What Remains up to 7 Months after Severe and Moderate Pneumonia in Non-Vaccinated Patients with Long COVID? Results of a CT Study.

BACKGROUND: There is a growing evidence of long-lasting lung changes after COVID-19. Our aim was to assess the degree of lung injury and evaluate the recovery process of 4-7-month-non-vaccinated convalescent patients discharged from hospital after moderate and severe COVID-19 pneumonia, who presented with symptoms of long-COVID. METHODS: On control lung CT after mean 5-month recovery period, we classified and determined the prevalence of residual radiological abnormalities in 39 symptomatic patients. To assess the advancement of the persisting changes we used the total severity score (TSS) and the chest CT score and then correlated the results with clinical data. RESULTS AND CONCLUSIONS: On follow-up CT images, 94.9% of patients showed persistent radiological abnormalities. The most frequent changes were ground-glass opacities (74.4%), reticular pattern (64.1%), fibrotic changes (53.8%), nodules (33.3%), bronchiectasis (15.4%), vascular enlargement (10.3%), and cavitation (5.1%). The median TSS score was 4.1 points (interquartile range 3), whereas the median of the chest CT score 5.4 points (interquartile range of 4.5). No significant differences were observed between sex subgroups and between the severe and moderate course groups. There were no association between both CT scores and the severity of the initial disease, indicating that, mean 5 months after the disease, pulmonary abnormalities reduced to a similar stage in both subgroups of severity.

Influence of Clinical and Genetic Factors on the Progression of Age-Related Macular Degeneration: A 3-Year Follow-Up.

The aim of the present study was to analyze the relationship of age-related macular degeneration (AMD) progression with clinical characteristics, demographic, and environmental risk factors that would affect disease development. In addition, the influence of three genetic AMD polymorphisms (CFH Y402H, ARMS2 A69S, and PRPH2 c.582-67T>A) on AMD progression was investigated. In total, 94 participants with previously diagnosed early or intermediate AMD in at least one eye were recalled for an updated re-evaluation after 3 years. The initial visual outcomes, medical history, retinal imaging data, and choroidal imaging data were collected to characterize the AMD disease status. Among the AMD patients, 48 demonstrated AMD progression, and 46 showed no disease worsening at 3 years. Disease progression was significantly associated with worse initial visual acuity (OR = 6.74, 95% CI = 1.24-36.79, p = 0.03) and the presence of the wet AMD subtype in fellow eyes (OR = 3.79, 95%CI = 0.94-15.2, p = 0.05). In addition, a higher risk of AMD progression appeared in the patients with active thyroxine supplementation (OR = 4.77, CI = 1.25-18.25, p = 0.002). The CC variant of CFH Y402H was associated with AMD advancement compared to the TC+TT phenotype (OR = 2.76, 95% CI: 0.98-7.79, p = 0.05). Identifying risk factors of AMD progression may lead to earlier intervention and better outcomes, preventing the expansion of the late stage of the disease.

Genetic factors associated with age-related macular degeneration: identification of a novel PRPH2 single nucleotide polymorphism associated with increased risk of the disease.

PURPOSE: Age-related macular degeneration (AMD) is associated with multiple environmental and genetic risk factors. Two main risk factors for AMD are variants in the CFH and ARMS2/HTRA1 genes. We investigated over 2000 variants in AMD patients and controls using high-throughput sequencing methods to search for variants associated with AMD. METHODS: A total of 296 AMD patients and 100 controls were enrolled in this study. Genetic analysis was performed with the Illumina NextSeq 500 system. RESULTS: Multivariate analysis of patients and controls, adjusted for age, sex and smoking status (pack-years), revealed that three SNPs were strong risk factors independently associated with AMD: CFH Y402H, ARMS A69S and PRPH2 c.582-67T>A (rs3818086). The TC genotype in CFH Y402H was associated with 1.90-fold higher odds, and the CC genotype was associated with 5.66-fold higher odds of AMD compared with the TT genotype. The GT genotype in ARMS A69S was associated with 2.40-fold higher odds, and the TT genotype was associated with 6.75-fold higher odds of disease compared with the GG genotype. In the case of rs3818086, the A allele could be considered a 'risk' allele, since AA + TA genotypes were associated with 2.33-fold higher odds of AMD compared with the TT genotype. CONCLUSIONS: Although PRPH2 mutations have been previously implicated in various forms of retinal degeneration, to the best of our knowledge, this study is the first to show that the rs3818086 variant increases the risk for AMD more than two times. Further studies on larger cohorts are required to elucidate how this variant affects protein structure.

Association between Light-Induced Dynamic Dilation of Retinal Vessels and Echocardiographic Parameters of the Left Ventricular Function in Hypertensive Patients.

BACKGROUND AND OBJECTIVES: The goal was to evaluate the association of dynamic retinal vessel analysis (DVA) with echocardiographic parameters assessing systolic and diastolic function of the left ventricle in hypertension (HT) patients with preserved left ventricle ejection fraction. MATERIALS AND METHODS: This observational retrospective study recruited 36 patients with HT and 28 healthy controls. Retinal vessel diameter and reactions to flicker light were examined. Each patient was examined with echocardiography to assess left ventricular systolic and diastolic function. RESULTS: Multivariate analysis revealed that hypertension was an independent factor associated with lower flicker-induced arterial vasodilatation (ß = -0.31, p = 0.029). In the HT group, there was a significant positive association between left ventricular ejection fraction and flicker-induced arterial vasodilation (Rs = +0.31, p = 0.007). Additionally, end-diastolic left ventricular diameter negatively correlated with both arterial (Rs = -0.26, p = 0.02) and venous (Rs = -0.27, p = 0.02) flicker responses. Additionally, the echocardiographic characteristics of the left atrium (LA) remodeling in the course of HT, including the area of the LA and its antero-posterior dimension, were both negatively correlated with the arterial flicker response (Rs = -0.34, p = 0.003; Rs = -0.33, p = 0.004, respectively). From tissue Doppler parameters, the left ventricular filling index E/e' negatively correlated with AVR (arteriovenous ratio) values (Rs = -0.36, p = 0.002). CONCLUSIONS: We revealed that systolic and diastolic function of the left ventricle in hypertensive patients is associated with retinal microvascular function.

Dietary and Lifestyle Factors Modulate the Activity of the Endogenous Antioxidant System in Patients with Age-Related Macular Degeneration: Correlations with Disease Severity.

Age-related macular degeneration (AMD) is a common cause of blindness in the elderly population, but the pathogenesis of this disease remains largely unknown. Since oxidative stress is suggested to play a major role in AMD, we aimed to assess the activity levels of components of the antioxidant system in patients with AMD. We also investigated whether lifestyle and dietary factors modulate the activity of these endogenous antioxidants and clinical parameters of disease severity. We recruited 330 patients with AMD (39 with early, 100 with intermediate and 191 with late form of AMD) and 121 controls in this study. At enrolment, patients' dietary habits and physical activity were assessed, and each study participant underwent a thorough ophthalmologic examination. The activity of several components of the antioxidant system were measured in red blood cells and platelets using both kinetic and spectrophotometric methods. Patients with AMD consumed much lower levels of fatty fish and eggs than the control group (p = 0.008 and p = 0.04, respectively). In the nAMD group, visual acuity (VA) correlated positively with green vegetable consumption (Rs = +0.24, p = 0.004) and omega-3-rich oil intake (Rs = +0.17, p = 0.03). In the AMD group, the total physical activity MET score correlated positively with VA (Rs = +0.17, p = 0.003) and correlated negatively with the severity of AMD (Rs = -0.14, p = 0.01). A multivariate analysis of patients and controls adjusted for age, sex, and smoking status (pack-years) revealed that AMD was an independent variable associated with a lower RBC catalase (ß = -0.37, p < 0.001) and higher PLT catalase (ß = +0.25, p < 0.001), RBC GPx (ß = +0.26, p < 0.001), PLT GPx (ß = +0.16, p = 0.001), RBC R-GSSG (ß = +0.13, p = 0.009), PLT R-GSSG (ß = +0.12, p = 0.02) and RBC GSH transferase (ß = +0.23, p < 0.001) activity. The activities of components of the antioxidant system were associated with disease severity and depended on dietary habits. The observed substantial increase in the activity of many critical endogenous antioxidants in patients with AMD further indicates that the required equilibrium in the antioxidant system is disturbed throughout the course of the disease. Our findings explicitly show that a diet rich in green vegetables, fish and omega-3-rich oils, supplemented by physical exercise, is beneficial for patients with AMD, as it might delay disease progression and help retain better visual function.

The Interplay Between Systemic Inflammatory Factors and MicroRNAs in Age-Related Macular Degeneration.

We aimed to explore the expression of systemic inflammatory factors and selected intracellular miRNAs that regulate inflammatory signaling pathways potentially involved in age-related macular degeneration (AMD) pathogenesis. A total of 179 patients with wet AMD, 175 with dry AMD and 121 controls were enrolled in the study. Soluble inflammatory factors were analyzed in plasma samples using Luminex technology. Expression of selected miRNAs was analyzed in isolated nucleated peripheral blood cells (PBNCs) using real-time qPCR. Wet AMD was an independent factor associated with higher concentrations of IL-6 (ß = +0.24, p = 0.0004), GM-CSF (ß = +0.31, p < 0.001), IFN-γ (ß = +0.58, p < 0.001), higher expression of miRNA-23a-3p (ß = +0.60, p < 0.0001), miRNA-30b (ß = +0.32, p < 0.0001), miRNA-191-5p (ß = +0.28, p < 0.0001) and lower concentration of IL-1ß (ß = -0.25, p = 0.0003), IL-5 (ß = -0.45, p < 0.001), IL-10 (ß = -0.45, p < 0.001), IL-12 (ß = -0.35, p < 0.001), lower expression of miRNA-16-5p (ß = -0.31, p < 0.0001), miRNA-17-3p (ß = -0.18, p = 0.01), miRNA-150-5p (ß = -0.18, p = 0.01) and miRNA-155-5p (ß = -0.47, p < 0.0001). Multivariate analysis revealed that dry AMD was an independent factor associated with higher concentration of GM-CSF (ß = +0.34, p < 0.001), IL-6 (ß = +0.13, p = 0.05), higher expression of miRNA-23a-3p (ß = +0.60, p < 0.0001), miRNA-126-3p (ß = +0.23, p = 0.0005), miRNA-126-5p (ß = +0.16, p = 0.01), miRNA 146a (ß = +0.14, p = 0.03), and mRNA191-5p (ß = +0.15, p = 0.03) and lower concentrations of TNF-α (ß = +0.24, p = 0.0004), IL-1ß (ß = -0.39, p < 0.001), IL-2 (ß = -0.20, p = 0.003), IL-5 (ß = -0.54, p < 0.001), IL-10 (ß = -0.56, p < 0.001), IL-12 (ß = -0.51, p < 0.001), lower expression of miRNA-16-5p (ß = -0.23, p = 0.0004), miRNA-17-3p (ß = -0.20, p = 0.003) and miRNA-17-5p (ß = -0.19, p = 0.004). Negative correlations between visual acuity and WBC, lymphocyte count, TNF-α, IL-1 ß, IL-2, IL-4, IL-6, IL-10 concentrations and miRNA-191-5p, as well as positive correlations between visual acuity and miRNA-126-3p, -126-5p, and -155-5p PBNCs expression were found in AMD patients. No such correlations were found in the control group. Our results may suggest the role of both intra- and extracellular mechanisms implicated in inflammatory response regulation in multifactorial AMD pathogenesis.

Associations of microRNAs, Angiogenesis-Regulating Factors and CFH Y402H Polymorphism-An Attempt to Search for Systemic Biomarkers in Age-Related Macular Degeneration.

Age-related macular degeneration (AMD) remains the leading cause of blindness in elderly people, but the pathophysiology of this disease is still largely unknown. We investigated the systemic expression of angiogenesis-regulating growth factors and selected miRNAs known to regulate angiogenesis in AMD patients. We also focused on possible correlations of their expression with the presence of CFH Y402H or ARMS A69S risk variants. A total of 354 AMD patients and 121 controls were enrolled in this study. The levels of angiogenesis-regulating factors were analyzed in plasma samples using Luminex technology. The expression of selected miRNAs was analyzed in peripheral blood plasma using real-time qPCR. The genetic analysis was performed with an Illumina NextSeq500 system. AMD was an independent factor associated with lower levels of angiogenin (ß = -0.29, p < 0.001), endostatin (ß = -0.18, p < 0.001), FGF-basic (ß = -0.18, p < 0.001), PlGF (ß = -0.24, p < 0.001), miRNA-21-3p (ß = -0.13, p = 0.01) and miRNA-155-5p (ß = -0.16, p = 0.002); and with higher levels of FGF-acidic (ß = 0.11, p = 0.03), miRNA-23a-3p (ß = 0.17, p < 0.001), miRNA-126-5p (ß = 0.13, p = 0.009), miRNA-16-5p (ß = 0.40, p < 0.001), miRNA-17-3p (ß = 0.13, p = 0.01), miRNA-17-5p (ß = 0.17, p < 0.001), miRNA-223-3p (ß = 0.15, p = 0.004), and miRNA-93 (ß = 0.11, p = 0.04). The expression of analyzed miRNA molecules significantly correlated with the levels of tested angiogenesis-regulating factors and clinical parameters in AMD patients, whereas such correlations were not observed in controls. We also found an association between the CFH Y402H polymorphism and miRNA profiles, whereby TT homozygotes showed evidently higher expression of miRNA-16-5p than CC homozygotes or TC heterozygotes (p = 0.0007). Our results suggest that the balance between systemic pro- and anti-angiogenic factors and miRNAs is vital in multifactorial AMD pathogenesis.

Preclinical Evaluation of Long-Term Neuroprotective Effects of BDNF-Engineered Mesenchymal Stromal Cells as Intravitreal Therapy for Chronic Retinal Degeneration in Rd6 Mutant Mice.

This study aimed to investigate whether the transplantation of genetically engineered bone marrow-derived mesenchymal stromal cells (MSCs) to overexpress brain-derived neurotrophic factor (BDNF) could rescue the chronic degenerative process of slow retinal degeneration in the rd6 (retinal degeneration 6) mouse model and sought to identify the potential underlying mechanisms. Rd6 mice were subjected to the intravitreal injection of lentivirally modified MSC-BDNF or unmodified MSC or saline. In vivo morphology, electrophysiological retinal function (ERG), and the expression of apoptosis-related genes, as well as BDNF and its receptor (TrkB), were assessed in retinas collected at 28 days and three months after transplantation. We observed that cells survived for at least three months after transplantation. MSC-BDNF preferentially integrated into the outer retinal layers and considerably rescued damaged retinal cells, as evaluated by ERG and immunofluorescence staining. Additionally, compared with controls, the therapy with MSC-BDNF was associated with the induction of molecular changes related to anti-apoptotic signaling. In conclusion, BDNF overexpression observed in retinas after MSC-BDNF treatment could enhance the neuroprotective properties of transplanted autologous MSCs alone in the chronically degenerated retina. This research provides evidence for the long-term efficacy of genetically-modified MSC and may represent a strategy for treating various forms of degenerative retinopathies in the future.

Correlation between Flicker-Induced Retinal Vessel Vasodilatation and Plasma Biomarkers of Endothelial Dysfunction in Hypertensive Patients.

PURPOSE: Hypertension (HT) strongly affects the vascular endothelium, resulting in chronic inflammatory disease. Dynamic vessel analysis (DVA) is a modern methodological approach to analyze vascular function in the retinal microcirculation. The aim of this study was to examine whether a defective retinal vessels response is associated with HT-induced endothelial dysfunction. MATERIALS AND METHODS: Retinal vessel reactions to flicker stimulation were examined by DVA in both eyes of 37 hypertensive and 41 healthy control subjects. Plasma concentrations of C-reactive protein (CRP), interleukin-6, and tumor necrosis factor alpha (TNFɑ) were measured using the enzyme-linked immunosorbent assay. RESULTS: Both arterial and vein responses to flicker stimulation were significantly decreased in patients with HT compared with the healthy controls (dilatation of the arteries was lower in the HT group by, on average, 1.31, p = 0.001 and dilatation of the veins was lower in the HT group by, on average, 1.32, p = 0.002) after independent adjustment for age, sex, body mass index, and pressure values. In the hypertensive group, there was a negative correlation between the arterial response to flicker stimulation and the plasma CRP concentration (Spearman's Rank-order Coefficient (Rs) = -0.29, p = 0.07). Similarly, the plasma TNFα concentrations negatively correlated with the arterial response to flicker stimulation (Rs = -0.39, p = 0.02). CONCLUSIONS: Our results indicate that DVA directly reflects the actual metabolic status of the retinal endothelium. DVA might be used as an early noninvasive screening tool to detect vascular dysregulation and pan-endothelial dysfunction in patients with HT.

Effect of carotid endarterectomy on retinal function in asymptomatic patients with hemodynamically significant carotid artery stenosis.

INTRODUCTION    The corrective effect of carotid endarterectomy (CEA) on impaired ophthalmic artery flow in patients with significant internal carotid artery (ICA) stenosis presenting with ocular ischemic syndrome (ie, symptomatic patients) is well established. However, there is no clear evidence regarding the efficacy of CEA for improvement of neuroretinal function in patients without symptoms of ocular ischemic syndrome. OBJECTIVES    We aimed to determine the effects of CEA on retinal function in asymptomatic patients with hemodynamically significant ICA stenosis. PATIENTS AND METHODS    We enrolled 46 patients with ICA stenosis referred for CEA. Full-field electroretinogram (ERG), pattern ERG, and pattern visual evoked potentials, as well as optical coherence tomography and ophthalmologic examination of both eyes were performed 1 day before and 3 months after CEA. We analyzed eyes ipsilateral (EIE) and contralateral (ECE) to CEA. RESULTS    We observed an increase in several ERG wave parameters in both eye groups, compared with baseline values: rod b-wave amplitudes (P <0.00001 for EIE and P = 0.0001 for ECE); rod-cone a-wave (P = 0.02 for EIE) and b-wave (P = 0.001 for EIE and P = 0.01 for ECE) amplitudes; cone single flash a-wave (P = 0.05 for EIE and P = 0.004 for ECE) and b-wave (P <0.0001 for EIE and P <0.0001 for ECE) amplitudes; cone 30-Hz flicker amplitudes (P = 0.0003 for EIE and P <0.0001 for ECE); and oscillatory potential wave index amplitudes (P <0.00001 for EIE). CONCLUSIONS    The amplitudes of the standard full-field ERG were significantly increased following CEA in EIE and, to a lesser extent, in ECE. Multimodality ERG may represent a unique tool for investigating the effects of carotid revascularization on neuroretinal function in asymptomatic patients with ICA stenosis.

Association between Asymptomatic Unilateral Internal Carotid Artery Stenosis and Electrophysiological Function of the Retina and Optic Nerve.

Purpose. This study was designed to assess retinal and optic nerve bioelectrical function in patients with unilateral asymptomatic but hemodynamically significant internal carotid artery stenosis (ICAS). Methods. Forty-two subjects with a diagnosis of unilateral ICAS and 34 controls were analyzed. Full-field electroretinogram (ERG), pattern electroretinogram (PERG), and pattern visual-evoked potentials, as well as optical coherence tomography and ophthalmological examination, were performed. Data analysis included eyes ipsilateral to ICAS (EIS) and eyes contralateral to ICAS (ECS). Results. Intraocular pressure was significantly decreased in EIS and ECS compared to that in the controls. In the macula, both the cube average thickness and cube volume values were significantly reduced both in EIS and ECS compared to those in the controls. Similarly, PERG P50 and N95 wave amplitudes were significantly smaller in EIS and ECS compared to those in the controls. The ERG rod b-wave and rod-cone a-wave amplitudes were decreased, and implicit times were significantly prolonged, whereas the OP wave index was reduced in EIS compared to that in the controls. No differences in IOP, OCT, or ERG and PERG parameters were identified between EIS and ECS. Conclusions. Our study demonstrated that retinal bioelectrical function is negatively affected by ICAS despite the absence of objective clinical signs and symptoms of ocular ischemia.

The Impact of Growth Hormone Therapy on the Apoptosis Assessment in CD34+ Hematopoietic Cells from Children with Growth Hormone Deficiency.

Growth hormone (GH) modulates hematopoietic cell homeostasis and is associated with apoptosis control, but with limited mechanistic insights. Aim of the study was to determine whether GH therapeutic supplementation (GH-TS) could affect apoptosis of CD34+ cells enriched in hematopoietic progenitor cells of GH deficient (GHD) children. CD34+ cells from peripheral blood of 40 GHD children were collected before and in 3rd and 6th month of GH-TS and compared to 60 controls adjusted for bone age, sex, and pubertal development. Next, apoptosis assessment via different molecular techniques was performed. Finally, to comprehensively characterize apoptosis process, global gene expression profile was determined using genome-wide RNA microarray technology. Results showed that GH-TS significantly reduced spontaneous apoptosis in CD34+ cells (p < 0.01) and results obtained using different methods to detect early and late apoptosis in analyzed cells population were consistent. GH-TS was also associated with significant downregulation of several members of TNF-alpha superfamily and other genes associated with apoptosis and stress response. Moreover, the significant overexpression of cyto-protective and cell cycle-associated genes was detected. These findings suggest that recombinant human GH has a direct anti-apoptotic activity in hematopoietic CD34+ cells derived from GHD subjects in course of GH-TS.

Alteration of Selected Neurotrophic Factors and their Receptor Expression in Mouse Brain Response to Whole-Brain Irradiation.

Ionizing radiation can significantly affect brain function in children and young adults, particularly in the hippocampus where neurogenic niches are located. Injury to normal tissue is a major concern when whole-brain irradiation (WBI) is used to treat central nervous system (CNS) tumors, and the pathogenesis of this injury remains poorly understood. We assessed the expression of selected neurotrophins (NTs) and NT receptors (NTRs) in brains of young mice after a single 10 Gy gamma-ray exposure using morphological and molecular analyses [qRT-PCR, Western blot, immunohistochemistry (IHC)] to evaluate WBI-induced injury in its acute phase. Activity of the NT-NTR axes was examined by analysis of ERK and Akt phosphorylation. Using Nissl staining of hippocampus slices to visualize morphological changes, and TUNEL assay and active caspase-3 detection to assess apoptotic cell death, we found evidence of apoptosis and degenerative changes in hippocampal tissue after WBI. Shortly after WBI, we also observed significant overexpression of several NTs (BDNF, NT-3, NGF and GDNF) and NTRs (TrkA, TrkB, TrkC, GFRα-1, and p75NTR) compared to control animals. The upregulated NT and NTR proteins, in part, originated from two analyzed neurogenic areas: the subgranular zone of the hippocampal dentate gyrus and the subventricular zone, as confirmed by IHC. Finally, components of intracellular signaling pathways, including Akt and MAPK, were activated in acute phase after WBI. Given the role of NTs in diverse biological mechanisms, including maintenance and growth of neurons in the adult brain, our findings of altered expression of neurotrophins and their receptors in brain tissue shortly after irradiation suggest that these molecules play a vital role in the pathophysiology of the acute phase of WBI-induced injury.

Clinical Evaluation of the Safety and Feasibility of Whole Autologous Cord Blood Transplant as a Source of Stem and Progenitor Cells for Extremely Premature Neonates: Preliminary Report.

OBJECTIVES: This is a preliminary, single-center, prospective study in the field of autologous cord blood transplant. We investigated the feasibility, safety, and tolerability of autologous whole cord blood transplant in extremely premature infants as a potential therapeutic modality to prevent developing complications related to prematurity. MATERIALS AND METHODS: This preliminary prospective study (ClinicalTrials.gov identifier NCT02050971) included preterm infants born at less than 32 weeks of gestational age who developed anemia because of prematurity. Infants were assigned to 2 groups: (1) those receiving an autologous cord blood transfusion within 5 days postpartum (n = 5) and (2) those who obtained only an allogeneic red blood cell transfusion when necessary (n = 9; control group). Vital measurements were performed during and after transfusion, and peripheral blood pH, hematocrit, glucose, and calcium and potassium ion levels were measured over the next 4 days. RESULTS: Oxygen saturation was significantly increased throughout the cord blood transfusion and in the subsequent 48 hours. No significant differences were found in vital measurements, such as arterial blood pressure (mean, systolic, and diastolic) or heart rate over the first 48 hours posttransfusion. Similarly, no significant differences were found in biochemical analyses of blood with the exception of pH level. We found initial pH level to be significantly augmented in the cord blood recipient group by the first day after transplant, which remained significantly higher for next 24 hours compared with that shown in the control group. CONCLUSIONS: Collection, preparation, and short-term storage of unfrozen cord blood are feasible for clinical use. Our results showed general safety and tolerability of the procedure of whole autologous cord blood transplant in recruited preterm newborns. However, because our study group was small, these results need to be confirmed in further investigations with a larger patient cohort.

Endogenous regeneration of damaged retinal pigment epithelium following low dose sodium iodate administration: an insight into the role of glial cells in retinal repair.

The retinal pigment epithelium (RPE) has been reported to demonstrate feasible self-regenerative potential under specific conditions. However, the precise underlying mechanisms involved in this process are still elusive. Here, we performed a sequential morphological, molecular, and functional analysis of retinal injury and subsequent tissue regeneration after intravenous administration of a low dose of sodium iodate (15 mg/kg) in mice over long-term observation, up to 3 months post-injury. To assess the kinetics of the injury/recovery process, the electroretinography (ERG) responses were correlated with ongoing alterations in retinal structure and the global gene expression profile of injured retinas using genome-wide RNA microarray technology, western blotting and immunohistochemical analyses. We observed considerable improvement in the rod cell-mediated ERG response, which was accompanied by the regeneration of RPE within the injury site by the 3rd month post-injury. Our results confirm that the repairing mechanisms within injured retinas involve a significant glial cell reaction marked by glial cell proliferation, migration from their original location toward the injury site, followed by a significant overproduction of NTs such as BDNF, GDNF and NT-3. The global gene expression analysis revealed that initially up-regulated genes associated with cell death, apoptosis, acute response to stress pathways underwent considerable down-regulation in the late post-injury period. Accordingly, the genes implicated in nervous tissue remodeling and neuron development, the regulation of synaptic transmission and the establishment of localization were substantially induced by the 3rd month. Collectively, our observations support the view that Müller glial cells might well play an active role not only in retinal cell reorganization following injury but potentially also in RPE regeneration, which appears to be the key event in retinal reparative process. Furthermore, we provided novel compelling evidence of the crucial role of neurotrophins in the pathophysiology of retinal repair and identified the signaling pathways that are activated during this process.

Clinical relevance of thyroid dysfunction in human haematopoiesis: biochemical and molecular studies.

OBJECTIVE: Abnormalities in haematological parameters have been noted in patients with thyroid diseases. Nevertheless, the exact mechanism of thyroid hormones' (THs) action on human haematopoiesis is still not entirely clear. DESIGN: The influence of THs through TH receptors (TRalpha-1 and TRbeta-1) on haematopoiesis in patients with hypo- and hyperthyroidism was analysed. METHODS: TR gene expression at the mRNA and protein levels in human CD34(+)-enriched haematopoietic progenitor cells (HPCs) obtained from the peripheral blood of patients with thyroid disorders and healthy volunteers was analysed. The cell populations were also investigated for clonogenic growth of granulocyte macrophage-colony forming units and erythrocyte-burst forming units (BFU-E). The level of apoptosis was determined by annexin V/propidium iodide staining and quantitative RT-PCR. RESULTS: The studies revealed that hypo- and hyperthyroidism modify TR gene expression in HPCs in vivo. TH deficiency resulted in a decrease in total blood counts and clonogenic potential of BFU-E. In contrast, hyperthyroid patients presented increased clonogenic growth and BFU-E number and significantly higher expressions of cell cycle-regulating genes such as those for PCNA and cyclin D1. Finally, an increase in the frequency of apoptotic CD34(+)-enriched HPCs in hypo- and hyperthyroidism with a modulation of apoptosis-related genes was detected. CONCLUSIONS: The following conclusions were derived: i) TR expression in human haematopoietic cells depends on TH status, ii) both hypo- and hyperthyroidism significantly influence clonogenicity and induce apoptosis in CD34(+)-enriched HPCs and iii) the molecular mechanism by which THs influence haematopoiesis might provide a basis for designing novel therapeutic interventions in thyroid diseases.