Age-Related Changes of the Pineal Gland in Humans: A Digital Anatomo-Histological Morphometric Study on Autopsy Cases with Comparison to Predigital-Era Studies

Investigation of the Effects of Light, Darkness, and Dim Light on Rat Brain Tissue: A Biochemical and Histological Study

This study evaluates acetylcholinesterase (AChE) enzyme activity levels, oxidative stress parameters, histopathological findings, and serum melatonin levels in rat brain tissue. 32 male Wistar Albino rats were randomly divided into four groups: Control, Light, Dark, Dim light (n = 8 each group). After a 30 day experiment, brain tissues were collected to measure AChE, glutathione S-transferase (GST), glutathione (GSH), and malondialdehyde (MDA) levels and conduct histopathological analyses. Serum melatonin levels were also measured. In this study, we observed a significant increase in MDA levels in dim light, dark, and light groups. AChE and α-GST enzyme activity levels were significantly decreased in the dark group compared with the other groups. Additionally, there was a statistical difference in melatonin levels between the light and dark groups. In the light microscope examination of the sections stained with hematoxylin-eosin from the dark group brain tissue, mild perineuronal edema was observed in all areas. Our study is the first to compare the effects of three groups on the brain: continuous light, continuous darkness, and dim light at night. Additionally, it is the only study to examine the effects of light exposure differences on the brain AChE levels.

Morphology of the Human Pineal Gland Studied by Freeze-Fracturing in Scanning Electron Microscopy

The human pineal gland is the largest producer of the hormone melatonin. Pineal acervuli (brain sand), calcified concretions in the pineal gland, have long been studied because of their association with ageing, melatonin production, and neurological disorders. The solid inorganic matter of the hydroxyapatite crystals often renders sample sectioning impossible, to the extent that the sections lose value. Technically, freeze-fracturing has revealed the detailed structure and cell relationships without tissue damage. In our electron microscopic study, samples of the human pineal gland were obtained during autopsy from 20 donors with mean age 69 years. Samples underwent freeze-fracturing and standard histological procedures, and were analysed by scanning electron microscopy (SEM) in high vacuum. Based on our results, freeze-fracturing enabled identification of a mulberry-like acervulus topography. The acervuli were situated in specific "nest-like" structures, which were surrounded by pinealocytes, interstitial cells, and nerve fibres. A fractured surface of the intrapineal acervuli exhibited a regular lamellar structure. Freeze-fracturing the pineal gland and imaging by SEM enabled complex structural analysis. This approach permits viewing the surface acervuli spherical and internal lamellar architecture. Our results confirmed that the parenchyma of this small but important gland contains two types of acervuli, depending on their size: non-aggregated and aggregated. We propose to include these forms of acervuli in the new edition of the Terminologica Histologica. In conclusion, pineal gland freeze-fracturing by SEM is suitable for complex structural analysis. Our description of our methods can be a guide for other scientists who want to study the pineal gland with electron microscopy methods.

Impact of Modern Lifestyle on Circadian Health and Its Contribution to Adipogenesis and Cancer Risk

BACKGROUND

Recent research underscores a crucial connection between circadian rhythm disruption and cancer promotion, highlighting an urgent need for attention.

OBJECTIVES

Explore the molecular mechanisms by which modern lifestyle factors-such as artificial light exposure, shift work, and dietary patterns-affect cortisol/melatonin regulation and cancer risk.

METHODS

Employing a narrative review approach, we synthesized findings from Scopus, Google Scholar, and PubMed to analyze lifestyle impacts on circadian health, focusing on cortisol and melatonin chronobiology as molecular markers. We included studies that documented quantitative changes in these markers due to modern lifestyle habits, excluding those lacking quantitative data or presenting inconclusive results. Subsequent sections focused solely on articles that quantified the effects of circadian disruption on adipogenesis and tumor microenvironment modifications.

RESULTS

This review shows how modern habits lead to molecular changes in cortisol and melatonin, creating adipose microenvironments that support cancer development. These disruptions facilitate immune evasion, chemotherapy resistance, and tumor growth, highlighting the critical roles of cortisol dysregulation and melatonin imbalance.

CONCLUSIONS

Through the presented findings, we establish a causal link between circadian rhythm dysregulation and the promotion of certain cancer types. By elucidating this relationship, the study emphasizes the importance of addressing lifestyle factors that contribute to circadian misalignment, suggesting that targeted interventions could play a crucial role in mitigating cancer risk and improving overall health outcomes.

Pineal gland ADC values in children aged 0 to 4 years: normative data and usefulness in the differential diagnosis with trilateral retinoblastoma

PURPOSE

Normative ADC values of the pineal gland in young children are currently lacking, however, these are potentially useful in the differential diagnosis of pineal involvement in trilateral retinoblastoma, which is challenging when the size of the tumor is less than 10-15 mm. The main objective of this study was to establish ADC reference values of the normal pineal gland in a large cohort of children between 0 and 4 years.

METHODS

This retrospective study was conducted in a tertiary pediatric hospital. We collected 64 patients with normal MRI examination (between 2017 and 2024) and clinical indication unrelated to the pineal gland, and divided them into 5 age groups (0 to 4 years). Gland size and mean ADC values were calculated, using the ellipsoid formula and ROI/histogram analysis, respectively. The established values were tested in three cases of trilateral retinoblastoma (10 to 20 months).

RESULTS

Mean ADC values were always above 1000 × 10- 6 mm2/s, while in patients with trilateral retinoblastoma they were around 800 × 10- 6 mm2/s. Pineal ADC values were identical in both genders. The volume of the pineal gland showed a tendency to increase with age.

CONCLUSIONS

We present ADC reference data for the pineal gland in children under 4 years of age. The distribution of mean ADC values of trilateral retinoblastoma was significantly different from the normative values, hence, the use DWI/ADC may help to identify small trilateral retinoblastoma in children with ocular pathology.

The role of pineal gland volume in the development of scoliosis

PURPOSE

Adolescent idiopathic scoliosis (AIS) is believed to be caused by genetic, neurological, osseous growth anomalies, histological variables including muscle fiber percentage and core structure changes, metabolic and hormonal dysfunction, vestibular dysfunction, and platelet microarchitecture. The objective of this study was to contribute to the determination of the cause of AIS by analyzing the changes in pineal gland volume in AIS cases.

METHODS

Study (AIS) and control group were each comprised of 26 patients who met the inclusion requirements. Scoliosis radiograph and MRI of the pineal glands were used for radiological examinations. The distribution of age, gender, Risser grading for skeletal radiological development, and sexual maturation according to Tanner categorization were uniform and statistically insignificant between groups.

RESULTS

When the pineal gland volumes of the cases were evaluated according to age, the AIS group was found to have significantly reduced pineal gland volumes in all age groups. The pineal gland volume was found to be 38.1% lower in the AIS group compared to the control group (p˂0.001). In the AIS group, patients aged 13 years had the lowest pineal gland volume (77.2 ± 13.86 mm³), while patients aged 15 years had the highest volume (97.9 ± 16.47 mm³).

CONCLUSION

Changes in pineal gland volume support the role of the pineal gland in the etiopathogenesis of AIS.

Digital histological morphometry of the human pineal gland in a postmortem study, with endocrine and neurological clinical implications

The pineal gland is a small-sized, photo neuroendocrine organ in the midline of the brain that synthesises and secretes melatonin and serotonin. Chords and islands of pinealocytes constitute the secretory parenchyma, while glial tissue and calcifications represent degenerative changes. This study examined human postmortem pineal glands to microscopically assess morphological changes possibly associated with clinical data, by using digital techniques. A retrospective autopsy study has been performed on 72 paediatric and adult autopsy cases. The glands have been processed for histological analysis and immunohistochemical staining with synaptophysin (SYN), neuron-specific enolase (NSE), and neurofilament (NF). Slides were digitally scanned. Morphometric data were obtained using CaseViewer and ImageJ. The comorbidities used for correlation with morphometric data were obesity, type 2 diabetes, adrenal gland adenoma, goitre, chronic pancreatitis, arterial hypertension, and mixed dementia. Thirty-three females and 39 males were included in the study. Increased secretory parenchyma was found in patients with chronic pancreatitis, arterial hypertension, and adrenal gland adenoma. Reduced activity was found in patients with type 2 diabetes, obesity, advanced pineal calcification, mixed dementia, and old age. There were no changes associated with goitre, cachexia, or Willis's polygon atherosclerosis. No significant differences between gender were found. The activity of the pineal gland can be assessed by quantitative immunohistochemistry of neuroendocrine and structural pinealocyte markers and observation of glial tissue and calcifications. There is a need for further research to evaluate the clinical impact of these morphological changes on the neuroendocrine systems, with clinical implications in endocrinology, neurology, and even psychiatry. Digital techniques offer a more exact analysis of histological data.

Pineal morphology of the clinical high-risk state for psychosis and different psychotic disorders

BACKGROUND

Pineal volume reductions have been reported in schizophrenia and clinical high-risk states for the development of psychosis, supporting the role of melatonin dysregulation in the pathophysiology of psychosis. However, it remains unclear whether pineal volume is associated with the later onset of psychosis in individuals at clinical high-risk (CHR) of psychosis or if pineal atrophy is specific to schizophrenia among different psychotic disorders.

METHODS

This magnetic resonance imaging study examined the volume of and cyst prevalence in the pineal gland in 135 individuals at CHR of psychosis [52 (38.5%) subsequently developed psychosis], 162 with first-episode psychosis (FEP), 89 with chronic schizophrenia, and 87 healthy controls. The potential contribution of the pineal morphology to clinical characteristics was also examined in the CHR and FEP groups.

RESULTS

Pineal volumes did not differ significantly between the CHR, FEP, and chronic schizophrenia groups, but were significantly smaller than that in healthy controls. However, pineal volumes were not associated with the later onset of psychosis in the CHR group or FEP sub-diagnosis (i.e., schizophrenia, schizophreniform disorder, affective psychosis, and other psychoses). No significant differences were observed in the prevalence of pineal cysts between the groups, and it also did not correlate with clinical characteristics in the CHR and FEP groups.

CONCLUSION

These results suggest that pineal atrophy is a general vulnerability marker of psychosis, while pineal cysts do not appear to contribute to the pathophysiology of psychosis.

Techniques for digital histological morphometry of the pineal gland

INTRODUCTION

The pineal gland is a small photo-neuro-endocrine organ. This study used human post-mortem pineal glands to microscopically assess immunohistochemical marker intensity and percentage of positivity using known and novel digital techniques.

MATERIALS AND METHODS

An experimental non-inferiority study has been performed on 72 pineal glands harvested from post-mortem examinations. The glands have been stained with glial fibrillary acidic protein (GFAP), synaptophysin (SYN), neuron-specific enolase (NSE), and neurofilament (NF). Slides were digitally scanned. Morphometric data were obtained using optical analysis, CaseViewer, ImageJ, and MorphoRGB RESULTS: Strong and statistically significant correlations were found and plotted using Bland-Altman diagrams between the two image analysis software in the case of mean percentage and intensity of GFAP, NSE, NF, and SYN.

DISCUSSIONS

Software such as SlideViewer and ImageJ, with our novel software MorphoRGB were used to perform histological morphometry of the pineal gland. Digital morphometry of a small organ such as the pineal gland is easy to do by using whole slide imaging (WSI) and digital image analysis software, with potential use in clinical settings. MorphoRGB provides slightly more accurate data than ImageJ and is more user-friendly regarding measurements of parenchyma percentage stained by immunohistochemistry. The results show that MorphoRGB is not inferior in functionality.

CONCLUSIONS

The described morphometric techniques have potential value in current practice, experimental small animal models and human pineal glands, or other small endocrine organs that can be fully included in a whole slide image. The software we used has applications in quantifying immunohistochemical stains.

Short histological kaleidoscope - recent findings in histology. Part I

This article is a review of new advances in histology, concerning either classification or structure of different tissular elements (basement membrane, hemidesmosomes, urothelium, glandular epithelia, adipose tissue, astrocytes), and various organs' constituents (blood-brain barrier, human dental cementum, tubarial salivary glands, hepatic stellate cells, pineal gland, fibroblasts of renal interstitium, Leydig testicular cells, ovarian hilar cells), as well as novel biotechnological techniques (tissue engineering in angiogenesis), recently introduced.