Relationship between plasma l-lysine concentrations and levels of HIV-1 RNA

L-lysine: its antagonism with L-arginine in controlling viral infection. Narrative Literature Review

Knowledge about viral characteristics, mechanisms of entry into the host cell and multiplication/dissemination can help in the control and treatment of viral pathologies. Several nutritional factors linked to the host may favor viral multiplication and their control, may lead to new prophylactic alternatives and/or antiviral therapies. The objective of this review is to discuss the relationship between the amino acid L-lysine and the control of viral infections, aiming at a possible therapeutic property. This research used databases such as PubMed, Web of Science, Scielo, Medline and Google Scholar, as well as searching for references cited by journals. The time frame covered the period between 1964 and January 2022. The observed studies have shown that the usual antiviral therapies are not able to interfere with the viruses in their latent state, however, they can interfere with the adhesion and fusion of viral particles or the production of proteins, which play an important role in viral epidemiology and control, particularly in the initial moment and in the reactivation. Lysine is an amino acid that can interfere mainly in the formation of capsid proteins and DNA by a competitive antagonism with amino acid arginine, which is an essential amino acid for some viruses and also by promoting the increase of arginase, increasing the catabolism of arginine. Although there is evidence of the importance of L-lysine in viral control, more studies are needed, with a view to new antiviral therapies.

Stabilities of Three Key Biological Trisulfides with Implications for Their Roles in the Release of Hydrogen Sulfide and Bioaccumulation of Sulfane Sulfur

Trisulfides and higher polysulfides are important in the body due to their function as key reservoirs of sulfane sulfur and their rapid reactions to release persulfides. Recent work has shown that persulfides act as powerful antioxidants and release hydrogen sulfide, an emerging gasotransmitter with numerous therapeutic effects. Despite the important role of polysulfides, there is a lack of understanding of their stabilities in aqueous systems. To investigate the reactivity of trisulfides and polysulfides, three key biologically important trisulfides were synthesized from cysteine, glutathione, and N-acetylcysteine, and the tetrasulfide of N-acetylcysteine was synthesized as a representative polysulfide. The stabilities of sulfides were monitored in buffered D₂O using ¹H NMR spectroscopy under a range of conditions including high temperatures and acidic and alkaline environments. The tri- and tetrasulfides degraded rapidly in the presence of primary and tertiary amines to the corresponding disulfide and elemental sulfur. The half-lives of N-acetylcysteine tri- and tetrasulfides in the presence of butylamine were 53 and 1.5 min, respectively. These results were important because they suggest that tri- and tetrasulfide linkages are short-lived species in vivo due to the abundance of amines in the body. Under basic conditions, cysteine and glutathione trisulfides were unstable due to the deprotonation of the ammonium group, exposing an amine; however, N-acetylcysteine trisulfide was stable at all pH values tested. Hydrogen sulfide release of each polysulfide in the presence of cysteine was quantified using a hydrogen sulfide-sensitive electrode and ¹H NMR spectroscopy.

MicroRNAs and Mammarenaviruses: Modulating Cellular Metabolism

Mammarenaviruses are a diverse genus of emerging viruses that include several causative agents of severe viral hemorrhagic fevers with high mortality in humans. Although these viruses share many similarities, important differences with regard to pathogenicity, type of immune response, and molecular mechanisms during virus infection are different between and within New World and Old World viral infections. Viruses rely exclusively on the host cellular machinery to translate their genome, and therefore to replicate and propagate. miRNAs are the crucial factor in diverse biological processes such as antiviral defense, oncogenesis, and cell development. The viral infection can exert a profound impact on the cellular miRNA expression profile, and numerous RNA viruses have been reported to interact directly with cellular miRNAs and/or to use these miRNAs to augment their replication potential. Our present study indicates that mammarenavirus infection induces metabolic reprogramming of host cells, probably manipulating cellular microRNAs. A number of metabolic pathways, including valine, leucine, and isoleucine biosynthesis, d-Glutamine and d-glutamate metabolism, thiamine metabolism, and pools of several amino acids were impacted by the predicted miRNAs that would no longer regulate these pathways. A deeper understanding of mechanisms by which mammarenaviruses handle these signaling pathways is critical for understanding the virus/host interactions and potential diagnostic and therapeutic targets, through the inhibition of specific pathologic metabolic pathways.

Metabolomics of sleep disorders in HIV: a narrative review

PURPOSE

Sleep disturbances are prevalent among patients with human immunodeficiency virus (HIV), even those who are being treated on antiretroviral therapy. It is important to understand the metabolomic mechanisms underlying sleep disturbances among people living with HIV (PLWH).

METHODS

A review of recent literature was performed to explore the use of metabolomics in understanding sleep among PLWH.

RESULTS

We found only two studies that used metabolomics to explore sleep health among PLWH.

CONCLUSION

This paper reviews common sleep disorders in HIV, the existing metabolomic studies that may explain the relationship, and implications for future research. The use of metabolomics in exploring sleep disorders among PLWH will help to elucidate mechanistic links to improve patient outcomes.

Favourable outcome in a child with symptomatic diagnosis of Glutaric aciduria type 1 despite vertical HIV infection and minor head trauma

The first case of Glutaric aciduria Type 1(GA1) in an African child was reported in 2001. GA1 has a prevalence of 1:5000 in black South Africans. Although early diagnosis is essential for a favourable outcome, newborn screening is not routine in South Africa where an estimated 320,000 children have HIV infection. Neurodevelopmental delay and encephalopathy are complications of both HIV and GA1. In such a setting it is important to recognise that HIV and GA1 can occur simultaneously. We present an HIV-infected South African male child of Xhosa descent with macrocephaly who commenced combination antiretroviral therapy (ART) at 8 weeks of age in a clinical trial which included a neurodevelopmental sub-study. He developed short-lived focal seizures at 16 months after minor head trauma. Neurological examination was normal. Neuroimaging showed temporal lobe atrophy, subtle hyperintense signal change in the globus pallidus, and focal haemosiderosis in the right Sylvian fissure region. As findings were not in keeping with HIV encephalopathy, a urine metabolic screen was undertaken which suggested GA1. Genetic testing confirmed Arg293Trp mutation. He began L-carnitine and a low protein diet as a restricted diet was not practicable. At 21 months he developed pulmonary tuberculosis, requiring 6 months treatment. He did not develop any neurologic motor symptoms. Serial neurodevelopmental and neuropsychological test scores until 9 years were similar to healthy neighbourhood controls, except for mild language delay at 3½ years. Detection of GA1, probably facilitated through participation in a clinical trial, was pivotal for a favourable outcome. The concomitant use of ART and anti-tuberculous therapy in a child with GA1 appears safe.

Homoarginine and inhibition of human arginase activity: kinetic characterization and biological relevance

The inhibition of arginase, resulting in higher arginine (ARG) availability for nitric oxide synthesis, may account for the putative protective effect of homoarginine (HOMOARG) against atherosclerosis and cardiovascular disease. However, uncertainty exists regarding the significance of HOMOARG-induced arginase inhibition in vivo. A novel UPLC-MS method, measuring the conversion of ARG to ornithine (ORN), was developed to determine arginase 1 and arginase 2 inhibition by HOMOARG, lysine (LYS), proline (PRO), agmatine (AG), asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA), and NG-Monomethyl-L-arginine (L-NMMA). Plasma HOMOARG, ARG and ORN concentrations were further measured in 50 healthy older adults >65 years (27 males and 23 females). HOMOARG inhibited arginase 1 with IC50 and Ki values of 8.14 ± 0.52 mM and 6.1 ± 0.50 mM, and arginase 2 with IC50 and Ki values of 2.52 ± 0.01 mM and 1.73 ± 0.10 mM, respectively. Both arginase isoforms retained 90% activity vs. control when physiological HOMOARG concentrations (1-10 µM) were used. In partial correlation analysis, plasma HOMOARG was not associated with ARG (P = 0.38) or ARG/ORN ratio (P = 0.73) in older adults. Our results suggest that arginase inhibition is unlikely to play a significant role in the reported cardio-protective effects of HOMOARG.

Plasma L-Carnitine and L-Lysine Concentrations in HIV-Infected Patients

Background:

Virus infections are associated with significant alterations in host cells amino acids profiles that support biosynthetic demands necessary for production of viral progeny. Amino acids play an important role in the pathogenesis of all virus-related infections both as basic substrates for protein synthesis and as regulators in many metabolic pathways.

Objective:

Our aim was to determine the changes in plasma L-carnitine levels and its amino acid precursor (L-lysine) in HIV-infected patients.

Methods:

We performed a case-control study of 430 HIV-1 infected males (non-vegetarians) without any restriction in the nourishment, before highly active antiretroviral therapy (HAART) and 125 HIV-1 subjects after the introduction of HAART who were periodically monitored in the Municipal Center of HIV/AIDS prophylaxis, Surgut, Russian Federation

Results:

The plasma total (TC) and free (FC) L-carnitine concentrations markedly decreased with the clinical stages of HIV infection. The mean plasma TC, FC and L-lysine levels were significantly lower in asymptomatic stage (A) and advanced CDC stages (B, C) HIV-infected patients compared with our reference values. The total and free L-carnitine and its amino acid precursor concentrations mild increased in HIV-infected subjects after the introduction of HAART.

Our data revealed that L-lysine amino acid and its derivative (TC) levels were negatively correlated with viral load and inversely with CD4 count lymphocytes in the total cohort.

Conclusion:

The study results show that there was evidence for an association between plasma L-carnitine, L-lysine and HIV-1 RNA levels, immunological markers and clinical stages of HIV infection. The obtained data indicate that level changes of these host essential nutritional elements can play an important role in the HIV life cycle. These findings are important for understanding the pathophysiology of HIV infection and must be considered in further research for the development of new approaches in the treatment of the disease.

Influence of L-lysine amino acid on the HIV-1 RNA replication in vitro

BACKGROUND

Virus replication strongly depends on host metabolic machinery and essential cellular factors, in particular, on amino acid profiles. Amino acids play an important role in the pathogenesis of all virus-related infections both as basic substrates for protein synthesis and as regulators in many metabolic pathways, including gene expression. The inhibitory effects of deficiency or excess of these essential elements on virus replication are widely appreciated. Although the same interrelationship between host cellular factors and HIV have been recognized for a long time, the effects of amino acids on HIV-1 RNA replication dynamic is not yet well documented. Our aim was to determine in this pilot study the direct effect of L-lysine amino acid on HIV-1 RNA replication in vitro in HIV-infected patients.

METHODS

A total of 100 HIV-1-infected males without highly active antiretroviral therapy (HAART) were monitored in our center. The patients were in stage A of the disease according to the 1993 Centers for Disease Control (CDC) classification system for HIV-infection. Patients with HIV were enrolled in one stage (A) of the disease with the average amount CD4 lymphocytes in the range of 200-300 cells/µL at the time of sample acquisition. For evaluation of the effects of essential L-lysine amino acid on HIV-1 RNA replication level, we used a model of amino acid-excess system in vitro following incubation of plasma samples for 24 h at 25 °C. Quantitative HIV-1 RNA assay was performed using (RT-PCR) reverse-transcriptase polymerase chain reaction (Rotor-Gene Q, QIAGEN, Germany).

RESULTS

The mean HIV-1 RNA levels were significantly higher in the enriched peripheral blood mononuclear cells plasma samples HIV-infected subjects after 24 h incubation at 25 °C temperature than in the plasma samples the same patients studied on the date of blood tests (p < 0.0001). The number of HIV-1 RNA copies increased in 1.5 times. We observed that in plasma of the same HIV-infected patients after adding L-lysine and following incubation in vitro, viral load increased significantly in comparison with standard samples (p < 0.0001). The increased viral load was found in 100/92 (92%) of HIV-infected subjects. The average number of HIV-1 RNA copies in samples had increased by 4.0 times. However, we found no difference in HIV-1 RNA levels after replacement of L-lysine for L-arginine in comparison samples in the same HIV-infected patients. It is obvious that the addition of L-arginine does not increase viral replication in vitro as L-lysine amino acid supplement does. Additionally, no increase in viral load was determined after adding L-lysine and non toxic doses of its inhibitor (L-lysine alpha-oxidase) in plasma samples.

CONCLUSIONS

The results show that L-lysine amino acid excess is characterized by significant increased of HIV-1 RNA copies in enriched peripheral blood mononuclear cells plasma samples of HIV-infected patients. There was evidence for an association between L-lysine supplementation and HIV-1 RNA replication and the level changes of this host essential nutritional element play a key role in the synthesis of the virus proteins and in transcription initiation of the retrovirus life cycle. High intake of L-lysine amino acid may increase the risk of high viral load, subsequent acceleration of immunosuppression and HIV progression. Overall results demonstrate that the simple L-lysine-related model in vitro can be widely used for practical purposes to evaluate HIV-1 RNA replication dynamic, disease prognosis and new approaches in treatment of the patients with human immunodeficiency virus. Although the impact mechanism of L-lysine amino acid on the viral load in the pathogenesis of HIV-infection is at present conjectural and requires further development, the results highlight an interesting target in antiviral therapy, and this statement remains to be proved in further research and clinical trials.