clinical practice. This study aimed to address this knowledge gap by inducing in vitro PAS resistance in Mycobacterium tuberculosis (MTB) using 7H11 medium and discovering a new PAS resistance mechanism. Our research revealed that spontaneous mutations occurring in the promoter region of the methionine transporting gene, metM, can upregulate the expression of metM, resulting in increased intracellular transport of methionine and consequently high-level resistance of Mycobacterium tuberculosis to PAS. Notably, this resistance phenotype cannot be observed when using the commonly recommended 7H10 medium, possibly due to the lack of additional methionine supply compared with that when using the 7H11 medium. Mutations on the regulatory region of metM were also found in some clinical MTB strains. These findings may have important implications for the unexplained PAS resistance observed in clinical settings and provide insight into the failures of PAS treatment. Additionally, they underscore the importance of considering the choice of culture media when conducting drug susceptibility testing for MTB.

The aminosalicylate - folate connection.

Two aminosalicylate isomers have been found to possess useful pharmacological behavior: p-aminosalicylate (PAS, 4AS) is an anti-tubercular agent that targets M. tuberculosis, and 5-aminosalicylate (5AS, mesalamine, mesalazine) is used in the treatment of ulcerative colitis (UC) and other inflammatory bowel diseases (IBD). PAS, a structural analog of pABA, is biosynthetically incorporated by bacterial dihydropteroate synthase (DHPS), ultimately yielding a dihydrofolate (DHF) analog containing an additional hydroxyl group in the pABA ring: 2'-hydroxy-7,8-dihydrofolate. It has been reported to perturb folate metabolism in M. tuberculosis, and to selectively target M. tuberculosis dihydrofolate reductase (mtDHFR). Studies of PAS metabolism are reviewed, and possible mechanisms for its mtDHFR inhibition are considered. Although 5AS is a more distant structural relative of pABA, multiple lines of evidence suggest a related role as a pABA antagonist that inhibits bacterial folate biosynthesis. Structural data support the likelihood that 5AS is recognized by the DHPS pABA binding site, and its effects probably range from blocking pABA binding to formation of a dead-end dihydropterin-5AS adduct. These studies suggest that mesalamine acts as a gut bacteria-directed antifolate, that selectively targets faster growing, more folate-dependent species.

Dopamine-based selective spectrophotometry p-aminosalicylic acid assay by hydrolyzate-triggered formation of azamonardine-like products.

BACKGROUND: The selective recognition of drugs and its metabolism or decomposition products is significant to drug development and drug resistance research. Fluorescence-based techniques provide satisfying sensitivity by target-triggered chemical reaction. However, the interference from the matrix or additives usually restricts the specific detection. It is highly desirable to explore specific chemical reactions for achieving selective perception of these species. RESULTS: We report a specific m-aminophenol (MAP)-dopamine (DA) reaction, which generates highly fluorescent azamonardine-like products. Based on this reaction, fluorometric and indirect detection of p-aminosalicylic acid (typical antituberculosis drug, PAS) can be realized using the DA-based probe with high sensitivity. The acid induces the decarboxylation of PAS and produces MAP, which reacts with DA and generates fluorescent azamonardine-like products. The practical application of the proposed method is validated by the accurate PAS analysis in urine samples and Pasinazid tablets. Interestingly, none of additives in the Pasinazid tablets contribute comparable fluorescence variation. SIGNIFICANCE: This work discovers a new MAP-DA reaction for the first time, it not only explores sensitive PAS drug detection probe, but also demonstrates the feasibility of the development of novel drug analysis platform by recognizing decomposition product with specific reaction. Thus, new avenues for the exploration of simple and rapid spectrophotometric probes toward various drug analytes with high specify and sensitivity based on this tactic might be possible in analytical and drug-related fields.

Histological Remission Placebo Rates in Ulcerative Colitis Trials: A Systematic Review and Meta-analysis.

BACKGROUND: High histologic remission rates have been reported with placebos in randomized controlled trials (RCTs) evaluating ulcerative colitis (UC) therapies and have varied based on trial designs. We performed a systematic review and meta-analysis to quantify placebo histological remission rates and identify factors influencing those rates. METHODS: MEDLINE, EMBASE, and the Cochrane library were searched from inception of the databases until December 2021. We included placebo-controlled RCTs of adult patients with UC treated with aminosalicylates, corticosteroids, immunosuppressives, biologics, and small molecules. We pooled estimates using a random-effects model and performed subgroup analysis and meta-regression to evaluate the effect of different covariates on placebo rates. RESULTS: Thirty-three studies (30 induction and 3 maintenance) were included. The overall placebo histological remission rate was 15.7% (95% confidence interval, 12.9%-19%) across all 33 studies. High heterogeneity was observed among studies with I2 = 62.10%. The pooled estimate of histological remission was 15.8% in induction studies and 14.5% in maintenance studies. Subgroup analysis revealed statistically significant differences in placebo rates when accounting for background medications, the intervention drug class, and disease severity (P = .041, .025, and .025, respectively). There was no statistical difference between induction vs maintenance studies or between different histological scales (P = .771, and .075, respectively). CONCLUSIONS: Placebo histological remission rates range from 13% to 19% in UC RCTs, but studies are highly heterogeneous. Factors found to influence placebo rates include presence of background medications, the drug used, and the disease severity. These observations inform future trial designs to minimize placebo rates and reduce heterogeneity.

High histological remission rates have been reported with placebos in ulcerative colitis randomized control trials. This review aims to quantify placebo histological remission rates and identify factors influencing those rates to improve future trial designs.

A High CMRR Differential Difference Amplifier Employing Combined Input Pairs for Neural Signal Recordings.

This article introduces a Combined .symmetrical and complementary Input Pairs (CIP) of a Differential Difference Amplifier (DDA), to boost the total Common-Mode Rejection Ratio (CMRR) for multi-channel neural signal recording. The proposed CIP-DDA employs three input pairs (transconductors). The dc-coupled input neural signal connection, via the gate terminal of the first transconductor, yields a high input impedance. The high-pass corner frequency and dc quiescent operation point are stabilized by the second transconductor. The calibration path of differential-mode gain and Common-Mode Feedback (CMFB) is provided by the proposed third transconductor. The parallel connection has no need for extra voltage headroom of input and output. The proposed CIP-DDA is targeted at integrated circuit realization and designed in a 0.18-µm CMOS technology. The proposed CIP-DDAs with system CMFB achieve an average CMRR of 103 dB, and each channel consumes circa 3.6 µW power consumption.

Whole genome sequencing reveals candidate genes involving in PAS resistance in M. Tuberculosis isolated from patients in Thailand.

Para-amino salicylic acid (PAS) was first reported by Lehmann in 1946 and used for tuberculosis treatment. However, due to its adverse effects, it is now used only as a second line anti-tuberculosis drug for treatment of multidrug resistant or extensively drug resistant M. tuberculosis. The structure of PAS is similar to para-amino benzoic acid (pABA), an intermediate metabolite in the folate synthesis pathway. The study has identified mutations in genes in folate pathway and their intergenic regions for their possibilities in responsible for PAS resistance. Genomic DNA from 120 PAS-resistant and 49 PAS-sensitive M. tuberculosis isolated from tuberculosis patients in Thailand were studied by whole genome sequencing. Twelve genes in the folate synthesis pathway were investigated for variants associated with PAS resistance. Fifty-one SNVs were found in nine genes and their intergenic regions (pabC, pabB, folC, ribD, thyX, dfrA, thyA, folK, folP). Functional correlation test confirmed mutations in RibD, ThyX, and ThyA are responsible for PAS resistance. Detection of mutation in thyA, folC, intergenic regions of thyX, ribD, and double deletion of thyA dfrA are proposed for determination of PAS resistant M. tuberculosis.

Association between mutations in a thyX-hsdS.1 region and para-aminosalicylic acid resistance in Mycobacterium tuberculosis clinical isolates.

Although para-aminosalicylic acid (PAS) has been used to treat tuberculosis agent for decades, its mechanisms of resistance are still not thoroughly understood. Previously, sporadic studies showed that certain mutations in the thyX-hsdS.1 region caused PAS resistance in M. tuberculosis, but a comprehensive analysis is lacking. Recently, we found a G-10A mutation in thyX-hsdS.1 in a PAS-resistant clinical isolate, but it did not cause PAS resistance. SNPs in thyX-hsdS.1 in 6550 clinical isolates were analyzed, and 153 SNPs were identified. C-16 T was the most common SNP identified (54.25%, 83/153), followed by C-4T (7.19%, 11/153) and G-9A (6.54%, 10/153). Subsequently, the effects of those SNPs on the promoter activity of thyX were tested, and the results showed that mutations C-1T, G-3A, C-4T, C-4G, G-7A, G-9A, C-16T, G-18C, and C-19G led to increased promoter activity compared with the wild-type sequence, but other mutations did not. Then, thyX and wild-type thyX-hsdS.1, or thyX-hsdS.1 containing specific SNPs, were overexpressed in M. tuberculosis H37Ra. The results showed that mutations resulting in increased promoter activity also caused PAS resistance. Moreover, the results of an electrophoretic mobility shift assay showed that thyX-hsdS.1 containing the C-16T mutation had a higher binding capacity to RNA polymerase than did the wild-type sequence. Taken together, our data demonstrated that among the SNPs identified in thyX-hsdS.1 of M. tuberculosis clinical isolates, only those able to increase the promoter activity of thyX caused PAS resistance and therefore can be considered as molecular markers for PAS resistance.

Bandwidth-Controllable Third-Order Band Pass Filter Using Substrate-Integrated Full- and Semi-Circular Cavities.

The article presents a novel circular substrate-integrated waveguide (SIW) bandpass filter (BPF) with controllable bandwidth. The proposed BPF was configured using two microstrip feed lines, semi-circular SIW cavities, capacitive slots, and inductive vias. The circular cavity was divided into two halves, and the two copies were cascaded. The resulting bisected and cascaded structures were then connected back-to-back. Finally, by introducing two inductive vias to the circular center cavity, a transmission zero was generated. In order to examine the design concept, a coupling matrix was generated. To demonstrate the theory, a third-order BPF was realized, fabricated, and experimentally validated. The BPF prototype features a wide passband of 8.7%, a low insertion loss of 1.1 dB, and a stopband of 1.5 f0 with a rejection level better than 20 dB, which makes it a potential candidate for microwave sensing and communication industries.

Antimycobacterial pyridine carboxamides: From design to in vivo activity.

Tuberculosis is the number one killer of infectious diseases caused by a single microbe, namely Mycobacterium tuberculosis (Mtb). The success rate of curing this infection is decreasing due to emerging antimicrobial resistance. Therefore, novel treatments are urgently needed. As an attempt to develop new antituberculars effective against both drugs-sensitive and drug-resistant Mtb, we report the synthesis of a novel series inspired by combining fragments from the first-line agents isoniazid and pyrazinamide (series I) and isoniazid with the second-line agent 4-aminosalicylic acid (series II). We identified compound 10c from series II with selective, potent in vitro antimycobacterial activity against both drug-sensitive and drug-resistant Mtb H37Rv strains with no in vitro or in vivo cytotoxicity. In the murine model of tuberculosis, compound 10c caused a statistically significant decrease in colony-forming units (CFU) in spleen. Despite having a 4-aminosalicylic acid fragment in its structure, biochemical studies showed that compound 10c does not directly affect the folate pathway but rather methionine metabolism. In silico simulations indicated the possibility of binding to mycobacterial methionine-tRNA synthetase. Metabolic study in human liver microsomes revealed that compound 10c does not have any known toxic metabolites and has a half-life of 630 min, overcoming the main drawbacks of isoniazid (toxic metabolites) and 4-aminosalicylic acid (short half-life).

Effects of sodium para-aminosalicylic acid on chelation treatment in Pb-exposed mice.

Lead (Pb) is a corrosion-resistant, heavy, non-ferrous metal. Several metal chelators have been used for the treatment of Pb poisoning. However, the efficacy of sodium para-aminosalicylic acid (PAS-Na) in enhancing Pb excretion has yet to be fully characterized. Healthy male mice (90) were divided into six groups, the normal control group was intraperitoneally (i.p.) injected with saline and the remaining group of mice i.p. 120 mg/kg Pb acetate. Four hour later, mice were subcutaneously (back) injected (s.c.) with (80, 160, 240 mg/kg) PAS-Na or 240 mg/kg edetate calcium disodium (CaNa2EDTA) or an equivalent amount of saline, once per day for 6 days. After 24-h urine sample collections, the animals were anesthetized with 5% chloral hydrate and sacrificed in batches on the 2nd, 4th, or 6th day. Levels of Pb [including manganese (Mn) and copper (Cu)] in the urine, whole blood, and brain tissues were analyzed by graphite furnace atomic absorption spectrometry. The results showed that Pb exposure increased its levels in urine and blood, and PAS-Na treatment may afford antagonistic effect on Pb poisoning, suggesting that PAS-Na is a potentially effective treatment to promote excretion of Pb.

Aminosalicylates target GPR35, partly contributing to the prevention of DSS-induced colitis.

GPR35, a class A G-protein-coupled receptor, is considered an orphan receptor; the endogenous ligand and precise physiological function of GPR35 remain obscure. GPR35 is expressed relatively highly in the gastrointestinal tract and immune cells. It plays a role in colorectal diseases like inflammatory bowel diseases (IBDs) and colon cancer. More recently, the development of GPR35 targeting anti-IBD drugs is in solid request. Nevertheless, the development process is in stagnation due to the lack of a highly potent GPR35 agonist that is also active comparably in both human and mouse orthologs. Therefore, we proposed to find compounds for GPR35 agonist development, especially for the human ortholog of GPR35. As an efficient way to pick up a safe and effective GPR35 targeting anti-IBD drug, we screened Food and Drug Administration (FDA)-approved 1850 drugs using a two-step DMR assay. Interestingly, we found aminosalicylates, first-line medicine for IBDs whose precise target remains unknown, exhibited activity on both human and mouse GPR35. Among these, pro-drug olsalazine showed the most potency on GPR35 agonism, inducing ERK phosphorylation and ß-arrestin2 translocation. In dextran sodium sulfate (DSS)-induced colitis, the protective effect on disease progression and inhibitory effect on TNFα mRNA expression, NF-κB and JAK-STAT3 pathway of olsalazine are compromised in GPR35 knock-out mice. The present study identified a target for first-line medicine aminosalicylates, highlighted that uncleaved pro-drug olsalazine is effective, and provided a new concept for the design of aminosalicylic GPR35 targeting anti-IBD drug.

The correlation between serum levels and placental tissue expression of PLGF and sFLT-1 and the FIGO grading of the placenta accreta spectrum disorders.

OBJECTIVE: This study aims to further explore the role of angiogenic vs anti-angiogenic factors in placenta accreta spectrum (PAS). METHODS: This cohort study included all patients with placenta previa and placenta accreta spectrum (PAS) disorders undergoing surgery at Dr. Soetomo Hospital (Academic Hospital of Universitas Airlangga, Surabaya, Indonesia) from May to September 2021. Venous blood samples for PLGF and sFlt-1 were drawn immediately prior to surgery. Placental tissue samples were taken during surgery. The FIGO grading was diagnosed intraoperatively by an experienced surgeon and confirmed by the pathologist and followed by immunohistochemistry (IHC) staining. The sFlt-1 and PLGF serum were performed by an independent laboratory technician. RESULTS: Sixty women were included in this study (20 women with placenta previa; 10 women with FIGO PAS grade 1; 8 women with FIGO PAS grade 2; 22 women with FIGO PAS grade 3). The median with 95% Confidence interval of PLGF serum values in placenta previa, FIGO grade I, grade II, and grade III were 233.68 (0.00-2434.00), 124.39 (10.42-663.68), 236.89 (18.83-418.99) and 237.31 (2.26-3101.00) (p = .736); the median values with 95% CI of serum sFlt-1 levels in placenta previa, FIGO grade I, grade II, and grade III were 2816.50 (418.00-12925.00), 2506.00 (227.50-16104.00), 2494.50 (888.52-20812.00), and 1601.00 (662.16-9574.00) (p = .037). Placental PLGF expression in placenta previa, FIGO grade 1, grade II, and grade III showed median values (with 95% CI) of 4.00 (1.00-9.00), 4.00 (2.00-9.00), 4.00 (4.00-9.00), and 6.00 (2.00-9.00) (p = .001); sFlt-1 expression median values (with 95% CI) were 6.00 (2.00-9.00), 6.00 (2.00-9.00), 4.00 (1.00-9.00), and 4.00 (1.00-9.00) (p = .004). Serum PLGF and sFlt-1 levels did not correlate with placental tissue expression (p = .228; p = .586). CONCLUSION: There are differences in PAS's angiogenic processes ​according to the severity of trophoblast cell invasion. But there is no overall correlation between serum levels and PLGF and sFlt-1 expression in the placenta, suggesting the imbalance between angiogenic and anti-angiogenic are local mechanisms in the placental and the uterine wall.

Variation in missed doses and reasons for discontinuation of anti-tuberculosis drugs during hospital treatment for drug-resistant tuberculosis in South Africa.

BACKGROUND: Updated World Health Organization (WHO) treatment guidelines prioritize all-oral drug-resistant tuberculosis (DR-TB) regimens. Several poorly tolerated drugs, such as amikacin and para-aminosalicylic acid (PAS), remain treatment options for DR-TB in WHO-recommended longer regimens as Group C drugs. Incomplete treatment with anti-TB drugs increases the risk of treatment failure, relapse, and death. We determined whether missed doses of individual anti-TB drugs, and reasons for their discontinuation, varied in closely monitored hospital settings prior to the 2020 WHO DR-TB treatment guideline updates. METHODS: We collected retrospective data on adult patients with microbiologically confirmed DR-TB between 2008 and 2015 who were selected for a study of acquired drug resistance in the Western Cape Province of South Africa. Medical records through mid-2017 were reviewed. Patients received directly observed treatment during hospitalization at specialized DR-TB hospitals. Incomplete treatment with individual anti-TB drugs, defined as the failure to take medication as prescribed, regardless of reason, was determined by comparing percent missed doses, stratified by HIV status and DR-TB regimen. We applied a generalized mixed effects model. RESULTS: Among 242 patients, 131 (54%) were male, 97 (40%) were living with HIV, 175 (72%) received second-line treatment prior to first hospitalization, and 191 (79%) died during the study period. At initial hospitalization, 134 (55%) patients had Mycobacterium tuberculosis with resistance to rifampicin and isoniazid (multidrug-resistant TB [MDR-TB]) without resistance to ofloxacin or amikacin, and 102 (42%) had resistance to ofloxacin and/or amikacin. Most patients (129 [53%]) had multiple hospitalizations and DST changes occurred in 146 (60%) by the end of their last hospital discharge. Incomplete treatment was significantly higher for amikacin (18%), capreomycin (18%), PAS (17%) and kanamycin (16%) than other DR-TB drugs (P<0.001), including ethionamide (8%), moxifloxacin (7%), terizidone (7%), ethambutol (7%), and pyrazinamide (6%). Among the most frequently prescribed drugs, second-line injectables had the highest rates of discontinuation for adverse events (range 0.56-1.02 events per year follow-up), while amikacin, PAS and ethionamide had the highest rates of discontinuation for patient refusal (range 0.51-0.68 events per year follow-up). Missed doses did not differ according to HIV status or anti-TB drug combinations. CONCLUSION: We found that incomplete treatment for second-line injectables and PAS during hospitalization was higher than for other anti-TB drugs. To maximize treatment success, interventions to improve person-centered care and mitigate adverse events may be necessary in cases when PAS or amikacin (2020 WHO recommended Group C drugs) are needed.

Synthesis, biological evaluation and molecular docking study of some new 4-aminosalicylic acid derivatives as anti-inflammatory and antimycobacterial agents.

In this study, new derivatives of the antitubercular and anti-inflammatory drug, 4-aminosaliclic acids (4-ASA) were synthesized, characterized, and evaluated for these activities. In vivo and in viro evaluation of anti-inflammatory activity revealed that compounds 10, 19 and 20 are the most active with potent cyclooxygenase-2 (COX-2) and 5-lipooxgenase (5-LOX) inhibition and without causing gasric lesions. The minimum inhibitory concentrations (MIC) of the newly synthesized compound were, also, measured against Mycobacterium tuberculosis H37RV. Among the tested compounds 17, 19 and 20 exhibited significant activities against the growth of M. tuberculosis. 20 is the most potent with (MIC 1.04 µM) 2.5 folds more potent than the parent drug 4-ASA. 20 displayed low cytotoxicity against normal cell providing a high therapeutic index. Important structure features were analyzed by docking and structure-activity relationship analysis to give better insights into the structural determinants for predicting the anti-inflammatory and anti-TB activities. Our results indicated that compounds 19 and 20 are potential lead compounds for the discovery of dual anti-inflammatory and anti-TB drug candidates.

Sodium Para-Aminosalicylic Acid Modulates Autophagy to Lessen Lead-Induced Neurodegeneration in Rat Cortex.

Lead (Pb) is a common heavy metal contaminant in the environment, and it may perturb autophagy and cause neurodegeneration. Although sodium para-aminosalicylic (PAS-Na) has been shown to protect the brain from lead-induced toxicity, the mechanisms associated with its efficacy have yet to be fully understood. In this study, we evaluated the efficacy of PAS-Na in attenuating the neurotoxic effects of lead, as well as the specific mechanisms that mediate such protection. Lead exposure resulted in weight loss and injury to the liver and kidney, and PAS-Na had a protective effect against this damage. Both short-term and subchronic lead exposure impaired learning ability, and this effect was reversed by PAS-Na intervention. Lead exposure also perturbed autophagic processes through the modulation of autophagy-related factors. Short-term lead exposure downregulated LC3 and beclin1 and upregulated the expression of p62; subchronic lead exposure upregulated the expression of LC3, beclin1, and P62. It follows that PAS-Na had an antagonistic effect on the activation of the above autophagy-related factors. Overall, our novel findings suggest that PAS-Na can protect the rat cortex from lead-induced toxicity by regulating autophagic processes. (1) Short-term lead exposure inhibits autophagy, whereas subchronic lead exposure promotes autophagy. (2) PAS-NA ameliorated the abnormal process of lead-induced autophagy, which had a protective effect on the cerebral cortex.

Reduced humoral response to two doses of COVID-19 vaccine in patients with inflammatory bowel disease: Data from ESCAPE-IBD, an IG-IBD study.

BACKGROUND: Patients on immunosuppressive drugs have been excluded from COVID-19 vaccines trials, creating concerns regarding their efficacy. AIMS: To explore the humoral response to COVID-19 vaccines in patients with inflammatory bowel disease (IBD) METHODS: Effectiveness and Safety of COVID-19 Vaccine in Patients with Inflammatory Bowel Disease (IBD) Treated with Immunomodulatory or Biological Drugs (ESCAPE-IBD) is a prospective, multicentre study promoted by the Italian Group for the study of Inflammatory Bowel Disease. We present data on serological response eight weeks after the second dose of COVID-19 vaccination in IBD patients and healthy controls (HCs). RESULTS: 1076 patients with IBD and 1126 HCs were analyzed. Seropositivity for anti-SARS-CoV-2 IgG was reported for most IBD patients, even if with a lesser rate compared with HCs (92.1% vs. 97.9%; p<0.001). HCs had higher antibody concentrations (median OD 8.72 [IQR 5.2-14-2]) compared to the whole cohort of IBD patients (median OD 1.54 [IQR 0.8-3.6]; p<0.001) and the subgroup of IBD patients (n=280) without any treatment or on aminosalicylates only (median OD 1.72 [IQR 1.0-4.1]; p<0.001). CONCLUSIONS: Although most IBD patients showed seropositivity after COVID-19 vaccines, the magnitude of the humoral response was significantly lower than in HCs. Differently from other studies, these findings seem to be mostly unrelated to the use of immune-modifying treatments (ClinicalTrials.govID:NCT04769258).

Preventive treatment with sodium para-aminosalicylic acid inhibits manganese-induced apoptosis and inflammation via the MAPK pathway in rat thalamus.

Excessive exposure to manganese (Mn) may lead to neurotoxicity, referred to as manganism. In several studies, sodium para-aminosalicylic acid (PAS-Na) has shown efficacy against Mn-induced neurodegeneration by attenuating the neuroinflammatory response. The present study investigated the effect of Mn on inflammation and apoptosis in the rat thalamus, as well as the underlying mechanism of the PAS-Na protective effect. The study consisted of sub-acute (Mn treatment for 4 weeks) and sub-chronic (Mn and PAS-Na treatment for 8 weeks) experiments. In the sub-chronic experiments, pro-inflammatory cytokines, namely tumor necrosis factor α (TNF-α), interleukin 1ß (IL-1ß), and cyclooxygenase 2 (COX-2) were significantly increased in the Mn-exposed group compared to the control II. PAS-Na treatment led to a significant reduction in the Mn-induced neuroinflammation by inhibiting IL-1ß and COX-2 mRNA expression and reducing IL-1ß secretion and JNK/p38 MAPK pathway activity. Furthermore, immunohistochemical analysis showed that the expression of caspase-3 was significantly increased in both the sub-acute and sub-chronic experimental paradigms concomitant with a significant decrease in B-cell lymphoma 2 (Bcl-2) in the thalamus of Mn-treated rats. PAS-Na also decreased the expression levels of several apoptotic markers downstream of the MAPK pathway, including Bcl-2/Bax and caspase-3, while up-regulating anti-apoptotic Bcl-2 proteins. In conclusion, Mn exposure led to inflammation in the rat thalamus concomitant with apoptosis, which was mediated via the MAPK signaling pathway. PAS-Na treatment antagonized effectively Mn-induced neurotoxicity by inhibiting the MAPK activity in the same brain region.

Sodium para-aminosalicylic acid ameliorates brain neuroinflammation and behavioral deficits in juvenile lead-exposed rats by modulating MAPK signaling pathway and alpha-synuclein.

Lead (Pb) is a developmental neurotoxin that can disrupt brain development and damage the brain regions responsible for executive function, behavioral regulation and fine motor control. Sodium para-aminosalicylic acid (PAS-Na) is a non-steroidal anti-inflammatory drug that can cross the blood-brain barrier. The purpose of this study was to examine the effects of juvenile rat Pb exposure on behavioral changes and brain inflammation, and the efficacy of PAS-Na in ameliorating these effects. The results showed that Pb exposure during the juvenile period (from weaning to adult period) delayed rats' growth development and impaired their motor learning. Pb exposure not only increased Pb concentrations in several brain regions (including hippocampus, striatum and substantia nigra), but also disrupted metal-homeostasis in the brain, as higher levels of iron (Fe) and calcium (Ca) were observed in the substantia nigra. Moreover, Pb activated the MAPK pathway and increased levels of inflammatory factors such as IL-1ß, TNF-α and IL-6 in the hippocampus, striatum and substantia nigra. Furthermore, Pb increased the levels of alpha-synuclein (α-syn) in these brain sites. PAS-Na improved the motor deficits and brain inflammation in the Pb-exposed rats. Moreover, the elevated Pb, Fe and Ca concentrations in the brain were significantly reduced by PAS-Na, which contains amino, carboxyl and hydroxyl functional groups, suggesting that it may act as a chelator of brain metals. In addition, PAS-Na inhibited the Pb-induced MAPK pathway activation and α-syn accumulation in the same brain regions. Taken together, our novel study suggest that PAS-Na shows efficacy in improving the Pb-induced behavioral changes in rats by inhibiting MAPK-dependent inflammatory pathways and reducing α-syn accumulation.

Hybridization Approach Toward Novel Antituberculars: Design, Synthesis, and Biological Evaluation of Compounds Combining Pyrazinamide and 4-Aminosalicylic Acid.

Apart from the SARS-CoV-2 virus, tuberculosis remains the leading cause of death from a single infectious agent according to the World Health Organization. As part of our long-term research, we prepared a series of hybrid compounds combining pyrazinamide, a first-line antitubercular agent, and 4-aminosalicylic acid (PAS), a second-line agent. Compound 11 was found to be the most potent, with a broad spectrum of antimycobacterial activity and selectivity toward mycobacterial strains over other pathogens. It also retained its in vitro activity against multiple-drug-resistant mycobacterial strains. Several structural modifications were attempted to improve the in vitro antimycobacterial activity. The δ-lactone form of compound 11 (11') had more potent in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv. Compound 11 was advanced for in vivo studies, where it was proved to be nontoxic in Galleria mellonella and zebrafish models, and it reduced the number of colony-forming units in spleens in the murine model of tuberculosis. Biochemical studies showed that compound 11 targets mycobacterial dihydrofolate reductases (DHFR). An in silico docking study combined with molecular dynamics identified a viable binding mode of compound 11 in mycobacterial DHFR. The lactone 11' opens in human plasma to its parent compound 11 (t1/2 = 21.4 min). Compound 11 was metabolized by human liver fraction by slow hydrolysis of the amidic bond (t1/2 = 187 min) to yield PAS and its starting 6-chloropyrazinoic acid. The long t1/2 of compound 11 overcomes the main drawback of PAS (short t1/2 necessitating frequent administration of high doses of PAS).

Sodium Para-aminosalicylic Acid Inhibits Lead-Induced Neuroinflammation in Brain Cortex of Rats by Modulating SIRT1/HMGB1/NF-κB Pathway.

Lead (Pb) is considered to be a major environmental pollutant and occupational health hazard worldwide which may lead to neuroinflammation. However, an effective treatment for Pb-induced neuroinflammation remains elusive. The aim of this study was to investigate the mechanisms of Pb-induced neuroinflammation, and the therapeutic effect of sodium para-aminosalicylic acid (PAS-Na, a non-steroidal anti-inflammatory drug) in rat cerebral cortex. The results indicated that Pb exposure induced pathological damage in cerebral cortex, accompanied by increased levels of inflammatory factors tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1ß). Moreover, Pb decreased the expression of silencing information regulator 2 related enzyme 1 (SIRT1) and brain-derived neurotrophic factor (BDNF), and increased the levels of high mobile group box 1 (HMGB1) expression and p65 nuclear factor-κB (NF-κB) phosphorylation. PAS-Na treatment ameliorated Pb-induced histopathological changes in rat cerebral cortex. Moreover, PAS-Na reduced the Pb-induced increase of TNF-α and IL-1ß levels concomitant with a significant increase in SIRT1 and BDNF levels, and a decrease in HMGB1 and the phosphorylation of p65 NF-κB expression. Thus, PAS-Na may exert anti-inflammatory effects by mediating the SIRT1/HMGB1/NF-κB pathway and BDNF expression. In conclusion, in this novel study PAS-Na was shown to possess an anti-inflammatory effect on cortical neuroinflammation, establishing its efficacy as a potential treatment for Pb exposures.