Dental Caries: Unveiling the State-of-the-Art Insights and Crafting Hypotheses for Oral Health.

The pathophysiological understanding of dental caries explains that the primary factor responsible is linked to an imbalance in microbial composition within the oral cavity, stemming from both artificial and natural sources. Streptococcus mutans (S. mutans) is the most accountable and prevalent pathogen for caries development among the diverse pool. S. mutans, an acidogenic bacterium, lowers oral pH through the metabolic conversion of dietary sugar into organic acids, leading to enamel demineralization and dental caries. Numerous antibacterial interventions have been employed in the past to address this issue. However, adopting such an approach poses the risk of exacerbating concerns related to Antimicrobial Resistance (AMR) and long-term oral cytotoxicity. In response to this, a sustainable strategy is suggested, involving the utilization of L-Arginine (L-Arg) as a probiotic nutrient supplement for non-pathogenic microbes. It will help in creating a natural competitive environment against the pathogenic microbes responsible for initiating dental caries. The hypothesis involves utilizing a combination of a nutrient supplement and the repurposed drug Piceatannol, specifically for its anti-biofilm properties. This combination synergistically improves the effectiveness of the therapy by converting the complex microbial biofilm into a planktonic state.

Effect of L-arginine on cystic fibrosis Pseudomonas aeruginosa biofilms.

Cystic fibrosis (CF) airways are L-arginine deficient which may affect susceptibility to infection with certain pathogens. The potential impact of L-arginine supplementation on Pseudomonas aeruginosa, a common CF airway pathogen, is unclear. This study investigated the effects of L-arginine on P. aeruginosa biofilm cultures, using the laboratory strain PAO1 and multi-drug resistant CF clinical isolates. P. aeruginosa biofilms were grown in a chambered cover-glass slide model for 24 h, then exposed to either L-arginine alone or combined with tobramycin for an additional 24 h. Biofilms were visualized using confocal microscopy, and viable cells were measured via plating for colony-forming units. Increasing concentrations of L-arginine in bacterial culture medium reduced the biovolume of P. aeruginosa in a dose-dependent manner. Notably, L-arginine concentrations within the physiological range (50 mM and 100 mM) in combination with tobramycin promoted biofilm growth, while higher concentrations (600 mM and 1200 mM) inhibited growth. These findings demonstrate the potential of L-arginine as an adjuvant therapy to inhaled tobramycin in treating P. aeruginosa infections in people with CF.

Elevated Plasma Levels of Arginines During Labor Among Women with Spontaneous Preterm Birth: A Prospective Cohort Study.

PROBLEM: Preterm birth (PTB) is a leading cause of infant mortality and morbidity. The pathogenesis of PTB is complex and involves many factors, including socioeconomy, inflammation and infection. Asymmetric dimethylarginine, ADMA and symmetric dimethylarginine, SDMA are involved in labor as inhibitors of nitric oxide, a known relaxant of the uterine smooth muscles. Arginines are scarcely studied in relation to PTB and we aimed to investigate arginines (ADMA, SDMA and L-arginine) in women with spontaneous PTB and term birth. METHODS OF THE STUDY: The study was based on data from the population-based, prospective cohort BASIC study conducted in Uppsala County, Sweden, between September 2009 and November 2018. Arginines were analyzed by Ultra-High Performance Liquid Chromatography using plasma samples taken at the onset of labor from women with spontaneous PTB (n = 34) and term birth (n = 45). We also analyzed the inflammation markers CRP, TNF-R1 and TNF-R2 and GDF-15. RESULTS: Women with spontaneous PTB had higher plasma levels of ADMA (p < 0.001), and L-Arginine (p = 0.03). In addition, inflammation marker, TNF-R1 (p = 0.01) was higher in spontaneous PTB compared to term birth. Further, in spontaneous PTB, no significant correlations could be observed when comparing levels of arginines with inflammation markers, except ADMA versus CRP. CONCLUSIONS: These findings provide novel evidence for the potential involvement of arginines in the pathogenesis of spontaneous PTB and it seems that arginine levels at labor vary independently of several inflammatory markers. Further research is warranted to investigate the potential of arginines as therapeutic targets in the prevention and management of spontaneous PTB.

Effects of n-hexane fraction of Piper guineense seed extract on Nω-nitro-L-arginine methyl ester hydrochloride-induced hypertension in rats.

This study aimed to investigate the effects of the n-hexane fraction of the ethanolic seed extract of PG (NFESEPG) on hypertension induced by Nω-nitro-L-arginine methyl ester (L-NAME) in rats. Specifically, the study examined the impact of NFESEPG on blood pressure, oxidative stress markers, NO concentration, angiotensin-converting enzyme (ACE) and arginase activities, and cardiac biomarkers in hypertensive rats. The study involved collecting, identifying, and processing the PG plant to obtain the ethanolic seed extract. The extract was then partitioned with solvents to isolate the n-hexane fraction. Hypertension was induced in rats by oral administration of L-NAME for 10 days, while concurrent treatment with NFESEPG at two doses (200 and 400 mg/kg/day) was administered orally. Blood pressure was measured using a noninvasive tail-cuff method, and various biochemical parameters were assessed. Treatment with both doses of NFESEPG significantly reduced systolic and diastolic blood pressure in L-NAME-induced hypertensive rats. Additionally, NFESEPG administration increased NO concentration and decreased ACE and arginase activities, malondialdehyde (MDA) levels, and cardiac biomarkers in hypertensive rats. The findings indicate that NFESEPG effectively lowered blood pressure in hypertensive rats induced by L-NAME, potentially through mechanisms involving the modulation of oxidative stress, NO bioavailability, and cardiac biomarkers. These results suggest the therapeutic potential of NFESEPG in managing hypertension and related cardiovascular complications.

The effect of L-Arginine therapy on achilles tendon healing: A histological and biomechanical investigation in an animal model.

PURPOSE: Several clinical and experimental studies have revealed that L-Arginine, which has antioxidant properties, accelerates tissue healing. This study examined the in vivo effects of oral L - Arginine supplementation on tendon regeneration in Wistar rats. METHOD: For each weighting of an average of 250-300 g, 24 Wistar rats were separated into three equal groups. Each rat's right hind leg Achilles tendons were tenotomized and then repaired. The first group (Control) was followed up with a regimen of standard food and water. In the second group (L-Arg Low Dose), 300 mg/kg, and in the third group (L-Arg High Dose), 600 mg/kg L-Arginine was administered in water daily with a regimen of standard food and water ad libitum. After eight weeks, the rats were sacrificed, and the tendons were histologically and biomechanically analyzed. RESULTS: Tendon peak strength values of the L-Arg Low Dose and L-Arg High Dose groups were similar but significantly higher than the control group. A statistically significant difference was observed between the groups in terms of ground substance, fiber arrangement, cellularity, hyalinization, and GAG properties ( p = 0.05, p = 0.002, p = 0.016, p = 0.027, p = 0.05). There was no statistically significant difference between the groups according to the histological examination of collagen properties, fiber structure, tenocyte properties, rounding of the nuclei, and collagen stainability. (p = 0.999, p = 0.061, p = 0.195, p = 0.195, p = 0.130). No mortality, wound complications, or re-ruptures were observed. CONCLUSION: Compared with the control group, histologically and biomechanically distinct therapeutic effects of L-Arginine supplementation on tendon healing were determined. LEVEL OF CLINICAL EVIDENCE: 5.

Therapeutic Modulation of Arginase with nor-NOHA Alters Immune Responses in Experimental Mouse Models of Pulmonary Tuberculosis including in the Setting of Human Immunodeficiency Virus (HIV) Co-Infection.

L-arginine metabolism is strongly linked with immunity to mycobacteria, primarily through the antimicrobial activity of nitric oxide (NO). The potential to modulate tuberculosis (TB) outcomes through interventions that target L-arginine pathways are limited by an incomplete understanding of mechanisms and inadequate in vivo modeling. These gaps in knowledge are compounded for HIV and Mtb co-infections, where activation of arginase-1 due to HIV infection may promote survival and replication of both Mtb and HIV. We utilized in vitro and in vivo systems to determine how arginase inhibition using Nω-hydroxy-nor-L-arginine (nor-NOHA) alters L-arginine pathway metabolism relative to immune responses and disease outcomes following Mtb infection. Treatment with nor-NOHA polarized murine macrophages (RAW 264.7) towards M1 phenotype, increased NO, and reduced Mtb in RAW macrophages. In Balb/c mice, nor-NOHA reduced pulmonary arginase and increased the antimicrobial metabolite spermine in association with a trend towards reduced Mtb CFU in lung. In humanized immune system (HIS) mice, HIV infection increased plasma arginase and heightened the pulmonary arginase response to Mtb. Treatment with nor-NOHA increased cytokine responses to Mtb and Mtb/HIV in lung tissue but did not significantly alter bacterial burden or viral load. Our results suggest that L-arginine pathway modulators may have potential as host-directed therapies to augment antibiotics in TB chemotherapy.

L-arginine combination with 5-fluorouracil inhibit hepatocellular carcinoma cells through suppressing iNOS/NO/AKT-mediated glycolysis.

L-arginine can produce nitric oxide (NO) under the action of inducible nitric oxide synthase (iNOS), while 5-fluorouracil (5-FU) can induce the increase of iNOS expression. The present study was to investigate the mechanism of L-arginine combined with 5-FU regulating glucose metabolism of hepatocellular carcinoma (HCC) through iNOS/NO/AKT pathway. The combination of L-arginine and 5-FU resulted in decreased cell survival and exhibited synergistic cytotoxic effects in HepG2 and SMMC7721 cells. Meanwhile, L-arginine increased 5-FU inhibitory effect on HepG2 and SMMC7721 cells by increasing NO production. Co-treatment with L-arginine and 5-FU resulted in a significant decrease in both G6PDH and LDH enzymatic activities, as well as reduced levels of ATP and LD compared to treatment with L-arginine or 5-FU alone. Moreover, the combination of L-arginine and 5-FU resulted in a decrease in the expression of GLUT1, PKM2, LDHA, p-PI3K and p-AKT. Furthermore, the combination demonstrated a synergistic effect in downregulating the expression of HIF-1α and ß-catenin, which were further diminished upon the addition of shikonin, a specific inhibitor of PKM2. LY294002 treatment further reduced the expression of GLUT1, PKM2, and LDHA proteins induced by combined L-arginine and 5-FU treatment compared to the combined group. However, the reduction in p-PI3K, p-AKT, and GLUT1 expression caused by L-arginine and 5-FU combination was also reversed in HepG2 and SMMC7721 cells with iNOS knockdown, respectively. Additionally, the combination of L-arginine and 5-FU led to a greater reduction in the enzymatic activity of ALT, AST, G6PDH and LDH, as well as a significant reduction in hepatic index, AFP, AFP-L3, ATP and LD levels in a rat model of HCC. Moreover, the simultaneous administration of L-arginine and 5-FU significantly improved the gross morphology of the liver, reduced nuclear atypia, inhibited the proliferation of cancer cells, and decreased the expression levels of p-PI3K, p-AKT, GLUT1, PKM2, and LDHA, while iNOS expression was increased in the combination group. Taking together, L-arginine and 5-FU combination resulted in the inhibition of enzymes in aerobic glycolysis via the iNOS/NO/AKT pathway, which led to the suppression of glucose metabolism and downregulation of nuclear transcription factors, thereby impeding the proliferation of hepatocellular carcinoma cells.

Mitochondria-engine with self-regulation to restore degenerated intervertebral disc cells via bioenergetic robust hydrogel design.

Previous studies have confirmed that intervertebral disc degeneration (IDD) is closely associated with inflammation-induced reactive oxygen species (ROS) and resultant cell mitochondrial membrane potential (MMP) decline. Clearance of ROS in an inflammatory environment is essential for breaking the vicious cycle of MMP decline. Additionally, re-energizing the mitochondria damaged in the inflammatory milieu to restore their function, is equally important. Herein, we proposed an interesting concept of mitochondrion-engine equipped with coolant, which enables first to "cool-down" the inflammatory environment, next to restore the MMP, finally to allow cells to regain normal energy metabolism through materials design. As such, we developed a multi-functional composite composed of a reactive oxygen species (ROS)-responsive sodium alginate/gelatin hydrogel infused into a rigid 3D-printed thermoplastic polyurethane (TPU) scaffold. The TPU scaffold was coated with conductive polypyrrole (PPy) to electrophoretically deposit l-arginine, which could upregulate the Mammalian target of rapamycin (mTOR) pathway, thus increasing MMP and energy metabolism to stimulate extracellular matrix synthesis for IVD repair. While the ROS-responsive hydrogel acting as the "mito-engine coolant" could scavenge the excessive ROS to create a favorable environment for IVD cells recovery. Demonstrated by in vitro and in vivo evaluations, the mito-engine system markedly promoted the proliferation and collagen synthesis of nucleus pulposus cells while enhancing the mitochondrial respiration and MMP under oxidative stress. Radiological and histological assessments in vivo revealed the efficacy of this system in IVD repair. This unique bioinspired design integrated biomaterial science with mitochondrial biology, presents a promising paradigm for IDD treatment.

L-Arginine Doped Carbon Nanodots from Cinnamon Bark for Improved Fluorescent Yeast Cell Imaging.

In this study, we present an economical and efficient synthesis method for carbon nanodots (CNDs) derived from cinnamon bark wood powder, with the incorporation of L-arginine as a dopant at varying ratios (Cinnamon : L-Arginine - 1:0.25, 1:0.5) via a hydrothermal reaction. Extensive structural and optical characterization was conducted through techniques such as FTIR, XRD, HR-TEM, DLS, UV-Vis, and PL spectra, providing a comprehensive understanding of the properties of CNDs and doped-CNDs. Quantum yields (QY) were quantified for synthesized materials, contributing to the assessment of their fluorescence efficiency. The synthesized CNDs were successfully applied for bioimaging of yeast cells, employing fluorescence microscopy to visualize their interaction. Remarkably, L-arginine-doped CNDs exhibited enhanced fluorescence, showcasing the influence of the dopant. The nature of these CNDs was rigorously investigated, confirming their biocompatibility. Notably, this work presents a novel approach to synthesizing CNDs from a renewable and sustainable source, cinnamon bark wood powder, while exploring the effects of L-arginine doping on their optical and biological properties. This work not only contributes to the synthesis and characterization of CNDs but also highlights their potential for diverse applications, emphasizing their structural, optical, and biological attributes. The findings underscore the versatility of CNDs derived from cinnamon bark wood powder and their potential for advancing biotechnological and imaging applications.

Sitagliptin ameliorates L-arginine-induced acute pancreatitis via modulating inflammatory cytokines expression and combating oxidative stress.

Background: Acute pancreatitis (AP) is an inflammatory condition that resolves spontaneously, but occasionally, develops into systemic inflammation, organ failure and mortality. Oxidative stress and activation of inflammatory pathways represent major players in AP pathogenesis. Current management of AP relies on attenuating injuries to the pancreas and putting the inflammatory process under control. In this study, we investigated the role of sitagliptin in modulating L-arginine-induced AP in rats. Methods: Swiss rats were subdivided into a healthy control group, AP group (a single dose of L-arginine 250 mg/100 g, intraperitoneal), and sitagliptin + L-arginine-treated group (10 mg sitagliptin/kg body weight/day, orally). Sitagliptin treatment started 1 hour after L-arginine injection and continued for 3days. Biochemical and histopathological investigations were performed on serum and tissue samples collected from test animals. Results: L-arginine increased pancreatic meyloperoxidase and serum amylase- and lipase activities and serum levels of TNF-α, LT-α, IFN-γ, IL-1α/ß, IL-6, IL-10, IL-12, and IL-15. AP animals showed elevated MDA and NO and decreased GSH and serum calcium levels. Histopathological changes were observed by H&E staining. Sitagliptin treatment significantly ameliorated these biochemical and histological changes diminishing the signs of AP. Conclusion: Sitagliptin treatment was effective in ameliorating L-arginine-induced AP which can be regarded to its anti-inflammatory and antioxidant effect.

L-Arginine-induced acute pancreatitis and its associated lung injury in rats: Down-regulation of TLR-4/MAPK-p38/JNK signaling pathway via Ginkgo biloba extract EGb 761.

Objectives: Acute pancreatitis (AP) is an abrupt inflammatory condition characterized by a storm of inflammatory cytokines leading to high morbidity and mortality. The current study aimed to examine the efficacy of Ginkgo biloba extract EGb 761 (GBE) in the treatment of L-arginine-induced AP and its associated lung injury. Materials and Methods: Forty rats were randomly assigned into four groups. The normal group received only saline intraperitoneally while the other groups received two intraperitoneal L-arginine injections (250 mg/100 g b.wt) separated by a 1-hour interval to provoke AP. GBE (200 and 400 mg/kg/day, PO) was administered for 2 weeks post-induction of pancreatitis. Sera and pancreatic tissues were isolated. Results: The outcome of the present study revealed that GBE ameliorated the elevated levels of serum amylase, lipase, and pancreatic inflammatory mediators viz., tumor necrosis factor-alpha (TNF-α), mitogen-activated protein kinase P38 (MAPK-P38), c-Jun N-terminal kinase 1 (JNK1), and nuclear factor-kappa B (NF-κB). Moreover, GBE restored the pancreatic gene expression of Toll-like receptor 4 (TLR4) and prostatic acid phosphatase-2 (PAP-2). Pancreatic and lung histopathological examinations confirmed the aforementioned parameters. Conclusion: GBE interfered with the mechanistic pathway of L-arginine-induced acute pancreatic and its associated lung injury. Due to its anti-inflammatory properties, GBE can be used as a novel therapeutic candidate for the treatment of AP through down-regulating TLR-4/MAPK-p38/JNK and MAPK- p38/NF-κB signaling cascades.

Products of oxidative and non-oxidative metabolism of L-arginine as potential regulators of Ca2+ transport in mitochondria of uterine smooth muscle.

Mitochondria play a crucial role in maintaining Ca2+ homeostasis in cells. Due to the critical regulatory role of the products of oxidative and non-oxidative metabolism of L-arginine, it is essential to clarify their effect on Ca2+ transport in smooth muscle mitochondria. Experiments were performed on the uterine myocytes of rats and isolated mitochondria. The possibility of NO synthesis by mitochondria was demonstrated by confocal microscopy and spectrofluorimetry methods using the NO-sensitive fluorescent probe DAF-FM and Mitotracker Orange CM-H2TMRos. It was shown that 50 µM L-arginine stimulates the energy-dependent accumulation of Ca2+ in mitochondria using the fluorescent probe Fluo-4 AM. A similar effect occurred when using nitric oxide donors 100 µM SNP, SNAP, and sodium nitrite (SN) directly. The stimulating effect was eliminated in the presence of the NO scavenger C-PTIO. Nitric oxide reduces the electrical potential in mitochondria without causing them to swell. The stimulatory effect of spermine on the accumulation of Ca2+ by mitochondria is attributed to the enhancement of NO synthesis, which was demonstrated with the use of C-PTIO, NO-synthase inhibitors (100 µM NA and L-NAME), as well as by direct monitoring of NO synthesis fluorescent probe DAF-FM. A conclusion was drawn about the potential regulatory effect of the product of the oxidative metabolism of L-arginine - NO on the transport of Ca2+ in the mitochondria of the myometrium, as well as the corresponding effect of the product of non-oxidative metabolism -spermine by increasing the synthesis of NO in these subcellular structures.

Effect of l-arginine compared to placebo on sexual function in women with major depressive disorder: a randomized controlled trial.

BACKGROUND: While some evidence suggests that l-arginine may improve sexual function and alleviate depression, it has not been investigated in women with depression to assess both its effects on the depression and sexual function concurrently. METHODS: Patients who had received a diagnosis of major depressive disorder, as determined by predetermined inclusion and exclusion criteria, were enrolled in this triple-blind clinical trial. Patients were divided into two groups: group A, received L-arginine 1 gram twice daily, and group B, received a placebo for four weeks. They were evaluated at baseline, after four and eight weeks with the Hamilton Depression Rating Scale (HDRS), and Rosen's questionnaire or Female Sexual Function Index (FSFI). RESULTS: A decrease in the severity of depression was observed in all patients, which was determined due to Hamilton's questionnaire (P-value < 0.001). During the time in group A, FSFI increased. Based on the FSFI questionnaire, they had improvement in some domains, including the lubrication index and orgasm index, which significantly changed in the eighth week compared to the baseline (P-value < 0.05). However, these two indicators did not change statistically significantly compared to the placebo group. CONCLUSION: L-arginine supplementation can improve sexual function, particularly lubrication and orgasm, and mood in women with depression, with minimal side effects observed. Additional research is necessary to validate these results by examining the effects of higher dosages, extended durations, and larger populations of depressed patients. TRIAL REGISTRATION: Iranian Registry of Clinical Trial: IRCT20100127003210N26.

Gut microbial alterations in arginine metabolism determine bone mechanical adaptation.

Although mechanical loading is essential for maintaining bone health and combating osteoporosis, its practical application is limited to a large extent by the high variability in bone mechanoresponsiveness. Here, we found that gut microbial depletion promoted a significant reduction in skeletal adaptation to mechanical loading. Among experimental mice, we observed differences between those with high and low responses to exercise with respect to the gut microbial composition, in which the differential abundance of Lachnospiraceae contributed to the differences in bone mechanoresponsiveness. Microbial production of L-citrulline and its conversion into L-arginine were identified as key regulators of bone mechanoadaptation, and administration of these metabolites enhanced bone mechanoresponsiveness in normal, aged, and ovariectomized mice. Mechanistically, L-arginine-mediated enhancement of bone mechanoadaptation was primarily attributable to the activation of a nitric-oxide-calcium positive feedback loop in osteocytes. This study identifies a promising anti-osteoporotic strategy for maximizing mechanical loading-induced skeletal benefits via the microbiota-metabolite axis.

M1 Macrophage-Targeted Curcumin Nanocrystals with l-Arginine-Modified for Acute Lung Injury by Inhalation.

Acute Lung Injury/Acute Respiratory Distress Syndrome (ALI/ARDS) with clinical manifestations of respiratory distress and hypoxemia remains a significant cause of respiratory failure, boasting a persistently high incidence and mortality rate. Given the central role of M1 macrophages in the pathogenesis of acute lung injury (ALI), this study utilized the anti-inflammatory agent curcumin as a model drug. l-arginine (L-Arg) was employed as a targeting ligand, and chitosan was initially modified with l-arginine. Subsequently, it was utilized as a surface modifier to prepare inhalable nano-crystals loaded with curcumin (Arg-CS-Cur), aiming for specific targeting of pulmonary M1 macrophages. Compared with unmodified chitosan-curcumin nanocrystals (CS-Cur), Arg-CS-Cur exhibited higher uptake in vitro by M1 macrophages, as evidenced by flow cytometry showing the highest fluorescence intensity in the Arg-CS-Cur group (P < 0.01). In vivo accumulation was greater in inflamed lung tissues, as indicated by small animal imaging demonstrating higher lung fluorescence intensity in the DiR-Arg-CS-Cur group compared to the DiR-CS-Cur group in the rat ALI model (P < 0.05), peaking at 12 h. Moreover, Arg-CS-Cur demonstrated enhanced therapeutic effects in both LPS-induced RAW264.7 cells and ALI rat models. Specifically, treatment with Arg-CS-Cur significantly suppressed NO release and levels of TNF-α and IL-6 in RAW264.7 cells (p < 0.01), while in ALI rat models, expression levels of TNF-α and IL-6 in lung tissues were significantly lower than those in the model group (P < 0.01). Furthermore, lung tissue damage was significantly reduced, with histological scores significantly lower than those in the CS-Cur group (P < 0.01). In conclusion, these findings underscore the targeting potential of l-arginine-modified nanocrystals, which effectively enhance curcumin concentration in inflammatory environments by selectively targeting M1 macrophages. This study thus introduces novel perspectives and theoretical support for the development of targeted therapeutic interventions for acute inflammatory lung diseases, including ALI/ARDS.

L-Arginine-Dependent Nitric Oxide Production in the Blood of Patients with Type 2 Diabetes: A Pilot, Five-Year Prospective Study.

Backgound: Type 2 diabetes mellitus (T2DM) is a major cardiovascular risk factor. Nitric oxide (NO) is one of the many molecules that regulate vascular tone, and red blood cells (RBCs) are known to play an important role in adjusting cardiac function through NO export from RBCs. Our study prospectively investigated the L-arginine (L-arg)-nitric oxide (NO) metabolic pathway in the erythrocytes and plasma of subjects with T2DM. Methods: RBCs and plasma were collected from patients with T2DM (n = 10), at first clinical onset (baseline) and after five years of disease evolution (follow-up). L-arg content was assayed by competitive enzyme-linked immunoassay. Arginase activity and nitrate/nitrite levels were measured using spectrophotometry. Results: When compared to baseline, L-arg content decreased in RBCs and remained similar in the plasma; NO production decreased in RBCs and the plasma; and arginase activity was lower in RBCs and increased in plasma. Conclusions: The L-arg/NO metabolic pathway decreases in the RBCs of patients with T2DM five years after the first clinical onset. The persistent decrease in RBCs' arginase activity fails to compensate for the sustained decrease in RBCs' NO production in the diabetic environment. This pilot study indicates that the NO-RBC pool is depleted during the progression of the disease in the same cohort of T2DM patients.

Kinetics of Human Serum Albumin Adsorption on Polycation Functionalized Silica.

The adsorption kinetics of human serum albumin (HSA) on bare and poly-L-arginine (PARG)-modified silica substrates were investigated using reflectometry and atomic force microscopy (AFM). Measurements were carried out at various pHs, flow rates and albumin concentrations in the 10 and 150 mM NaCl solutions. The mass transfer rate constants and the maximum protein coverages were determined for the bare silica at pH 4.0 and theoretically interpreted in terms of the hybrid random sequential adsorption model. These results were used as reference data for the analysis of adsorption kinetics at larger pHs. It was shown that the adsorption on bare silica rapidly decreased with pH and became negligible at pH 7.4. The albumin adsorption on PARG-functionalized silica showed an opposite trend, i.e., it was negligible at pH 4 and attained maximum values at pH 7.4 and 150 mM NaCl, the conditions corresponding to the blood serum environment. These results were interpreted as the evidence of a significant role of electrostatic interactions in the albumin adsorption on the bare and PARG-modified silica. It was also argued that our results can serve as useful reference data enabling a proper interpretation of protein adsorption on substrates functionalized by polyelectrolytes.

Icarifil® in Association with Daily Use of Tadalafil (5 mg) versus Standard Tadalafil Daily Dose (5 mg) or Alone: Results from a Controlled, Randomized Clinical Trial.

Background: The management of erectile dysfunction (ED) shows several grey zones and new treatments are required to reduce the percentage of patients discontinuing treatment. Here, we aim to evaluate the role of a natural mixture named Icarifil® (L-Citrulline, L-Carnitine, Eruca vesicaria, Panax ginseng, Tribulus terrestris, Turnera diffusa, Taurine, Vitamin E, Zinc) in the management of patients with ED. Methods: From September 2022 to March 2023, all patients attending 3 urological institutions due to ED were randomized to receive the following for 3 months: Icarifil® 1 sachet every 24 h (Group 1) or Icarifil® 1 sachet + tadalafil 5 mg 1 tablet every 24 h (Group 2) or tadalafil 5 mg 1 tablet daily (Group 3). All patients underwent urologic visits and dedicated questionnaires (IIEF-5, SEP-2, SEP-3) at enrollment and at the follow-up evaluation (3 months). Patient-Reported Outcomes (PROs) at the follow-up evaluation were used. The primary endpoint was the difference in the questionnaires at the follow-up visit compared to the one at enrollment among the study groups. Results: In the per-protocol analysis, 52 patients in Group 1, 55 in Group 2 and 57 in Group 3 were analyzed. At the follow-up evaluation, IIEF-5 scores improved in all the 3 groups between enrollment and the follow-up evaluation, but a statistically significant difference was reported between Group 2 (+7.4) and Group 1 (+4.1) or Group 3 (+5.1), (p < 0.001; p < 0.001). Moreover, 47 patients (94.0%) in Group 2 showed an improvement in the SEP questionnaires, when compared with the baseline, while 29 in Group 1 (56.9%) and 42 in Group 3 (82.3%) showed a statistically significant difference (p = 0.004; p = 0.003) among the groups. The PRO analysis reported better efficacy and patient satisfaction in Group 2 when compared with Group 1 or Group 3. Conclusions: In conclusion, Icarifil® is able to improve penile erectile function in mild-moderate ED and significantly improve the clinical efficacy of daily used tadalafil 5 mg. Icarifil® could represent an interesting alternative treatment in patients experiencing adverse effects or with contraindications for chronic treatment with PDE5-is.

l-arginine promotes angio-osteogenesis to enhance oxidative stress-inhibited bone formation by ameliorating mitophagy.

Background: Osteoporosis is one of the most common bone diseases in middle-aged and elderly populations worldwide. The development of new drugs to treat the disease is a key focus of research. Current treatments for osteoporosis are mainly directed at promoting osteoblasts and inhibiting osteoclasts. However, there is currently no ideal approach for osteoporosis treatment. l-arginine is a semi-essential amino acid involved in a number of cellular processes, including nitric production, protein biosynthesis, and immune responses. We previously reported that l-arginine-derived compounds can play a regulatory role in bone homeostasis. Purpose: To investigate the specific effect of l-arginine on bone homeostasis. Methods: Mildly aged and ovariectomized mouse models were used to study the effects of l-arginine on osteogenesis and angiogenesis, assessed by micro-computed tomography and immunostaining of bone tissue. The effect of l-arginine on osteogenesis, angiogenesis, and adipogenesis was further studied in vitro using osteoblasts obtained from cranial cap bone, endothelial cells, and an adipogenic cell line. Specific methods to assess these processes included lipid staining, cell migration, tube-forming, and wound-healing assays. Protein and mRNA expression was determined for select biomarkers. Results: We found that l-arginine attenuated bone loss and promoted osteogenesis and angiogenesis. l-arginine increased the activity of vascular endothelial cells, whereas it inhibited adipogenesis in vitro. In addition, we found that l-arginine altered the expression of PINK1/Parkin and Bnip3 in the mitochondria of osteoblast-lineage and endothelial cells, thereby promoting mitophagy and protecting cells from ROS. Similarly, l-arginine treatment effectively ameliorated osteoporosis in an ovariectomized mouse model. Conclusion: l-arginine promotes angio-osteogenesis, and inhibits adipogenesis, effects mediated by the PINK1/Parkin- and Bnip3-mediated mitophagy. The Translational Potential of this Article: L-arginine supplementation may be an effective adjunct therapy in the treatment of osteoporosis.

Reconciling the Cooperative-Competitive Patterns among Tumor and Immune Cells for Triple-Negative Breast Cancer Treatment Using Multimodule Nanocomplexes.

Targeting the competitive-cooperative relationships among tumor cells and various immune cells can efficiently reverse the immune-dysfunction microenvironment to boost the immunotherapies for the triple-negative breast cancer treatment. Hence, a bacterial outer membrane vesicle-based nanocomplex is designed for specifically targeting malignant cells and immune cells to reconcile the relationships based on metabolic-immune crosstalk. By uniquely utilizing the property of charge-reversal polymers to realize function separation, the nanocomplexes could synergistically regulate tumor cells and immune cells. This approach could reshape the immunosuppressive competition-cooperation pattern into one that is immune-responsive, showcasing significant potential for inducing tumor remission in TNBC models.