Robust Immunohistochemical Staining of Several Classes of Proteins in Tissues Subjected to Autolysis

Detection and Estimation of Age of Injuries in Fresh Bodies Using Immunohistochemistry

ABSTRACT

A cross-sectional study of the wound age estimation from the forensic skin wound samples was performed immunohistochemically with a sample size of 40 (n = 40). The samples were segregated according to the appropriate stages of wound healing with the help of hematoxylin-eosin staining. Later, they were subjected to immunohistochemistry staining with anti-AQP3 antibody. Quantification of the expression of AQP3 in the injured and uninjured formalin-fixed skin tissues was done semiquantitatively and manually under 400× magnifications. The AQP3-positive cells were correlated with the duration of injury, and the results were statistically analyzed. More AQP3 expressions were found in the proliferative phase than the inflammatory and maturation phase of wound healing. Neither the diversity in age group nor the sex differentiation showed any specific correlation with the expression of keratinocytic aquaporin cells. Likewise, parameters such as the type of injury, mode of injury, and the postmortem interval also did not show any significant relationship with the expression of the aquaporin positivity. Thus, it is revealed that skin wounds between 5 and 10 days expressed aquaporin cell numbers of more than 300. Hence AQP3 estimation helps in determining the time since injury with a more accuracy.

Histological examination of renal nerve distribution, density, and function in humans

BACKGROUND

Renal denervation is optimised when guided by knowledge of nerve distribution.

AIMS

We aimed to assess sympathetic nerve distribution along the renal arteries, especially in post-bifurcation vessel segments.

METHODS

Renal arteries and surrounding tissue from 10 body donors were collected and examined histologically. Immunohistochemical staining was used to analyse nerve distribution and to identify afferent and efferent sympathetic nerves.

RESULTS

A total of 6,781 nerves surrounding 18 renal arteries were evaluated. The mean lumen-nerve distance of the left renal artery (2.32±1.95 mm) was slightly greater than the right (2.29±2.03 mm; p=0.161); this varied across the arteries' courses: 3.7±2.3 mm in proximal segments, 2.5±2.0 mm in middle segments, 1.9±1.6 mm in distal prebifurcation segments and 1.3±1.0 mm in post-bifurcation segments (p<0.001). The number of nerves per quadrant was highest in the proximal segments (13.7±18.6), followed by the middle (9.7±7.9), distal prebifurcation (8.0±7.6), and distal post-bifurcation (4.3±4.0) segments (p<0.001). Circumferentially, the number of nerves was highest in the superior (7.8±9.4) and the ventral (7.6±13.1) quadrants (p=0.638). The mean tyrosine hydroxylase (TH) to calcitonin gene-related peptide (CGRP) ratio increased from proximal (37.5±33.5) to distal (72.0±7.2 in the post-bifurcation segments; p<0.001). Thirty-eight neuroganglia were identified along 14 (78%) renal arteries.

CONCLUSIONS

Nerves converge to the renal arteries' lumen in the distal segments and along branches, resulting in the lowest number of nerves per quadrant and the shortest lumen-nerve distance in the distal post-bifurcation segments. Efferent nerves occur predominantly, and the ratio of efferent to afferent nerves continues to increase in the vessels' course.

Myocarditis in the forensic setting - a review of the literature

Diagnosis of myocarditis as the cause of death at post-mortem is currently determined by a forensic pathologist. There is no systematic method for diagnosis and thus the determination is subject to inter-observer variability and is non-reproducible. Postmortem studies often rely on the clinical method of diagnosis, which is inaccurate. Furthermore, there is no current standardized method of distinguishing between myocarditis as cause of death, and myocardial inflammation as an incidental finding post-mortem. Only a few studies have investigated a method of quantifying this difference using variables such as number of inflammatory cells and presence of myocyte necrosis, however, there are several limitations hindering the reproducibility of this research. This review investigates the current practices and limitations associated with the diagnosis of myocarditis as cause of death in the autopsy setting.

Components separation technique of the abdominal wall: Which muscle release produces the greatest reduction in tension on the mideline?

BACKGROUND

The components separation technique (CS) is used for the reconstruction of complex abdominal wall defects. Release and undermining of the rectus abdominis muscle (RAM) and external oblique muscle (EOM) decrease tension on the abdominal midline, reducing recurrence of ventral hernia, but causes major changes in the physiology of abdominal wall. The purpose of the study was to determine which muscle release and undermining produces the lowest tension on the midline.

METHODS

Twenty fresh cadavers were dissected and the anterior and posterior layers of the rectus sheath were isolated in the midline. The forces necessary to advance the layers of the rectus sheath to the mid abdomen were measured bilaterally at two points located 3 cm above and 2 cm below the umbilicus, and at 3 different stages: before any muscle release; after release and undermining of the right RAM and left EOM; and after release and undermining of the left RAM and right EOM. Comparisons of tensile forces were conducted separately for the different muscles involved, layers of the rectus sheath, measurement points, and stages of separation.

RESULTS

Tension on the abdominal midline after the release and undermining of both the RAM and EOM was reduced by 56% (p <0.05), 42% after the release and undermining of the EOM alone (p <0.05), and 35% after release and undermining of the RAM alone (p <0.05).

CONCLUSION

Release and undermining of the EOM by CS led to lower tension on the abdominal midline compared to that associated with the release of the RAM alone.

A Proteomic Atlas of Cardiac Amyloid Plaques

Background

In vivo mechanisms of amyloid clearance and cardiac tissue damage in cardiac amyloidosis are not well understood.

Objectives

We aimed to define and quantify the amyloid plaque proteome in cardiac transthyretin amyloidosis (ATTR) and light chain amyloidosis (AL) and identify associations with patient characteristics and outcomes.

Methods

A proteomics approach was used to identify all proteins in cardiac amyloid plaques, and to compare both normal and diseased controls. All proteins identified within amyloid plaques were defined as the expanded proteome; only proteins that were enriched in comparison to normal and disease controls were defined as the amyloid-specific proteome.

Results

Proteomic data from 292 patients with ATTR and 139 patients with AL cardiac amyloidosis were included; 160 and 161 unique proteins were identified in the expanded proteomes, respectively. In the amyloid-specific proteomes, we identified 28 proteins in ATTR, 19 in AL amyloidosis, with 13 proteins overlapping between ATTR and AL. ATTR was characterized by a higher abundance of complement and contractile proteins and AL by a higher abundance of keratins. We found that the proteome of kappa AL had higher levels of clusterin, a protective chaperone, and lower levels of light chains than lambda despite higher levels of circulating light chains. Hierarchical clustering identified a group of patients with worse survival in ATTR, characterized by high levels of PIK3C3, a protein with a central role in autophagy.

Conclusions

Cardiac AL and ATTR have both common and distinct pathogenetic mechanisms of tissue damage. Our findings suggest that autophagy represents a pathway that may be impaired in ATTR and should be further studied.

Hypercalcemia of Malignancy in a Dog Diagnosed With Cholangiocellular Carcinoma

A 4-year-old, neutered male Golden Retriever was presented with a 1-week history of weight loss, polyuria, and polydipsia. The diagnostic workup showed an increased ionized calcium concentration, mild increase in serum creatinine and urea concentration, and severe hyperlipasemia. A complete abdominal ultrasound revealed multiple hepatic nodules. A cytological diagnosis of malignant epithelial neoplasia, highly suggestive of bile duct adenocarcinoma was made. In order to confirm the presumptive diagnosis of hypercalcemia of malignancy due to the presence of a hepatic neoplasia, serum parathormone-related peptide concentration was measured, and the result revealed an increased concentration. The dog was hospitalized and received supportive treatments consisting of intravenous furosemide and fluid therapy. After ruling out lymphoma and hypoadrenocorticism, oral prednisone was initiated and ionized calcium concentration decreased gradually down to normal concentration after 7 days of hospitalization. Chemotherapy with intravenous epirubicin was initiated based on the cytological diagnosis. One month after diagnosis and due to the worsening of its clinical condition, the dog was humanely euthanized. Postmortem examination confirmed a cholangiocellular carcinoma. To our knowledge, this is the first report of malignant hypercalcemia associated with cholangiocellular carcinoma in a dog.

Usability of Immunohistochemistry in Forensic Samples With Varying Decomposition

Immunohistochemistry (IHC) is an important diagnostic tool in anatomic and surgical pathology but is used less frequently in forensic pathology. Degradation of tissue because of postmortem decomposition is believed to be a major limiting factor, although it is unclear what impact such degradation actually has on IHC staining validity. This study included 120 forensic autopsy samples of liver, lung, and brain tissues obtained for diagnostic purposes. The time from death to autopsy ranged between 1 and more than 14 days. Samples were prepared using the tissue microarray technique. The antibodies chosen for the study included KL1 (for staining bile duct epithelium), S100 (for staining glial cells and myelin), vimentin (for endothelial cells in cerebral blood vessels), and CD45 (for pulmonary lymphocytes). Slides were evaluated by light microscopy. Immunohistochemistry reactions were scored according to a system based on the extent and intensity of the positive stain. An overall correlation between the postmortem interval and the IHC score for all tissue samples was found. Samples from decedents with a postmortem interval of 1 to 3 days showed positive staining with all antibodies, whereas samples from decedents with a longer postmortem interval showed decreased staining rates. Our results suggest that IHC analysis can be successfully used for postmortem diagnosis in a range of autopsy samples showing lesser degrees of decomposition.

Sudden unexpected death from an undiagnosed histiocytic sarcoma in an adolescent female

A previously well 15-year-old female who was awaiting medical investigations for a proptosed right eye collapsed and died suddenly while walking. Postmortem examination revealed diffuse distortion and infiltration of multiple organs by a suspected neoplastic process. Histology confirmed the invasion of multiple organs by atypical cells and myocardial infiltration was the likely cause of death. An extensive panel of immunohistochemistry established the diagnosis of a histiocytic sarcoma. Sudden unexpected death due to a clinically undiagnosed neoplasia in childhood and adolescence is uncommon. This is the first report of a histiocytic sarcoma causing sudden unexpected death and highlights the importance of considering undiagnosed hematological malignancies when examining a case of sudden death at postmortem.

Translational Research in Pediatrics IV: Solid Tissue Collection and Processing

Solid tissues are critical for child-health research. Specimens are commonly obtained at the time of biopsy/surgery or postmortem. Research tissues can also be obtained at the time of organ retrieval for donation or from tissue that would otherwise have been discarded. Navigating the ethics of solid tissue collection from children is challenging, and optimal handling practices are imperative to maximize tissue quality. Fresh biopsy/surgical specimens can be affected by a variety of factors, including age, gender, BMI, relative humidity, freeze/thaw steps, and tissue fixation solutions. Postmortem tissues are also vulnerable to agonal factors, body storage temperature, and postmortem intervals. Nonoptimal tissue handling practices result in nucleotide degradation, decreased protein stability, artificial posttranslational protein modifications, and altered lipid concentrations. Tissue pH and tryptophan levels are 2 methods to judge the quality of solid tissue collected for research purposes; however, the RNA integrity number, together with analyses of housekeeping genes, is the new standard. A comprehensive clinical data set accompanying all tissue samples is imperative. In this review, we examined: the ethical standards relating to solid tissue procurement from children; potential sources of solid tissues; optimal practices for solid tissue processing, handling, and storage; and reliable markers of solid tissue quality.

Anatomic assessment of sympathetic peri-arterial renal nerves in man

BACKGROUND

Although renal sympathetic denervation therapy has shown promising results in patients with resistant hypertension, the human anatomy of peri-arterial renal nerves is poorly understood.

OBJECTIVES

The aim of our study was to investigate the anatomic distribution of peri-arterial sympathetic nerves around human renal arteries.

METHODS

Bilateral renal arteries were collected from human autopsy subjects, and peri-arterial renal nerve anatomy was examined by using morphometric software. The ratio of afferent to efferent nerve fibers was investigated by dual immunofluorescence staining using antibodies targeted for anti-tyrosine hydroxylase and anti-calcitonin gene-related peptide.

RESULTS

A total of 10,329 nerves were identified from 20 (12 hypertensive and 8 nonhypertensive) patients. The mean individual number of nerves in the proximal and middle segments was similar (39.6 ± 16.7 per section and 39.9 ± 1 3.9 per section), whereas the distal segment showed fewer nerves (33.6 ± 13.1 per section) (p = 0.01). Mean subject-specific nerve distance to arterial lumen was greatest in proximal segments (3.40 ± 0.78 mm), followed by middle segments (3.10 ± 0.69 mm), and least in distal segments (2.60 ± 0.77 mm) (p < 0.001). The mean number of nerves in the ventral region (11.0 ± 3.5 per section) was greater compared with the dorsal region (6.2 ± 3.0 per section) (p < 0.001). Efferent nerve fibers were predominant (tyrosine hydroxylase/calcitonin gene-related peptide ratio 25.1 ± 33.4; p < 0.0001). Nerve anatomy in hypertensive patients was not considerably different compared with nonhypertensive patients.

CONCLUSIONS

The density of peri-arterial renal sympathetic nerve fibers is lower in distal segments and dorsal locations. There is a clear predominance of efferent nerve fibers, with decreasing prevalence of afferent nerves from proximal to distal peri-arterial and renal parenchyma. Understanding these anatomic patterns is important for refinement of renal denervation procedures.

Postmortem cardiac tissue maintains gene expression profile even after late harvesting

Background

Gene expression studies can be used to help identify disease-associated genes by comparing the levels of expressed transcripts between cases and controls, and to identify functional genetic variants (expression quantitative loci or eQTLs) by comparing expression levels between individuals with different genotypes. While many of these studies are performed in blood or lymphoblastoid cell lines due to tissue accessibility, the relevance of expression differences in tissues that are not the primary site of disease is unclear. Further, many eQTLs are tissue specific. Thus, there is a clear and compelling need to conduct gene expression studies in tissues that are specifically relevant to the disease of interest. One major technical concern about using autopsy-derived tissue is how representative it is of physiologic conditions, given the effect of postmortem interval on tissue degradation.

Results

In this study, we monitored the gene expression of 13 tissue samples harvested from a rapid autopsy heart (non-failed heart) and 7 from a cardiac explant (failed heart) through 24 hours of autolysis. The 24 hour autopsy simulation was designed to reflect a typical autopsy scenario where a body may begin cooling to ambient temperature for ~12 hours, before transportation and storage in a refrigerated room in a morgue. In addition, we also simulated a scenario wherein the body was left at room temperature for up to 24 hours before being found. A small fraction (< 2.5%) of genes showed fluctuations in expression over the 24 hr period and largely belong to immune and signal response and energy metabolism-related processes. Global expression analysis suggests that RNA expression is reproducible over 24 hours of autolysis with 95% genes showing < 1.2 fold change. Comparing the rapid autopsy to the failed heart identified 480 differentially expressed genes, including several types of collagens, lumican (LUM), natriuretic peptide A (NPPA) and connective tissue growth factor (CTGF), which allows for the clear separation between failing and non-failing heart based on gene expression profiles.

Conclusions

Our results demonstrate that RNA from autopsy-derived tissue, even up to 24 hours of autolysis, can be used to identify biologically relevant expression pattern differences, thus serving as a practical source for gene expression experiments.

Apical CD36 immunolocalization in human and porcine taste buds from circumvallate and foliate papillae

CD36 is the receptor for long chain fatty acids (LCFA), and is expressed in lingual taste cells from rodents. In these animals, CD36 has been proposed to play an important role in oral detection of LCFA, and subsequently, determines their dietary fat preference. Humans also seem to detect LCFA in the oral cavity, however, information on the molecular mechanism of this human orosensory LCFA recognition is currently lacking. The aim of our study was to investigate whether CD36 is also expressed in lingual human and porcine taste buds cells. Using fluorescence immunohistochemistry, apical CD36 expression was revealed in human and porcine taste bud cells from circumvallate and foliate papillae. These data suggest CD36 as the putative orosensory receptor for dietary LCFA in human, and, therefore, may be involved in our preference for fatty foods.

Elastic fibers in the anterior abdominal wall

PURPOSE

The aim of this study was to substantiate the hypothesis as to whether an altered amount of elastic fibers in the linea alba aponeurosis occurs or not in anterior abdominal wall hernias (epigastric, incisional and umbilical), comparing the findings with those of a control group of cadavers without hernias.

METHODS

Thirty patients (15 males and 15 females) with anterior abdominal wall hernias were evaluated for analysis of the elastin content in samples from the linea alba aponeurosis, with immunohistochemistry and orcein staining using videomorphometry.

RESULTS

The results showed a greater amount of elastin in patients with abdominal wall hernias compared to the control group of cadavers without hernias (P < 0.05). The elastic fibers were greatly thickened, tortuous and fragmented in the patients.

CONCLUSION

It is essential to analyze the anterior abdominal wall concerning its anatomical condition and histological components. Altered collagen and elastic fibers play an important role in hernia formation, indicating that the main factor may be biological.

Use of Tissue Cross-reactivity Studies in the Development of Antibody-based Biopharmaceuticals

Tissue cross-reactivity (TCR) studies are screening assays recommended for antibody and antibody-like molecules that contain a complementarity-determining region (CDR), primarily to identify off-target binding and, secondarily, to identify sites of on-target binding that were not previously identified. At the present time, TCR studies involve the ex vivo immunohistochemical (IHC) staining of a panel of frozen tissues from humans and animals, are conducted prior to dosing humans, and results are filed with the initial IND/CTA to support first-in-human clinical trials. In some cases, a robust TCR assay cannot be developed, and in these cases the lack of a TCR assay should not prevent a program from moving forward. The TCR assay by itself has variable correlation with toxicity or efficacy. Therefore, any findings of interest should be further evaluated and interpreted in the context of the overall pharmacology and safety assessment data package. TCR studies are generally not recommended for surrogate molecules or for comparability assessments in the context of manufacturing/cell line changes. Overall, the design, implementation, and interpretation of TCR studies should follow a case-by-case approach.

Glomerular protein levels of matrix metalloproteinase-1 and tissue inhibitor of metalloproteinase-1 are lower in diabetic subjects

Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) regulate extracellular matrix turnover throughout the body, including in renal glomeruli. We investigated protein levels of multiple MMPs (MMP-1, MMP-2, MMP-3, and MMP-9) and TIMP-1 in glomeruli and investigated whether disease phenotypes were associated with levels of these proteins. Renal cortex was collected from 100 adult autopsy subjects arrayed across 17 tissue microarrays. Immunohistochemical staining intensity for each MMP and TIMP-1 was determined using quantitative color deconvolution techniques. We observed significantly decreased glomerular MMP-1 and TIMP-1 staining in subjects with diabetes, hypertension, and an estimated glomerular filtration rate <30 ml/min/1.73 m(2) in univariate analyses. MMP-1 staining, but not TIMP-1 staining, was inversely correlated with increased glomerular fibrosis (r = -0.40). In multivariable analysis, diabetes was robustly associated with decreased staining intensity. This study indicates that in human subjects, the long-term sequelae of diseases such as diabetes that cause chronic renal failure result in decreased TIMP-1 and MMP-1 proteins in renal glomeruli. This manuscript contains online supplemental material at http://www.jhc.org. Please visit this article online to view these materials.

Use of human vascular tissue microarrays for measurement of advanced glycation endproducts

Advanced glycation endproducts (AGEs) are present in the vasculature and are associated with vascular disease. We determined levels of AGEs in eight distinct adult vascular tissues using tissue microarray (TMA) technology and associated these levels with clinical characteristics. Medium-to-large caliber blood vessels were harvested from 100 adult autopsies to create 17 TMAs. AGE levels were evaluated by IHC using a polyclonal anti-AGE antibody on over 700 unique blood vessels. Slides were digitally scanned, and quantitative analysis was performed using a color deconvolution image analysis technique. Medial AGE staining was strongly correlated between all eight blood vessels. In the media, AGE staining levels were significantly higher at older ages (p=0.009), in white subjects (p<0.001) and with longer postmortem interval (PMI; p<0.0001). These associations remained significant after simultaneous adjustment for age, race/ethnicity, PMI, and diabetes status. Diabetes was associated with elevated AGE levels but only after adjustment for confounding by clinical variables including race/ethnicity, hypertension, and kidney function. This extensive vascular study shows that AGE accumulation in the macrovasculature is a global process affecting atherosclerosis-prone and -resistant vessels. It also suggests ethnicity has a previously undescribed role in vascular tissue AGE levels. This manuscript contains online supplemental material at http://www.jhc.org. Please visit this article online to view these materials.

Creation, validation, and quantitative analysis of protein expression in vascular tissue microarrays

BACKGROUND

Tissue microarrays (TMAs) are collections of multiple tissue cores placed in parallel in a single acceptor block and traditionally used to investigate protein expression in neoplastic tissues. We validated the use of TMAs to investigate protein expression in vascular segments.

METHODS

Vascular tissues were collected from 100 adult subjects undergoing autopsy. A diverse set of vessels were harvested and arrayed over 17 TMAs. A total of 1377 unique tissues, each with a 1.5-mm feature size, were analyzed using histochemical and immunohistochemical (IHC) diaminobenzidine (DAB) methods.

RESULTS

Histomorphometric analysis of vascular disease demonstrated the TMA features captured the majority of the vascular alterations (intimal hyperplasia and atherosclerosis) seen in the original blood vessel section. Measurements of IHC staining intensity based on color deconvolution were used to quantify antigen abundance in defined regions of interest (ROI). Validation was performed using antibodies to connective tissue growth factor (CTGF), receptor for advanced glycation end products (AGER/RAGE), and matrix metalloproteinase 3 (MMP-3). IHC staining was highly correlated between duplicate features from the same vascular site over these three proteins.

CONCLUSION

This study validates the use of TMA technology to investigate the vascular wall utilizing staining intensity data.

Collagen in the transversalis fascia of patients with indirect inguinal hernia: a case-control study

BACKGROUND

The aim of this study was to analyze the constituents of total and types I and III collagen fibers in the transversalis fascias of patients with indirect inguinal hernias, compared with samples removed from nonherniated cadavers.

METHODS

Biopsy samples from 26 patients and 26 cadavers were analyzed. Hematoxylin-eosin and picrosirius staining techniques were used. The images obtained were analyzed using a video morphometric technique to determine the constituents of total collagen and types I and III collagen in the transversalis fascia. The picrosirius-stained tissues were submitted to observation under polarized-light microscopy.

RESULTS

The results showed 17.3% less total collagen in patients with hernias compared with the control group (P < .01). Type I collagen in patients with indirect inguinal hernias was 23.7% less than the control group (P < .01), type III collagen was 6.4% less in the controls (P < .01).

CONCLUSION

The lower percentages of total collagen and type I collagen in the transversalis fascias of patients with indirect inguinal hernias could be a factor in hernia formation.

Tissue inhibitor of matrix metalloproteinase-3 levels in the extracellular matrix of lung, kidney, and eye increase with age

Tissue inhibitor of matrix metalloproteinase-3 (TIMP-3) is an important regulator of matrix metalloproteinase activity in many types of disease, including atherosclerosis, neoplasia, and inflammatory conditions. Among TIMPs, TIMP-3 uniquely binds the extracellular matrix (ECM). We performed IHC staining on 17 tissue microarrays containing >1500 samples to determine the location of ECM TIMP-3 staining in a variety of predominantly vascular tissues. We found a unique pattern of TIMP-3 staining in the ECM of renal arterioles, small pulmonary vessels and parenchyma, and Bruch's membrane in the retina. There was no staining in larger caliber arteries including coronary and internal mammary arteries. TIMP-3 protein accumulation was found to be an age-dependent phenomenon, with staining appearing in all three tissues in early adulthood and becoming more robust among the elderly. These findings may help to explain the late onset of the TIMP-3-associated ocular diseases Sorsby fundus dystrophy and age-related macular degeneration and suggest a similar phenomenon could be at work in other age-related conditions.

Immunohistochemical markers for quantitative studies of neurons and glia in human neocortex

Reproducible visualization of neurons and glia in human brain is essential for quantitative studies of the cellular changes in neurological disease. However, immunohistochemistry in human brain specimens is often compromised because of prolonged fixation. To select cell lineage-specific antibodies for quantitative studies of neurons and the major types of glia, we used 29 different antibodies, different epitope retrieval methods, and different detection systems to stain tissue arrays of formalin-fixed human brain. The screening pointed at CD45/leukocyte common antigen (LCA), CD68(KP1), 2',3' cyclic nucleotide phosphatase (CNPase), glial fibrillary acidic protein (GFAP), HLA-DR, Ki67, neuronal nuclei (NeuN), p25alpha-antigen, and S100beta as candidates for future cell counting purposes, because these markers visualized specific neuronal and glial cell bodies. However, significant negative correlation between staining result and formalin fixation was observed by blinded scoring of staining for CD45/LCA, CNPase, GFAP, and NeuN in brain specimens fixed by immersion and stored up to 10 years in 4% formalin solution at room temperature, independent of donor sex and postmortem interval. In contrast, improved preservation of NeuN and CNPase staining, and full preservation of GFAP and CD45/LCA staining in tissue fixed by perfusion and stored for up to 3 years in 0.1% paraformaldehyde solution at 4C, indicated that immunohistochemistry can be performed in well-preserved biobank material.