Dehydroepiandrosterone (DHEA) is a steroidal hormone that is increasingly used as a dietary supplement, particularly among young men. Despite its widespread use, information regarding its potential adverse effects on vital organs remains limited. Therefore, the present study aimed to investigate the chronic effects of high‑dose DHEA supplementation on the liver, kidneys, heart, and muscle tissues in young male rats and to evaluate the potential protective role of vitamin E (Vit E) against DHEA‑induced tissue damage. Male Sprague Dawley rats were divided into three groups: Control, DHEA‑treated, and DHEA + Vit E‑treated groups. Following chronic administration of DHEA, tissue samples from the liver, kidneys, heart, and skeletal muscle were collected. Histological, ultrastructural, and biochemical analyses were performed to evaluate possible tissue injury and to assess the potential protective effects of Vit E supplementation. DHEA administration resulted in significant histopathological, ultrastructural, and biochemical alterations, indicating tissue injury. In contrast, rats receiving both DHEA and Vit E demonstrated significantly reduced levels of damage compared with the DHEA only group. The findings revealed that prolonged high‑dose DHEA supplementation caused notable injury in the liver and kidneys, whereas no significant damage was observed in muscle tissues. Chronic high‑dose DHEA supplementation may induce detrimental effects, particularly in the liver and kidneys, in young male rats. However, Vit E supplementation may partially mitigate these adverse effects, suggesting a potential protective role against DHEA‑induced organ toxicity.

Perfusion fixation is widely used in neuroscience to prepare mammalian brain tissue for histological and ultrastructural analysis. Perfusion protocols are commonly assessed using macroscopic indicators such as gross appearance and neuroimaging, which assess the extent to which perfusate has been distributed throughout the brain. There is a critical need to determine to what extent these metrics can accurately predict high-quality ultrastructural preservation, particularly as new perfusion protocols are developed for connectomics. In this technical report, we describe evidence that these two measures can be decoupled by the addition of dehydrating agents to the perfusate solution. In three human brain donors and one canine brain donor perfused with a fixative solution containing 10% mannitol and 10% polyethylene glycol 35 kDa, macroscopic and radiological indicators of perfusion quality appeared adequate or favorable. However, electron microscopy revealed expanded extracellular space, shrunken cellular processes, and distorted cell membranes, consistent with an osmotic shock artifact resulting from severe hyperosmotic dehydration. Similar ultrastructural artifacts were observed in a canine brain donor perfused with 20% mannitol in 20% neutral buffered formalin without PEG. We compare these ultrastructural findings with findings from previously reported cases perfused with standard neutral buffered formalin without osmotic additives. These findings illustrate a risk of optimizing brain perfusion protocols designed to preserve neural circuitry based on macroscopic or radiological perfusion quality metrics alone, since these metrics can be satisfied while the ultrastructure is severely compromised.

Langerhans cell sarcoma (LCS) and Langerhans cell histiocytosis (LCH) are proliferative conditions involving cells that exhibit Langerhans cell features. While LCH can have a variable behavior ranging from benign hyperplasia to a fatal multisystemic disease, LCS represents a rare, aggressive, high-grade malignancy. Central Nervous System (CNS) involvement is rare, and extra-axial lesions can frequently mimic meningiomas or carcinomatous infiltrates, posing a significant diagnostic challenge. We report the case of a 31-year-old male who presented with severe holocranial headache, projectile vomiting, and focal neurological deficits. Brain magnetic resonance imaging revealed a right supratentorial extra-axial mass, initially misdiagnosed as a meningioma. Histopathological examination demonstrated a proliferation of cells with high mitotic activity and conspicuous atypia. Immunohistochemistry showed positivity for S100, CD68, CD1a, and Langerin. Crucially, ultrastructural analysis by electron microscopy revealed the pathognomonic presence of Birbeck granules, confirming the diagnosis of LCS. This case highlights an exceptional presentation of CNS LCS mimicking a meningioma radiologically. It underscores the absolute necessity of integrating clinical, immunohistochemical, and ultrastructural findings to accurately differentiate high-grade histiocytic proliferations from other dural-based non-meningothelial lesions.

Inflammatory cardiomyopathy (ICM), resulting from persistent myocardial inflammation, is associated with life-threatening ventricular arrhythmias (VA). Recent studies suggested overlap between ICM-associated VA and desmosomal diseases affecting the intercalated discs (ID), which are critical for electromechanical coupling. Genetic variants in desmosomal genes cause arrhythmogenic cardiomyopathies and genodermatoses, supporting a potential link between desmosomal dysfunction and arrhythmic risk. This single-center pilot study explored cutaneous abnormalities in patients with ICM complicated by VA, focusing on desmosomal alterations in skin tissue. Four patients (mean age 56 ± 6 years, 50% male) with cardiac magnetic resonance- and endomyocardial biopsy-proven ICM, documented VA, and available myocardial and cutaneous tissue were retrospectively evaluated. Two patients carried genetic variants (DSP and FLNC), while two had systemic autoimmune diseases. Transmission electron microscopy revealed consistent ultrastructural abnormalities in cardiac biopsies, including widened intercellular cleft width (ICW), a marker associated with arrhythmic risk. Similar abnormalities were observed in cutaneous biopsies, including small, narrow, or clustered desmosomes and dermal-epidermal junction detachments. Patients with greater cutaneous desmosomal coupling variability exhibited more complex VA, lower left ventricular ejection fraction, and a genetic etiology. These findings suggest that cutaneous desmosomal abnormalities may mirror cardiac changes and represent a potential biomarker for arrhythmic risk stratification.

Busulfan (BUS), a chemotherapeutic agent used to treat chronic myeloid leukemia, is associated with hepatotoxicity and nephrotoxicity. This study used transmission electron microscope (TEM) to characterize BUS-induced ultrastructural alterations in the liver and kidney of rats, and to evaluate the protective effects of quercetin (QCT), bradykinin potentiating peptide (BPP) and their combination. To our knowledge, these ultrastructural changes have not been previously reported. Rats received two BUS doses (10 mg/kg b.w.) at a 21-day interval. BUS caused marked hepatic alterations, including mitochondrial swelling with loss of cristae, rough endoplasmic reticulum (RER) dilatation, sinusoidal endothelial cell damage and increased collagen synthesis. Renal changes included thrombotic microangiopathy affecting the glomerular capillary, thickened glomerular basement membranes, reactive changes of podocyte and parietal epithelial cells, mesangial cell proliferation, Bowman's space dilatation, and increased periglomerular collagen deposition. Concomitant treatment with QCT markedly reduced most hepatic alterations, whereas the BUS+BPP group exhibited comparatively limited protection. The combined QCT+BPP treatment produced the greatest hepatic protection. In the kidney, co-treatment with QCT partially ameliorated BUS-induced damage, while BUS+BPP and BUS+QCT+BPP restored ultrastructural features to near normal. In conclusions, these findings demonstrate that BUS induces marked ultrastructural injury in the liver and kidney, QCT, BPP, particularly in combination, provide substantial protection against these alterations.

The cerebellum is particularly vulnerable to intoxication and poisoning due to its complex structure. Sodium Nitrite is commonly used as a food additive, as well as in fertilizers and rodenticides. Quercetin, a widely distributed flavonoid in nature, has been investigated for its potential protective effects. This research aimed to evaluate the histological and biochemical changes in the cerebellar cortex of adult male albino rats resulting from Sodium Nitrite exposure, and to assess the protective role of Quercetin and the reversibility of these changes after stopping Sodium Nitrite. Fifty-four healthy adult male albino rats were divided into four groups: I) Control group, II) Sodium Nitrite treated group, III) Sodium Nitrite and Quercetin treated group, and IV) Withdrawal group. Tissue sections from the cerebellar cortex were stained with H&E and examined microscopically and ultrastructurally. Expression levels of GFAP and Caspase 3 in the cerebellar tissue were assessed immunohistochemically, while MDA and SOD levels were measured. The results showed that Sodium Nitrite significantly disrupted cerebellar tissue structure, leading to increased expression of GFAP and Caspase 3. Quercetin supplementation alleviated apoptosis in the cerebellar tissue and reduced the expression of both GFAP and Caspase 3. The withdrawal group exhibited only slight improvement. In conclusion, Quercetin supplementation effectively alleviated cerebellar neurotoxicity induced by Sodium Nitrite while recovery after discontinuation of Sodium Nitrite was limited.

Silicosis and thoracic sarcoidosis are both diffuse interstitial lung diseases, one occupational and the other idiopathic. The clinical and pathological findings of these two conditions show strong similarities, which can make diagnosis difficult. The main objective of this study is to present the mineralogical analysis techniques that can be performed on lung samples to provide new insights for distinguishing silicosis from thoracic sarcoidosis. A systematic review of the literature was conducted using the PubMed and Web of Science databases. A systematic review of the literature was conducted using the PubMed and Web of Science databases. Twenty-six articles published between 1975 and 2024 were included in the final analysis. The review identified seven mineralogical analysis techniques. Scanning and transmission electron microscopy are the oldest techniques, applicable to lung samples following digestion or in situ preparation. Methods for automating these techniques are emerging. X-ray diffraction and ICP-AES are techniques usable only on samples following digestion preparation and provide quantitative information only in terms of atomic compounds. Micro-PIXE and LIBS are more sophisticated techniques enabling the visualization of the distribution of atoms (silicon, aluminum, etc.) within tissues. Mineralogical analysis techniques, particularly electron microscopy coupled with elemental analysis and LIBS, represent valuable adjuncts in pulmonary pathology for identifying inorganic particles and supporting the differential diagnosis between pneumoconiosis and sarcoidosis in diagnostically challenging cases.

Diabetic retinopathy (DR) is a main cause of visual impairment globally. DR is mostly considered neurovascular degeneration. Gabapentin exerts antioxidant and anti-inflammatory effects. This study aimed to explore gabapentin's neuroprotective potential against DR. Forty-five adult male rats were divided into 3 groups; Control group I. Diabetic group II received an intraperitoneal dose of streptozotocin (STZ) (50 mg/kg) to induce diabetes. Blood glucose was assessed 48 h following STZ. Rats with blood glucose ≥ 250 mg/dl were considered diabetic. Gabapentin-treated diabetic group III in which the diabetic rats received gabapentin (300 mg/kg/12 h) by gastric tube. After 8 weeks, retinal samples were prepared for histological, immunohistochemical and ultrastructural studies. Diabetic group II revealed diminished cells of outer and inner nuclear layers, reduction in retinal thickness and ganglion cell number; and elevation of caspase-3 and Glial fibrillary acidic protein (GFAP) immune-expression and number of blood vessels expressing vascular endothelial growth factor. Disorganized discs of photoreceptors and neurons with shrunken nuclei were found. Gabapentin-treated diabetic group III showed preserved histology and ultrastructure and reduction in caspase-3 and GFAP immune-expression and number of blood vessels. In conclusion, gabapentin has neuroprotective potential against DR and might represent a valuable therapeutic tool in the future.

We report two cases of SMARCA4-deficient LCNEC (SD-LCNEC) presenting as cutaneous masses: an asymptomatic 3 cm right flank subcutaneous nodule in a 59-year-old male with concurrent pulmonary mass and metastases to cervical lymph node, and a painful 5 × 10 cm ulcerated left perineal mass in a 56-year-old female with hidradenitis suppurativa and concurrent pulmonary small cell carcinoma. To date, SD-LCNEC has been described almost exclusively as a thoracic malignancy. While various SMARCA4-deficient undifferentiated neoplasms (SD-UMN) have been identified in the skin, none have been definitively characterized as neuroendocrine. In both cases, neuroendocrine marker expression was markedly reduced on immunohistochemistry, precluding IHC-based classification as LCNEC. Electron microscopy performed on formalin-fixed paraffin-embedded tissue demonstrated abundant membrane-bound dense-core neurosecretory granules and well-formed desmosomes in both cases, ultrastructurally confirming the diagnosis. To our knowledge, these are the first reported cases of cutaneous SD-LCNEC confirmed by electron microscopy.

This study aimed to evaluate two intermittent fasting (IF) protocols (8:16 and 5:2) on sperm parameters and testicular microarchitecture in rats fed a high-fructose (HF) diet. Forty 12-week-old male Wistar albino rats were divided into four groups: Control, HF(20% fructose), (8:16)+HF (16-h daily fast), and (5:2)+HF(two fasting days/week). Following the 8-week treatment, biochemical, histological, and ultrastructural (TEM) analyses were performed.HF-diet led to significant weight gain and hyperglycemia. Both IF protocols effectively reduced body weight, while 8:16 IF significantly lowered glucose levels (p < .05). The control group showed significantly higher sperm counts and motility compared to the HF and 5:2 IF groups (p < .001). The 5:2 IF group showed the most severe degeneration, with significantly reduced Johnsen scores compared to both control and HF groups(p = .001).Histopathologically, the HF group exhibited deformed seminiferous tubules and basement membrane disorganization. Ultrastructural findings confirmed mitochondrial cristae loss, cytoplasmic vacuolization, and increased apoptosis in both IF groups, with the 5:2 protocol showing more pronounced heterochromatic nuclei and lipid droplet accumulation. While IF - particularly the 8:16 - effectively manages metabolic parameters like weight and glucose under HF diet conditions, it may exacerbate testicular damage and impair spermatogenesis. Specifically, the 5:2 IF protocol appears to have a more detrimental effect on sperm quality and testicular ultrastructure.

The future of organ-based therapies in monoclonal light chain-associated renal diseases is centered on the utilization of techniques that can identify specific targets to inhibit initiation and/or control progression. The present study of renal biopsies of patients with light chain deposition disease in different stages of glomerular involvement using spatial transcriptomics revealed unique gene expressions and activation of cellular pathways in mesangial cells responsible for the initiation and progression of the disease processes that can be targeted pharmacologically. Among the over-expressed genes were RPL41, RPS26, ACTA2-actin protein, TNC, and TGF (transforming growth factor) β1. The RPS and RPL genes regulate ribosomal function, their increase resulting in accentuated production of proteins. TGF-β drives matrix formation by mesangial cells, TNC is the gene responsible for the tenascin-rich mesangial nodules, and ACTA2 is an actin protein gene in myofibroblastic cells (phenotypically transformed mesangial cells), resulting in increased and cytoplasmic relocalization of actin in mesangial cells, leading to surface ruffling to promote interactions of monoclonal light chains with the SORL1 receptor. The pathways activated included the eukaryotic translation initiator, the extracellular matrix/proteoglycans and organization, and the TGF-β1 signaling, all aimed at increasing the extracellular matrix in the mesangium, responsible for its nodularity. The genes and cellular pathways differed in the various stages of glomerular LCDD, emphasizing the need for designing personalized therapies based on the evaluation of renal biopsies. Additional laboratory testing using existing models of LCDDs should be utilized to prove the efficacy of the proposed targeted interventions.

Primary renal neuroendocrine tumors (PRNETs) are exceptionally rare neoplasms that account for less than 1% of genitourinary neuroendocrine neoplasms and pose considerable diagnostic difficulty because of their non-specific clinicoradiological presentations and diverse histomorphology, which frequently mimics conventional renal epithelial tumors. We describe two adult patients with well-differentiated PRNET managed by partial nephrectomy including a 41-year-old male with a complex bosniak category IV cystic renal lesion, and another 43-year-old female with a tumor arising from the isthmus of a horse-shoe kidney. Both tumors showed organoid, trabecular, nested, tubulocystic, and focal cribriform architecture with low mitotic activity. Case 1 additionally showed focal capsular and perineural invasion despite of low-grade morphology. Tumor cells were diffusely positive for synaptophysin, chromogranin, and CD99, and negative for PAX8, CK7, CK20, WT1, TTF1, and CDX2, with a Ki-67 index below 2% in both. Electron microscopy confirmed dense-core neurosecretory granules, and both patients remain disease-free on radioimaging based follow-up. These cases illustrate that PRNET should be considered whenever a renal mass, including a complex cystic lesion or arising in a congenital anomalous kidney, not confirming thetypical epithelial morphology, and a combined histomorphological, immunohistochemical, and ultrastructural approach with prolonged surveillance is essential for accurate diagnosis and management.

This study investigated the effects of N-acetyl-seryl-aspartyl-lysyl-proline (AC-SDKP) treatment on the NLRP3 inflammasome complex and blood-spinal cord barrier (BSCB) permeability in a rat model of spinal cord injury (SCI). Male Wistar rats were divided into control, sham, and experimental groups, with the experimental group further divided into saline-treated and AC-SDKP-treated subgroups. SCI was induced using extradural clip compression, and AC-SDKP was administered intraperitoneally for 7 days post-injury. Spinal cord tissue samples were evaluated using light and electron microscopy, immunohistochemistry, and qRT-PCR. Biochemical analyses of IL-1β and IL-18 levels in blood and tissue samples were performed. Results showed that AC-SDKP treatment reduced edema, hemorrhage, and cavitation, and supported histological recovery. Immunohistochemistry revealed increased NeuN expression and decreased MMP-9 levels in the treatment group, indicating neuroprotection and reduced inflammation. AC-SDKP treatment also preserved BSCB integrity by increasing occludin, claudin-5, and VE-cadherin expression. Molecular analyses showed that AC-SDKP suppressed NF-κB activity and NLRP3 inflammasome levels, leading to decreased caspase-1, IL-1β, and IL-18 levels in both blood and spinal cord tissue. These findings suggest that AC-SDKP exerts neuroprotective effects by regulating inflammation at the cellular level and preserving BSCB integrity, making it a promising therapeutic agent for reducing secondary tissue damage and supporting recovery following SCI.

This study aimed to determine whether intrathecal administration of an interleukin-6 (IL-6) neutralizing antibody could reduce ultrastructural neuronal and vascular damage in a rat model of permanent middle cerebral artery occlusion (MCAO). Forty male Wistar rats were randomly assigned to four groups: Control, Sham-operated, Occlusion (MCAO + saline), and Treatment (MCAO + anti-rat IL-6 antibody). One week later, ischemic core brain tissue was processed for transmission electron microscopy to evaluate neuronal, axonal, and microvascular integrity. The Occlusion group showed severe ischemic injury, including mitochondrial swelling with cristolysis, cytoplasmic vacuolization, axonal edema, endothelial swelling, and perivascular astrocyte edema. By contrast, the Treatment group demonstrated marked ultrastructural preservation. Endothelial swelling and perivascular edema were reduced, neuronal nuclei were more preserved, and myelin sheath separation in white matter fibers was less pronounced than in the Occlusion group. Direct intrathecal IL-6 blockade was associated with qualitative cellular-level neuroprotection after permanent focal cerebral ischemia. The treatment attenuated inflammatory vascular injury and white matter damage, supporting IL-6 as a potential therapeutic target for limiting secondary stroke injury.

Acute kidney injury (AKI) is primarily caused by renal ischemia/reperfusion (I/R) injury, which is clinically linked to significant morbidity and death in both developed and developing countries. Therefore, the aim of this work is to compare the possible ameliorative effect of dapagliflozin (DAPA) versus human umbilical cord mesenchymal stem cells derived microvesicles (HUC-MSC-MVs) through biochemical, light, and electron microscope studies. Fifty-six adult male albino rats were divided into four groups: control, I/R, I/R+DAPA, and I/R+MVs groups. Both serum and tissue samples were collected for biochemical analysis. Renal specimens were processed to evaluate the histological structure, collagen content, desmin, and β-catenin immune expression. Morphometric and statistical analyses were performed. I/R group revealed prominent histoarchitectural alterations and a significant rise in the serum urea, creatinine, oxidative stress markers, and inflammatory mediators. Alterations were partially attenuated by DAPA therapy, whereas HUC-MSC-MVs significantly improved all parameters. We concluded that MSC-MVs administration exert a more significant ameliorative effect comparing to DAPA therapy via attenuating the oxidative stress and inflammation in addition to, restoring angiogenesis and cell proliferation. However, these findings remain preclinical and further researches are acclaimed for dose optimization, safety evaluation, and clinical validation before application in human AKI.