Ultrastructural Study of Clitoral Cavernous Tissue and Clitoral Blood Flow From Type 1 Diabetic Premenopausal Women on Phosphodiesterase-5 Inhibitor.

BACKGROUND: The effects of phosphodiesterase-type 5 (PDE5) inhibitors on the in vivo clitoral structure of women with diabetes have never been investigated. AIM: To study the in vivo structural and hemodynamic changes of the clitoris in premenopausal women with type 1 diabetes on PDE5 inhibitors. METHODS: 38 premenopausal women with type 1 diabetes aged 36 -46 years. A randomized 1:1 study design was used: Study Group (group A) on Tadalafil 5 mg daily, and control group (group B). Blood samples were taken from each woman to measure HbA1c, testosterone, and Free Androgen Index. The women underwent microbiopsy of the clitoral body by means of semiautomatic gun during total anesthesia for surgery therapy of a benign gynecological pathology. The tissue removed was processed for electron microscopy. Translabial color Doppler ultrasound was used to measure the peak systolic velocity (PSV), the end diastolic velocity (EDV), and the pulsatility index (PI) of clitoral arteries. MAIN OUTCOME MEASURES: Micro-ultrastructure observation of clitoral tissue and color Doppler sonography of clitoral blood flow. RESULTS: Of the 38 women, 13 (68.4%) of group A and 15 (78.9%) of group B completed the study. Group A showed a mean PSV and EDV increase, and a mean PI decrease with respect to baseline (P < .001). Group B did not show any change in both the parameters (P = NS). By a quantitative study in both groups a variable degree of ultrastructural abnormalities of smooth muscle cells (SMCs) was observed, consisting in increased glycogen and lipoic deposits, cytoplasmic vacuoles, and focal increase of electron density of SMCs. Moreover, the mean SMC thickness of group A (1.83 ± 0.68 µm) was larger than that of group B (1.3 ± 0.41 µm) (P = .02). CLINICAL IMPLICATIONS: PDE5 inhibitors could be used to treat diabetic women with genital arousal disorder. STRENGTHS & LIMITATIONS: The study shows a clear effect of PDE5 inhibitors on clitoral SMCs. However, a limit was to not have investigated the sexual function/behavior of women of both groups, this was because of the short time of the study. CONCLUSION: This study could help to understand in what way PDE5 inhibitors act on the ultrastructural pathophysiological clitoral cavernous tissue of women with diabetes. It could support PDE5 inhibitor usage in women with genital sexual arousal disorder due to metabolic diseases. Caruso S, Cianci A, Cianci S, et al. Ultrastructural Study of Clitoral Cavernous Tissue and Clitoral Blood Flow From Type 1 Diabetic Premenopausal Women on Phosphodiesterase-5 Inhibitor. J Sex Med 2019;16:375-382.

Glutamate utilization promotes meningococcal survival in vivo through avoidance of the neutrophil oxidative burst.

Polymorphonuclear neutrophil leucocytes (PMNs) are a critical part of innate immune defence against bacterial pathogens, and only a limited subset of microbes can escape killing by these phagocytic cells. Here we show that Neisseria meningitidis, a leading cause of septicaemia and meningitis, can avoid killing by PMNs and this is dependent on the ability of the bacterium to acquire L-glutamate through its GltT uptake system. We demonstrate that the uptake of available L-glutamate promotes N. meningitidis evasion of PMN reactive oxygen species produced by the oxidative burst. In the meningococcus, L-glutamate is converted to glutathione, a key molecule for maintaining intracellular redox potential, which protects the bacterium from reactive oxygen species such as hydrogen peroxide. We show that this mechanism contributes to the ability of N. meningitidis to cause bacteraemia, a critical step in the disease process during infections caused by this important human pathogen.

Effects of XeCl UV308 nm laser radiation on survival and mutability of recA-proficient and recA-defective Escherichia coli strains.

recA1, recA13 and recA56 are considered null alleles of the Escherichia coli recA gene because they were shown to have essentially no activity in vivo. In this study, we used strains harboring the recA null alleles and their recA-proficient congenic counterpart to assess the lethal and the mutagenic effects elicited by near-UV(308 nm) coherent radiation generated by a XeCl excimer laser. We compared these effects with those produced by a conventional far-UV(254 nm) germicidal lamp. Compared to the germicidal lamp, the excimer laser was able to better discriminate the different recA-defective strains on the basis of their UV-radiation sensitivity, which was progressively higher in the strains with the alleles in the order recA1, recA56 and recA13. This finding was consistent with previous data on residual biochemical activities of the respective mutated RecA proteins in vitro. The discrepancy between the results obtained with the lamp and laser irradiation suggested that the biological response to the two radiations involves distinct mechanisms. This hypothesis was supported by the evidence that exposure to near-UV(308 nm) radiation induced mutagenesis in recA-defective strains at an extent considerably greater than in recA-proficient strains. In contrast, far-UV(254 nm)-radiation-induced mutagenesis was reported to be largely dependent on a functional recA allele.

Identification of a meningococcal L-glutamate ABC transporter operon essential for growth in low-sodium environments.

GdhR is a meningococcal transcriptional regulator that was previously shown to positively control the expression of gdhA, encoding the NADP-specific L-glutamate dehydrogenase (NADP-GDH), in response to the growth phase and/or to the carbon source. In this study we used reverse transcriptase-PCR-differential display (to identify additional GdhR-regulated genes. The results indicated that GdhR, in addition to NADP-GDH, controls the expression of a number of genes involved in glucose catabolism by the Entner-Doudoroff pathway and in l-glutamate import by an unknown ABC transport system. The genes encoding the putative periplasmic substrate-binding protein (NMB1963) and the permease (NMB1965) of the ABC transporter were genetically inactivated. Uptake experiments demonstrated an impairment of L-glutamate import in the NMB1965-defective mutant in the absence or in the presence of a low sodium ion concentration. In contrast, at a sodium ion concentration above 60 mM, the uptake defect disappeared, possibly because the activity of a sodium-driven secondary transporter became predominant. Indeed, the NMB1965-defective mutant was unable to grow at a low sodium ion concentration (<20 mM) in a chemically defined medium containing L-glutamate and four other amino acids that supported meningococcal growth, but it grew when the sodium ion concentration was raised to higher values (>60 mM). The same growth phenotype was observed in the NMB1963-defective mutant. Cell invasion and intracellular persistence assays and expression data during cell invasion provided evidence that the l-glutamate ABC transporter, tentatively named GltT, was critical for meningococcal adaptation in the low-sodium intracellular environment.

Regulation and differential expression of gdhA encoding NADP-specific glutamate dehydrogenase in Neisseria meningitidis clinical isolates.

Meningococcal gdhA, encoding the NADP-specific l-glutamate dehydrogenase (NADP-GDH), is essential for systemic infection in an infant rat model. In this paper, a limited transcriptional analysis detected differences in gdhA expression among clinical isolates. In strains expressing high levels of gdhA mRNA, two promoters, gdhA P1 and gdhA P2, initiated transcription of gdhA. In contrast, in strains expressing low mRNA levels, gdhA P2 was not active because of weak expression of gdhR, an associated regulatory gene. Gene knock-out and complementation of a gdhR-defective mutant confirmed that GdhR is a positive regulator for gdhA P2. Trans-activation of gdhA P2 was maximal in complex medium during late logarithmic growth phase and in chemical defined medium (MCDA) when glucose (MCDA-glucose) instead of lactate (MCDA-lactate) was used as a carbon source in the presence of glutamate. gdhR knock-out mutants lost both growth phase and carbon source regulation, and exhibited a growth defect more severe in MCDA-glucose than in MCDA-lactate. DNA-protein interaction studies demonstrated that 2-oxoglutarate, a product of the catabolic reaction of the NADP-GDH and an intermediate of the tricarboxylic acid (TCA) cycle, inhibits binding of GdhR to gdhA P2.