Safety of Readministration of EGFR-TKI After Onset of Interstitial Lung Disease in Advanced EGFR-Mutated NSCLC: A Systematic Review and Meta-Analysis.

BACKGROUND: In patients with epidermal growth factor receptor (EGFR) mutated non-small-cell lung cancer (NSCLC), EGFR-tyrosine kinase inhibitor (TKI) interruption due to EGFR-TKI-induced interstitial lung disease (ILD) is a factor for shorter overall survival (OS). Several retrospective cohort studies have reported an OS-prolonging effect of the readministration of EGFR-TKIs. This study aimed to determine the safety of readministration of EGFR-TKIs after the onset of EGFR-TKI-induced ILD. METHODS: The PubMed, CINAHL, and Web of Science databases were systematically searched until May 30, 2023. The primary outcome was successful readministration of EGFR-TKIs after the onset of EGFR-TKI-induced ILD. RESULTS: A total of 690 patients were included in this meta-analysis. The initial EGFR-TKI-induced ILD rate was 13.6% (95% confidence interval [CI]:6.4-20.9). Readministration rate of EGFR-TKI after onset of EGFR-TKI-induced ILD was 40.2% (95% CI: 26.7-53.7). The successful readministration rate of EGFR-TKIs after onset of EGFR-TKI-induced ILD was 81.9% (95% CI: 73.8-90.0). Successful rate of EGFR-TKI readministration in patients with Grade 2 or higher adverse events post initial EGFR-TKI therapy was 76.1% (95% CI: 55.6-96.6). CONCLUSIONS: Although initial EGFR-TKI-induced ILD has a relatively high incidence, EGFR-TKI readministration after the onset of EGFR-TKI-induced ILD may be a viable treatment option.

Quinonoid dihydropteridine reductase, a tetrahydrobiopterin-recycling enzyme, contributes to 5-hydroxytryptamine-associated platelet aggregation in mice.

Quinonoid dihydropteridine reductase (QDPR) regenerates tetrahydrobiopterin (BH4), which is an essential cofactor for catecholamine and serotonin (5-hydroxytryptamine, 5-HT) biosynthesis. Serotonin is known as an important platelet agonist, but its role under BH4-synthesizing or recycling enzymes deficiency is unknown. In the present study, we evaluated the effect of Qdpr gene disruption on platelet aggregation using knockout (Qdpr-/-) mice. Platelet aggregation was monitored by light transmission aggregometry using adenosine diphosphate (ADP) and collagen as agonists. We also assessed how platelet aggregation was modified by 5-HT recovery through supplementation with 5-hydroxytryptophan (5-HTP), a 5-HT precursor, or by blocking the serotonin 5-HT2A receptor. Platelet aggregation in the Qdpr-/- mice was significantly suppressed in comparison with that in wild-type (Qdpr+/+) mice, particularly at the maintenance phase of aggregation. 5-HT storage was decreased in Qdpr-/- platelets, and 5-HTP supplementation recovered not only the intraplatelet 5-HT levels but also platelet aggregation. In addition, 5-HT signal blockade using sarpogrelate suppressed platelet aggregation in Qdpr+/+ mice, and platelets in Qdpr-/- mice were hardly affected. Our results indicate that QDPR deficiency suppresses platelet aggregation by impairing 5-HT biosynthesis in mice.

Priapism caused by partial deficiency of tetrahydrobiopterin through hypofunction of the sympathetic neurons in sepiapterin reductase gene-disrupted mice.

6R-L-erythro-5,6,7,8-tetrahydrobiopterin (BH4) is an essential cofactor for aromatic L-amino acid hydroxylases, including tyrosine hydroxylase (TH), alkylglycerol monooxygenase, and three types of nitric oxide (NO) synthases (NOS). Sepiapterin reductase (SPR) catalyzes the third step of BH4 biosynthesis. SPR gene-disrupted (Spr-/- ) mice exhibit a dystonic posture, low body weight, hyperphenylalaninemia, and unstable hypertension with endothelial dysfunction. In this study, we found that Spr-/- mice suffered from a high incidence of severe priapism. Their erections persisted for months. The biopterin, BH4, and norepinephrine contents, and TH protein levels in the penile tissue of Spr-/- mice without and with priapism were significantly reduced compared to those of Spr+/+ mice. In contrast, their neural NOS (nNOS) protein levels were increased, and the cyclic guanosine monophosphate (cGMP) levels were remarkably elevated in the penises of Spr-/- mice with priapism. The symptoms were relieved by repeated administration of BH4. The biopterin, BH4, and norepinephrine contents were increased in penile homogenates from BH4-supplemented Spr-/- mice, and the TH protein levels tended to increase, and their nitrite plus nitrate levels were significantly lower than those of vehicle-treated Spr-/- mice and were approximately the same as vehicle- and BH4-supplemented Spr+/+ mice. Thus, we deduced that the priapism of Spr-/- mice is primarily caused by hypofunction of the sympathetic neurons due to cofactor depletion and the loss of TH protein and, further, dysregulation of the NO/cGMP signaling pathway, which would be caused by disinhibition of nNOS-containing neurons and/or abnormal catabolism of cyclic nucleotides is suggested.

Salivary neopterin and related pterins: their comparison to those in plasma and changes in individuals.

Neopterin (NP), biopterin (BP) and monapterin (MP) exist in saliva. The physiological role of salivary NP as well as the pathophysiological role of increased NP in the immune-activated state has been unclear. Saliva is a characteristic specimen different from other body fluids. In this study, we analysed salivary NP and related pterin compounds, BP and MP and revealed some of its feature. High-performance liquid chromatography (HPLC) analysis of saliva and plasma obtained from 26 volunteers revealed that salivary NP existed mostly in its fully oxidized form. The results suggested that salivary NP as well as BP would mostly originate from the oral cavity, perhaps the salivary glands, and that salivary NP levels might not reflect those in the plasma. We also found that a gender difference existed in correlations between concentrations of salivary total concentrations of NP (tNP) and BP (tBP). HPLC analysis of saliva obtained from 5 volunteers revealed that the concentrations of salivary tNP as well as tBP fluctuated in an irregular fashion in various individuals. MP, a diastereomer of NP, might have come from oral cavity NP itself or its precursor. These results indicated that the nature of salivary NP might be different from that of NP in the blood or urine.

Effects of plasma glycosyltransferase on the ABO(H) blood group antigens of human von Willebrand factor.

Von Willebrand factor (VWF) is one of the plasma protein carrying ABO(H) blood group antigens, but the combining process of these antigens is not clear. In the present study, we examined whether plasma glycosyltransferase affects the blood group antigens on VWF. VWF expressing H-antigen (H-VWF) from blood group O and bovine serum albumin conjugated with H-antigen (H-BSA) were incubated with recombinant α1-3-N-acetylgalactosaminyltransferase (rA-transferase) and A-plasma with or without an additional UDP-GalNAc. Transformed antigens were detected by western blotting and ELISA, using an anti-A antibody. Both H-VWF and H-BSA acquired the A-antigen after incubation with rA-transferase and UDP-GalNAc. Incubation with A-plasma very weakly converted the H-antigen on BSA and VWF to A-antigen only in the presence of supplemented UDP-GalNAc. This conversion was enhanced on desialylation of H-VWF. These results indicate that sugar chains of plasma VWF can be modified by the external glycosyltransferase, but that plasma glycosyltransferase has no effect on the blood group antigens of VWF due to its low activity and the lack of donor sugars. Further, sialic acid residues of VWF may exert a protective effect against post-translational glycosylation. Our results clearly exclude the possibility that blood group antigens of VWF are constructed extracellularly in plasma.

Sepiapterin reductase gene-disrupted mice suffer from hypertension with fluctuation and bradycardia.

(6R)-l-erythro-5,6,7,8-Tetrahydrobiopterin (BH4) is an essential cofactor for monoamine and nitric oxide (NO) production. Sepiapterin reductase (SPR) catalyzes the final step in BH4 biosynthesis. We analyzed the cardiovascular function of adult Spr gene-disrupted (Spr-/-) mice for the first time. After weaning, Spr-/- mice suffered from hypertension with fluctuation and bradycardia, while the monoamine contents in these mice were less than 10% of those in the wild-type mice as a result of BH4 depletion. Heart rate variability analysis indicated the sympathetic dominant state in Spr-/- mice. The endothelium-dependent vascular relaxation in response to acetylcholine was significantly impaired in Spr-/- mice after sexual maturation (above 4 months old). Protein amounts of α1 adrenergic receptor and eNOS in the aorta were not altered. Spr-/- mice exhibited hypoglycemia and elevation of plasma renin activity. Our results suggest that the hypertension with fluctuation and bradycardia of Spr-/- mice would be caused by an imbalance of sympathetic and parasympathetic input and impaired nitric oxide production in endothelial cells. We suggest an important role of BH4 and SPR in age-related hypertension and a possible relationship with the cardiovascular instabilities in autonomic diseases, including Parkinson's disease and spinal cord injury.