Plasma Citrulline Research Articles

Abstract 14913: Renal Function Underpins Cox-2: Methylarginine Axis in Mouse and Man

Introduction and Hypothesis: Through the production of prostacyclin (PGI2), cyclooxygenase (COX)-2 protects the cardio-renal system. Restraining methylarginines (ADMA, SDMA), which are biomarkers of renal and cardiovascular disease and inhibitors (ADMA) of cardioprotective endothelial nitric oxide synthase (eNOS), has been suggested as a contributory pathway. However, the relationship between renal function, COX-2 and methylarginines remains unclear. Methods: Using plasma from genetically modified mice with germline global deletion of COX-2 or PGI 2 synthase (PGIS) and human plasma from a unique individual lacking COX-derived prostaglandins due to a loss of cPLA 2 , before and after receiving a cPLA 2 -replete transplanted donor kidney, we measured methylarginines, arginine and citrulline using UHPLC-MS/MS. Renal function was assessed by measuring cystatin C by ELISA. To eliminate the impact of renal function in vivo , methylarginine and PGI 2 release from organotypic kidney slices in culture were quantified by ELISA. Results: Plasma ADMA, SDMA, citrulline and cystatin C, were similarly elevated in samples from the patient lacking COX/PGI 2 capacity compared to levels in healthy volunteers. Renal function, ADMA, SDMA and citrulline returned towards normal range when the patient received a genetically normal kidney, capable of COX/PGI 2 activity. Cystatin C correlated with ADMA, SDMA and citrulline. Loss of COX-2 or PGIS in mice increased plasma levels of ADMA, SDMA and cystatin C. As in human, SDMA, ADMA and citrulline but not arginine positively correlated with cystatin C. Levels of analytes in conditioned media of kidney slices (24h) were not altered in tissue from COX-2 KO (6-keto=14.0±1.8, ADMA=1.0±0.06, SDMA=0.30±0.05; n=8) compared to wildtype mice (66-keto=15.0±1.7, ADMA=0.98±0.06, SDMA=0.24±0.01; n=12). Conclusions: COX-2 and PGI2 are critical regulators of renal function. Plasma methylarginines are integrally linked to renal homeostasis.

Thin-cap fibroatheroma and increased coronary intima-media thickness are associated with an altered balance of arginine metabolites.

Arginase inhibition increases plasma citrulline and citrulline / ornithine (C/O) ratio, and reduces plasma ornithine and ornithine / arginine (O/A) ratio in an animal model of myocardial infarction (MI). We hypothesized that the presence of thin‑cap fibroatheroma (TCFA) in the culprit lesion and increased non‑culprit intima‑media thickness of an infarct‑related artery (IRA) are associated with an altered balance of arginine metabolites. Arginine and its metabolites were measured using liquid chromatography and tandem mass spectrometry in 100 consecutive MI patients upon admission and at 6‑month follow‑up. TCFA and adjacent to culprit lesion proximal and distal 10‑mm segments were assessed with optical coherence tomography in the acute phase. Twenty five patients without coronary lesions on angiography served as controls. The C/O ratio increased 5.33 times (P <0.001), while the O/A ratio decreased 2.53 times (P <0.001) at the 6‑month follow‑up, as compared with the acute phase of MI. The patients with (n = 75) vs without (n = 25) TCFA had lower C/O ratio by 29% (P = 0.003), while the mean intima‑media diameter of adjacent non‑culprit region correlated with the follow‑up O/A ratio (R = 0.337; P = 0.003). In a multivariable analysis, a higher acute phase C/O ratio was associated with a lower risk of TCFA presence (odds ratio, 0.978; 95% CI, 0.962-0.994; P = 0.006), whereas a higher follow‑up O/A ratio correlated with larger intima‑media diameter of the adjacent segments (β coefficient, 0.227; 95% CI for β coefficient, 0.045-0.409; P = 0.018). Enhanced arginase activity over nitric oxide synthase following ischemia was associated with the presence of TCFA in the culprit lesion, while a similar metabolic shift in the chronic phase correlated with a greater thickness of the intima‑media in the adjacent non‑culprit IRA segments.

S3154 Severe Noncirrhotic Hyperammonemia: What Urea-lly Should Consider

Introduction: Hyperammonemia is often the result of liver pathology. When hyperammonemia is not the result of liver disease, an occult disorder of metabolism must be on the differential for unexplained hyperammonemia, such as a urea cycle disorder (UCD). Case Description/Methods: A 57-year-old man with heart failure with recovered ejection fraction, atrial fibrillation, hypertension, and cervical neck fracture who had undergone a recent cervical spine corpectomy and fusion presented with worsening dysphagia and was found to have a cervical fluid collection for which he received a dexamethasone taper and a lumbar drain. He had no known underlying liver disease and denied significant alcohol history. He was later admitted to the intensive care unit (ICU) for unstable atrial fibrillation with rapid ventricular response (RVR). In the ICU, he became more somnolent and was unable to follow commands. Encephalopathy workup was significant for elevated BUN with normal creatinine, ammonia 772, and mildly elevated transaminases. His labs and imaging did not demonstrate cirrhosis or acute liver failure. Workup for inborn errors of metabolism showed mildly decreased citrulline. Urine and plasma amino acids were otherwise normal. His hyperammonemia resolved and his mentation improved with lactulose and rifaximin. UCD gene panel and further genetic workup is ongoing and to be continued outpatient. Discussion: Patients with elevations of ammonia present with encephalopathy, which may progress quickly to cerebral herniation. Survival requires immediate reduction of ammonia levels. Although the differential for hyperammonemia is broad, inborn errors of metabolism (IEM), like a UCD, should be considered when hyperammonemia is of unclear etiology. This patient’s liver workup revealed no findings consistent with cirrhosis or liver failure. Potential causes for his hyperammonemia include ischemic liver disease secondary to atrial fibrillation with RVR or degradation of blood products. IEMs may also be unmasked by steroid therapy, which is plausible in this patient who was on a steroid taper prior to his hyperammonemic state. Although IEMs often have early age of onset, UCDs have multiple modes of inheritance and can present at later stage. Ornithine transcarbamylase deficiency is the most common UCD and can present with reduced plasma citrulline in both kids and adults. Treatment for a potential IEM begins prior to confirmation of an etiology. Geneticists should be consulted early on for evaluation and management.

Effects of Gamma-Tocotrienol on Partial-Body Irradiation-Induced Intestinal Injury in a Nonhuman Primate Model.

Exposure to high doses of radiation, accidental or therapeutic, often results in gastrointestinal (GI) injury. To date, there are no therapies available to mitigate GI injury after radiation exposure. Gamma-tocotrienol (GT3) is a promising radioprotector under investigation in nonhuman primates (NHP). We have shown that GT3 has radioprotective function in intestinal epithelial and crypt cells in NHPs exposed to 12 Gy total-body irradiation (TBI). Here, we determined GT3 potential in accelerating the GI recovery in partial-body irradiated (PBI) NHPs using X-rays, sparing 5% bone marrow. Sixteen rhesus macaques were treated with either vehicle or GT3 24 h prior to 12 Gy PBI. Structural injuries and crypt survival were examined in proximal jejunum on days 4 and 7. Plasma citrulline was assessed using liquid chromatography–tandem mass spectrometry (LC-MS/MS). Crypt cell proliferation and apoptotic cell death were evaluated using Ki-67 and TUNEL staining. PBI significantly decreased mucosal surface area and reduced villous height. Interestingly, GT3 increased crypt survival and enhanced stem cell proliferation at day 4; however, the effects seemed to be minimized by day 7. GT3 did not ameliorate a radiation-induced decrease in citrulline levels. These data suggest that X-rays induce severe intestinal injury post-PBI and that GT3 has minimal radioprotective effect in this novel model.

P7.09: Population Model Confirms Predictable Pharmacokinetic (PK) And Pharmacodynamic (PD) Profile for Apraglutide: Data From Two Randomized Phase 1 Studies

Background: Apraglutide, a novel long-acting glucagon-like peptide-2 (GLP-2) analogue that promotes intestinal growth in animals and increases intestinal absorption, is in Phase III development for the treatment of short bowel syndrome with intestinal failure (SBS-IF). Pharmacokinetic (PK) and pharmacodynamic (PD) characterization revealed a predictable linear PK distribution and elimination kinetics and a dose-dependent PD relationship. A model was created to enable characterization of PK and PD relationships at the population level using plasma citrulline, a biomarker of small intestine functional enterocytic mass. Methods: A population PK/PD model was created by combining PK and citrulline data from two randomized, placebo-controlled, Phase I studies of apraglutide in healthy adult volunteers. In Study 1, 64 volunteers received either a single ascending dose of apraglutide (2.8, 5.7, 11.4, 28.4, or 56 mg), 3 weekly doses of apraglutide (11.4, 28.4, or 56 mg) or placebo by subcutaneous (SC) injection. In Study 2, 24 volunteers received 6 weekly SC administrations of apraglutide (1, 5 or 10 mg) or placebo. A one-compartmental structural model with zero-order absorption and linear clearance was used to describe apraglutide PK. Plasma citrulline levels were described by a turnover model with a synthesis and degradation rate. The effect of apraglutide on citrulline synthesis was modeled with a stimulatory effect on the citrulline synthesis rate using an Emax relationship. Population PK and PD parameters were estimated using the stochastic approximation of expectation-maximization algorithm (Monolix Suite 2019 R1). Inter-subject variability was modelled using log-normal distributions. Simulations included the impact of covariates. Results: Actual PK observations were best matched by a population PK/PD model with a dose covariate on absorption duration and body weight covariates on V1/F and Cl/F. The parameter estimates for a 70-kg individual receiving apraglutide 5 mg SC were an apparent volume of distribution of 31.3 L and time to maximal concentration (T) of 1.39 days. Simulated PK and PD profiles with weekly apraglutide 2.5, 5, or 10 mg sc are shown in Figure 1. The PK/PD model did not indicate any accumulation of apraglutide over time for a weekly administration. Although accumulation of citrulline was apparent during the first 3 weeks of treatment, a steady state concentration was subsequently reached. Conclusions: This population PK/PD model enables prediction of the effect of different apraglutide doses on plasma citrulline levels as well as the impact of covariates, such as body weight, at the population level. This further demonstrates apraglutide’s predictable PK profile with no accumulation during once weekly sc dosing and its ability to induce a dose-dependent citrulline increase.

Impact of mucositis on oral bioavailability and systemic exposure of ciprofloxacin Gram-negative infection prophylaxis in patients with haematological malignancies.

Patients with haematological malignancies frequently endure neutropenia and gastrointestinal (GI)-mucositis after high-dose chemotherapy. In these patients, ciprofloxacin is used for Gram-negative infection prophylaxis. We investigate ciprofloxacin pharmacokinetics after oral administration in patients with haematological malignancies and explore the impact of GI-mucositis on oral bioavailability and clearance in order to assure adequate systemic exposure. Adult haematological patients from two Dutch University Medical Centres received 500 mg twice daily oral ciprofloxacin for Gram-negative prophylaxis. The ciprofloxacin plasma concentrations were collected at various timepoints after oral ciprofloxacin administration and at various days after completion of chemotherapy. Data obtained after oral and intravenous ciprofloxacin administration in 28 healthy volunteers without mucositis served as a control group (391 samples). For haematological patients the degree of GI-mucositis was assessed using the Daily Gut Score (DGS), plasma citrulline and albumin. Data were analysed by non-linear mixed-effects modelling. In total, 250 blood samples were collected in 47 patients with a wide variety of haematological malignancies between 0-30 days after start of chemotherapy. Mucositis was generally mild [DGS median (IQR) 1 (1-1) and citrulline 16 μmol/L (12-23)]. The time to Cmax was slower in haematological patients compared with healthy volunteers although no association with the degree of mucositis (defined as DGS or citrulline) could be identified. Ciprofloxacin bioavailability and clearance were 60% and 33.2 L/h, respectively. This study supports oral dosing of ciprofloxacin as Gram-negative infection prophylaxis in haematological patients with mild-to-moderate mucositis capable of oral intake.

Nitric Oxide Synthesis Metabolites-As Potential Markers in Chronic Kidney Disease in Children.

Nitric oxide (NO) is an important signaling molecule for many physiological and pathological processes. Diseases associated with abnormal NO synthesis include cardiovascular diseases, insulin-dependent diabetes, or chronic kidney disease (CKD). The aim of the paper was to evaluate NO synthesis metabolites, i.e., asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA), dimethylamine (DMA), arginine, citrulline in plasma of patients with different severity of CKD and to seek possible links between these parameters and the development of this disease. Forty-eight CKD children and thirty-three age-matched controls were examined. Patients were divided into groups depending on the CKD stages (Group II-stage II, Group III-stage III, Group IV-stage IV, and Group RRT children on dialysis). To determine the concentrations of the above-mentioned metabolites in plasma liquid chromatography-mass spectrometry was used. There were significant differences observed in levels of ADMA, SDMA, DMA, and citrulline between control vis CKD groups (p values ranging from <0.001 to 0.029). Plasma arginine concentration was also higher in CKD patients compared to the control group but statistically insignificant. ADMA levels in CKD children were statistically significantly higher in relation to particular stages of CKD (RRT vis II stage of CKD: p = 0.01; RRT vis III-IV stages of CKD: p < 0.046). Citrulline levels in CKD children were statistically significantly higher in RRT group vis control (p < 0.001). Children with CKD develop disturbances in most metabolites of NO synthesis. Dialysis children treated show the greatest disturbances of plasma ADMA and citrulline levels. ADMA seems to be a good indicator of the gradual progression of the CKD, which is proved by the negative correlation with eGFR.

Citrulline and long-term mortality in patients with cardiovascular disease.

Cardiovascular disease (CVD) is associated with intestinal barrier dysfunction and increased intestinal permeability. Increased intestinal permeability to gut microbial metabolites may accelerate the progression of CVD. Plasma citrulline levels are a marker of functional enterocyte mass, and reduced citrulline levels indicate intestinal epithelial damage. Citrulline was reported as a useful prognostic marker in critically ill patients. However, data are lacking on the association of citrulline with long-term mortality in patients with CVD and with the levels of trimethylamine N-oxide (TMAO), a microbiota-derived metabolite which has been implicated in the pathogenesis of CVD. To assess the effect of citrulline levels, a marker of intestinal barrier disruption, on long-term mortality in patients with CVD. Moreover, the relationship between the concentrations of 2 biomarkers - citrulline and TMAO - was assessed. Serum citrulline levels were retrospectively assessed in 1036 consecutive patients with CVD (median age: 62 years; 61% men) hospitalized between 2013 and 2015. Associations of citrulline levels with 5-year mortality rates as well as anthropometric and biochemical parameters were evaluated for the entire study group and in subgroups of patients with acute coronary syndrome (ACS), chronic coronary syndrome, chronic heart failure (chronic HF), and atrial fibrillation (AF). Correlations between serum citrulline and TMAO levels were assessed. The median citrulline level in the study population was 22.5 μM (interquartile range (IQR): 17.8-27.9). Citrulline levels were not associated with 5-year mortality in patients with CVD (hazard ratio (HR) = 0.99; 95% confidence interval (95% CI): 0.97-1.00; p = 0.49). Median citrulline levels differed significantly between deceased patients and survivors at 5 years in patients with ACS (p = 0.025). There were no significant correlations between citrulline and TMAO levels (Kendall's tau = 0.027). Decreasing citrulline levels do not predict long-term mortality of hospitalized patients with CVD. Moreover, they are not associated with the serum levels of TMAO in these patients.

Different dietary starch patterns in low-protein diets: effect on nitrogen efficiency, nutrient metabolism, and intestinal flora in growing pigs

BackgroundProtein releases amino acids faster than starch releases glucose in digestive tract of pigs fed low-protein (LP) diets. Poor synchronization of dietary glucose and amino acids supply leads to compromised nitrogen efficiency. Dietary starch patterns modulation may improve this situation.MethodsGrowing barrows (29.7 ± 2.0 kg) were randomly allotted into 5 dietary treatments with LP diets consisting of different purified starches. Treatments included: waxy corn starch (W LP), corn starch + waxy corn starch (C + W LP), corn starch (C LP), pea starch + waxy corn starch (P + W LP) and pea starch (P LP). In the experiment, growth performance, protein deposition, nutrient metabolism, and fecal microbial community of pigs were investigated. In vitro starch digestion was used for predicting the in vivo glucose response.ResultsDietary starch in vitro glucose release profile was determined by starch source and the ratio of amylopectin and amylose. C + W LP treatment showed decreased total nitrogen excretion and plasma citrulline concentration and improved plasma leptin concentration among treatments (P < 0.05). Besides, the highest nitrogen apparent biological value, whole-body protein deposition and growth performance and lowest urinary nitrogen excretion were also observed in C + W LP treatment. Compared with the other groups, C + W LP and C LP showed increased plasma pyruvate, IGF-1, and lipase concentrations (P < 0.05). The W LP group presented dramatically increased plasma alanine and urea nitrogen concentration and decreased aldolase and leptin concentrations (P < 0.05). Dietary starch patterns did not make an impact on bacterial richness and diversity, but changed the taxonomic and functional structures of the microbial communities. Microbial protein fermentation product (isobutyrate and isovalerate) presented increased in P LP treatments compared with the other treatments (P < 0.05).ConclusionsDietary starch patterns modulation can regulate dietary glucose release profile, nutrient metabolism, protein turnover, and fecal microbial fermentation in pigs. The optimal dietary glucose release profile effectively strengthened whole-body protein deposition and improve nitrogen efficiency and growth performance in growing pigs fed LP diets.

EARLY MARKERS OF THE KIDNEYS DAMAGE IN PATIENTS WITH RESISTANT HYPERTENSION

Objective: To define early specific markers for assessing the degree of kidney damage in patients with resistant hypertension (RH). Design and method: We examined 235 patients with RH confirmed by the office and ambulatory BP monitoring despite the use of 3 antihypertensive medications with diuretic. Chronic kidney disease (CKD) was diagnosed using estimated glomerular filtration rate (eGFR) according to the CKD-EPI equation. Microalbuminuria (MAU) was defined as levels of albumin ranging from 30 to 300 mg in a 24-h urine collection. In all pts plasma levels of citrulline, creatinine, matrix metalloproteinase-12 (MM-12), C-reactive protein (CRP), fibrinogen, uric acid were measured. Results: Patients were assigned to 3 groups: without CKD (Gr.I pts), CKD stage 1 (GFR more than 90 ml/ min/ 1.73 m2) (Gr.II pts), and CKD stages 2–3 (GFR 30–90 ml / min/1.73 m2) (Gr.III pts). Plasma citrulline content was significantly higher in Gr.II pts and Gr.III pts than that in Gr.I pts: 92.2 ± 4.3 and 116.50 ± 5.06 mol/l vs 71.0 ± 6.2 mol/l (p &lt; 0.05 in both cases). The difference between Gr.II and Gr.III pts was also significant (p &lt; 0.05). Patients with kidney damage had a significantly (p &lt; 0.05) higher level of markers of systemic inflammation (CRP, fibrinogen, MM-12) compared with the group of patients without CKD. There was no significant difference in creatinine or uric acid content between pts without CKD (Gr.I) and CKD stage 1 pts. (Gr.II). There was negative correlative relationship between blood levels of citrulline, CRP, MM-12, fibrinogen and eGFR (r = -0,532; P &lt; 0.04; r = -0,384; P &lt; 0.05; r = -0,332; P &lt; 0.05; r = -0,331; P &lt; 0.05 accordingly). Conclusions: Citrulline level could be used to estimate the early degree of renal damage in RH pts that in conjunction with identifying inflammatory markers may be useful in developing effective strategies for the prevention or early detection and treatment of impaired renal function. Relationship between citrulline, CRP, MM-12, fibrinogen and eGFR may indicates on underlying tubulointerstitial dysfunction and chronic inflammation in mechanism of kidney damage of hypertensive nephropathy in patients with RH.

CARDIOVASCULAR AND KIDNEY OUTCOMES IN TREATED RESISTANT HYPERTENSIVE PATIENTS

Objective: To evaluate the incidence of cardiovascular (CV) and kidney outcomes and its predictors in treated resistant hypertensive (rHTN) patients. Design and method: We studied 117 rHTN patients and 114 controlled hypertensives (cHTN) patients on a triple fixed-dose combination of RAAS blockers / CCB / thiazide or thiazide-like diuretic. Patients with rHTN treated with the same type of triple fixed-dose combination in maximally tolerated doses plus the individually defined most effective fourth-line agent (spironolactone/eplerenone 56.1%, torasemide 26.8%, nebivolol 14.6%, moxonidine 2.5%); the fifth class of antihypertensive drug was added for 35.2 % of patients. A composite CV (CV death, myocardial infarction and/or revascularization, stroke, atrial fibrillation, and peripheral arterial disease) and kidney outcome (dialysis or GFR decline by 40% or greater) were estimated after five years (a mean follow-up 5.1 ± 0.1). The combined endpoint was defined as total CV and renal outcome events. Results: The goal office and 24-h BP were achieved at 49.6 and 34.2 % rHTN patients by the end of 5-year follow-up. During follow-up the incidence of all outcomes were higher at rHTN patients compared to cHTN pts: composite CV events (26.5 % vs 7 %, P = 0.001), kidney outcomes (4.3 % vs 0.9 %, P = 0.01), and diabetes (3.4 % vs 0.9 %, P = 0.02). The independent predictors of combined end point identified by multivariant logistic regression analysis were initial 24-h systolic BP ( = 0.099; OR = 1.10; 95 % CI 1.03 – 1.18; P = 0.008), blood concentration of endothelial progenitor cells (CD45+/CD34+) ( = - 0.89; OR = 0.41; 95 % CI: 0.21 – 0.79), P = 0.007) and citrulline ( = - 0.89; OR = 1.13; 95 % CI: 1.07 – 1.20; P &lt; 0.001). Conclusions: Despite significant improvement in BP control the incidence of CV and renal outcomes in rHTN patients were higher than in cHTN patients. The independent predictors of combined CV and renal events were higher baseline systolic blood pressure, citrulline plasma level, and low concentration of endothelial progenitor cells.

A Phase 1 study of ADI‐PEG20 (pegargiminase) combined with cisplatin and pemetrexed in ASS1‐negative metastatic uveal melanoma

Metastatic uveal melanoma (UM) is a devastating disease with few treatment options. We evaluated the safety, tolerability and preliminary activity of arginine depletion using pegylated arginine deiminase (ADI‐PEG20; pegargiminase) combined with pemetrexed (Pem) and cisplatin (Cis) chemotherapy in a phase 1 dose‐expansion study of patients with argininosuccinate synthetase (ASS1)‐deficient metastatic UM. Eligible patients received up to six cycles of Pem (500 mg/m2) and Cis (75 mg/m2) every 3 weeks plus weekly intramuscular ADI (36 mg/m2), followed by maintenance ADI until progression (NCT02029690). Ten of fourteen ASS1‐deficient patients with UM liver metastases and a median of one line of prior immunotherapy received ADIPemCis. Only one ≥ grade 3 adverse event of febrile neutropenia was reported. Seven patients had stable disease with a median progression‐free survival of 3.0 months (range, 1.3–8.1) and a median overall survival of 11.5 months (range, 3.2–36.9). Despite anti‐ADI‐PEG20 antibody emergence, plasma arginine concentrations remained suppressed by 18 weeks with a reciprocal increase in plasma citrulline. Tumour rebiopsies at progression revealed ASS1 re‐expression as an escape mechanism. ADIPemCis was well tolerated with modest disease stabilisation in metastatic UM. Further investigation of arginine deprivation is indicated in UM including combinations with immune checkpoint blockade and additional anti‐metabolite strategies.

Relationship of citrulline and tissue transglutaminase antibody with duodenal histopathology among children with celiac disease

ObjectivesNon-invasive biomarkers, for the diagnosis of celiac disease, can reduce the need for biopsy, particularly in pediatric patients. The aim of this study was to investigate the levels tissue transglutaminase antibody (tTG) and plasma citrulline and its correlation with intestinal biopsy. MethodsIn this cross-sectional descriptive study, Pediatric patients with celiac disease referred to (XXX)were included. The patients underwent tTG antibody test along with plasma citrulline measurements using HPLC ((high performance liquid chromatography). Biopsy was performed in all the patients and clinical and demographic findings were recorded in a patient form. The data were statistically analyzed using SPSSv22. ResultsOf 118 patients with celiac disease, the mean level of citrulline in patients was 17.48 ± 6.92 and the mean tTG titer was 183.17 ± 41.25. The two variables were inversely correlated with each other, p < 0.01. With an increase in Marsh levels, a significant reduction in citrulline levels and an increase in plasma tTG levels were seen, p < 0.01, respectively. The mean citrulline and tTG titer was not associated with gender and the age of the patients. ConclusionOur findings indicate that citrulline and tTG antibody titer are significant biomarkers for the diagnosis of celiac disease and the severity of intestinal atrophy among pediatric patients.

Posaconazole bioavailability of the solid oral tablet is reduced during severe intestinal mucositis

ObjectivesThis study aimed to describe the absolute oral bioavailability of the solid oral formulation of posaconazole and the impact of severe intestinal mucositis in haematology patients. This study also aimed to describe posaconazole protein binding in haematology patients. MethodsA pharmacokinetic study was performed of patients receiving induction chemotherapy or a haematopoietic cell transplantation who were randomized to receive 7 days of intravenous posaconazole therapy followed by 9 days of oral therapy, or vice versa. Patients received a posaconazole licensed dose until day 12, after which a reduced once-daily dose of 200 mg was given. At days 7, 12, and 16, blood samples were obtained for pharmacokinetic curves, and trough samples were collected on all other days. Total and unbound posaconazole pharmacokinetics were analyzed by population pharmacokinetic modelling. The presence of severe intestinal mucositis was assessed by plasma citrulline levels and analyzed as a binary covariate using 10 μmol/L as the cut-off. Monte Carlo simulations were performed to simulate posaconazole exposure at a steady state. ResultsTwenty-three patients were included for analysis, with 581 total posaconazole concentrations and 91 paired unbound concentrations. Absolute bioavailability in the final model was estimated at 51.4% (percentage relative standard error (%RSE): 56.5) and 67.6% (%RSE: 75.0) in patients with and without severe intestinal mucositis, respectively. Posaconazole unbound fraction was estimated at 2.7% (%RSE: 3.9). DiscussionPosaconazole bioavailability is reduced in haematological patients with severe intestinal mucositis, requiring an increase in oral posaconazole dose to 400 mg twice daily on day 1, followed by 400 mg once daily or a switch to intravenous therapy.

Erythrocyte fatty acid membrane composition in children on long-term parenteral nutrition enriched with ω-3 fatty acids

Composite lipid emulsions containing soybean oil (30%), medium-chain triglycerides (30%), olive oil (25%), and fish oil (15%) (SMOF) are now widely used. We aimed to evaluate the tolerance, the efficiency, and the erythrocyte fatty acid (FA) profile for children on long-term home parenteral nutrition (HPN) receiving a composite fish oil-based emulsion (FOLE). At baseline, children (n=46) with severe intestinal failure highly dependent on parenteral nutrition (PN) for ≥1 y were included in the study when they had received the composite FOLE for >6 mo. Out of this baseline group, only 25 children remained highly PN-dependent (SMOF1, n=25) and could be assessed a second time, 2.4 y later (SMOF2, n=25). An independent control group ("weaned off PN" group; n=24) included children who had been weaned off PN for >2 y (median: 4 y). RBC-FA composition was established by GC-MS. Growth parameters, plasma citrulline, conjugated bilirubin, FA profiles, and the Holman ratio (20:3ω-9/20:4ω-6) were compared between groups. No difference for growth parameters, citrulline, and bilirubin was observed between the SMOF groups after 2.4 y (0.2<P<0.8). The weaned-off group did not differ from the SMOF groups for growth parameters (0.2<P<0.4) but citrulline was higher (P<0.0001) and conjugated bilirubin lower (P<0.01). The composite FOLE induced higher proportions of EPA (20:5n-3) (8.4%±2.9%) and DHA (22:6n-3) (11.7%±2.2%) than what was observed in weaned-off children (0.8%±0.4% and 6.6%±2.3%, respectively) but lower proportions of arachidonic acid (20:4n-6). However, the Holman ratio did not vary between groups (P=0.9), whereas the PUFA concentrations varied widely. Long-term use of the composite FOLE was well tolerated in HPN-dependent children. The RBC-FA profile alterations were consistent with the ω-3 PUFA-enriched composition of this emulsion without evidence of essential FA deficiency.

THE EFFECT OF S-ADEMETIONINE ON PLASMA CITRULLINE LEVEL DURING CHEMOTHERAPY-INDUCED OXIDATIVE STRESS IN PATIENTS WITH CHRONIC LYMPHOPROLIFERATIVE DISORDERS.

The aim: To investigate the effect of S-ademetionine on plasma citrulline level in patients with chronic lymphoproliferative disorders (CLPD) during chemotherapy-induced oxidative stress. Materials and methods: 25 patients with CLPD were examined. Examinations were conducted twice: before chemotherapy (CT) and after 3 courses of CT. Several biochemical markers in the blood were determined: the activity of catalase, the level of plasma citrulline, the concentration of N-acetylneuraminic acid (NANA) and the concentration of substances that form a trimethine complex (TBARS) with 2-thiobarbituric acid. Patients were divided into groups: І (n=14) - patients who underwent only CT; ІІ (n=16) - patients who during CT received S-ademetionine, at a dose of 1000 mg/day intravenously for 10 days, then 500 mg twice a day for 20 days. ІІІ (n=20) -the control group of 20 practically healthy individuals. Results: Patients in both groups with CLPD had pre-existed mucosal injury that was characterized by 1.25 (p=0.0025) and 1.26 times (р=0.006) higher blood NANA concentration compared to the control group. The conduction of CT was associated with enterocytes dysfunction, which was characterized by 1,66 times (p=0,0002) lower plasma citrulline level in patients of group I compared to the initial examination. The infusion of S-ademetionine attenuated intestinal dysfunction that was associated with 1,23 times (p=0,0005) higher blood citrulline level after the CT as compared to group I. Conclusions: The infusion of S-ademetionine as adjuvant treatment in patients with CLPD provided effective prophylaxis of intestinal injury that was associated with higher blood citrulline level after the conduction of CT.

Maternal oral supplementation with citrulline increases plasma citrulline but not arginine in pregnant Merino ewes and neonatal lambs

Context Arginine supplementation can counter the negative effects of fetal growth restriction in ewes bearing multiple lambs by increasing birth weight and brown adipose fat stores in lambs; however ruminal degradation limits its bioavailability and necessitates ruminal protection. The arginine precursor citrulline increases circulating arginine after a single oral dose without ruminal protection, and bolus intravenous infusion of citrulline increases maternal and fetal circulating arginine for at least 4 h post infusion. Responses to oral and chronic citrulline have not, however, been evaluated in neonatal lambs. Aims This experiment sought to determine whether orally fed citrulline would increase circulating plasma concentrations of citrulline and arginine in pregnant Merino ewes. Methods Pregnant Merino ewes were fed citrulline (CIT, 8 g/day, n = 9) or no supplement (CON, n = 9) from Day 125 of gestation (DG 125) until parturition. Ewe (DG 125) and neonatal lamb serum (&lt;2 h old) was analysed for circulating plasma citrulline and arginine concentrations. Key results Circulating concentrations of citrulline were higher in CIT than CON ewes 4 h post feeding at DG 125, and in CIT compared to CON neonatal lambs. Despite higher citrulline concentrations, supplementation did not increase maternal or neonatal circulating arginine concentrations. Conclusions Maternal supplementation with this dose of citrulline was not effective in increasing circulating levels of arginine. Implications Further studies may be merited in pregnant sheep to determine whether higher doses of oral citrulline can increase arginine availability during gestation.

Plasma homoarginine concentrations in ewe's pregnancy and association with the number of fetuses

A striking increase in homoarginine concentrations, about more than 100-fold that observed in humans, was recently reported during pregnancy in a nutritionally induced model of intra-uterine growth restriction in ewes. To determine whether this phenomenon is at least partially related to the nutritional regimen, estrus synchronization, or analytical method, thirty-four one-year-old primiparous, non-synchronized, and well-fed Sarda breed ewes were exposed to fertile rams allowing those who came into estrus to naturally mate. Plasma arginine, homoarginine, asymmetric dimethylarginine, symmetric dimethylarginine, mono methylarginine, and citrulline concentrations were measured in each sample using LC-MS/MS. Homoarginine concentrations showed a 44-fold variation between the highest and the lowest values while the fluctuations of arginine and its analogues and metabolites were much smaller, between 1.1 and 1.6-fold. Repeated-measures correlation analysis showed a significant negative correlation between homoarginine/arginine and arginine/asymmetric dimethylarginine ratios (Rm = −0.40; P < 0.000001). Furthermore, median homoarginine concentrations significantly increased with the number of fetuses. The marked increase in homoarginine concentrations with advancing gestational age is genuine and independent of mating, feeding, diet, and hormone treatment. The higher homoarginine concentrations found in ewes bearing multiple fetuses suggest the presence of a physiological link between this arginine analog and energy metabolism in pregnancy that warrants further investigation.

Circulating concentrations of citrulline, neopterin, kynurenine, and tryptophan during chemoradiation in patients with cervical carcinoma

Abstract The aim of this study was to investigate the changes in circulating concentrations of citrulline, neopterin, kynurenine, and tryptophan during the course of chemoradiation in patients with cervical cancer. Sixteen patients with histologically confirmed carcinoma of the uterine cervix, aged 53 ± 15 years (range 29–76 years), were included in this study. Plasma neopterin, kynurenine, and tryptophan were determined with an enzyme-linked immunosorbent assay. Plasma citrulline was measured with high-performance liquid chromatography. Compared to baseline, citrulline concentration was markedly and statistically significantly decreased at visits 2, 3, and 4, while returning to pretreatment concentrations at visit 5. A significant increase in serum neopterin concentrations was observed at visits 4 and 5. With the exception of decreased kynurenine/tryptophan ratio at visit 3, no significant changes were observed in the concentrations of kynurenine, tryptophan, and kynurenine/tryptophan ratio throughout the course of the treatment. In conclusion, present data demonstrate that citrulline concentrations decrease early and neopterin concentrations increase late during the course of chemoradiation in patients with cervical carcinoma. Citrulline represents a biomarker of intestinal toxicity in this population.

Adipokine, gut and thyroid hormone responses to probiotic application in chukar partridges (Alectoris chukar) exposed to heat stress.

The aim of this study was to investigate the effect of Lactobacillus reuteri E81 (LRE) probiotic supplementation on heat stress responses in chukar partridges (Alectoris chukar). The birds were divided into two groups, one of which was exposed to heat stress (HS). Within each group, four subgroups, each including 64 birds, were created for the three treatment doses (200, 400 or 600 mg/kg) of LRE and the control. The experiment was started with day-old birds, kept at a temperature of 25 °C or 37 °C. After a 7-day adjustment period, the LRE supplementation lasted for 35 days. The levels of different adipokines, including visfatin (VF), adiponectin (ADP), chemerin (CHEM), as well as the concentration of plasma citrulline (CIT) and the levels of thyroid hormones (T3 and T4) and thyroid-stimulating hormone (TSH) in the blood were measured at 21 and 42 days of age. A significant correlation (P < 0.01) was found between LRE supplementation and the decrease in serum VF, ADP, CIT, T3 and T4 levels in partridges exposed to HS. On the other hand, no significant relationship was found between LRE supplementation and the serum CHEM and TSH levels (P > 0.05). We concluded that the addition of 600 mg/kg LRE is beneficial in preventing intestinal damage and inflammation provoked by HS.