Letter to the editor: “Role of the human erythrocyte in generation and storage of asymmetric dimethylarginine”

Großkopf, Henning; Böhmer, Anke; Tsikas, Dimitrios

doi:10.1152/ajpheart.00449.2012

Cited by 4 publications

(1 citation statement)

References 10 publications

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“…The underlying mechanisms are unknown and remain to be resolved. It is worth mentioning that human erythrocytes are rich in ADMA-containing proteins (not including hemoglobin), the proteolysis of which may release considerable amounts of free ADMA into the circulation Davids et al 2012;Grosskopf et al 2012).…”

Section: Amino Acids Of the L-arg/no Pathwaymentioning

confidence: 99%

The l-arginine/NO pathway, homoarginine, and nitrite-dependent renal carbonic anhydrase activity in young people with type 1 diabetes mellitus

et al. 2015

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High circulating levels of asymmetric dimethylarginine (ADMA) and low circulating levels of homoarginine (hArg) are known cardiovascular risk factors in adults. While in adults with type 1 diabetes mellitus (T1DM) circulating ADMA is significantly elevated, in children and adolescents the reported ADMA data are contradictory. In 102 children with T1DM and 95 healthy controls (HC) serving as controls, we investigated the L-arginine (Arg)/nitric oxide (NO) pathway. Children with T1DM were divided into two groups, i.e., in children with newly diagnosed diabetes mellitus [T1DM-ND; n = 10; age, 8.8 (4.4-11.2) years; HbA1c, 13 (8.9-13.9) %] and in those with long-term treatment [T1DM-T; n = 92; age, 12.5 (10.5-15.4) years; HbA1c, 8.0 (7.2-8.6) %]. The age of the HC was 11.3 (8-13.3) years. Amino acids and NO metabolites of the Arg/NO pathway, creatinine and the oxidative stress biomarker malondialdehyde (MDA) were measured by GC-MS or GC-MS/MS. Plasma hArg, ADMA and the hArg/ADMA molar ratio did not differ between the T1DM and HC groups. There was a significant difference between T1DM-T and HC with regard to plasma nitrite [0.53 (0.48-0.61) vs 2.05 (0.86-2.36) µM, P < 0.0001] as well as to urinary nitrite [0.09 (0.06-0.17) vs 0.22 (0.13-0.37) μmol/mmol creatinine, P < 0.0001]. Plasma, but not urinary nitrite, differed between T1DM-ND and HC [0.55 (0.50-0.66) vs 2.05 (0.86-2.36) µM, P < 0.0001]. Plasma MDA did not differ between the groups. The urinary nitrate-to-nitrite molar ratio (UNOXR), a measure of nitrite-dependent renal carbonic anhydrase (CA) activity, was higher in T1DM-T [1173 (738-1481), P < 0.0001] and T1DM-ND [1341 (1117-1615), P = 0.0007] compared to HC [540 (324-962)], but did not differ between T1DM-T and T1DM-ND (P = 0.272). The lower nitrite excretion in the children with T1DM may indicate enhanced renal CA-dependent nitrite reabsorption compared with healthy children. Yet, lower plasma nitrite concentration in the T1DM patients may have also contributed to the higher UNOXR. Patients' age correlated positively with plasma hArg and hArg/ADMA and urinary DMA/ADMA. Plasma ADMA and urinary ADMA, DMA, nitrite and nitrate correlated negatively with age of the T1DM-T children. Significant correlations were found between plasma hArg and plasma Arg (r = 0.468, P < 0.0001), and urinary DMA (r = -0.426, P = 0.0001), ADMA (r = -0.266, P = 0.021) and nitrate (r = -0.234, P = 0.043). Plasma hArg correlated positively with age at diagnosis (r = +0.337, P = 0.002). ADMA, but not hArg, correlated with HbA1c in T1DM-T (r = -0.418, P < 0.0001) and T1DM-ND (r = +0.879, P = 0.0016). The greatest differences between T1DM-T and T1DM-ND were observed for urinary ADMA, DMA/ADMA ratio, nitrite and nitrate. The Arg/NO pathway is altered in T1DM in childhood and adolescence, yet the role and the importance of hArg and ADMA in T1DM remain to be elucidated. In young T1DM patients, oxidative stress (lipid peroxidation) is not elevated.

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Section: Amino Acids Of the L-arg/no Pathwaymentioning

confidence: 99%

The l-arginine/NO pathway, homoarginine, and nitrite-dependent renal carbonic anhydrase activity in young people with type 1 diabetes mellitus

et al. 2015

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Asymmetric dimethylarginine (ADMA) in human blood: effects of extended haemodialysis in the critically ill patient with acute kidney injury, protein binding to human serum albumin and proteolysis by thermolysin

et al. 2015

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Free, non-protein bound asymmetrically guanidine-dimethylated arginine (ADMA) is an endogenous inhibitor of nitric oxide (NO) synthesis. Human erythrocytic membrane comprises considerable amounts of large (>50 kDa) ADMA-containing proteins. Location in the erythrocyte membrane and identity and physiological functions of ADMA-containing proteins are unrevealed. In healthy subjects, the concentration of free ADMA in heparinised plasma is almost identical to that of serum. We hypothesised that the robustness of free ADMA concentration in human blood is due to a remarkable resistance of erythrocytic ADMA-containing proteins against proteases. In vivo, we investigated the course of the concentration of ADMA in serum and EDTA plasma of a critically ill patient with acute kidney injury during extended haemodialysis. In vitro, we studied the effects of thermolysin, a useful experimental proteolytic enzyme of erythrocyte membrane proteins, on erythrocytic ADMA. The protein binding (PB) of ADMA to human serum albumin (HSA) was also determined. In these studies, ADMA was measured by a previously reported, fully validated GC-MS/MS method. We measured almost identical ADMA concentrations in plasma and serum samples of the patient. During dialysis, the circulating ADMA concentration decreased slowly and moderately indicating removal of this substance, which was however much less than expected from its low molecular weight (202 Da) and high water solubility. After dialysis, circulating ADMA concentration increased again, a phenomenon called rebound, and ADMA reached higher levels compared to the baseline. The PB value of ADMA to HSA was about 30 %. This surprisingly high PB value of ADMA to HSA may be an explanation for the rather poor dialysance of ADMA. Washed human erythrocytes suspended in phosphate-buffered physiological saline were found not to release appreciable amounts of free and ADMA-containing proteins. The lack of effect of coagulation or anticoagulation on the concentration of circulating free ADMA in humans is likely to be due to a remarkable resistance of ADMA-containing proteins in the erythrocyte membrane against proteases in vivo in humans. Our study suggests that free ADMA is released in the circulating blood at relatively high rates. The considerable PB of ADMA to HSA is likely to add to the apparently poor dialysability of ADMA. Other contributing factors could be redistribution of free ADMA between plasma and erythrocytes in favour of plasma ADMA and parallel formation of free ADMA from erythrocytic ADMA-containing proteins during haemodialysis.

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Utility of homoarginine in the GC-MS quantification of asymmetric dimethylarginine (ADMA) in human serum proteins

Bollenbach

Hanff

Tsikas

2018

Analytical Biochemistry

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Letter to the editor: “Role of the human erythrocyte in generation and storage of asymmetric dimethylarginine”

Cited by 4 publications

References 10 publications

The l-arginine/NO pathway, homoarginine, and nitrite-dependent renal carbonic anhydrase activity in young people with type 1 diabetes mellitus

The l-arginine/NO pathway, homoarginine, and nitrite-dependent renal carbonic anhydrase activity in young people with type 1 diabetes mellitus

Asymmetric dimethylarginine (ADMA) in human blood: effects of extended haemodialysis in the critically ill patient with acute kidney injury, protein binding to human serum albumin and proteolysis by thermolysin

Utility of homoarginine in the GC-MS quantification of asymmetric dimethylarginine (ADMA) in human serum proteins

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