HiSStology: high spectral and spatial resolution magnetic resonance imaging detection of vasculature validated by histology and micro-computed tomography

High spectral and spatial resolution (HiSS) data, acquired with echo-planar spectroscopic imaging (EPSI), can be used to acquire water spectra from each small image voxel. These images are sensitive to changes in local susceptibility caused by superparamagnetic iron oxide particles (SPIO); therefore, we hypothesized that images derived from HiSS data are very sensitive to tumor neovasculature following injection of SPIO. Accurate image registration was used to validate HiSS detection of neovasculature with histology and micro-computed tomographic (microCT) angiography. Athymic nude mice and Copenhagen rats were inoculated with Dunning AT6.1 prostate tumor cells in the right hind limb. The tumor region was imaged pre- and post-intravenous injection of SPIO. Three-dimensional assemblies of the CD31-stained histologic slices of the mouse legs and the microCT images of the rat vascular casts were registered with EPSI. The average distance between HiSS-predicted regions of high vascular density on magnetic resonance imaging and CD31-stained regions on histology was 200 μm. Similarly, vessels identified by HiSS in the rat images coincided with vasculature in the registered microCT image. The data demonstrate a strong correlation between tumor vasculature identified using HiSS and two gold standards: histology and microCT angiography.     

Relationship between the prostatic tissue components and natural history of benign prostatic hyperplasia

OBJECTIVE: Few reports have been published on the relationship between prostatic tissue components and the natural history of benign prostatic hyperplasia (BPH). The present study was undertaken to evaluate this relationship. STUDY DESIGN: Forty-nine patients with BPH who underwent suprapubic prostatectomy were studied. Six infant prostates and 10 non-BPH specimens were obtained from autopsy. Specimens were stained with antibodies to alpha-smooth muscle actin, and the mean ratio of the stroma was determined with computer image analysis. Stromal ratios were evaluated according to resected prostate weight and age. RESULTS: The stroma comprised 82.6 +/- 8.4% of the prostate area at 0-1 year of age and 43.7 +/- 5.1% at 15-28 years of age. In BPH, the stromal proportion increased to 55.9 +/- 10.2%, but decreased with increases in prostate weight and/or age. CONCLUSION: The stromal component increased in patients with BPH and decreased with increased prostate weight and/or age, comprising approximately 42-47% of the prostate area, as in the non-BPH prostate, indicating a balance in prostatic tissue components in both patients with BPH and the non-BPH prostate.     

Immunohistochemical comparative analysis of transforming growth factor alpha, epidermal growth factor, and epidermal growth factor receptor in normal, hyperplastic and neoplastic human prostates.

Immunoreaction to TGF-alpha was limited to the basal epithelial cells of focal areas in the normal prostates. In benign prostatic hyperplasia (BPH) the immunostained areas were more widespread and immunolabelling was observed in both basal and columnar (secretory) cells of the epithelium. Some cells in the connective tissue stroma were also stained. In prostatic adenocarcinoma, epithelial immunostaining was even more extensive and intense than in BPH, and some stromal cells were also stained. Epidermal growth factor (EGF) immunostaining was only present in some basal cells in normal prostates. In BPH, this immunoreaction was strong in the basal cells and even stronger in the secretory cells. In prostatic cancer, the intensity of epithelial cell immunoreactivity was intermediate between that of normal prostates and that of BPH specimens. EGF-receptor immunostaining was focal and located in the basal cells in normal prostates. In BPH, labelling was also localized in basal cells but extended to wider areas. Some stromal cells appeared weakly labelled. In the prostatic carcinoma, both basal and columnar cells appeared stained and the number of immunolabelled stromal cells was higher than in BPH. The results presented suggest that, in normal conditions, EGF and TGF-alpha act as autocrine growth factors for the basal cells of the prostatic epithelium. In BPH this action is maintained and, in addition, the columnar cells start to secrete both factors which are bound by the basal cell receptors, giving rise to a paracrine regulation which probably overstimulates basal cell proliferation. In prostatic carcinoma, besides these regulatory mechanisms, the acquisition of EGF-receptors by the secretory cells develops an autocrine regulation which might induce their proliferation.     

Retrograde perfusion and filling of mouse coronary vasculature as preparation for micro computed tomography imaging

Visualization of the vasculature is becoming increasingly important for understanding many different disease states. While several techniques exist for imaging vasculature, few are able to visualize the vascular network as a whole while extending to a resolution that includes the smaller vessels. Additionally, many vascular casting techniques destroy the surrounding tissue, preventing further analysis of the sample. One method which circumvents these issues is micro-Computed Tomography (μCT). μCT imaging can scan at resolutions <10 microns, is capable of producing 3D reconstructions of the vascular network, and leaves the tissue intact for subsequent analysis (e.g., histology and morphometry). However, imaging vessels by ex vivo μCT methods requires that the vessels be filled with a radiopaque compound. As such, the accurate representation of vasculature produced by μCT imaging is contingent upon reliable and complete filling of the vessels. In this protocol, we describe a technique for filling mouse coronary vessels in preparation for μCT imaging. Two predominate techniques exist for filling the coronary vasculature: in vivo via cannulation and retrograde perfusion of the aorta (or a branch off the aortic arch), or ex vivo via a Langendorff perfusion system. Here we describe an in vivo aortic cannulation method which has been specifically designed to ensure filling of all vessels. We use a low viscosity radiopaque compound called Microfil which can perfuse through the smallest vessels to fill all the capillaries, as well as both the arterial and venous sides of the vascular network. Vessels are perfused with buffer using a pressurized perfusion system, and then filled with Microfil. To ensure that Microfil fills the small higher resistance vessels, we ligate the large branches emanating from the aorta, which diverts the Microfil into the coronaries. Once filling is complete, to prevent the elastic nature of cardiac tissue from squeezing Microfil out of some vessels, we ligate accessible major vascular exit points immediately after filling. Therefore, our technique is optimized for complete filling and maximum retention of the filling agent, enabling visualization of the complete coronary vascular network--arteries, capillaries, and veins alike.     

Three-dimensional characterization of the vascular bed in bone metastasis of the rat by microcomputed tomography (MicroCT)

Background

Angiogenesis contributes to proliferation and metastatic dissemination of cancer cells. Anatomy of blood vessels in tumors has been characterized with 2D techniques (histology or angiography). They are not fully representative of the trajectories of vessels throughout the tissues and are not adapted to analyze changes occurring inside the bone marrow cavities.

Methodology/Principal Findings

We have characterized the vasculature of bone metastases in 3D at different times of evolution of the disease. Metastases were induced in the femur of Wistar rats by a local injection of Walker 256/B cells. Microfil®, (a silicone-based polymer) was injected at euthanasia in the aorta 12, 19 and 26 days after injection of tumor cells. Undecalcified bones (containing the radio opaque vascular casts) were analyzed by microCT, and a first 3D model was reconstructed. Bones were then decalcified and reanalyzed by microCT; a second model (comprising only the vessels) was obtained and overimposed on the former, thus providing a clear visualization of vessel trajectories in the invaded metaphysic allowing quantitative evaluation of the vascular volume and vessel diameter. Histological analysis of the marrow was possible on the decalcified specimens. Walker 256/B cells induced a marked osteolysis with cortical perforations. The metaphysis of invaded bones became progressively hypervascular. New vessels replaced the major central medullar artery coming from the diaphyseal shaft. They sprouted from the periosteum and extended into the metastatic area. The newly formed vessels were irregular in diameter, tortuous with a disorganized architecture. A quantitative analysis of vascular volume indicated that neoangiogenesis increased with the development of the tumor with the appearance of vessels with a larger diameter.

Conclusion

This new method evidenced the tumor angiogenesis in 3D at different development times of the metastasis growth. Bone and the vascular bed can be identified by a double reconstruction and allowed a quantitative evaluation of angiogenesis upon time.     

Quantitative Ex-Vivo Micro-Computed Tomographic Imaging of Blood Vessels and Necrotic Regions within Tumors

Techniques for visualizing and quantifying the microvasculature of tumors are essential not only for studying angiogenic processes but also for monitoring the effects of anti-angiogenic treatments. Given the relatively limited information that can be gleaned from conventional 2-D histological analyses, there has been considerable interest in methods that enable the 3-D assessment of the vasculature. To this end, we employed a polymerizing intravascular contrast medium (Microfil) and micro-computed tomography (micro-CT) in combination with a maximal spheres direct 3-D analysis method to visualize and quantify ex-vivo vessel structural features, and to define regions of hypoperfusion within tumors that would be indicative of necrosis. Employing these techniques we quantified the effects of a vascular disrupting agent on the tumor vasculature. The methods described herein for quantifying whole tumor vascularity represent a significant advance in the 3-D study of tumor angiogenesis and evaluation of novel therapeutics, and will also find potential application in other fields where quantification of blood vessel structure and necrosis are important outcome parameters.     

Polyamines and prostatic cancer

The importance of polyamines in prostatic growth and differentiation has prompted studies to evaluate the clinical relevance of the ornithine decarboxylase/polyamine system in prostatic cancer. These studies show that differences in biological behaviour of prostatic (cancer) cells are associated with changes in polyamine levels and/or the activity of their metabolic enzymes. Faulty antizyme regulation of polyamine homoeostasis may play an important role in the growth and progression of prostatic carcinoma. Treatment of human prostate carcinoma cells with inhibitors of polyamine metabolic enzymes or polyamine analogues induces cell growth arrest or (apoptotic) cell death. Our recent in vitro studies using conformationally restricted polyamine analogues show that these compounds inhibit cell growth, probably by inducing antizyme-mediated degradation of ornithine decarboxylase. Sensitivity of human prostate cancer cells for these compounds was increased in the absence of androgens. These results suggest that these analogues might have chemotherapeutic potential in case prostatic cancer has become androgen-independent. Pilot data in an in vivo model show that these analogues have effects on tumour cell proliferation, vascularity, blood perfusion and tissue hypoxia. Overall, these studies show that polyamines may serve as important biomarkers of prostatic malignancy and provide a promising target for chemotherapy of prostatic cancer.     

Human prostatic aldehyde dehydrogenase of healthy controls and diseased prostates.

Aldehyde dehydrogenase (ALDH, EC 1.2.1.3) of the human prostate was the subject of investigation in this study. The possible physiological role of aldehyde dehydrogenase in the human prostate might be to detoxify aldehydes arising from the oxidation of the polyamines via monoamine or diamine oxidases. The specific activity of the enzyme with 1 mM propionaldehyde as substrate and 0.5 mM NAD at pH 7.4 in the control normal prostates and prostates afflicted with the disease, benign prostatic hyperplasia (BPH), was 26.06 +/- 2.96 and 5.17 +/- 0.48 nmol/g prostate per min, respectively. When 100 microM gamma-aminobutyraldehyde was used as a substrate, the specific activity in the normal controls and prostates with benign prostatic hyperplasia was 19.80 +/- 1.33 and 2.95 +/- 2.46 nmol/g prostate per min, respectively. Upon isoelectric focusing of the extracts of the control prostates when the gels were developed for aldehyde dehydrogenase activity, there were three aldehyde dehydrogenase activity bands visible, pI 4.9 (mitochondrial), 5.4 (cytosolic) and about 6.0-6.5, on the IEF gels developed with gamma-aminobutyraldehyde as a substrate. With the extracts of prostates with benign prostatic hyperplasia the pI 4.9 band was significantly reduced, the pI 5.4 band enhanced and the approx. pI 6.0 band was not detectable on the IEF gels with propionaldehyde as a substrate. There was no detectable aldehyde dehydrogenase activity in the extract of the prostate with cancer on IEF gels nor in the activity assays with propionaldehyde or gamma-aminobutyraldehyde as substrates.     

fucosyltransferase1 and H-type complex carbohydrates modulate epithelial cell proliferation during prostatic branching morphogenesis

The prostate undergoes branching morphogenesis dependent on paracrine interactions between the prostatic epithelium and the urogenital mesenchyme. To identify cell-surface molecules that function in this process, monoclonal antibodies raised against epithelial cell-surface antigens were screened for antigen expression in the developing prostate and for their ability to alter development of prostates grown in serum-free organ culture. One antibody defined a unique expression pattern in the developing prostate and inhibited growth and ductal branching of cultured prostates by inhibiting epithelial cell proliferation. Expression cloning showed that this antibody binds fucosyltransferase1, an alpha-(1,2)-fucosyltransferase that synthesizes H-type structures on the complex carbohydrate modifications of some proteins and lipids. The lectin UEA I that binds H-type 2 carbohydrates also inhibited development of cultured prostates. These data demonstrate a previously unrecognized role for fucosyltransferase1 and H-type carbohydrates in controlling the spatial distribution of epithelial cell proliferation during prostatic branching morphogenesis. We also show that fucosyltransferase1 is expressed by epithelial cells derived from benign prostatic hyperplasia or prostate cancer; thus, fucosyltransferase1 may also contribute to pathological prostatic growth. These data further suggest that rare individuals who lack fucosyltransferase1 (Bombay phenotype) should be investigated for altered reproductive function and/or altered susceptibility to benign prostatic hyperplasia and prostate cancer.     

A lectin histochemistry comparative study in human normal prostate, benign prostatic hyperplasia, and prostatic carcinoma

The partial oligosaccharide sequences of glycoconjugates and the nature of their glycosidic linkages were investigated in normal human prostate, benign prostatic hyperplasia (BPH) and prostatic carcinoma by means of lectin histochemistry, using light microscopy and Western blot analysis. The labeling pattern of BPH differed from that of normal prostate in having more intense staining with DSA, HPA, UEA-I and AAA, and in showing lesser staining with WGA and SBA. Prostatic carcinoma differed from normal prostates in displaying the more intense labeling with PNA, DSA, SBA, DBA, UEA-I and AAA, and in having lesser labeling with WGA. The main differences in labeling pattern between prostatic carcinoma and BPH were that the latter specimens showed more marked staining with PNA, DSA, DBA, SBA, UEA-I and AAA, and lesser staining with WGA and HPA. The staining patterns of SNA, MAA, ConA, LCA and GNA were similar in all three groups of specimens. For most of the lectins studied, including those showing a similar immunohistochemical staining in the three groups of specimens studied, the Western blot analysis showed differences in the banding pattern among normal, hyperplastic, and carcinomatous prostates. Present results suggest that the glycosylation of proteins was modified in both BPH and prostatic carcinoma. In BPH a strong expression of N-acetylgalactosamine residues occurred, while in prostatic carcinoma an increase of sialic aci, galactose and fucose residues was observed. No changes in mannose residues were detected.     

Lack of an Additive Effect between the Deletions of Klf5 and Nkx3-1 in Mouse Prostatic Tumorigenesis

Prostate cancer is one of the most common malignancies.The development and progression of prostate cancer are driven by a series of genetic and epigenetic events including gene amplification that activates oncogenes and chromosomal deletion that inactivates tumor suppressor genes.Whereas gene amplification occurs in human prostate cancer,gene deletion is more common,and a large number of chromosomal regions have been identified to have frequent deletion in prostate cancer,suggesting that tumor suppressor inactivation is more common than oncogene activation in prostatic carcinogenesis (Knuutila et al.,1998,1999;Dong,2001).Among the most frequently deleted chromosomal regions in prostate cancer,target genes such as NKX3-1 from 8p21,PTENfrom 10q23 andATBF1 from 16q22 have been identified by different approaches (He et al.,1997;Li et al.,1997;Sun et al.,2005),and deletion of these genes in mouse prostates has been demonstrated to induce and/or promote prostatic carcinogenesis.For example,knockout of Nkx3-1 in mice induces hyperplasia and dysplasia (Bhatia-Gaur et al.,1999;Abdulkadir et al.,2002) and promotes prostatic tumorigenesis (Abate-Shen et al.,2003),while knockout of Pten alone causes prostatic neoplasia (Wang et al.,2003).Therefore,gene deletion plays a causal role in prostatic carcinogenesis (Dong,2001).     

Optimization of microCT imaging and blood vessel diameter quantitation of preclinical specimen vasculature with radiopaque polymer injection medium

Vascular networks within a living organism are complex, multi-dimensional, and challenging to image capture. Radio-angiographic studies in live animals require a high level of infrastructure and technical investment in order to administer costly perfusion mediums whose signals metabolize and degrade relatively rapidly, diminishing within a few hours or days. Additionally, live animal specimens must not be subject to long duration scans, which can cause high levels of radiation exposure to the specimen, limiting the quality of images that can be captured. Lastly, despite technological advances in live-animal specimen imaging, it is quite difficult to minimize or prevent movement of a live animal, which can cause motion artifacts in the final data output. It is demonstrated here that through the use of postmortem perfusion protocols of radiopaque silicone polymer mediums and ex-vivo organ harvest, it is possible to acquire a high level of vascular signal in preclinical specimens through the use of micro-computed tomographic (microCT) imaging. Additionally, utilizing high-order rendering algorithms, it is possible to further derive vessel morphometrics for qualitative and quantitative analysis.     

A chemical proteomics approach for the identification of accessible antigens expressed in human kidney cancer

A promising avenue toward the development of more selective anticancer drugs consists in the targeted delivery of bioactive molecules to the tumor environment by means of binding molecules specific to tumor-associated markers. We have used a chemical proteomics approach based on the ex vivo perfusion and biotinylation of accessible structures within surgically resected human kidneys with tumor to gain information about accessible and abundant antigens that are overexpressed in human cancer. This procedure led to the selective labeling with biotin of vascular structures. Biotinylated proteins were purified on streptavidin resin and identified using mass spectrometric methodologies, revealing 637 proteins, 184 of which were only found in tumor specimens and 223 of which were only found in portions of normal kidneys. Immunohistochemical and PCR analysis confirmed that several of the putative cancer antigens identified in this study are indeed preferentially expressed in tumors. In conclusion, we have developed a methodology that allows the identification of accessible biomarkers in human tissues. The tumor-associated antigens identified in this study may be suitable targets for antibody-based anticancer therapies. The experimental approach described here should be applicable to other surgical specimens and to other pathologies as well as to the study of basic physiological and immunological processes.     

Correlation of estrogen and androgen receptor status in prostatic disease measured by high pressure liquid chromatography

To further characterize human prostatic estrogen receptors (ER) determined by high pressure liquid chromatography (HPLC), we checked our procedure by which we nullify estrogen binders (including testosterone binding globulin, TeBG) other than ER by preincubation of cytosols with dihydrotestosterone (DHT). We also showed that the ER exhibited ligand specificity and that ER is present in BPH nuclear extract at 10-fold its concentration in the corresponding cytosols. Of seven prostates with localized cancer determined preoperatively, only 3 showed localization; ER concentration in the cancer parts was lower than in the corresponding surrounding BPH. A total of 22 specimens were evaluated for ER and androgen receptors (AR). Statistically, AR had higher values than ER but there was no correlation between the corresponding AR and ER for each tissue.     

Binding characteristics of naftopidil and alpha 1-adrenoceptor antagonists to prostatic alpha-adrenoceptors in benign prostatic hypertrophy.

Binding properties of naftopidil and alpha 1-adrenoceptor antagonists to alpha-adrenoceptors in prostates from benign prostatic hypertrophy (BPH) were characterized by radioreceptor assays using [3H]prazosin and [3H]rauwolscine. Specific binding of [3H]prazosin and [3H]rauwolscine in human prostatic membranes was saturable and of high affinity, and it showed a pharmacological specificity which characterized alpha 1 and alpha 2-adrenoceptors, respectively. Naftopidil and several alpha 1 antagonists competed for prostatic [3H]prazosin binding in order: R-(-)-YM-12617 greater than prazosin greater than bunazosin greater than terazosin greater than naftopidil greater than urapidil, and the inhibitory effect (Ki = 11.6 nM) of naftopidil was 10 to 45 times less potent than quinazoline derivatives such as prazosin, bunazosin and terazosin. The potencies of these antagonists in competing for [3H]prazosin binding sites in human prostates correlated well with their pharmacological potencies (pA2). Scatchard analysis indicated that the decrease of prostatic [3H]prazosin binding by naftopidil was due to a marked increase in the Kd value without a change in the Bmax value. The inhibition of prostatic [3H]prazosin binding by naftopidil was reversible. Naftopidil also inhibited prostatic [3H]rauwolscine binding (Ki = 70.0 nM). Thus, it is suggested that naftopidil antagonizes alpha 1-adrenoceptors in human prostates in a competitive and reversible manner.     

Immunoexpressions of p21, Rb, mcl-1 and bad gene products in normal, hyperplastic and carcinomatous human prostates

A comparative study of the expression of p21, Rb, mcl-1, and bad gene products, which are involved in the control of the cell cycle, was performed in normal, hyperplastic, and carcinomatous human prostates by means of a semiquantitative immunochemical study. This included Western blot, ELISA, and immunohistochemistry procedures. In normal prostates, immunoexpression of the four gene products was scanty or absent. In men with benign prostatic hyperplasia, immunoreactions to the four proteins studied were found in many epithelial cells and some stromal cells. In prostatic carcinoma, the immunostaining pattern was as in hyperplastic prostates but the numbers of both epithelial and stromal cells were higher. Present results indicate that immunoexpression of p21, Rb (both the phosphorylated and dephosphorylated forms), mcl-1, and bad gene products are markedly increased in prostates with proliferative alterations but that these proteins do not discriminate between benignant (hyperplasia) and malignant (adenocarcinoma) prostatic tumours, although immunoexpression is higher in prostatic carcinoma.     

Morphological and histological study of castration-induced degeneration and androgen-induced regeneration in the mouse prostate

Degenerative and regenerative changes in the ductal architecture of the ventral and dorsolateral prostates (VP and DLP) of the adult mouse were investigated in microdissected specimens over a time-course of 14 days following castration and subsequently during 14 days of administration of testosterone propionate. After castration, about 35% of the ductal tips and branch-points were lost in distal regions (usually near the capsule) in both prostatic lobes. By contrast, in more proximal regions of the prostate (closer to the urethra), the ducts survived in an atrophic condition. The ductal morphology that had been lost in the distal regions completely regenerated after testosterone propionate was administered to the castrated males. In the VP, androgen replacement simply returned the gland to its former size with moderate ductal distension; in the DLP, excessive epithelial infoldings and ductal distension were elicited in the distal regions of the ducts after 14 days of treatment with testosterone propionate. These results suggest that androgenic responsiveness and dependency are different in distal versus proximal ducts. Distal ducts are exquisitely androgen-dependent and androgen-sensitive; in proximal regions, androgen-dependency is not as strict.     

Establishment and characterization of monoclonal antibody against androgen receptor

Hybrid cell lines were prepared by the fusion of BALB/c myeloma NS-1 cells with the lymphocytes of BALB/c mice that were immunized with partially purified androgen receptor (AR) from human prostates. Nine clones of the hybrid progeny were determined for the production of antibodies against AR by immunoprecipitation assay. One of the clones, referred to as "5F4", was chosen for analysis of the detailed specificity. The clone "5F4" secreted IgM class antibodies against AR. Competition study demonstrated that "5F4" antibody inhibited androgen binding of AR, suggesting that the antibody identifies androgen binding site of AR. Immunoblotting analysis showed that the antibody identified the ARs as two proteins, 95 kD and 41 kD proteins, on a sodium dodecyl sulfate polyacrylamide gel. It is suspected that a 95 kD protein should be a monomeric AR and a 41 kD protein is a proteolytic fragment of AR. Immunohistochemical analysis demonstrated that androgen-dependent tissues--human prostatic hypertrophy tissues, an AR abundant prostatic cancer tissue and fibroblast cells from human genital skin--were stained intensely with "5F4" monoclonal antibody, while androgen-independent tissues--fibroblast cells from lymph nodes, an AR deficient prostatic cancer tissue and human prostatic cancer cell line, PC-3--showed no staining. These results also support the specificity of the antibody for AR.     

Pigment epithelium-derived factor regulates the vasculature and mass of the prostate and pancreas

Angiogenesis sustains tumor growth and metastasis, and recent studies indicate that the vascular endothelium regulates tissue mass. In the prostate, androgens drive angiogenic inducers to stimulate growth, whereas androgen withdrawal leads to decreased vascular endothelial growth factor, vascular regression and epithelial cell apoptosis. Here, we identify the angiogenesis inhibitor pigment epithelium-derived factor (PEDF) as a key inhibitor of stromal vasculature and epithelial tissue growth in mouse prostate and pancreas. In PEDF-deficient mice, stromal vessels were increased and associated with epithelial cell hyperplasia. Androgens inhibited prostatic PEDF expression in cultured cells. In vivo, androgen ablation increased PEDF in normal rat prostates and in human cancer biopsies. Exogenous PEDF induced tumor epithelial apoptosis in vitro and limited in vivo tumor xenograft growth, triggering endothelial apoptosis. Thus, PEDF regulates normal pancreas and prostate mass. Its androgen sensitivity makes PEDF a likely contributor to the anticancer effects of androgen ablation.     

Age-Related Changes of the Concentrations of Select Elements in the Prostates of Japanese

To elucidate compositional changes of the prostate with aging, the authors investigated age-related changes of elements in the prostates and the relationships among their elements using Japanese and Thai. After ordinary dissections by students at Nara Medical University and Chiang Mai University were finished, the prostates were resected from the subjects. Fifty-seven Japanese subjects ranged in age from 65 to 101 years (average age = 82.5 ± 7.8 years), whereas 13 Thai subjects ranged in age from 43 to 86 years (average age = 67.9 ± 11.9 years). After ashing with nitric acid and perchloric acid, element contents were determined by inductively coupled plasma–atomic emission spectrometry. It was found that although there were no significant correlations between age and seven element contents, such as Ca, P, S, Mg, Zn, Fe, and Na, in the prostates of Japanese, high contents of Ca (>5 mg/g) and P (>4 mg/g) were contained in one fourth of the prostates of Japanese over 70 years of age. In the prostates of Thai, a significant direct correlation was found between age and Ca content, but it was not found between age and the other element contents, such as P, S, Mg, Zn, Fe, and Na. Regarding the relationships among their elements, extremely significant direct correlations were found among the contents of Ca, P, Mg, Zn, and Na in the prostates of Japanese. In the prostates of Thai, significant direct correlations were found among the contents of Ca, Mg, and Zn, but no significant correlations were found between Ca and P contents and between P and Mg contents. Regarding the relationships among their elements, there were differences between the prostates of Japanese and Thai. To examine whether element contents changed in prostatic hypertrophy, the transverse width of the Japanese prostates was measured. No significant correlations were found between the transverse width and element contents, such as Ca, P, S, Mg, Zn, Fe, and Na, in the Japanese prostates. Therefore, it is unlikely that the increase of elements results in prostatic hypertrophy.