MF AI Neuromorfologijos laboratorija (04.03.04)

Background. Heart areas enriched in endings of sensory nerve fibres (NEs) play a role as reflexogenic zones (RZs), where primary afferent signals initiate neural mechanisms controlling heart activity. Distribution, appearance, and chemical phenotypes of cardiac NEs remain under consideration. Study aims to characterise the morphological diversity of NEs in mammalian and human hearts, exposing links between their structural patterns and chemical phenotypes.

Introduction The jugular/nodose ganglia (J/NG) complex contains sensory neurons expressing neuropeptides such as CGRP, nNOS, and TTN3, which are essential for vagal signaling. Aging and arterial hypertension may induce structural remodeling of these ganglia and alter the morphology of peptide-expressing neurons. However, the relationship between ganglion morphology, neuronal size, and peptide-specific expression across age and hypertensive states remains poorly defined. Aim of the study To evaluate age- and hypertension-related morphological changes in the J/NG complex, focusing on ganglion size, neuronal soma size, neuron density, and peptide-specific neuronal morphology in Wistar–Kyoto (WKY) and spontaneously hypertensive (SHR) rats. Materials and methods Cryosections of the J/NG complex were immunohistochemically stained for CGRP, nNOS, TTN3, and PGP9.5. Fluorescent secondary antibodies (Cy3, FITC, A488) were used for visualization by fluorescence microscopy. Ganglion area, neuronal soma area, neuron density, and peptide-specific neuronal morphology were quantified using ImageJ and AxioImage software. Results Ganglion size positively correlated with neuron number in young and middle-aged animals, whereas this relationship was absent in aged rats. SHR exhibited increased neuron density during early stages of hypertension, while WKY rats demonstrated age-dependent increases in neuron density. Neuronal soma size increased with age in SHR but remained relatively stable in WKY rats; however, neurons in SHR were consistently smaller than those in WKY rats in young and middle-aged groups. Peptide- and side-specific differences in neuronal morphology were prominent in younger animals but progressively diminished with aging. Conclusions Aging and hypertension are associated with distinct, peptide-specific morphological remodeling of the jugular/nodose ganglia. Hypertension primarily affects neuronal size and density at earlier stages, while aging reduces structural and peptide-specific differences, leading to convergence of neuronal morphology in older animals.

INTRODUCTION Since the American Medical Association classified obesity as a disease, it has become a major public health concern. With obesity rates rising rapidly, especially among young adults, the increasing prevalence of related conditions – particularly cardiovascular diseases and infertility – is alarming. Given the limited long-term success of lifestyle-based treatments, researchers have turned to genetic approaches for obesity treatment. To date, 74 genes have been identified as influencing obesity through mechanisms involving food intake regulation, energy expenditure, fat metabolism, and adipose tissue accumulation. AIM To compare different gene therapy approaches for obesity treatment. METHODS & MATERIALS This study is conducted based on the articles obtained through scientific databases of PubMed, SpringerLink, Oxford Medicine Online, Taylor & Francis and Wiley Online Library The search has been done using the combination of keywords obesity, gene therapy, FGF21, CRISPR-Cas9, FABP-4, UCP-1, genome-wide association studies. DISCUSSION Uncoupling Protein-1 (UCP1) gene therapy, which enhances glucose tolerance and insulin sensitivity by stimulating endogenous UCP1 expression in adipose tissue. This process promotes the formation of brown adipocyte-like cells, known to improve metabolic health via increasing catabolism of excess lipids. Fatty Acid Binding Protein-4 (FABP4) gene therapy, which reduces lipid accumulation and enhances lipolysis. Studies have shown that FABP4 gene therapy significantly decreases obesity-related inflammation while improving metabolic health and reversing lipid accumulation. Fibroblast Growth Factor 21 (FGF21) gene therapy, delivered via adeno-associated virus vectors. This method provides a long-term strategy for obesity management by increasing energy expenditure, enhancing insulin sensitivity, and promoting stable metabolic health, enabling individuals to maintain a healthy weight. CONCLUSION All 3 therapies are novel, have not yet been tested in human subjects. They have shown promising results in mice by reducing lipid accumulation and activating brown fat tissue to accelerate the breakdown of excess lipids, increasing energy expenditure. These make gene therapy targeting the before-mentioned genes a promising approach to treating obesity.

This study aimed to develop and evaluate cyano-phycocyanin (C-PC)-loaded enriched transfersomes for topical application, improved skin delivery, and antioxidant protection. The main objective was to overcome the limitations associated with C-PC's instability and poor skin permeability due to its high molecular weight and hydrophilicity. Six formulations were prepared using an organic solvent-free two-step method: glycerol-enriched transfersomes (Gly-transfersomes),glycerol and cholesterol-enriched transfersomes (Gly-chol-transfersomes),hyaluronate-enriched transfersomes (Hyal-transfersomes),hyaluronate and cholesterol-enriched transfersomes (Hyal-chol-transfersomes),glycerol and hyaluronate-enriched transfersomes (Hyal-gly-transfersomes), anda combination of all three (Hyal-gly-chol-transfersomes). Empty vesicles were prepared via direct sonication, then C-PC was gently loaded using mild sonication in a temperature-controlled ultrasonic bath. All formulations demonstrated properties suitable for skin delivery, with mean diameters <115 nm, polydispersity indexes <0.2, and zeta potential below -30 mV. Cryo- transmission electron microscopy confirmed spherical, unilamellar or oligolamellar morphology. Gly- and Gly-chol-transfersomes exhibited the highest encapsulation efficiency (∼52 %) and remained stable for up to 8 months at 4 °C. Antioxidant activity of C-PC (∼23-27 μmol TE/g of dry C-PC) was confirmed via DPPH assay. Biological tests on HaCaT cells exposed to H2O2-induced oxidative stress showed ∼80 % cell viability after treatment with C-PC formulations, compared to ∼60 % in untreated cells, indicating cytoprotective activity. Ex vivo skin penetration studies revealed significantly higher C-PC accumulation in the epidermis especially for Gly- and Gly-chol-transfersomes versus aqueous C-PC. These findings confirm the potential of enriched transfersomes as effective carriers to improve the skin delivery and bioactivity of C-PC in antioxidant skin care formulations.

In the primary visual cortex area V1 activation of inhibitory interneurons, which provide negative feedback for excitatory pyramidal neurons, can improve visual response reliability and orientation selectivity. Moreover, optogenetic activation of one class of interneurons, parvalbumin (PV) positive cells, reduces the receptive field (RF) width. These data suggest that in V1 the negative feedback improves visual information processing. However, according to information theory, noise can limit information content in a signal, and to the best of our knowledge, in V1 signal-to-noise ratio (SNR) has never been estimated following either pyramidal or inhibitory neuron activation. Therefore, we optogenetically activated pyramidal or PV neurons in the deep layers of cortical area V1 and measured the SNR and RF area in nearby pyramidal neurons. Activation of pyramidal or PV neurons increased the SNR by 267% and 318%, respectively, and reduced the RF area to 60.1% and 77.5%, respectively, of that of the control. A simple integrate-and-fire neuron model demonstrated that an improved SNR and a reduced RF area can increase the amount of information encoded by neurons. We conclude that in V1 activation of pyramidal neurons improves visual information processing since the location of the visual stimulus can be pinpointed more accurately (via a reduced RF area), and more information is encoded by neurons (due to increased SNR).

Background and Aim. Calcitonin gene-related peptide (CGRP) is localized in sensory fibers and innervates smooth heart muscles and vasculature. CGRP also participates in regulating cardiovascular events: 1) Locally in case of inflammation; 2) Systemically, (in animal studies), demonstrates that hypertension can be reduced due to its vasodilator activity. However, long-term hypertension damaging or compensatory aftereffects on the cardiac nervous system sensory part are not fully researched. Material and Methods. Atrial and ventricular epicardiac nerves of Spontaneously Hypertensive Rats (SHR, n=3) and normotensive Wistar Kyoto rats (WKY, n=3) were examined. We used either transverse cryosections. Animals were male and elderly (>18 months). Neural structures were stained immunohistochemically for protein gene product 9.5 (PGP9.5 – general neuronal marker) and CGRP. Nerve fractions stained by PGP9.5 and CGRP were measured using the threshold function and expressed as percentages from the total nerve area. Results were described as mean ± standard error and compared by Student t-test, p-value<0.05. Results. The seldom intrinsic nerves occur within the epicardium and on the surface of myocardium. The rest of the myocardium and endocardium contained only a meshwork of nerve fibers. Nerve cross-sections were arranged similarly on ventricles, but appeared smaller on the right one, especially SHR (leftWKY 908±87 vs. leftSHR 925±112 µm2, p=0.909; rightWKY 747±106 vs. rightSHR 581±59 µm2, p=0.147). The scarce area fraction stained with PGP9.5 occupies only half of cross-section, more plentiful in WKY on the right (WKY 59±2.5% vs. SHR 51±2.2%, p=0.012), and in SHR – on the left (WKY 51±1.7% vs. SHR 59±1.6%, p=0.001). On the other hand, the CGRP area fraction significantly (almost twice) increased in the hypertensive group, probably due to compensatory vasodilative activity (WKY 1.31±0.09 vs. SHR 2.51±0.13, p<0.001). Conclusions. The epicardiac nerve total neuronal material with the accent to the sensory component is altered by long-term hypertension.

Introduction: Poorly controlled blood pressure is associated with an increased risk of asymptomatic diverticular disease (DD),1 which is influenced by excessive contraction of the colonic smooth muscles (CSM), leading to diverticula formation. This study aimed to compare the gene expression of Angiotensin II type 1 and type 2 receptors (AT1R and AT2R) and the effect of Ang II on colonic circular muscle (CCM) contraction in patients with and without DD. Methods: The control samples were obtained from patients with colorectal carcinoma, while the other group samples were collected from patients with DD. CCM strips were dissected and placed in warm, oxygenated Krebs solution for isometric recording of muscular activity in response to different concentrations of Ang II. RT- PCR was used to investigate the presence of AT1R and AT2R mRNA in both groups. Immunohistochemistry (IHC) was performed to examine the intramuscular location of AT1R and AT2R in the colonic muscular tissue, with comparisons made between the groups. Results: CCM in the DD group showed stronger contractile responses to Ang II at all concentrations (10−8, 10−7, 10−6 M) compared to the control group (p = 0.0001). AT1R transcription activity was slightly lower in the CSM of DD patients (p = 0.772), while AT2R showed higher gene activity in DD patient samples (p = 0.003). IHC revealed pre-dominant expression of AT2R in the myenteric plexus and colonic smooth muscle cells, while AT1R was not detected.Conclusions: DD enhances CCM contraction, increasing AT2R gene expression due to AT1R desensitization.