Symmetric Dimethylarginine Levels Research Articles

Reference intervals for selected blood and urinary parameters related to renal function in clinically healthy ferrets (Mustela putorius furo)

Diagnosis of chronic kidney disease can be challenging in ferrets. Physiological creatinine values are lower than in dogs and cats and marked elevations may only be detected in advanced disease. In canine and feline patients, specific staging and treatment guidelines are available, based on serum creatinine, symmetric dimethylarginine (SDMA) levels, presence of proteinuria and blood pressure measurement. No such guidelines exist for ferrets, and there is a lack of data concerning certain laboratory parameters. Blood and urine samples were taken from 60 clinically healthy pet ferrets to establish species-specific reference intervals for serum SDMA and urine protein/creatinine ratio (UPC ratio). Liquid-chromatography tandem mass spectrometry (HPLC-MS) was used for determination of serum SDMA, a colorimetric spectrophotometric method for urinary protein and an enzymatic method for urine creatinine. The calculated reference interval for serum SDMA (2.78-7.66 µg/dl) was found to be lower than in dogs and cats, while the UPC ratio is similar to dogs (<0.5).

Abstract 3227: Developing brain-penetrating MAT2A inhibitors for MTAP-deleted brain metastatic cancer and GBM

Abstract Background: Homozygous deletion of MTAP is one of the most frequent genetic alterations in various solid tumors including glioblastoma (GBM), mesothelioma, pancreatic cancer and lung cancer. While MTAP-deleted cancers are associated with a poor prognosis, there are no approved drugs for the treatment of patients with MTAP deficiency. MAT2A has emerged as a potential target for selective anticancer effects in MTAP-deleted cancers. However, development of brain-penetrating MAT2A inhibitors are yet to be reported in preclinical or clinical stages despite of high MTAP deletion fraction in GBM and brain metastatic cancers. Here, we present highly potent and selective MAT2A inhibitors capable of brain penetration for MTAP deleted cancer therapy. Methods: A MAT2A biochemical enzyme assay was performed with phosphonate colorimetric kit. To evaluate in vitro and in vivo activities of compounds, S-adenosylmethionine (SAM) and symmetrical dimethyl arginine (SDMA) levels were measured using LC-MS/MS and high-content screening systems. Cell growth inhibition assay was evaluated to confirm the selectivity in isogenic pairs of HCT116 WT and MTAP-deleted cells. In vivo efficacy was conducted using the MTAP-deleted HCT116 xenograft. Results: To develop novel brain penetrating scaffolds, we focused on interaction of hydrogen bond acceptor in the scaffolds with arginine residue Arg313 in MAT2A protein and the improvement of physicochemical properties, including logP and logBB. A series of MAT2A inhibitors significantly inhibited MAT2A enzymatic activity, resulting in the reduction of intracellular SAM level, the direct product of MAT2A. These compounds showed highly potent inhibition of SDMA and cell proliferation in MTAP-deleted cells, while displaying minimal effect on MTAP-WT cells, showing &amp;gt;100-fold selectivity towards MTAP-deletion over MTAP-WT. Furthermore, anti-proliferative activity of MAT2A inhibitors were observed in MTAP-deleted cancer cells across various cancer types, including GBM, breast cancer, and non-small cell lung cancer. Remarkably, mouse pharmacokinetic study revealed high level of plasma and brain exposure with outstanding brain-to-plasma ratio (&amp;gt; 0.75). Robust tumor growth inhibition as well as reduction in tumor SAM levels were observed as monotherapy in an MTAP-deleted HCT116 xenograft model. Conclusion: We have identified novel brain-penetrating MAT2A inhibitors displaying encouraging in vitro and in vivo pharmacological profiles, indicating the potential use of these compounds as therapeutic agents for MTAP deleted brain metastatic cancer and GBM. Citation Format: Soyoung Ki, Jinhee Kim, Jungtae Na, Ilkyoo Koh, Hyunho Cho, Ho Yeon Lee, Hoiyun Jung, Gyeonghi Cho, Mijin Moon, Yongje Shin, Sook-Kyung Park. Developing brain-penetrating MAT2A inhibitors for MTAP-deleted brain metastatic cancer and GBM [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3227.

Abstract 4596: Targeting arginine methylome in 9p21/MTAP-deleted malignant cancers with a next generation PRMT5-specific inhibitor CTS3497

Abstract It remains largely challenging to treat cancer patients with chromosome 9p21-deletion which occurs in approximately 15% of human cancers. Recently, specific targeting of protein arginine methyltransferase 5 (PRMT5), a key member of the type-II PRMT family and a master epigenetic modulator of arginine methylome essential for cancer progression, has emerged as a promising therapy in various hematological and solid tumors with MTAP deletion serving as a precision biomarker. To optimize the potential of targeting PRMT5, we developed CTS3497, a potent, brain-penetrable, orally bioavailable MTA-cooperative PRMT5 inhibitor, using our EpigenPLUSTM platform. The overall excellent drug-like properties of CTS3497 support fast track IND application, and it is anticipated to enter Phase 1 trials in 2024. CTS3497 demonstrated potent PRMT5 inhibitory activity in cellular pharmacodynamics (PD) assays, evidenced by the suppression of symmetric dimethylarginine (SDMA). Additionally, it exhibited profound cell growth inhibition with a low single-digit nM IC50 and 171-fold high selectivity for MTAPnull over isogenic MTAPwt cell lines. Moreover, CTS3497 displayed strong inhibitory effects on cell growth across diverse panels of MTAPnull cancer cell lines and patient-derived xenograft organoids (PDXOs) spanning various lineages. In vivo, oral administration of CTS3497 resulted in significant tumor regression in multiple MTAP-deleted xenograft models, notably MTAPnull brain tumors. The observed anti-tumor activity correlated with PRMT5 modulation, as indicated by reduced SDMA levels. Impressively, sustained tumor growth inhibition led to the complete tumor regression, with no regrowth even after discontinuation of CTS3497 treatment. The brain penetration property of CTS3497 underscores its therapeutic potential for both primary brain tumors, and brain metastases arising from specific cancers like lung cancer. At the molecular level, PRMT5 inhibition by CTS3497 induced substantial and distinctive RNA splicing defects and differentially expressed gene signatures, impacting key cellular activities downstream of arginine and epigenetic reprogramming in MTAPnull cancer cells. Furthermore, a synergistic anti-tumor effect was observed in multiple MTAP-deleted tumors when combining PRMT5 inhibition with CTS2190, an investigational type-I PRMT inhibitor currently in phase I/II clinical trials. In summary, CTS3497, a PRMT5 inhibitor selectively targeting MTAPnull tumor cells, demonstrated robust and durable anti-tumor responses both in vitro and in vivo across diverse lineages of MTAP-deleted tumors. Its superior ADME properties and favorable safety profiles observed in preclinical studies mark a breakthrough in the next generation epigenetic therapy. CTS3497 emerges as a promising therapeutic option for patients with MTAP-deleted malignancies. Citation Format: Yilin Liu, Long Wang, Hui Shi, Yuanyuan Liu, Qiugeng Ouyang, Xingnian Fu, Meng Wang, Jiannan Guo, Yiqin Wang, Youzhen Wang, Guoliang Xu, Yuan Mi, Haiping Wu. Targeting arginine methylome in 9p21/MTAP-deleted malignant cancers with a next generation PRMT5-specific inhibitor CTS3497 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4596.

Asymmetric and symmetric dimethylarginine as markers of endothelial dysfunction in cerebrovascular disease: A prospective study

Background and aimAsymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) have been proposed as mediators of endothelial dysfunction. In this study, we aimed to investigate the diagnostic and prognostic role of ADMA and SDMA in acute cerebrovascular disease. Methods and resultsA prospective case-control study was performed, enrolling 48 patients affected by ischemic stroke with no cardioembolic origin, 20 patients affected by TIA, 40 subjects at high cardiovascular risk and 68 healthy subjects.ADMA levels were significantly lower in high-risk subjects (18.85 [11.78–22.83] μmol/L) than in patients with brain ischemic event, both transient (25.70 [13.15–40.20] μmol/L; p = 0.032) and permanent (24.50 [18.0–41.33] μmol/L; p = 0.001). SDMA levels were different not only between high-risk subjects and ischemic patients, but also between TIA and stroke patients, reaching higher levels in TIA group and lower levels in stroke group (1.15 [0.90–2.0] vs 0.68 [0.30–1.07] μmol/L; p < 0.001). SDMA was also correlated with short-term prognosis, with lower levels in case of adverse clinical course, evaluated by type of discharge (p = 0.009) and need of prolonged rehabilitation (p = 0.042). ConclusionsThe present study highlights the relationship between l-arginine, ADMA, SDMA and acute cerebrovascular events. Therefore, our results suggested a potential role of SDMA as a specific marker of transient ischemic damage and as a short-term positive prognostic marker.

Assay validation and determination of the reference interval for symmetric dimethylarginine in healthy rabbits

BackgroundChronic kidney disease (CKD) is common in older rabbits. The renal biomarkers blood urea and creatinine can be insensitive as indicators of renal disease in rabbits. Symmetric dimethylarginine (SDMA) has been shown to be an earlier and more sensitive biomarker for the assessment of glomerular filtration rate and the evaluation of CKD in several animal species. An immunoassay for SDMA has been validated in a number of species. The purpose of this study was to validate the SDMA immunoassay for rabbit serum and plasma and to determine the normal rabbit reference interval (RI) for SDMA. MethodsClinically healthy rabbits (n=167) between 5 months and 8 years of age, of any breed or sex, participated in the study. Heparinized plasma or serum was collected for clinical chemistry and used for assay validation. Analytical validation of the SDMA immunoassay for rabbit serum and plasma was performed and included assessment of assay accuracy, precision, analytical sensitivity, linearity, interference testing, and plasma/ serum bias. The SDMA reference interval (RI) was determined. ResultsThe SDMA immunoassay met all set quality requirements assessed in analytical validation. The RI for SDMA was determined to be between 4 - 18 µg/dL. Conclusions and clinical relevanceThe SDMA immunoassay demonstrated acceptable performance in both rabbit serum and heparinized plasma as determined by the validation criteria. Although the utility of SDMA as a biomarker of renal disease in rabbits has not been determined, validation of the SDMA immunoassay should facilitate evaluation of SDMA levels in rabbits with confirmed renal disease.

Symmetric dimethylarginine correlates with the urea, creatinine, potassium, and clinical scores in feline urethral obstructions.

A urethral obstruction (UO) is an emergency commonly observed in male cats, which can result in significant clinical and laboratory alterations, leading to complications and death. This study aimed to correlate symmetric dimethylarginine (SDMA) with the urea, creatinine, potassium, and bicarbonate levels in cats with UO. In addition, the correlation between clinical score and time of obstruction was evaluated. Thirty male cats were selected and allocated into a control group (CG, n = 13) and an obstruction group (OG, n = 17). The laboratory analyses were conducted before treatment (M0) and at different times after treatment (12 h [M12], 24 h [M24], and 48 h [M48]). Correlations were established between SDMA and creatinine, urea, bicarbonate, potassium, time of obstruction, and the clinical score. A strong correlation (r > 0.6) was observed between SDMA and creatinine, urea, and potassium in the OG. Furthermore, there was substantial agreement (kappa value) between SDMA and creatinine at M24. A higher clinical score was associated with a longer time of obstruction. In the OG, at M48, the SDMA and creatinine levels were 50% and 41.2% higher, respectively. A correlation was observed between SDMA and creatinine in obstructed cats, and significant agreement between these values was observed 24 h after the unblocking treatment. A correlation among SDMA, urea, and potassium was observed. Approximately 9% more cats continued to have elevated SDMA levels after 48 h of treatment compared to creatinine. This suggests a slightly lower sensitivity of the latter biomarker but does not exclude the possibility of congruent and normalized values after a longer evaluation period.

Abstract B177: The discovery and preclinical characterization of AMG 193, a first-in-class MTA-cooperative PRMT5 inhibitor with broad activity against MTAP-null cancers

Abstract Homozygous deletion of the methylthioadenosine phosphorylase (MTAP) gene occurs in approximately 15% of all cancers due to its proximity to the commonly deleted tumor suppressor gene CDKN2A. Elevated methylthioadenosine (MTA) levels, driven by loss of MTAP, compete with the methyl donor S-adenosylmethionine (SAM) for binding to protein arginine N-methyltransferase 5 (PRMT5), placing the methyltransferase in a hypomorphic state, and vulnerable to further PRMT5 inhibition. The screening of a DNA-encoded library, designed to identify small molecules that preferentially bind to PRMT5 in the presence of MTA, resulted in the identification of AM-9934 as a promising hit. Using structure-based drug design, potency and cooperativity were enhanced to deliver AM-9747, an MTA-cooperative PRMT5 inhibitor suitable for in vivo proof-of-concept studies. Further optimization led to AMG 193, an orally bioavailable and MTA-cooperative PRMT5 inhibitor with potent biochemical and cellular activity, and an improved pharmacokinetic profile. Insights into the binding mode of AMG 193 were elucidated by the crystal structure of AMG 193 bound to the MTA-PRMT5 complex. AMG 193 activity is enriched in MTAP-null cells in vitro, as illustrated in the HCT116 isogenic pair; AMG 193 is ~40X selective for MTAP-null cells (IC50 = 0.1 mM) over MTAP WT cells (IC50 &amp;gt; 4 mM) in viability assays and &amp;gt;100X selective in an assay evaluating symmetric dimethylarginine (SDMA) levels. AMG 193 was profiled in a panel of &amp;gt;850 cancer cell lines, and response demonstrated preferential sensitivity in MTAP-null cells compared to WT across multiple cancer lineages, including pancreatic, lung, biliary tract, and lymphoma. Response strongly correlated with both MTAP and CDKN2A copy number loss, and cell lines that were dependent on PRMT5, as shown by RNAi and CRISPR knockdown, were most sensitive to AMG 193 treatment. In vitro mechanism-of-action studies demonstrated that PRMT5 inhibition induced DNA damage, cell cycle arrest in G2/M, and an increase in alternative mRNA splicing in MTAP-null cells. In mice oral, once-daily administration of AMG 193 selectively inhibited SDMA in tumor versus normal tissue and was well tolerated with no hematologic perturbations. Importantly, AMG 193 demonstrated robust anti-tumor activity across a broad range of MTAP-null CDX and PDX tumor models derived from NSCLC, pancreatic, and esophageal cancers. In vitro synergy was observed with the combination of AMG 193 and several chemotherapeutic agents, including carboplatin and paclitaxel, or the KRASG12C inhibitor, sotorasib. In vivo, these combinations led to enhanced anti-tumor activity relative to single agent in MTAP-null NSCLC tumor models. In February 2022, AMG 193 became the first MTA-cooperative PRMT5 inhibitor to enter clinical development and is currently being evaluated in subjects with advanced MTAP-null solid tumors in the ongoing FIH study (NCT05094336). Citation Format: Brian Belmontes, Katherine Slemmons, Siyuan Liu, Antonia Policheni, Jodi Moriguchi, Hong Tan, Fang Xie, Famke Aeffner, Matthew G Rees, Melissa M Ronan, Jennifer A Roth, Mikkel Vestergaard, Sanne Cowland, Jan Andersson, Ian Sarvary, Patricia Lopez, Nuria Tamayo, Liping H Pettus, Susmith Mukund, Jennifer R Allen, Sanne Glad, Matthew P Bourbeau. The discovery and preclinical characterization of AMG 193, a first-in-class MTA-cooperative PRMT5 inhibitor with broad activity against MTAP-null cancers [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr B177.

Antitumor effects of PRMT5 inhibition in sarcomas.

Patients with advanced soft-tissue sarcomas (STSs) have few therapeutic options. Protein arginine methyltransferase 5 (PRMT5), an anticancer target, has been extensively investigated in recent years in epithelial tumors. To date, no data related to the biological role of PRMT5 inhibition and its potential effect as a treatment in STS have been reported. To investigate the therapeutic potential of PRMT5 targeting in STS, we first evaluated the prognostic value of PRMT5 expression in 2 different cohorts of patients with STS. We then used the potent and selective GSK3326595 (GSK595) compound to investigate the antitumor effect of the pharmacological inhibition of PRMT5 in vitro via MTT, apoptosis, cell cycle, clonogenicity and proliferation assays. In vivo studies were performed with two animal models to evaluate the effects of GSK595 on tumor growth. The mechanisms of action were investigated by RNA sequencing, metabolic pathway analysis, Western blotting and glucose uptake/lactate production assays. High PRMT5 gene expression levels were significantly associated with worsened metastasis-free survival of STS patients. GSK595 decreased the global symmetric dimethylarginine level, the proliferation rate and clonogenicity of STS cell lines in vitro and tumor growth in vivo. Moreover, PRMT5 inhibition regulated aerobic glycolysis through downregulation of key enzymes of glycolysis as well as glucose uptake and lactate production. The present study demonstrated that PRMT5 regulates STS cell metabolism and thus represents a potential therapeutic target for STS. Additional studies in diverse sarcoma subtypes will be essential to confirm and expand upon these findings.

Vitamin D Supplementation Influences Ultramarathon-Induced Changes in Serum Amino Acid Levels, Tryptophan/Branched-Chain Amino Acid Ratio, and Arginine/Asymmetric Dimethylarginine Ratio.

Exercise affects serum levels of amino acids and their metabolites, with important metabolic consequences. Since vitamin D impacts skeletal muscle protein degradation, we hypothesised that it would also impact exercise-induced changes in serum amino acid levels and the serum levels of arginine metabolites, influencing the body's ability to synthesise NO. Accordingly, we analysed the effect of a single high-dose vitamin D supplementation on the serum levels of various amino acids in ultramarathon runners. Thirty-five male amateur runners were assigned to the supplemented group, administered 150,000 IU vitamin D in vegetable oil 24 h before the run (n = 16), or the control (placebo) group (n = 19). Blood was sampled 24 h before, immediately after, and 24 h after the run. Changes in the serum levels of some amino acids were distinct in the two groups. The asymmetric dimethyl arginine levels were significantly decreased immediately after the run and increased 24 h later and were not affected by the supplementation. The symmetric dimethyl arginine levels were increased after the run in both groups but were lower in the supplemented group than in the placebo group 24 h after the run. The dimethylamine levels increased significantly in the supplemented group as compared to the placebo group. In conclusion, vitamin D impacts exercise-induced changes in serum amino acids and methylated arginine metabolites.

Relationship between Excreted Uremic Toxins and Degree of Disorder of Children with ASD.

Autism spectrum disorder (ASD) is a complex developmental disorder in which communication and behavior are affected. A number of studies have investigated potential biomarkers, including uremic toxins. The aim of our study was to determine uremic toxins in the urine of children with ASD (143) and compare the results with healthy children (48). Uremic toxins were determined with a validated high-performance liquid chromatography coupled to mass spectrometry (LC-MS/MS) method. We observed higher levels of p-cresyl sulphate (pCS) and indoxyl sulphate (IS) in the ASD group compared to the controls. Moreover, the toxin levels of trimethylamine N-oxide (TMAO), symmetric dimethylarginine (SDMA), and asymmetric dimethylarginine (ADMA) were lower in ASD patients. Similarly, for pCS and IS in children classified, according to the intensity of their symptoms, into mild, moderate, and severe, elevated levels of these compounds were observed. For mild severity of the disorder, elevated levels of TMAO and comparable levels of SDMA and ADMA for ASD children as compared to the controls were observed in the urine. For moderate severity of ASD, significantly elevated levels of TMAO but reduced levels of SDMA and ADMA were observed in the urine of ASD children as compared to the controls. When the results obtained for severe ASD severity were considered, reduced levels of TMAO and comparable levels of SDMA and ADMA were observed in ASD children.

Abstract 6273: CTS3157, a novel MTA-cooperative PRMT5 inhibitor for targeting MTAP-deleted human tumors

Abstract MTAP deletion is common in about 15% of all human cancers and coincides with the deletion of tumor suppressor locus containing CDKN2A/B. Methylthioadenosine (MTA), the substrate of MTAP, accumulates as a result of MTAP deletion. Increased levels of MTA result in partial inhibition of the PRMT5 enzyme by competing with S-adenosylmethionine (SAM, the methyl donor for PRMT5 substrate) due to structural similarity. Cancer cell lines with MTAP-deletion exhibit profound sensitivity to PRMT5 inhibition, suggesting MTAPnull-selective PRMT5 inhibitors have the potential to treat patients with MTAP deficiency (Kryukov et al., 2016). We identified CTS3157 as an orally bioavailable small molecule MTA-cooperative PRMT5 inhibitor that binds to PRMT5-MTA complex and inhibits PRMT5 enzymatic activity. Cell-based assays revealed that CTS3157 demonstrated potent PRMT5 inhibition as evidenced by suppression of symmetric dimethylarginine (SDMA) and cell growth inhibitory activity for MTAP-deleted cell lines over isogenic MTAPWT cell lines. Moreover, CTS3157 series compounds exhibited strong cell growth inhibition in a diverse panel of MTAPnull human tumor cell lines across several lineages. In vivo, CTS3157 demonstrated potent antitumor response after once-daily oral administration in MTAP-deleted xenograft models. The anti-tumor activity is correlated with PRMT5 modulation as measured by reduced SDMA levels. At molecular level, PRMT5 inhibition by CTS3157 resulted in massive RNA splicing defects and differentially expressed genes involving key cellular activities in MTAPnull cells. In summary, MTAPnull-selective PRMT5 inhibitor CTS3157 showed strong and durable antitumor responses in vitro and in vivo in MTAP-deleted tumors across diverse lineages. CTS3157 is an effective and promising therapeutics against MTAP-deleted tumors. Citation Format: Long Wang, Yilin Liu, Hui Shi, Yuanyuan Liu, Qiugeng Ouyang, Jiannan Guo, Yiqin Wang, Youzhen Wang, Guoliang Xu, Yuan Mi, Haiping Wu. CTS3157, a novel MTA-cooperative PRMT5 inhibitor for targeting MTAP-deleted human tumors. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6273.

Arginine, symmetric and asymmetric dimethylarginine levels in canine leishmaniasis

The study aimed to investigate the levels of arginine, symmetric dimethylarginine (SDMA), and asymmetric dimethylarginine (ADMA) in dogs with canine leishmaniasis (CanL) and their relationship with some renal and cardiovascular parameters. A total of 60 dogs were enrolled, including 40 with CanL and 20 healthy controls. The CanL group was divided into four stages based on clinical and laboratory findings. The levels of plasma arginine, SDMA, and ADMA were determined by high performance liquid chromatography (HPLC). The data from the healthy group were compared with those from the CanL group, and according to the stages. In dogs with CanL, systolic and diastolic blood pressure, plasma creatinine, cystatin-C, phosphorus, potassium, and low-density lipoprotein concentrations, the urine protein/creatinine ratio, the amount of nitric oxide, and creatine kinase-MB activity were higher, while the high-density lipoprotein concentration was lower compared to healthy controls. The concentration of arginine was low (p < 0.05) and the levels of ADMA (p < 0.001) and SDMA (p < 0.05) were high in dogs with CanL. There were no statistically significant differences in arginine concentration among the different stages of CanL. However, the concentration of plasma ADMA was higher in all stages of CanL compared to the healthy group, and the concentration of plasma SDMA was higher in Stage IV compared to the healthy group and Stage III. The present study demonstrates for the first time a decrease in arginine concentration and an increase in ADMA concentration in dogs with CanL. The increase in SDMA concentration in dogs with CanL was consistent with previous studies. However, compared to other renal parameters, SDMA exhibited limited performance distinguishing between clinical stages of CanL. These findings could be a source for future diagnostic and therapeutic studies to explain the renal and cardiovascular pathophysiology of CanL. Additional clinical studies that include treatment and patient follow-up with an assessment of the acute phase response are needed to provide a more detailed understanding of the changes observed in dogs with CanL.

IRIS-Stage 4 CKD in a Dog: Diagnostic Approaches and Staging of Chronic Kidney Disease: A Case Study

Chronic kidney disease (CKD) is a devastating disease of the kidneys that often arise from unresolved acute injury. As a chronic disease, CKD is challenging to diagnose, thus it needs a good combination of a comprehensive understanding of the kidney’s anatomy and physiology and thorough planning for a framework of diagnostic tools to be utilized. This study is intended to provide the diagnostic planning used to determine CKD in an approximately 5-year-old intact male dog that was brought to My Vets Animal Clinic for a check-up visit. On presentation, the dog was emaciated, mildly dehydrated, halitotic, and infested with ticks. A complete blood count (CBC) indicated a normocytic, normochromic, non-regenerative anemia, and lymphopenia. The blood chemistry panel indicated azotemia, elevated symmetric dimethylarginine (SDMA), hypocalcemia, and hyperphosphatemia. Elevated SDMA level (64 μg/dL, reference value: 0-14 μg/dL) and hypercreatinemia (5.9 mg/dL, reference value: 0.5-1.8 mg/dL) indicated impaired glomerular filtration. Physical and clinical pathological findings signified the presence of CKD in this dog, with a stage-4 severity based on International Renal Interest Society (IRIS) CKD staging criteria. The prognosis of this case was highly guarded, and the dog eventually passed away on the sixth day of hospitalization. In a case with an uncertain outcome, accuracy in both diagnosis and staging of CKD in dogs will aid the therapy regimen planning, which may improve the patient’s conditions.

Cystatin-c May Indicate Subclinical Renal Involvement, While Orosomucoid Is Associated with Fatigue in Patients with Long-COVID Syndrome

Long-COVID syndrome is associated with high healthcare costs, but its pathophysiology is not yet fully understood. Inflammation, renal impairment or disturbance of the NO system emerge as potential pathogenetic factors. We aimed to investigate the relationship between symptoms of long-COVID syndrome and serum levels of cystatin-c (CYSC), orosomucoid (ORM), l-arginine, symmetric dimethylarginine (SDMA) and asymmetric dimethylarginine (ADMA). A total of 114 patients suffering from long-COVID syndrome were included in this observational cohort study. We found that serum CYSC was independently associated with the anti-spike immunoglobulin (S-Ig) serum level (OR: 5.377, 95% CI: 1.822-12.361; p = 0.02), while serum ORM (OR: 9.670 (95% CI: 1.34-9.93; p = 0.025) independently predicted fatigue in patients with long-COVID syndrome, both measured at baseline visit. Additionally, the serum CYSC concentrations measured at the baseline visit showed a positive correlation with the serum SDMA levels. The severity of abdominal and muscle pain indicated by patients at the baseline visit showed a negative correlation with the serum level of L-arginine. In summary, serum CYSC may indicate subclinical renal impairment, while serum ORM is associated with fatigue in long-COVID syndrome. The potential role of l-arginine in alleviating pain requires further studies.

EVALUATION OF SYMMETRIC DIMETHYLARGININE AS AN ENDOGENOUS MARKER OF RENAL DISEASE IN GREATER FLAMINGOS (PHOENICOPTERUS ROSEUS).

Detection of renal disease in birds is currently reliant on biochemical measures such as uric acid, which is only elevated after significant renal compromise has occurred. Symmetric dimethylarginine (SDMA) production has not been previously evaluated in birds and no reference intervals (RI) for measurement exist in avian species. This study aimed to develop an RI for SDMA in greater flamingos (Phoenicopterus roseus) and evaluate the association between SDMA levels and renal disease. Blood from 60 flamingos was collected for RI development and the RI of SDMA was found to be 11.8-34.2 µg/dl. Symmetric dimethylarginine showed a strong positive correlation with uric acid, a moderate positive correlation with creatine kinase, and moderate negative correlations with total protein, albumin, and glucose. No correlation was found with pododermatitis score or body condition. Using the SDMA RI, six clinical cases were included for assessment of the clinical relevance of SDMA in renally compromised patients. All birds that were euthanized had elevated SDMA levels and severe renal or systemic pathology on necropsy.

Effect of cigarette smoking on serum methylarginine and α-klotho levels

Background and aimsSmoking causes many diseases such as cardiovascular, lung diseases, stroke and premature aging. However, the role of smoking in the pathogenesis of these diseases is unclear. Increasing evidence suggests that methylarginine pathway metabolites and α-klotho may be strong markers for pathologies such as premature aging, endothelial dysfunction, and oxidant damage. Therefore, the study aimed to measure the serum levels of arginine, asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA), N-monomethyl-l-arginine (L-NMMA), and α-klotho levels in smokers. Methods and resultsThis case-control analytical study included 65 smokers and 71 non-smokers. Sociodemographic characteristics, routine biochemistry parameters, Framingham risk scores and Fagerström Nicotine Dependence Test (FTND) were recorded. Serum methylarginine and α-klotho levels were analyzed by tandem mass spectrometry and enzyme-linked immunosorbent assay (ELISA), respectively. Serum ADMA (p < 0.001), L-NMMA (p = 0.024), SDMA (p < 0.001) levels of smokers were higher than non-smokers, and serum α-klotho (p < 0.001) and arginine levels (p < 0.001) were lower. There was a positive correlation between serum ADMA levels with FNDT, age and pack/year in smokers, while there was a negative correlation between klotho levels and age. A positive correlation was found between serum ADMA levels, Framingham risk score and age in non-smokers. ConclusionSmoking is related to premature aging and is a strong risk factor for various diseases such as cardiovascular, inflammatory, and renal diseases. Elevated serum methylarginine and decreased serum klotho levels were found in smokers. Therefore, our findings suggest that smoking may be involved in the pathogenesis of these diseases by affecting α-klotho and methylarginine-related pathways.

PS-BPC11-9: ADMA/SDMA RATIO AND ITS RELATIONS TO URIC ACID AND ALBUMIN IN CONTINUOUS AMBULATORY PERITONEAL DIALYSIS PATIENTS IN INDONESIA

Background and Aims: Asymmetric Dimethylarginine (ADMA) and Symmetric Dimethylarginine (SDMA), rarely reported together, are markers of endothel dysfunction and kidney function. ADMA was inversely related to albumin, while SDMA was positively correlated to albumin. Meanwhile, uric acid was positively correlated to both SDMA and ADMA. By using ADMA and SDMA as ratio, we postulated that their ratio can more precisely predict activity dimethylarginine dimethylaminohydrolase (DDAH), a key enzyme that metabolized ADMA, and not SDMA, and can be used as marker of NO activity. Low NO activity is related to high vascular tonus and peripheral resistance, hypertension and low Sodium excretion and cardiac output. Method: This was a cross-sectional study conducted in adults underwent chronic Continuous Ambulatory Peritoneal Dialysis (CAPD) in tertiary hospital in Jakarta, Indonesia. Uric acid, albumin, ADMA and SDMA levels were measured at the same time patients controlled to outpatient clinic after washout from hyperuricemia drug for 2 to 4 weeks. Analysis performed using Pearson for normal distribution data, Spearman for nonparametric analysis and linier regression test and ROC curve with SPSS v20. Results and Discussion: Total of 55 subjects (83%) were included, male 63.6%, mean age of 40.71 ± 14,4 year old. Median of CAPD use was 27 months. Causes of CKD were glomerulonephritis (47.3%), diabetes mellitus (25.5%), hypertension (25.5%) and polycystic kidney disease (1.8%). At the time of research, 90.9%, were uncontrolled hypertension patients. Median level of UA was 7.30 ± 1.59 mg/dl and 60% had UA levels of 7 mg/dl or higher. Albumin level lower than 3.5 g/dl (mean 3.55 ± 0.49 g/dl) were 24 patients (43.6%). Median ADMA level was 87.5 ± 16.64 ng/ml and SDMA level was 633.73 ± 231.54 ng/mL. Median ADMA/SDMA ratio was 0.13 + 0,08 ng/ml. ADMA, SDMA, ADMA/SDMA ratio were correlated with uric acid with p = 0.027 (95%CI 0.175–0.471), p &lt; 0.001 (95%CI 0.688–0.928) and p &lt; 0.001 (95%CI -14,96 to -5,03) with sensitivity and specificity 91% and 95%, 97% and 68% and 79% and 96%, respectively. ADMA, SDMA, ADMA/SDMA ratio were not statistically significantly correlated with albumin with p = 0.26, p = 0.14 and p = 0.23, respectively. Albumin level was caused by many factors that are not in the scope of this research, this might explain this result. Conclusion: ADMA/SDMA ratio had comparable sensitivity and specificity to ADMA or SDMA alone when correlated with uric acid in CAPD patients. Albumin might not correlated with ADMA, SDMA, or ADMA/SDMA ratio in CAPD patients.

Diagnostic assessment of two-dimensional shear wave elastography in relation to dimethyl arginine levels in dogs with chronic kidney disease.

In veterinary medicine, previous studies regarding the diagnostic performance of shear wave elastography (SWE) in chronic kidney disease (CKD) are not consistent with each other. Moreover, there has been no study evaluating the relationship between symmetric dimethyl arginine (SDMA) concentration and renal shear wave velocity (SWV) using two-dimensional SWE (2D SWE) in dogs with CKD. This study aimed to evaluate the diagnostic capability of 2D SWE in dogs with CKD and to assess the relationship between renal SWV and SDMA concentration. Dogs with healthy kidneys and dogs with CKD underwent 2D SWE and SDMA assay. Renal stiffness was estimated as renal SWV in m/s. SDMA concentration had a weak positive correlation with the left (r = 0.338, p = 0.022) and right renal SWV (r = 0.337, p = 0.044). Renal SWV was not significantly different between healthy kidney and CKD groups in the left (p = 0.085) and right (p = 0.171) kidneys. 2D SWE may could not distinguish between dogs with healthy kidney and dogs with early stage of CKD, but it would be useful for assessing the serial change of renal function in dogs.

Asymmetric Dimethylarginine in an NMU-induced Rat Mammary Tumor Model.

Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide (NO) production and a newly discovered risk factor involved in endothelial dysfunction and adverse cardiovascular events. Recently, both NO and ADMA have also emerged as molecules of interest in carcinogenesis and tumor growth progression. Our earlier studies have confirmed elevated plasma ADMA levels in patients with hematological malignancies. However, the cause of elevated ADMA was unclear. The aim of this study was to assess the concentrations of ADMA, symmetric dimethylarginine (SDMA) and L-arginine in rats exposed to N-nitroso-N-methylurea (NMU) for the induction of mammary tumors. A total of 95 female rats of the Sprague-Dawley strain were used in the study. Plasma concentrations of ADMA, SDMA and L-arginine were quantified and statistically analyzed. Mean ADMA levels were higher in the tumor-bearing group compared to the control group. Mean plasma levels of SDMA and L-Arginine were not significantly different between the groups. The L-ARG/ADMA ratio was lower in rats with tumors compared to controls. Histological assessment confirmed expression of ADMA within the tumor cells, which strongly suggests that these tumor cells were the source of ADMA. Other studies are warranted to further explain the role of ADMA in neoplastic diseases.

Asymmetric and symmetric dimethylarginine gingival crevicular fluid levels in periodontitis.

This study aimed to evaluate the level of ADMA (asymmetric dimethylarginine), SDMA (symmetric dimethylarginine), and IL-1β (Interleukin-1β) in gingival crevicular fluid (GCF) from periodontitis patients and control subjects. ADMA and SDMA are potentially hazardous non-proteinogenic amino acids that limit nitric oxide (NO) synthesis and have many functions in various human disorders. ADMA causes a structural change in nitric oxide synthase, while SDMA blocks arginine cell uptake. Increased plasma ADMA has been widely recognized as a "trigger" initiating impaired NO bioavailability and vascular dysfunction, which ultimately leads to oxidative stress. Twenty-five patients with periodontitis (P) (Stage III, Grade C, n=25) and 20 control (C) subjects were included in the study. The IL-1β level of GCF was measured by enzyme immunoassay (ELISA) and ADMA and SDMA by liquid chromatography-mass spectrometry (LC-MS/MS). Periodontitis patients had higher clinical parameters than controls (p < .001). Levels of IL-1β, ADMA and SDMA GCF were statistically significantly higher in group P than in group C (respectively; p=.003, p < .0001, p < .0001). There was no difference in the ADMA/SDMA ratio (p=.312) between the groups. There were significant positive correlations between clinical periodontal parameters and IL-1β, ADMA, and SDMA levels (p < .05). ADMA and SDMA levels were significantly correlated with IL-1β (p < .05). These findings suggest that ADMA and SDMA may be involved in the pathogenesis of the periodontal disease.