OBJECTIVE: To investigate tear neuropeptide Y (NPY) and substance P concentrations in individuals with type 1 diabetes, comparing those with and without both diabetic retinopathy (DR) and peripheral neuropathy.
METHODS: This cross-sectional study involved 41 participants with type 1 diabetes and none to moderate DR, and 22 healthy controls. Assessments included clinical ocular surface parameters, quantification of corneal nerve attributes (based on in vivo confocal microscopy imaging), DR grading, and evaluation for small and large fibre neuropathy. Concentrations of NPY and substance P in tear samples were measured using enzyme-linked immunosorbent assay.
RESULTS: Mean (±standard deviation) tear NPY concentrations in participants with type 1 diabetes and length-dependent small fibre neuropathy (SFN) was lower than in controls (10.84±4.10 ng/mL vs 14.72±3.12 ng/mL; p=0.004), but not significantly different from type 1 diabetes participants without SFN (13.39±4.66 ng/mL; p=0.11). Tear NPY levels were lower in individuals with type 1 diabetes and mild/moderate non-proliferative DR (10.44±3.46 ng/mL) compared to none/minimal DR (13.79±4.76 ng/mL; p=0.0005) and controls. In separate linear regression models, both the presence of SFN ((β=-0.75, p=0.02) and the presence of mild/moderate DR (β=-0.84, p=0.009) were significantly associated with tear NPY levels relative to controls, after adjusting for participant age, sex, and dry eye disease. There were no inter-group differences for tear substance P concentrations.
CONCLUSIONS: Tear NPY has potential utility as an indicator of peripheral microvascular complications associated with type 1 diabetes.

<b>Introduction:</b> Previous studies indicate a significant role of the inflammatory response in the etiopathogenesis of peripheral artery disease (PAD) and chronic pain (CP).<b>Aim:</b> The aim of the study was to determine the relationship between the concentration of SP and the level/concentration of inflammatory mediators (pro-inflammatory cytokines, positive and negative acute phase protein, anti-inflammatory cytokines) and pain intensity in people suffering from chronic pain (CP) in the course of PAD.<b>Material and methods:</b> We examined 187 patients of the Department of Vascular Surgery. As many as 92 patients with PAD and CP (study group) were compared to 95 patients with PAD without CP (control group). The relationship between SP and the level/concentration of fibrinogen, C-reactive protein (CRP), antithrombin III (AT), serum albumin, interleukin 10 (IL-10), tumor necrosis factor alpha (TNF-α) and pain intensity (Numeric Rating Scale; NRS) was analyzed. Statistical analysis was performed using the R program, assuming the level of statistical significance of α = 0.05.<b>Results:</b> Patients with CP had significantly higher levels of fibrinogen (P < 0.001), CRP (P < 0.001), SP (P < 0.001), IL-10 (P < 0.001), and lower serum albumin levels (P < 0.023). Higher SP concentration was associated with higher levels of IL-10, CRP, and pain intensity. In both groups, SP concentration correlated negatively with the level of fibrinogen (P < 0.001) as well as with albumin in the control group (P < 0.001).<b>Conclusions:</b> Thus, there is a relationship between the concentration of SP and fibrinogen, along with CRP, IL-10, and the intensity of pain in people suffering from CP in the course of PAD, and the level of albumin in the group without CP.

Hyperglycemia and hyperinsulinemia in type 2 diabetes result in complications exacerbated by oxidative stress, leading to cardiovascular, nephropathic, neuropathic, and retinopathic problems. Substance P(SP), a natural neuropeptide, inhibits cell death and enhances cell growth during oxidative or inflammatory stress, suggesting a potential role in reducing diabetic complications. Objective -investigate serum levels of SP, total antioxidant status (TAS), glycemic measures, and lipid profiles in non-obese type 2 diabetic patients and evaluate the relationships involving these biomarkers.
METHODS: A case-control study involved 85 adult subjects (46males & 39females), aged (30-60) year, included two groups; diabetic group:53(males & females) non-obese type 2 diabetic patients, healthy group: Apparently healthy subjects of 32 individuals chosen from the general population and matched with patients age, sex and BMI.
RESULTS: The results showed that patients\' glucose levels increased as percentage increase of (˃141%),mild elevated insulin levels (˃50%), higher insulin resistance (˃250%), the lipid parameters exhibited disruption in comparison to the control group, in diabetic group, the serum levels of TAS, SP decreased considerably in comparison to the control group.
CONCLUSIONS: As evidenced by the outcomes; the TAS showed significant negative correlations with fasting serum glucose and low-density lipoprotein, and positive correlations with high-density lipoprotein. Neither the glycemic indices nor the lipid profiles or TAS demonstrated any notable associations with SP levels. This suggests that while SP levels are reduced in type 2 diabetes, they do not appear to be directly linked with the measured biomarkers.

BACKGROUND: Inflammation affects labor by influencing contractions and dilation. Pain, often linked to tissue ischemia, involves mediators like nitric oxide (NO), TNF-α, and substance P (SP). Neuraxial analgesia, including combined spinal epidural analgesia (SEA) with levobupivacaine, is preferred for its effectiveness and minimal side effects in painless labor. Understanding the impact of painless labor techniques on biomolecular processes such as NO, TNF-α, and substance P levels is crucial for improving pain management strategies. This study investigates these effects in parturients undergoing SEA with levobupivacaine, contributing to the development of novel pain medications and enhancing obstetric care.
METHODS: This experimental study, conducted at a General Hospital in Indonesia, involved 60 expectant mothers in labor or in the third trimester, expected to give birth vaginally at Permata Hati Metro Hospital. Blood serum was used for analysis, and serum NO, TNF-α, and SP levels were assessed using ELISA kit.
RESULTS: There\'s a significant decrease in NO levels before and post-treatment in the SEA group compared to the control group (p < 0.05). However, no significant difference in TNF-α levels was observed between groups before and after treatment (p > 0.05). Additionally, there was no significant difference in SP levels between groups before treatment, but a significant difference was seen after treatment (p < 0.05). SEA significantly reduced labor pain compared to the control group (P < 0.05), with notable improvements in vital signs and APGAR scores, while also shortening labor duration (P < 0.001).
CONCLUSIONS: In conclusion, SEA with levobupivacaine during painless labor reduces NO levels significantly and shows a trend of decreasing TNF-α and substance P levels, although not statistically significant, with clinical benefits for both patients and babies.

Plastics are present in almost every aspect of our lives. Polyethylene terephthalate (PET) is commonly used in the food industry. Microparticles can contaminate food and drinks, posing a threat to consumers. The presented study aims to determine the effect of microparticles of PET on the population of neurons positive for selected neurotransmitters in the enteric nervous system of the jejunum and histological structure. An amount of 15 pigs were divided into three groups (control, receiving 0.1 g, and 1 g/day/animal orally). After 28 days, fragments of the jejunum were collected for immunofluorescence and histological examination. The obtained results show that histological changes (injury of the apical parts of the villi, accumulations of cellular debris and mucus, eosinophil infiltration, and hyperaemia) were more pronounced in pigs receiving a higher dose of microparticles. The effect on neuronal nitric oxide synthase-, and substance P-positive neurons, depends on the examined plexus and the dose of microparticles. An increase in the percentage of galanin-positive neurons and a decrease in cocaine and amphetamine-regulated transcript-, vesicular acetylcholine transporter-, and vasoactive intestinal peptide-positive neurons do not show such relationships. The present study shows that microparticles can potentially have neurotoxic and pro-inflammatory effects, but there is a need for further research to determine the mechanism of this process and possible further effects.

Polysulfides are endogenously produced in mammals and generally associated with protective functions. Our aim was to investigate the effect of dimethyl trisulfide (DMTS) in a mouse model of acute stress. DMTS activates transient receptor potential ankyrin 1 (TRPA1) channels and leads to neuropeptide release, potentially that of substance P (SP). We hypothesize that DMTS might inhibit the degrading enzymes of endocannabinoids, so this system was also investigated as another possible pathway for mediating the effects of DMTS. Trpa1 gene wild-type (WT) and knockout (KO) mice were used to confirm the role of the TRPA1 ion channel in mediating the effects of DMTS. C57BL/6J, NK1 gene KO, and Tac1 gene KO mice were used to evaluate the effect of DMTS on the release and expression of SP. Some C57BL/6J animals were treated with AM251, an inhibitor of the cannabinoid CB1 receptor, to elucidate the role of the endocannabinoid system in these processes. Open field test (OFT) and forced swim test (FST) were performed in each mouse strain. A tail suspension test (TST) was performed in Trpa1 WT and KO animals. C-FOS immunohistochemistry was carried out on Trpa1 WT and KO animals. The DMTS treatment increased the number of highly active periods and decreased immobility time in the FST in WT animals, but had no effect on the Trpa1 KO mice. The DMTS administration induced neuronal activation in the Trpa1 WT mice in the stress-related brain areas, such as the locus coeruleus, dorsal raphe nucleus, lateral septum, paraventricular nucleus of the thalamus, and paraventricular nucleus of the hypothalamus. DMTS may have a potential role in the regulation of stress-related processes, and the TRPA1 ion channel may also be involved in mediating the effects of DMTS. DMTS can be an ideal candidate for further study as a potential remedy for stress-related disorders.

Stimulation of the calcium-sensing receptor (CaSR) regulates vascular contractility, but cellular mechanisms involved remain unclear. This study investigated the role of perivascular sensory nerves in CaSR-induced relaxations of male rat mesenteric arteries. In fluorescence studies, colocalisation between synaptophysin, a synaptic vesicle marker, and the CaSR was present in the adventitial layer of arterial segments. Using wire myography, increasing external Ca2+ concentration ([Ca2+]o) from 1 to 10 mM induced vasorelaxations, previously shown to involve the CaSR, which were inhibited by pretreatment with capsaicin. [Ca2+]o-induced vasorelaxations were partially reduced by the calcitonin gene-related peptide (CGRP) receptor blockers, CGRP 8-37 and BIBN 4096, and the neurokinin 1 (NK1) receptor blocker L733,060. The inhibitory effect of CGRP 8-37 required a functional endothelium whereas the inhibitory action of L733,060 did not. Complete inhibition of [Ca2+]o-induced vasorelaxations occurred when CGRP 8-37 and L733,060 were applied together. [Ca2+]o-induced vasorelaxations in the presence of capsaicin were abolished by the ATP-dependent K+ channel (KATP) blocker PNU 37883, but unaffected by the endothelium nitric oxide synthase (eNOS) inhibitor L-NAME. We suggest that the CaSR on perivascular sensory nerves mediate relaxations in rat mesenteric arteries via endothelium-dependent and -independent mechanisms involving CGRP and NK1 receptor-activated NO production and KATP channels, respectively.

BACKGROUND: To study and compare the effects of venoactive drug (VAD) therapy and ovarian vein embolization or resection (OVE or OVR, accordingly) on the levels of vasoactive peptides and cytokines in patients with pelvic venous disorders (PeVDs).
METHODS: The study included 70 consecutive female patients with PeVD symptoms, such as chronic pelvic pain (CPP), dyspareunia, dysuria, and vulvar varicosities. Based on the results of clinical examination and duplex ultrasound of the pelvic veins, the patients were allocated to the VAD therapy (n = 38) or OVE/OVR (n = 32). Additionally, the enzyme-linked immunosorbent assay tests were performed to determine levels of calcitonin gene-related peptide (CGRP), substance P (SP), interleukins 6 and 8 (IL-6, IL-8) and monocyte chemotactic protein-1 (MCP-1) after a 2-month course of VAD therapy and at 3 months after OVE/OVR.
RESULTS: The VAD therapy was associated with a significant decrease in CPP in 84% of patients with PeVD and isolated lesions of the parametrial veins (PVs) and uterine veins (UVs). VAD had no significant effect on the pelvic venous reflux. No changes in the CGRP, SP, IL-6, IL-8, and MCP-1 levels were detected after treatment. At 3 months after OVE or OVR, all patients with PeVD and combined lesions of the ovarian veins (OVs), PVs and UVs reported almost complete relief of CPP. Along with elimination of reflux in ovarian veins, the disappearance of reflux in PVs and UVs was noted. A decrease in the CGRP and SP levels was observed (0.7 ± 0.1 ng/mL and 0.12 ± 0.02 ng/mL before treatment; 0.5 ± 0.12 ng/mL and 0.09 ± 0.06 ng/mL after treatment, respectively; all P < 0.05). No changes in cytokine levels were revealed.
CONCLUSIONS: Treatment with VAD is associated with the CPP relief, but has no significant effect on the CGRP, SP, IL-6, IL-8, and MCP-1 levels. OVE/OVR results in the CPP relief, elimination of the pelvic venous reflux and a significant decrease in the CGRP and SP levels, but does not change cytokine levels.

Bisphenols are dangerous endocrine disruptors that pollute the environment. Due to their chemical properties, they are globally used to produce plastics. Structural similarities to oestrogen allow bisphenols to bind to oestrogen receptors and affect internal body systems. Most commonly used in the plastic industry is bisphenol A (BPA), which also has negative effects on the nervous, immune, endocrine, and cardiovascular systems. A popular analogue of BPA-bisphenol S (BPS) also seems to have harmful effects similar to BPA on living organisms. Therefore, with the use of double immunofluorescence labelling, this study aimed to compare the effect of BPA and BPS on the enteric nervous system (ENS) in mouse jejunum. The study showed that both studied toxins impact the number of nerve cells immunoreactive to substance P (SP), galanin (GAL), vasoactive intestinal polypeptide (VIP), the neuronal isoform of nitric oxide synthase (nNOS), and vesicular acetylcholine transporter (VAChT). The observed changes were similar in the case of both tested bisphenols. However, the influence of BPA showed stronger changes in neurochemical coding. The results also showed that long-term exposure to BPS significantly affects the ENS.

Various etiologies, including diabetic keratopathy (DK), dry eye disease (DED), and neurotrophic keratopathy (NK), can disrupt corneal homeostasis, exacerbating corneal epithelial defects. Topical insulin has emerged as a promising therapy for promoting corneal wound healing and addressing underlying pathologies. This review systematically evaluates the efficacy of topical insulin across different corneal disorders. A literature review was conducted across the PubMed, Google Scholar, and Scopus research databases. The search resulted in a total of 19 articles, consisting of clinical trials, retrospective studies, and case reports. In DK, topical insulin accelerates corneal wound healing post-vitreoretinal surgery with lower concentrations showing higher outcomes when compared to conventional therapy, possibly due to improved epithelial stem cell migration. In comparison, the dry-eye disease results are inconclusive regarding patient-reported outcomes and corneal staining. For NK, topical insulin accelerates corneal wound healing and restores corneal nerve sensation. Other persistent epithelial defect (PED) etiologies that have been treated with topical insulin are infection, immune-mediated, mechanical and chemical trauma, and chronic ocular surface alterations. Although individual mechanisms for the benefits of topical insulin for each of these etiologies have not been studied, the literature demonstrates that topical insulin is efficacious for PEDs regardless of etiology. Future clinical trials need to be conducted to further evaluate optimal dosing, duration, and use of topical insulin for the restoration of the corneal surface.