Slow Metabolism Research Articles

In Vitro Rooting of Poplar: Effects and Metabolism of Dichlorprop Auxin Ester Prodrugs.

Efficient adventitious root formation is essential in micropropagation. Auxin prodrugs, inactive precursors that convert into active auxins within the plant, offer potentially improved rooting control and reduced phytotoxicity. This study investigated the efficacy of dichlorprop ester (DCPE), commercialized as Corasil® and Clemensgros® (originally intended to increase grapefruit size), in promoting in vitro root initiation in the model plant Populus × canadensis, compared to its hydrolyzed form DCP and the related compound C77. DCPE displayed a stronger root-inducing effect than DCP, especially at lower concentrations (0.01 and 0.1 µM). Notably, at 1 µM, both DCP and DCPE induced abundant aerial root formation, a phenomenon not previously observed in poplar with traditional auxin treatments. Metabolite analysis revealed distinct patterns. DCPE treatment resulted in rapid hydrolysis to DCP, leading to faster and more systemic distribution of the active auxin throughout the plant, compared to direct DCP application. C77 treatments showed slower uptake and limited translocation combined with slow metabolism to DCP. These results highlight the potential of auxin prodrugs like DCPE as an effective and controllable auxin source for optimizing in vitro rooting protocols in woody plant species.

Stereoselective In Vitro Metabolism, Hepatotoxicity, and Cytotoxic Effects of Four Enantiomers of the Fungicide Propiconazole.

Propiconazole (PRO) is a chiral triazole fungicide that has been widely used for several years. However, its metabolic characteristics and hepatotoxicity in the chiral level environment remain unclear. In this study, the stereoselective behavior of PRO was investigated by using liver microsome incubation, cell viability assay, inhalation exposure, and molecular docking. Our results demonstrated that the isomers trans (-)-2R,4R-PRO and cis (+)-2R,4S-PRO exhibited slower metabolic rates in rat liver microsomes. The cytochrome P450 family 1 subfamily A polypeptide 2 enzyme was found to play a key role in the metabolism of PRO, contributing to its stereoselective behavior. Histopathological and cell viability results showed that exposure to rac-PRO could induce severe hepatotoxicity in mice. This effect might be related to the accumulation of cis (+)-2R,4S-PRO in the liver, which has a slow metabolism and is highly toxic. Our findings indicate that avoiding the application of cis (+)-2R,4S-PRO in agriculture can significantly reduce adverse effects on nontarget organisms.

Determining Targets for Antiretroviral Drug Concentrations: A Causal Framework Illustrated With Pediatric Efavirenz Data From the CHAPAS-3 Trial.

Determining a therapeutic window for maintaining antiretroviral drug concentrations within an appropriate range is required for identifying effective dosing regimens. The limits of this window are typically calculated using predictive models. We propose that target concentrations should instead be calculated based on counterfactual probabilities of relevant outcomes and describe a counterfactual framework for this. The proposed framework is applied in an analysis including longitudinal observational data from 125 HIV-positive children treated with efavirenz-based regimens within the CHAPAS-3 trial, which enrolled children < 13 years in Zambia/Uganda. A directed acyclic graph was developed to visualize the mechanisms affecting antiretroviral concentrations. Causal concentration-response curves, adjusted for measured time-varying confounding of weight and adherence, are calculated using g-computation. The estimated curves show that higher concentrations during follow-up, 12/24 h after dose, lead to lower probabilities of viral failure (> 100 c/mL) at 96 weeks of follow-up. Estimated counterfactual failure probabilities under the current target range of 1-4 mg/L range from 24% to about 2%. The curves are almost identical for slow, intermediate and extensive metabolizers and show that a mid-dose concentration level of ≥ 3.5 mg/L would be required to achieve a failure probability of < 5%. Our analyses demonstrate that a causal approach may lead to different minimum concentration limits than analyses that are based on purely predictive models. Moreover, the approach highlights that indirect causes of failure, such as patients' metabolizing status, may predict patients' failure risk, but do not alter the threshold at which antiviral activity of efavirenz is severely reduced.

Selective production of the itaconic acid-derived compounds 2-hydroxyparaconic and itatartaric acid

There is a strong interest in itaconic acid in the medical and pharmaceutical sectors, both as an anti-bacterial compound and as an immunoregulator in mammalian macrophages. Fungal hosts also produce itaconic acid, and in addition they can produce two derivatives 2-hydroxyparaconic and itatartaric acid. Not much is known about these two derivatives, while their structural analogy to itaconate could open up several applications. In this study, we report the production of these two itaconate-derived compounds. By overexpressing the itaconate P450 monooxygenase Cyp3 in a previously engineered itaconate-overproducing Ustilago cynodontis strain, itaconate was converted to its lactone 2-hydroxyparaconate. The second product itatartarate is most likely the result of the subsequent lactone hydrolysis. A major challenge in the production of 2-hydroxyparaconate and itatartarate is their co-production with itaconate, leading to difficulties in their purification. Achieving high derivatives specificity was therefore the paramount objective. Different strategies were evaluated including process parameters such as substrate and pH, as well as strain engineering focusing on Cyp3 expression and product export. 2-hydroxyparaconate and itatartarate were successfully produced from glucose and glycerol, with the latter resulting in a higher derivatives specificity due to an overall slower metabolism on this non-preferred carbon source. The derivatives specificity could be further increased by metabolic engineering approaches including the exchange of the native itaconate transporter Itp1 with the Aspergillus terreus itaconate transporter MfsA. Both 2-hydroxyparaconate and itatartarate were recovered from fermentation supernatants following a pre-existing protocol. 2-hydroxyparaconate was recovered first through a process of evaporation, lactonization, and extraction with ethyl acetate. Subsequently, itatartarate could be obtained in the form of its sodium salt by saponification of the purified 2-hydroxyparaconate. Finally, several analytical methods were used to characterize the resulting products and their structures were confirmed by nuclear magnetic resonance spectroscopy. This work provides a promising foundation for obtaining 2-hydroxyparaconate and itatartarate in high purity and quantity. This will allow to unravel the full spectrum of potential applications of these novel compounds.

Biomass competition connects individual and community scaling patterns

Both metabolism and growth scale sublinearly with body mass across species. Ecosystems show the same sublinear scaling between production and total biomass, but ecological theory cannot reconcile the existence of these nearly identical scalings at different levels of biological organization. We attempt to solve this paradox using marine phytoplankton, connecting individual and ecosystem scalings across three orders of magnitude in body size and biomass. We find that competitive interactions determined by biomass slow metabolism in a consistent fashion across species of different sizes. These effects dominate over species-specific peculiarities, explaining why community composition does not affect respiration and production patterns. The sublinear scaling of ecosystem production thus emerges from this metabolic density-dependence that operates across species, independently of the equilibrium state or resource regime. Our findings demonstrate the connection between individual and ecosystem scalings, unifying aspects of physiology and ecology to explain why growth patterns are so strikingly similar across scales.

Do CYP2D6 polymorphisms affect the efficacy and toxicity of flecainide? A cohort study

Abstract Background The CYP2D6 enzyme, coded by the CYP2D6 gene, is the primary metabolic pathway for flecainide.(1,2) Over the years, studies on how different variants of this gene affect flecainide metabolism and efficacy have yielded contradictory results.(3–7) This is likely due to the fact that CYP2D6 pharmacogenetic classifications were not standardized until 2017.(8,9) Purpose To date, there has been no published study using a standardized classification to assess the efficacy and toxicity of flecainide across different CYP2D6 phenotypes; therefore, we decided to study this. Methods We conducted a cohort study with data collected through indirect methods, blinding all parties involved except the statistician. We identified patients with flecainide prescriptions (100 mg/12 h) and follow-up in our health area (n=450,136 people) between 2017 and 2021. A primary combined endpoint composed of initial inefficacy and early toxicity was pre-set, and a secondary combined endpoint of toxicity or inefficacy during follow-up. Results 104 patients met the criteria and agreed to participate: 38 (36.5%) intermediate metabolizers, 52 (50%) normal metabolizers, 2 (1.9%) could not be classified with certainty (compatible with intermediate or normal metabolizers), 7 (6.7%) poor metabolizers, 4 (3.8%) ultra-rapid metabolizers, and 1 (1%) possible hybrid. Intermediate and normal metabolizers showed an almost superimposable incidence of the primary endpoint (28,9% vs 28,8%, p=0.99), early inefficacy (21,6% vs 17,4%, p=0.97) and early toxicity (13,2% vs 13,3%, p=0.72). No significant differences were observed in multivariate analysis (p=0.76, picture 1) or in a combined endpoint of toxicity or inefficacy during follow-up (p=0.58, Kaplan-Meier in picture 2). Differences were seen in the primary endpoint when comparing poor metabolizers to the rest of the sample, although they did not reach statistical significance (p=0.07), likely due to the small number of patients in this group (n=7, absolute risk reduction -32%; 95% confidence interval: -41% to -23%). Conclusions Using the standardized classification for CYP2D6 pharmacogenetics, no statistically significant differences were detected between the two largest groups, intermediate and normal metabolizers. It is possible that better results are achieved in poor metabolizers. Based on these results, it is worth questioning whether, in an attempt to minimize the risk of flecainide toxicity, doses that are subtherapeutic in all groups except slow metabolizers have been used unknowingly.

Renal Allograft Function and the Tacrolimus C/D Ratio: Insights from a Prospective Study on MeltDose Tacrolimus

Background: The tacrolimus concentration-to-dose (C/D) ratio is valuable for optimizing nephrotoxicity-related renal outcomes. Prospective data on the C/D ratio in kidney transplant recipients newly treated with MeltDose tacrolimus are limited. We analyzed the C/D ratio pattern of MeltDose tacrolimus and its effect on posttransplant renal function, comparing it with the literature data on immediate-release tacrolimus (IR-Tac). Methods: In total, 101 adult kidney transplant recipients on a standard immunosuppressive regimen including MeltDose tacrolimus were enrolled in this prospective, multicenter cohort study and followed for 12 months. The C/D ratio classified patients as fast, intermediate, or slow metabolizers. Renal function was assessed via the estimated glomerular filtration rate (eGFR). MeltDose tacrolimus data were compared with previous IR-Tac data by bootstrapping. Results: The cohort exhibited a right-skewed C/D ratio distribution with a mean of 2.12 ng/mL × 1/mg, which was significantly greater than the 1.29 mean for IR-Tac (p &lt; 0.001). Compared with fast metabolizers, slow metabolizers of MeltDose tacrolimus experienced greater eGFR gains at 6 months post-transplantation (median +7.9 vs. −3.6 mL/min; p = 0.005). A Bayesian linear mixed-effects model predicting the eGFR at month 12 identified the baseline eGFR, time from transplant, body mass index, and log-transformed C/D ratio as significant variables. A one-unit increase in the log-transformed C/D ratio corresponded to an approximate increase of 4.5 mL/min in the eGFR at month 12. Conclusions: Slow metabolizers of MeltDose tacrolimus had significantly better renal function outcomes than fast metabolizers. MeltDose tacrolimus is associated with slower metabolism than is IR-Tac, as evidenced by its higher C/D ratios.

6404 Iodide Metabolism Anomalies in Patients with Thyroid Cancer; A Case Series

Abstract Disclosure: G.I. Uwaifo: None. Thyroid cancer is often treatable and often involves iodine ablation therapy. Iodine based imaging and/or therapy can be complicated in patients with abnormal iodide metabolism. We present two patients with thyroid cancer and disparate abnormal iodide metabolism. Case 1 is a 35 yr old Caucasian lady with papillary thyroid cancer (PTC) stage 1 with no metastases. After total thyroidectomy and prior to I-131 remnant ablation she had a contrast Chest CT for shortness of breath. A month after serum iodine was elevated (545 Ug/L; 40—92). 24 hr urine iodine levels was also elevated; (2,300Ug/day; 150-500). She denied dietary intake of iodine rich foods. Ablation was postponed and she commenced a strict “zero” iodine diet. Despite this and despite having no further contrast imaging serum and urinary iodine remain elevated for nearly 3 yrs. Further history indicated episodes of sensitivity to several medications and Cytochrome P450 genetic profiling revealed two polymorphisms of CYP P450 2C19 and 2D6 associated with slow drug metabolizer phenotype. 34 months after her Chest CT with serum iodine of 127Ug/L and 24 hr Urine iodine of 652 she had radio iodine-ablation (RIA) with 130Mci of I-131. She had post treatment dysgeusia and parotitis. She remains on a low iodine diet and is presumably cured. Case 2 is a 66 yr old Caucasian man referred for second opinion regarding therapeutic options for known metastatic PTC with metastases to thoracic spine and lungs. He was diagnosed with follicular variant PTC 7 yrs ago. He had total thyroidectomy and repeated RIAs with a total accumulated dose of ∼ 850Mci and last RIA 3 yrs ago. His latest two whole body I-131 scans were -ve despite elevated thyroglobulins and metastatic disease. He was unable to tolerate sorefanib. He is on thyroid hormone repletion and quarterly denosumab. Contrast PET-CT scan a week prior showed extensive metastatic disease and thyroglobulins in the 300—650 ng/ml range. Work up for repeat whole body I-131 scan revealed curiously that serum iodine was 46 Ug/L (40-92) despite his recent contrast study and this was confirmed on two repeats. 24 hr urine iodine was reduced; 87 ug/day (150-500) and he had a typical diet with no excess intake of goitrogens. Based on history of often needing significantly higher doses of medications like opioids, anesthetics and sedatives cytochrome P450 genetic profile obtained showed two polymorphisms (of CYP P450 2C-19 and CVPs 3A4 +3A5) associated with fast metabolizer phenotype. Given his unusually rapid iodine clearance the utility of any further iodine based imaging and/or therapy was deemed dubious. His current management continues without change. We present two patients with extremes of iodine metabolic processing that had clinical management significance. Careful evaluation of ambient iodine status of patients is an important part of the preparation of thyroid cancer patients for iodine based imaging and/or therapy. Presentation: 6/1/2024

Identification of pharmacological inducers of a reversible hypometabolic state for whole organ preservation

Drugs that induce reversible slowing of metabolic and physiological processes would have great value for organ preservation, especially for organs with high susceptibility to hypoxia-reperfusion injury, such as the heart. Using whole-organism screening of metabolism, mobility, and development in Xenopus, we identified an existing drug, SNC80, that rapidly and reversibly slows biochemical and metabolic activities while preserving cell and tissue viability. Although SNC80 was developed as a delta opioid receptor activator, we discovered that its ability to slow metabolism is independent of its opioid modulating activity as a novel SNC80 analog (WB3) with almost 1000 times less delta opioid receptor binding activity is equally active. Metabolic suppression was also achieved using SNC80 in microfluidic human organs-on-chips, as well as in explanted whole porcine hearts and limbs, demonstrating the cross-species relevance of this approach and potential clinical relevance for surgical transplantation. Pharmacological induction of physiological slowing in combination with organ perfusion transport systems may offer a new therapeutic approach for tissue and organ preservation for transplantation, trauma management, and enhancing patient survival in remote and low-resource locations.

Identification of pharmacological inducers of a reversible hypometabolic state for whole organ preservation.

Drugs that induce reversible slowing of metabolic and physiological processes would have great value for organ preservation, especially for organs with high susceptibility to hypoxia-reperfusion injury, such as the heart. Using whole-organism screening of metabolism, mobility, and development in Xenopus, we identified an existing drug, SNC80, that rapidly and reversibly slows biochemical and metabolic activities while preserving cell and tissue viability. Although SNC80 was developed as a delta opioid receptor activator, we discovered that its ability to slow metabolism is independent of its opioid modulating activity as a novel SNC80 analog (WB3) with almost 1000 times less delta opioid receptor binding activity is equally active. Metabolic suppression was also achieved using SNC80 in microfluidic human organs-on-chips, as well as in explanted whole porcine hearts and limbs, demonstrating the cross-species relevance of this approach and potential clinical relevance for surgical transplantation. Pharmacological induction of physiological slowing in combination with organ perfusion transport systems may offer a new therapeutic approach for tissue and organ preservation for transplantation, trauma management, and enhancing patient survival in remote and low-resource locations.

Post mortem chiral analysis of MDMA and MDA in human blood and hair

Drug-related fatalities in the EU are predominantly associated with opioids. MDMA (Ecstasy) consumption results in fewer lethal intoxications despite its widespread use. This study investigates MDMA-related fatalities, focusing on enantiomer ratios of MDMA and its metabolite MDA to explore the role of metabolism in fatal outcomes. MDMA induces euphoria, increased empathy, and physiological effects such as tachycardia, hypertension, and hyperthermia. Metabolism mainly involves CYP1A2 and CYP2D6, with polymorphism of the latter influencing metabolism rates. Our institute observed several MDMA-related fatalities, which prompted an investigation into the potential role of inefficient drug metabolism in these cases. A novel quantitative chiral analysis method was developed and validated for MDMA, MDA, amphetamine and methamphetamine enantiomers in human blood. Analysis of post mortem blood samples from eleven MDMA-related fatalities exhibited a wide range of concentrations and enantiomer ratios. Variability in R/S MDMA ratios, however, could be linked to the time period of metabolism. Hair analysis revealed high MDMA concentrations in all segments, irrespective of prior drug abuse anamnesis. Therefore, hair analysis may not be suitable for the assessment of past drug use in ecstasy-related fatalities. The results indicated that elevated levels of the MDMA enantiomer are correlated with longer survival times in cases of intoxication. However, there was no clear evidence for slowed MDMA metabolism as a cause of lethal intoxications. While challenges remain due to the diversity of cases, this study contributes valuable insights into ecstasy intoxications, aiding future interpretation of post mortem analysis.

Distribution of CYP3A4 and CYP3A5 Polymorphisms and Genotype Combination Implicated in Tacrolimus Metabolism.

Human cytochrome P450 (CYP), particularly CYP3A4 and CYP3A5 is mainly responsible for the metabolism of several drugs including tacrolimus. Significant interracial/interethnic variation in the expression and function of CYP3A5 and CYP3A4 is caused by Single Nucleotide Polymorphisms (SNPs) of genes encoding these proteins. The present study investigated the genetic polymorphisms CYP3A4*1B, CYP3A4*22, and CYP3A5*3 in the Tunisian population. We included in this study, Tunisian healthy subjects and renal transplant recipients receiving tacrolimus. CYP3A4 and CYP3A5 genotyping were performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). According to the genotypic combination of the three CYP polymorphisms, we have identified for the first time four metabolizers statuses: slow metabolizers (SM), intermediate metabolizers (IM), high metabolizers (HM), and extensive metabolizers (EM). A total of 101 renal transplant patients and 102 healthy subjects were included. Our results showed that the predominant alleles in the Tunisian population are a wild type of CYP3A4*1B (0.87), likewise CYP3A4*22 (0.975) and CYP3A5*3 (0.82). The genotype frequencies of CYP3A4*1B, CYP3A4*22, and CYP3A5*3 were found to be 3.9%, 0.0%, and 69.5%, respectively. Also, we found a significant linkage disequilibrium between CYP3A4*1B and CYP3A5*3. We approved that the IM is the predominant phenotype in our population with 124 patients followed by and EM with 41 patients, HM in 29 patients and SM in 9 patients. These results showed that Tunisians are most similar to Caucasians. The genetic background of these enzymes CYP3A4*1B, CYP3A4*22, and CYP3A5*3 in this study are important in the prescription of personalized medicine.

Cartilage Integrity: A Review of Mechanical and Frictional Properties and Repair Approaches in Osteoarthritis.

Osteoarthritis (OA) is one of the most common causes of disability around the globe, especially in aging populations. The main symptoms of OA are pain and loss of motion and function of the affected joint. Hyaline cartilage has limited ability for regeneration due to its avascularity, lack of nerve endings, and very slow metabolism. Total joint replacement (TJR) has to date been used as the treatment of end-stage disease. Various joint-sparing alternatives, including conservative and surgical treatment, have been proposed in the literature; however, no treatment to date has been fully successful in restoring hyaline cartilage. The mechanical and frictional properties of the cartilage are of paramount importance in terms of cartilage resistance to continuous loading. OA causes numerous changes in the macro- and microstructure of cartilage, affecting its mechanical properties. Increased friction and reduced load-bearing capability of the cartilage accelerate further degradation of tissue by exerting increased loads on the healthy surrounding tissues. Cartilage repair techniques aim to restore function and reduce pain in the affected joint. Numerous studies have investigated the biological aspects of OA progression and cartilage repair techniques. However, the mechanical properties of cartilage repair techniques are of vital importance and must be addressed too. This review, therefore, addresses the mechanical and frictional properties of articular cartilage and its changes during OA, and it summarizes the mechanical outcomes of cartilage repair techniques.

The role of β-Nicotyrine in E-Cigarette abuse liability I: Drug Discrimination.

β-Nicotyrine (β-Nic) is a unique minor alkaloid constituent in electronic nicotine delivery systems (ENDS) that is derived from nicotine (Nic) degradation and can reach 25% of Nic concentrations in ENDS aerosol. β-Nic slows Nic metabolism and prolongs systemic Nic exposure, which may alter the discriminability of Nic. The present study sought to examine β-Nic has interoceptive effects itself, and if it alters the subjective effects ENDS products within a drug-discrimination paradigm. The pharmacodynamics of β-Nic were examined in vitro, and a nicotine discrimination paradigm was used to determine if β-Nic (0 - 5.0 mg/kg) shares discriminative stimulus properties with Nic (0.2 mg/kg) in male (n = 13) and female (n = 14) rats after 10- & 60-min β-Nic pretreatment delays. A second group of rats was trained to discriminate β-Nic and Nornicotine (Nornic) from saline to determine if β-Nic alone has interoceptive properties and whether they are similar to Nornic. β-Nic had similar binding affinity and efficacy at the α4β2 nicotinic receptor subtype as Nornic, ~50% of Nic efficacy. However, β-Nic only weakly substituted for Nic during substitution testing in female rats, but not males, whereas Nornic fully substituted for Nic. Combination testing at the 10 and 60-min pretreatment intervals showed that β-Nic dose-dependently increased the duration of nicotine's discriminative stimulus effects, especially at the 60-min delay. Drug naïve rats could reliably discriminate Nornic, but not β-Nic, from Sal. β-Nic increased and prolonged the interoceptive stimulus properties of Nic, suggesting it may alter to the abuse liability of ENDS through its ability to slow Nic metabolism.

CYP2B6 and ABCB1 genotypes predict methadone plasma exposure among patients on maintenance therapy against opioid addictions in Tanzania.

Methadone maintenance therapy (MMT) exhibits significant variability in pharmacokinetics and clinical response, partly due to genetic variations. However, data from sub-Saharan African populations are lacking. We examined plasma methadone variability and pharmacogenetic influences among opioid-addicted Tanzanian patients. Patients attending MMT clinics (n = 119) in Tanzania were genotyped for common functional variants of the CYP3A4, CYP3A5, CYP2A6, CYP2B6, CYP2C19, CYP2D6, ABCB1, UGT2B7 and SLCO1B1 genotypes. Trough plasma concentrations of total methadone, S-methadone (S-MTD) and R-methadone (R-MTD), with their respective metabolites, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), were quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The methadone-to-EDDP metabolic ratio (MMR) was used to categorize the phenotype. The proportions of MMR-predicted ultrarapid, extensive, intermediate and slow methadone metabolizer phenotypes were 2.5%, 58.2%, 23.7% and 15.6%, respectively. CYP2B6 genotype significantly correlated with S-methadone (P = .006), total methadone (P = .03), and dose-normalized methadone plasma concentrations (P = .001). Metabolic ratios of R-methadone (R-MTD/R-EDDP), S-methadone (S-MTD/S-EDDP), and total methadone (MMR) were significantly higher among patients homozygous for defective variants (*6 or *18) than heterozygous or CYP2B6*1/*1 genotypes (P < .001). The metabolic ratio for S-MTD and total methadone was significantly higher among ABCB1c.3435T/T than in the C/C genotype. No significant effect of CYP2D6, CYP2C19, CYP3A4, CYP3A5, CYP2A6, UGT2B7 and SLCO1B1 genotypes on S-methadone, R-methadone, or total methadone was observed. Approximately one in six opioid-addicted Tanzanian patients are methadone slow metabolizers, influenced by genetic factors. Both the CYP2B6 and ABCB1 genotypes are strong predictors of methadone metabolic capacity and plasma exposure. Further investigation is needed to determine their predictive value for methadone treatment outcomes and to develop genotype-based dosing algorithms for safe and effective therapy.

The effect of agitating buffy coats on platelet quality before soft spin

BackgroundPlatelet plays a vital role in both physiological and pathological processes. However, the limited storage time of platelet in vitro poses an immense challenge for its applications because of the increased risk of bacterial contamination and platelet storage lesions. Agitation can inhibit lesions by facilitating continuous oxygenation of platelets and permitting excess carbon dioxide to be removed during storage. However, it is still not known whether agitating BCs gives a positive effect on platelet quality. Objectives: To evaluate the quality difference between platelet concentrates (PCs) from buffy coats (BCs) held rest and agitation. MethodsSamples were withdrawn for cell count, blood gas analysis, free hemoglobin level, hypotonic shock response, maximum aggregation rate, activation marker expression (CD62P and CD42b) and coagulation function. Results: We found the PCs prepared from the agitating BCs had fewer residual WBCs, exhibited a better gas exchange ability, slower metabolism (higher pH, higher content glucose, and lower lactic acid levels), better hypotonic shock response, and lower levels of CD62P. The TEG-PC assays showed no difference in coagulation function. Conclusion: Our findings showed that BC can be agitated overnight before a soft spin.

Perioperative platelet reactivityover time inpatients undergoing vascular surgery: An observational pilot study.

Despite Antiplatelet therapy (APT), cardiovascular patients undergoing revascularisation remain at high risk for thrombotic events. Individual response to APT varies substantially, resulting in insufficient protection from thrombotic events due to high on-treatment platelet reactivity (HTPR) in ≤40% of patients. Individual variation in platelet response impairs APT guidance on a single patient level. Unfortunately, little is known about individual platelet response to APT over time, timing for accurate residual platelet reactivity measurement, or the optimal test to monitor residual platelet reactivity. To investigate residual platelet reactivity variability over time in individual patients undergoing carotid endarterectomy (CEA) treated with clopidogrel. Platelet reactivity was determined in patients undergoing CEA in a prospective, single-centre, observational study using the VerifyNow (change in turbidity from ADP-induced binding to fibrinogen-coated beads), the VASP assay (quantification of phosphorylation of vasodilator-stimulated phosphoprotein), and a flow-cytometry-based assay (PACT) at four perioperative time points. Genotyping identified slow (CYP2C19*2 and CYP2C19*3) and fast (CYP2C19*17) metabolisers. Between December 2017 and November 2019, 50 patients undergoing CEA were included. Platelet reactivity measured with the VerifyNow (p = < .001) and VASP (p = .029) changed over time, while the PACT did not. The VerifyNow identified patients changing HTRP status after surgery. The VASP identified patients changing HTPR status after eight weeks (p = .018). CYP2C19 genotyping identified 13 slow metabolisers. In patients undergoing CEA, perioperative platelet reactivity measurements fluctuate over time with little agreement between platelet reactivity assays. Consequently, HTPR status of individual patients measured with the VerifyNow and VASP assay changed over time. Therefore, generally used perioperative platelet reactivity measurements seem unreliable for adjusting perioperative APT strategy.

Pattern of CYP3A5 and MDR-1 single nucleotide polymorphism and its impact on Tacrolimus levels and clinical outcomes in living renal allograft recipient

Abstract Introduction Renal transplant is best form of renal replacement therapy. Most favored immunosuppression includes Tacrolimus, mycophenolate mofetil and steroids. Tacrolimus has narrow therapeutic index and requires therapeutic drug monitoring (TDM). However, there is wide variation in tacrolimus level with weight based fixed dosage regimens. This variability is due to polymorphism of major pathways of metabolism ie CYP3A5 and MDR1 genes. Fast metabolizer require higher dosage and slow metabolizer require lower dosage. Genotype based dosing strategy may be useful to achieve early therapeutic level and reduce infections and rejections. Methodology 160 transplant patients at tertiary care hospital in India were included in this study from 2016 to 2018. Genetic polymorphism analysis in CYP3A5 and MDR1 gene was carried out at time of transplant. All patients were given a fixed weight-based dosage of Tacrolimus. Data was analyzed in relation to genotype polymorphism. Results and discussion 69.2% of Wild variants of CYP 3A5 (Fast metabolizers) have low initial tacrolimus levels. 51.5% of Homo variants (Slow metabolizers) have high initial tac levels. However, all variants achieve optimum tacrolimus levels at same time (mean 12.4 days). There were higher number of infections among slow metabolizers. Conclusion A fixed dosing regimen with TDM result in high and low initial tacrolimus levels in slow and fast metabolizers respectively and more infections in slow metabolizers. However, graft rejections being fewer in number, were not different. A larger sample with genotype based dosing is required to test such a strategy.

Evaluation of major adverse events of clozapine based on accordance to an international titration guideline.

Clozapine is the only antipsychotic approved for treatment-resistant schizophrenia, but without appropriate monitoring, it can be associated with potentially fatal outcomes. An International Adult Clozapine Titration Guideline categorizes patients into normal or slow metabolizers. Categorization provides clozapine titration schedules and recommends regular c-reactive protein (CRP) and clozapine concentration monitoring to reduce the risk of adverse drug reactions (ADRs). The impact of the guideline on clozapine ADRs has not been evaluated. A retrospective chart review assessed clozapine titrations, laboratory monitoring, ADRs, and discontinuations for clozapine-naive adult inpatients at a single center from January 1, 2013, to June 1, 2022. Each patient's cumulative weekly clozapine dosage was compared with their guideline recommended dosage to create a percent accordance. Linear logistic regression evaluated the relationship between titration speed and the presence of an ADR, while descriptive statistics analyzed laboratory monitoring. Forty-three patients were included, with the majority being White males with schizophrenia. An inverse relationship existed between the last inpatient week clozapine dose percent accordance and the probability of an ADR. Nonobese patients were less likely than obese patients to experience an ADR (odds ratio = 0.17; 95% CI, 0.03-0.99). CRP and clozapine concentration monitoring was suboptimal. Based on our small retrospective review of primarily White males, more aggressive clozapine titrations did not increase ADRs. Future studies with more diverse samples are needed and should focus on specific ADRs, which may have increased occurrence with rapid titrations. Obese patients were at higher risk of ADRs, correlating with the guideline-recommended slower titrations for these patients.

Comparative transcriptome analysis provides a glance into the regulatory of insulin-like peptide 1 gene in the Pacific white shrimp Litopenaeus vannamei

Insulin-like peptides (ILPs) have been reported to exert significant and diverse regulatory effects through the insulin signaling pathway in invertebrates. However, there is a large research gap in the functional analysis of ILP genes in crustaceans. In this study, we combined RNA interference (RNAi) technology with transcriptome sequencing to investigate the regulatory effects of the ILP1 gene in the Pacific white shrimp Litopenaeus vannamei. After two weeks of continuous RNAi of LvILP1, the shrimp in the dsLvILP1 group exhibited reduced body length gain, weight gain, molting rate, and hemolymph glucose concentration compared to the control dsEGFP group, indicating that knockdown of LvILP1 slowed shrimp growth, molting, and metabolism. Comparative transcriptome analysis of three tissues revealed that knockdown of LvILP1 inhibited muscle growth and development by modulating the mTOR and MAPK signaling pathways, and prevented the renewal of epidermal tissue through the Hippo signaling pathway. Meanwhile, it also suppressed certain growth signals in the hepatopancreas, such as juvenile hormone (JH) synthesis and 20-hydroxyecdysteroid (20E) signal activation. Additionally, it promoted the conversion pathway of some sugars into amino acid metabolism instead of energy metabolism after glycolysis in the hepatopancreas. Interestingly, knockdown of LvILP1 also affected carbohydrate metabolism by regulating the intracellular and extracellular transport of glucose and trehalose, as well as regulating the expression levels of key metabolic genes in three shrimp tissues. This disruption led to a decrease in blood glucose levels and suppressed energy production, ultimately providing less energy for shrimp growth and molting. This study provides valuable insights into the underlying genetic mechanism through which ILP1 regulates glucose metabolism and growth in shrimp. It enhances our understanding of the structure and function of the insulin pathway in crustaceans and serves as an important reference for the identification of candidate genes in molecular genetic breeding of shrimp.