Lack Of Trophic Support Research Articles

Examination of the Microvasculature During Wound Process of the Oral Mucosa when Using Dual-Wavelength Photodynamic Therapy: a Pre-Clinical Experimental Randomized Study

Background. Healing of open wounds in the oral cavity is often accompanied by infection and constant traumatization, which lead to impaired blood supply to the tissues, lack of trophic support and low oxygen supply to increasing proliferative processes. Recently, photodynamic therapy has taken its place among the methods for stimulating regeneration of oral mucosal tissues. The authors consider it essential to study the influence of photodynamic treatment on the functional state of the microvasculature in the wound tissues, which determines the transcapillary exchange and the tissue respiration, providing the tissue regeneration.Objective. To study the photodynamic effect of sequential dual-wavelength radiation on the microvasculature in the wound tissues of the oral mucosa in vivo.Methods. The study was carried out on 36 female outbred Wistar rats, weighing 200–250 g. The animals were divided into two groups: control group (n = 18) and experimental group (n = 18). Wound surfaces healed by secondary intention were modeled on the cheek mucosa of the animals. Dual-wavelength photodynamic therapy was performed in the 1st postoperative day in experimental group. The microcirculatory function was assessed by Doppler flowmetry before, and on days 3, 7 and 14 after wounding. The results were processed using IBM SPSS Statistics 26.0.0.1 (IBM Inc., USA).Results. It has been established that dual-wavelength photodynamic therapy has a positive effect on the restoration of the microvasculature of the wound tissues. This therapy facilitated bypassing for microcirculatory flow on the 3rd day of the study, and increased the perfusion of tissues on the 7th. The experimental group did not have congestive-ischaemic phenomena in the wound region; the microcirculatory flow was augmented through the microcirculation regulation by the 14th day.Conclusion. Following the obtained results the use of dual-wavelength photodynamic therapy can be considered as a promising method for restoration of the microvasculature of tissues in the oral mucosal trauma.

Three-dimensional coculture provides an improved in vitro model for papillary renal cell carcinoma.

Papillary renal cell carcinoma (pRCC) represents the second most common kidney cancer and can be distinguished from other types based on its unique histological architecture and specific pattern of genomic alterations. Sporadic type 1 pRCC is almost universally driven by focal or chromosomal amplification of the receptor tyrosine kinase MET, although the specific mode of its activation is unclear. Although the MET receptors found in human tumor specimens appear highly active, those found on the surface of in vitro-cultured tumor cells are only weakly activated in the absence of exogenous hepatocyte growth factor ligand. Furthermore, pRCC cells cultured in standard two-dimensional conditions with serum fail to respond functionally to MET knockdown or the selective MET inhibitor capmatinib despite clear evidence of kinase inhibition at the molecular level. To better model pRCC in vitro, we developed a three-dimensional coculture system in which renal tumor cells are layered on top of primary fibroblasts in a fashion that mimics the papillary architecture of human tumors. In this three-dimensional spheroid model, the tumor cells survive and proliferate in the absence of serum due to trophic support of hepatocyte growth factor-producing fibroblasts. Unlike tumor cells grown in monoculture, the proliferation of cocultured tumor cells is sensitive to capmatinib and parallels inhibition of MET kinase activity. These findings demonstrate the importance of stromal fibroblasts in pRCC and indicate that accurate in vitro representation of this disease requires the presence of both tumor and fibroblast cells in a structured coculture model.NEW & NOTEWORTHY Two-dimensional monoculture of papillary renal cancer cells fails to replicate several features of the disease found in humans. We hypothesized that this discordance results from lack of trophic support from renal fibroblasts, which are involved in the architecture of human papillary renal tumors. We found that three-dimensional layering of renal cancer cells on top of a fibroblast core using magnetic bioprinting produces a structured spheroid that more faithfully mimics the behavior of human tumors.

The effects of rotenone on TH, BDNF and BDNF-related proteins in the brain and periphery: Relevance to early Parkinson’s disease

Loss of dopaminergic neurons in the substantia nigra (SN) is one of the pathological hallmarks in Parkinson’s disease (PD). This neuron loss is accompanied by reduced protein and activity levels of tyrosine hydroxylase (TH), the rate-limiting enzyme of catecholamine synthesis. Reduced nigral brain-derived neurotrophic factor (BDNF) has been postulated to contribute to the loss of nigral dopaminergic neurons in PD by causing a lack of trophic support. Prior to this nigral cell loss many patients develop non-motor symptoms such as hyposmia, constipation and orthostatic hypotension. We investigated how TH, BDNF and BDNF related receptors are altered in the SN, olfactory bulb, adrenal glands and colon (which are known to be affected in PD) using rotenone-treated rats. Rotenone was administered to Sprague-Dawley rats at a dose of 2.75 mg/kg, 5 days/week for 4 weeks, via intraperitoneal injections. Rats underwent behavioural testing, and tissues were collected for western blot and ELISA analysis. This rotenone treatment induced reduced rears and distance travelled in the rearing and open field test, respectively but caused no impairments in forced movement (rotarod test). The SN had changes consistent with a pro-apoptotic state, such as increased proBDNF but no change in TH; whereas, the colon had significantly reduced TH and increased sortilin. Thus, our results indicate further investigation is warranted for this rotenone-dosing paradigm’s capacity for reproducing the early stage of PD, as we observed impairments in voluntary movement and pathology in the colon without overt motor symptoms or nigral dopaminergic loss.

ВПЛИВ ПРАЙМУВАННЯ ГІБЕРЕЛІНОМ ЗА ЯРОВИЗАЦІЇ НА РІСТ ТА ВМІСТ РОЗЧИННИХ ВУГЛЕВОДІВ В ПРОРОСТКАХ ПШЕНИЦІ М’ЯКОЇ

The present study was designed to investigate the influence of gibberellin (GA) priming under vernalization on the growth response, content and fractional composition of soluble carbohydrates in seedlings of 3 varieties of winter wheat - Doridna, Statna and Alians. Modeling different levels of trophic support of the vernalization process and investigating the influence of GA, the following variants were used in the experiments: 1) grains + water (control, optimal trophic support); 2) grains + 10 mg / l GA3, (optimal trophic support); 3) isolated embryos + water (control, lack of trophic support); 4) isolated embryos + 10 mg / l GA3 (lack of trophic support). Vernalization was carried out during 45 days at 4 ° C in Petri dishes on wet filter paper. According to the results, the stimulation of growth processes was identified under the GA effect in all investigated winter wheat varieties. The stimulation occurred as linear growth and biomass accumulation of seedlings, the intensity of which depended on the level of trophic support of these processes. The GA priming in the variant with the lack of trophic support did not significantly stimulate the content of carbohydrates in the varieties Doridna and Statna. It noticeably stimulated the content of carbohydrates in the Alians variety due to changes of oligosaccharides content. The patterns of phytohormonal and trophic regulation of vernalization processes in winter wheat are discussed.

Tau burden and the functional connectome in Alzheimer's disease and progressive supranuclear palsy.

Alzheimer's disease and progressive supranuclear palsy (PSP) represent neurodegenerative tauopathies with predominantly cortical versus subcortical disease burden. In Alzheimer's disease, neuropathology and atrophy preferentially affect 'hub' brain regions that are densely connected. It was unclear whether hubs are differentially affected by neurodegeneration because they are more likely to receive pathological proteins that propagate trans-neuronally, in a prion-like manner, or whether they are selectively vulnerable due to a lack of local trophic factors, higher metabolic demands, or differential gene expression. We assessed the relationship between tau burden and brain functional connectivity, by combining in vivo PET imaging using the ligand AV-1451, and graph theoretic measures of resting state functional MRI in 17 patients with Alzheimer's disease, 17 patients with PSP, and 12 controls. Strongly connected nodes displayed more tau pathology in Alzheimer's disease, independently of intrinsic connectivity network, validating the predictions of theories of trans-neuronal spread but not supporting a role for metabolic demands or deficient trophic support in tau accumulation. This was not a compensatory phenomenon, as the functional consequence of increasing tau burden in Alzheimer's disease was a progressive weakening of the connectivity of these same nodes, reducing weighted degree and local efficiency and resulting in weaker 'small-world' properties. Conversely, in PSP, unlike in Alzheimer's disease, those nodes that accrued pathological tau were those that displayed graph metric properties associated with increased metabolic demand and a lack of trophic support rather than strong functional connectivity. Together, these findings go some way towards explaining why Alzheimer's disease affects large scale connectivity networks throughout cortex while neuropathology in PSP is concentrated in a small number of subcortical structures. Further, we demonstrate that in PSP increasing tau burden in midbrain and deep nuclei was associated with strengthened cortico-cortical functional connectivity. Disrupted cortico-subcortical and cortico-brainstem interactions meant that information transfer took less direct paths, passing through a larger number of cortical nodes, reducing closeness centrality and eigenvector centrality in PSP, while increasing weighted degree, clustering, betweenness centrality and local efficiency. Our results have wide-ranging implications, from the validation of models of tau trafficking in humans to understanding the relationship between regional tau burden and brain functional reorganization.

Effect of trophic support on the dynamics of growth processes and carbohydrate content of winter wheat sprouts under vernalization

The influence of contrasting conditions of trophic support of vernalization on the growth reaction and dynamics of the content of various fractions of soluble carbohydrates of sprouts of two winter wheat varieties Statna and Doridna were studied. In experiments, the contrasting trophic conditions of vernalization were created by adding 3% sucrose solution, as well as isolation of endosperm, a natural reserve of carbohydrates and biologically active substances. It was shown that optimal conditions of trophic support (integral seeds + water) determined the maximum linear growth and accumulation of sprouts biomass during vernalization. The excess of exogenous sugars (integral seeds + 3% sucrose solution) inhibited growth processes. However, the deficit of trophic factors (isolated buds + 3% sucrose solution) also inhibited growth and the lack of trophic support (isolated buds + water) completely inhibited growth and accumulation of sprouts biomass during 45 days of vernalization. It was established that the dynamics of changes in soluble carbohydrates content in winter wheat sprouts also depended on the trophic support level of vernalization and correlated with changes of growth reaction. It was shown the oligosaccharide content was significantly higher than monosaccharide content of sprouts of all the variants of both varieties during the entire period of vernalization. In view of the fact that monosaccharides are the most metabolically active carbohydrates, they are probably spent as much as possible at the first stages of vernalization (15–30 days). It is discussed that different level of trophic support is able to be one of the important factors of genetic and/or epigenetic regulation of Triticum aestivum L. Thus, changes in metabolic processes, in particular carbohydrate metabolism, can effect on the reduction of VRN genes expression, which are the target of epigenetic regulation, and as a result, on the ability of soft wheat plants to flower. It is assumed that the regulatory role of carbohydrates in vernalization process can be realized only at the optimal level of trophic support.

GAS1 induces cell death through an intrinsic apoptotic pathway

Growth Arrest Specific 1 (GAS1) is a protein expressed when cells are arrested and during development. When ectopically expressed, GAS1 induces cell arrest and apoptosis of different cell lines, and we have previously demonstrated that the apoptotic process set off by GAS1 is caused by its capacity inhibiting the GDNF-mediated intracellular survival signaling. In the present work, we have dissected the molecular pathway leading to cell death. We employed the SH-SY5Y human neuroblastoma cell line that expresses GAS1 when deprived of serum. We observed, as we have previously described, that the presence of GAS1 reduces RET phosphorylation and inhibits the activation of AKT. We have now determined that the presence of GAS1 also triggers the dephosphorylation of BAD, which, in turn, provokes the release of Cytochrome-c from the mitochondria to the cytosol activating caspase-9, prompting the activity of caspase-3 and resulting in apoptosis of the cells. The apoptotic process is intrinsic, because there is no activation of caspase-8, thus this is consistent with apoptosis induced by the lack of trophic support. Interestingly, in cells where GAS1 has been silenced there is a significant delay in the onset of apoptosis.

Role of extracellular signal‐regulated protein kinase and phosphatidylinositol 3‐kinase in neuronal cell death and survival

AbstractThe survival of neurons requires, at some point, the presence of neurotrophic factors and depends on competition for a limited supply of survival factors. The neurotrophin brain‐derived neurotrophic factor (BDNF) is the ligand for the TrkB neurotrophin receptor, the most abundant Trk receptor in the brain. Two key signaling pathways are induced following binding of BDNF to its cognate receptor that are characterized by the activation of extracellular signal‐regulated protein kinase (ERK) and phosphatidylinositol 3‐kinase (PI3 kinase). Many reports have assigned a cellular survival function to the activation of ERK and/or PI3 kinase, in line with the reported neuroprotective activity of neurotrophin receptor activation. The activation of PI3 kinase by BDNF represents the dominant survival pathway, whereas the ERK signaling pathway has no or only a marginal role. However, a sustained activation of ERK, lasting for several hours, protects neurons from growth factor deprivation‐induced cell death, indicating that the duration of ERK activation is of major importance for its neuroprotective biological function. The activation of ERK and PI3 kinase does not provide protection against oxidative glutamate toxicity. Thus, the biochemical events underlying neuronal cell death induction by the lack of trophic support or via oxidative stress are distinct.

Human immunodeficiency virus type 1 glycoprotein gp120 reduces the levels of brain‐derived neurotrophic factor in vivo: potential implication for neuronal cell death

Neuronal loss has been observed in post mortem brains of patients with human immunodeficiency virus type 1 (HIV-1). Experimental evidence has implicated HIV-1-derived envelope glycoprotein 120 (gp120) in the neuronal cell death observed in these patients. However, the intrinsic mechanisms by which gp120 causes neurotoxicity are still unknown. We have recently shown that the neurotoxic effect of gp120 in vitro is reduced by brain-derived neurotrophic factor (BDNF). We therefore tested the hypothesis that low levels of BDNF render neurons more sensitive to gp120. Gp120 was injected acutely into the striatum of BDNF heterozygous mice and wild-type littermates. BDNF heterozygous mice exhibited more apoptotic neurons in the striatum than wild-type mice, suggesting that BDNF is neuroprotective also in vivo. Because several neurodegenerative disorders are characterized by lack of trophic support, we tested the hypothesis that gp120 may cause apoptosis by reducing BDNF expression. Gp120 was injected acutely in the rat striatum and BDNF levels determined by a two-site immunoassay at various times after the injection. Gp120 elicited a dramatic decrease in BDNF protein levels by 24 h. Reduced BDNF levels were still present at 4 days. Cellular localization of BDNF immunoreactivity revealed that gp120 decreases BDNF immunoreactivity mainly in neuronal processes. This effect of gp120 precedes the peak of caspase-3 activation and neuronal cell death. We propose that one of the mechanisms whereby gp120 causes neurotoxicity is a reduction of the neurotrophic factor environment crucial for cell survival.

Exercise, antidepressant treatment, and BDNF mRNA expression in the aging brain

Principal mental disorders affecting the geriatric population include dementia and depression. A lack of trophic support is thought to contribute to the pathology of these disorders. Physical activity and antidepressant treatment increase the expression of brain-derived neurotrophic factor (BDNF) in the young rat hippocampus. Herein, we investigated the responsiveness of the aging rat hippocampus to antidepressant treatment and voluntary exercise. In situ hybridization revealed that, in young animals, exercise, antidepressant treatment, or their combination elevated BDNF mRNA levels in several hippocampal regions, most notably in the CA3, CA4, and dentate gyrus (DG). This effect was rapid (detectable at 2 days) and sustainable to 20 days. In aged (22-month-old) rats, hippocampal responsiveness to antidepressant treatment and exercise was also rapid and sustainable, but evident mostly in the CA1 and CA2. Daily swimming also revealed that small amounts of activity led to marked elevations in hippocampal BDNF mRNA. The differences in regional patterns of BDNF mRNA elevations between young and aged animals observed with running were maintained with this different exercise modality. Our results indicate that the aged brain is responsive to exercise and antidepressant treatment, and changes in regional response patterns may reflect shifts in hippocampal physiology during the lifespan.

The peripheral insulin-like growth factor system in amyotrophic lateral sclerosis and in multiple sclerosis.

A lack of trophic support may lead to degeneration of adult nerve cells. Several growth factors, including insulin-like growth factor I (IGF-I), control the survival of spinal motor neurons during development as well as after experimental injury. These neurons are selectively affected in patients with amyotrophic lateral sclerosis (ALS). Thus, we analyzed whether reduced levels of circulating IGF-I may be present in this disease. Significant increases were found in three of four of the main circulating IGF-binding proteins in ALS patients, whereas serum IGF-I and insulin levels were significantly reduced. On the contrary, multiple sclerosis patients did not show any significant change in the IGF-I trophic system even though oligodendrocytes are known targets of the trophic action of IGF-I. These results suggest an involvement of the peripheral IGF-I trophic system in ALS.

Basic fibroblast growth factor treatment partially protects from visual deficits but does not increase retinal ganglion cell survival following controlled optic nerve crush

Lack of trophic support after axonal injury leads to the degeneration of neurons. To study whether the application of trophic factor can improve functional recovery and retinal ganglion cell (RGC) survival after unilateral controlled optic nerve crush injury, we have now treated adult rats intraocularly (i.o.) with basic fibroblast growth factor (bFGF). To monitor visual deficits, rats were trained in a two-choice pattern discrimination test. Immediately after the crush, and on postoperative days 3 and 6, either 1.1 μg recombinant bFGF or phosphate buffered saline (PBS) was injected i.o. Sham-operated controls received intraocular injection of PBS or bFGF. Within the first few days after the crush, all animals showed a loss of discrimination ability which was followed by a significant recovery within 2-3 weeks. Animals treated with bFGF had a significantly smaller initial deficit and thus recovered earlier compared to PBS controls. Retrograde RGC death was evaluated using retrograde HRP-tracing technique, but bFGF-treatment had no neuroprotective effect. Thus, the behavioral effects of bFGF could not be related to neuroprotection of RGCs and therefore other mechanisms may have to be considered.

The pattern of axonal degeneration in the peripheral nervous system varies with different types of lesion

Degeneration of axons in the mouse sciatic nerve was examined using conventional silver staining and by noting the presence or absence of a compound action potential on stimulating the nerve distal to the point of crush or cut. The presence of myeloperoxidase-positive cells was also examined in frozen sections of the nerve. In all experiments the distal, disconnected segment was studied. Degeneration after crushing with fine watchmakers forceps always began in the most distal part of the nerve and proceeded in a distoproximal direction, from the nerve entry point into a muscle back to the crush site. Myeloperoxidase-positive cells were also recruited into the nerve starting at the distal rather than proximal (the originally injured) end. This result favours the view that degeneration is triggered by lack of trophic support from the cell body rather than entry of deleterious substances at the site of the injury, for the terminals furthest from both the source of supply and the injury are affected first. Degeneration following nerve section was always more rapid than after crushing. The rate of axonal sealing at the injury was, however, no slower than after crushing, so it does not seem likely that greater entry of possible degeneration-triggering material at the injury site is the explanation for this. Crush lesions in which the perineurium was also cut open and the blood supply at the site was damaged, degenerated at the slower rate characteristic of simple crushes. Hence, it does not seem likely that perineurial or vascular damage, both of which are much more extensive following nerve section, provide an explanation for the more rapid degeneration of cut nerves. If a sufficiently large length of sciatic was frozen or if it was ligatured with fine silk, degeneration was as rapid as after nerve section, while, if a ligature was immediately untied, degeneration was as slow as that following crush with forceps. It is concluded that continuing contact of the distal with the proximal nerve stump slows degeneration, possibly by allowing Schwann cells above and below the lesion to continue communicating or by providing a minimal supply of trophic material.