Surrogate tissue analysis: monitoring toxicant exposure and health status of inaccessible tissues through the analysis of accessible tissues and cells

Genomics and proteomics have made it possible to define molecular physiology in exquisite detail, when tissues are accessible for sampling. However, many tissues are not accessible for human diagnostic evaluations or experimental studies, creating the need for surrogates that afford insight into exposures and effects in such tissues. Surrogate tissue analysis (STA) incorporating contemporary genomic and proteomic technologies may be useful in determining toxicant exposure and effect, or disease state, in target tissues at the pre- or early clinical stage. We present here a discussion of STA based on presentations given at the Society of Toxicology's 2003 annual meeting's "Innovations in Applied Toxicology" symposium. Speakers at the symposium (Box 1) discussed various potential applications of STA, including the use of peripheral blood lymphocytes (PBLs) as a source of genetic biomarkers to monitor radiation exposure; the use of gene expression analysis of PBLs and hair follicles as a means to monitor the impact of toxicants on inaccessible organs; the characterization of disease-associated gene signatures in peripheral blood mononuclear cells (PBMCs) of renal cell carcinoma (RCC) patients; the use of sperm RNA to determine genetic and environmental effects on sperm development in the testis; and the use of serum protein profiles to monitor the development and progression of various cancers. Also discussed are some of the challenges that must be overcome if the utility of STA is to be proven, and thus permit researchers to move this concept from the laboratory to the clinical environment.     

Mouse Ovarian Tissue Cryopreservation Has Only a Minor Effect on In Vitro Follicular Maturation and Gene Expression

Purpose : To establish a protocol for ovarian tissue cryopreservation which can retain fertility potential after thawing and to evaluate the impact of cryopreservation on development and gene expression during folliculogenesis. Methods : A controlled randomized study in a clinical and academic research setting in a university medical center was conducted to study cryopreservation and in vitro maturation (IVM) of mouse ovarian follicles. Preantral follicles isolated from either fresh (Group A) or cryopreserved (Group B) murine ovarian tissues were used to test their fertility potential by in vitro culture–in vitro maturation (IVC-IVM). Expression of Graafian follicles derived from both groups were detected by DNA microarray techniques for comparison. Results : Although there were no significant differences in IVM outcomes and follicular gene expression between the two experimental groups, cryopreservation appears to induce the expression of heat shock proteins, DNA-damage-inducible protein 45 and death-related apoptosis genes (i.e., Fas and Fas-ligand). Conclusion : Cryopreservation may trigger biological events not amenable to normal cell function and follicular development. However, neither follicular development nor gene expression was dramatically changed after cryopreservation. These data suggest that although our current cryopreservation techniques yield competent follicles and mature oocytes, subtle changes observed in gene expression imply that the present cryopreservation techniques need to be further refined.     

Coordination of early antral follicles by luteal estradiol administration provides a basis for alternative controlled ovarian hyperstimulation regimens

OBJECTIVE: To investigate whether luteal E(2) administration reduces size discrepancies of early antral follicles. DESIGN: Prospective, crossover study. SETTING: ART unit, Clamart, France. PATIENT(S): Sixty women and 120 cycles. INTERVENTION(S): On cycle day 3 (baseline day 3), all women underwent measurements of early antral follicles by ultrasound and serum FSH and ovarian hormones. From day 20 until the next cycle day 2, 30 of them received oral 17beta-E(2), whereas the remaining women served as controls. The day after E(2) discontinuation (E(2) day 3) or on subsequent cycle day 3 (control day 3), participants were reevaluated as on baseline day 3. MAIN OUTCOME MEASURE(S): Magnitude of follicular size discrepancies. RESULT(S): Follicular size discrepancies and follicular diameters were significantly attenuated on E(2) day 3 (3.7 +/- 0.5 mm) as compared with baseline day 3 (4.9 +/- 1.0 mm), but not in controls (5.0 +/- 0.8 vs. 4.9 +/- 0.8 mm). FSH (4.3 +/- 1.9 vs. 7.3 +/- 3.3 mIU/mL) and inhibin B (34 +/- 28 vs. 71 +/- 32 pg/mL) levels were consistently lower on E(2) day 3 than on baseline day 3 but remained unchanged in controls. CONCLUSION(S): Luteal E(2) administration reduces the size and improves the homogeneity of early antral follicles on day 3. This approach may be instrumental in synchronizing follicular development during controlled ovarian hyperstimulation.     

Aging women with polycystic ovary syndrome who achieve regular menstrual cycles have a smaller follicle cohort than those who continue to have irregular cycles

OBJECTIVE: To examine whether follicle loss due to ovarian aging is responsible for the occurrence of regular menstrual cycles in aging women with polycystic ovary syndrome (PCOS), the size of the FSH-sensitive follicle cohort was estimated by the exogenous follicle-stimulating hormone ovarian reserve test (EFORT) and related to the follicle count as measured by ultrasound. DESIGN: Prospective study. SETTING: Reproductive endocrinology unit of an academic medical center. PATIENT(S): Twenty-seven aging women with PCOS (35.8-49.4 years): 20 with regular menstrual cycles and 7 with oligomenorrhea or amenorrhea. INTERVENTION(S): EFORT and transvaginal ultrasound. MAIN OUTCOME MEASURE(S): Baseline (cycle day 2, 3, or 4) FSH, androstenedione (A), T, E(2), and inhibin B levels, the E(2) and inhibin B increment after the EFORT, and the follicle count. RESULT(S): After correction for the body mass index (BMI), the inhibin B increment was higher in the irregular menstrual group, but the E(2) increment did not differ significantly between the two groups. Ultrasound showed a median follicle count of 8.5 (4.0-18.0) in women with regular menstrual cycles (n = 16), compared with 18.0 (8.0-35.0) in irregularly menstruating women (n = 7). The follicle count was significantly correlated to the FSH-induced E(2) increment (r = 0.656) as well as to the inhibin B increment (r = 0.654). The regularly menstruating group was significantly older, had a higher basal FSH concentration, and had lower androgens than the irregularly menstruating group. CONCLUSION(S): The smaller follicle count, the older age, the higher FSH concentration, and the lower FSH-induced inhibin B increment found in women with PCOS and a regular menstrual cycle confirm that a decrease in the size of the follicle cohort due to ovarian aging is largely responsible for the regular menstrual cycles in aging PCOS women.     

Reproductive aging and variability in the ovarian antral follicle count: application in the clinical setting

OBJECTIVE: To determine the extent of intercycle and interobserver variability in antral follicle (AF) count and their impact on stimulation quality in IVF. DESIGN: Prospective evaluation of the impact on AF count of GnRH agonist down-regulation and interobserver variability. Retrospective evaluation of intercycle variability in AF count. SETTING: University ART clinic. PATIENT(S): Twenty subjects were used to evaluate the effect of GnRH agonist down-regulation upon AF count; six of whom were used to evaluate interobserver variability. Fifty patients experiencing two or three cycles of IVF within a 1-year interval. INTERVENTION(S): Transvaginal ultrasound exams before and after down-regulation with a GnRH agonist. Videotaped day-3 transvaginal ultrasound exams. MAIN OUTCOME MEASURE(S): [1] Intercycle and interobserver variability in antral follicle count. [2] Oocytes retrieved, peak estradiol, gonadotropin dose, duration of stimulation and cancellation rates. RESULT(S): There is moderate intercycle and interobserver variability in AF counts. GnRH agonist down-regulation does not significantly change AF count. In infertility patients undergoing IVF, paired analysis between the low- and high-AF count cycles did not show a difference in quality of stimulation or cycle cancellation rates. CONCLUSIONS: Within an individual patient, higher AF count in a given cycle was not predictive of better stimulation compared with the case of a lower count cycle.     

Partial restoration of hair growth in the DEBR model for Alopecia areata after in vivo depletion of CD4+ T cells

Alopecia areata (AA) is widely believed to be an autoimmune disease. Hair loss is associated with a peri- and intrafollicular inflammatory infiltrate of anagen hair follicles primarily composed of CD4 + and CD8 + cells. A previous investigation involved in vivo depletion of CD8 + cells in the DEBR rat model to examine the cells' potential pathogenic activity in AA. The rat model is used here in a comparable study of CD4 + cell pathogenic activity. Eight AA affected DEBR rats were given intraperitoneal injections of a CD4 + cell depleting OX-35/OX-38 monoclonal antibody (MoAb) cocktail over a 15-day therapy course. A further eight AA-affected rats comprised a control group and were injected with equivalent volumes of an irrelevant MoAb, OX-21. Changes in both CD4 + and CD8 + peripheral blood cell populations were analysed by flow cytometry, and macrophotography was used to record any changes in hair growth. Of the eight CD4 + cell-depleted rats six responded with hair growth. The rats revealed significant hair growth within 23 days of treatment initiation. With rapid replacement of the CD4 + cell population the newly generated pelage hair was eventually lost. Two control rats also showed limited hair growth within the 112-day study period. In vivo depletion of CD4 + cells partially restores hair growth in AA affected rats. The response suggests that CD4 + cells may be actively involved in the pathogenesis of AA. Further research may elucidate whether CD4 + cells have a direct effect on hair follicles or exert their influence through their classic T helper cell supporting role for CD8 + cells.     

Effect of Pentagastrin on Regional Gastric Blood Flow in Conscious Cats

Total gastric flow studies indicated that a transient, considerable flow increase was followed by a more moderate increase of total gastric flow during pentagastrin stimulation in anesthetized cats. In conscious cats regional gastric flow studies, using hydrogen clearance techniques, suggested that raised flow to the corpus region during the stimulation period was accompanied by a moderate decrease of antral flow.     

大鼠实验性胃溃疡自愈期间胃窦粘膜G、D细胞变化的免疫组织化学研究

本实验用成年雄性Wistar大鼠53只,分为溃疡组、盐水对照组和正常对照组。在手术后4、10,14、21及28天分批取材。用Sternberger PAP法进行免疫组织化学染色,分别显示胃窦粘膜胃泌素细胞(G细胞)和生长抑素细胞(D细胞),观察大鼠实验性胃溃疡自愈期间,G和D细胞的形态变化,并进行了细胞计数和统计学分析。本文结果表示,溃疡组G细胞数量在术后10至14天明显增多(P<0.01),21、28天趋于减少,但仍高于对照组。有些G细胞排列成群,密集呈明显带状。正常时G细胞分布在幽门腺的中、下1/3处,而溃疡组可见有些G细胞分布在腺的上部。D细胞数量仅在术后10天增多(P<0.01),与正常对照组相比差异显著。用免疫组织化学双重染色法,可见G细胞和D细胞之间存在着形态上的接触。溃疡自愈期间,G/D细胞比值未见明显改变。本实验结果提示,胃窦粘膜局部G、D细胞的变化和大鼠实验性胃溃疡自愈修复之间有着一定的联系。     

Expression and activity of microsomal epoxide hydrolase in follicles isolated from mouse ovaries.

Microsomal epoxide hydrolase (mEH) is involved in the detoxification of xenobiotics that are or can form epoxide metabolites, including the ovotoxicant, 4-vinylcyclohexene (VCH). This industrial chemical is bioactivated by hepatic CYP450 to the diepoxide metabolite, VCD, which destroys mouse small preantral follicles (F1). Since ovarian mEH may play a role in VCD detoxification, these studies investigated the expression and activity of mEH in isolated ovarian fractions. Mice were given 1 or 15 daily doses (ip) of VCH (7.4 mmol/kg/day) or VCD (0.57 mmol/kg/day); 4 h following the final dose, ovaries were removed, distinct populations of intact follicles (F1, 25-100 microm; F2, 100-250 microm; F3, > 250 microm) and interstitial cells (Int) were isolated, and total RNA and protein were extracted. Real-time polymerase chain reaction and the substrate cis-stilbene oxide (CSO; 12.5 microM) were used to evaluate expression and specific activity of mEH, respectively. Confocal microscopy evaluated ovarian distribution of mEH protein. Expression of mRNA encoding mEH was increased in F1 (410 +/- 5% VCH; 292 +/- 5% VCD) and F2 (1379 +/- 4% VCH; 381 +/- 11% VCD) follicles following repeated dosing with VCH or VCD. Catalytic activity of mEH increased in F1 follicles following repeated dosing with VCH/VCD (381 +/- 11% VCH; 384 +/- 27% VCD). Visualized by confocal microscopy, mEH protein was distributed throughout the ovary with the greatest staining intensity in the interstitial cells and staining in the theca cells that was increased by dosing (56 +/- 0.8% VCH; 29 +/- 0.9% VCD). We conclude that mEH is expressed and is functional in mouse ovarian follicles. Additionally,in vivo dosing with VCH and VCD affects these parameters.     

小切口剔除毛囊大汗腺保留真皮乳头层血管网治疗腋臭

目的：探讨采用小切口剔除毛囊大汗腺保留真皮乳头层血管网治疗腋臭的方法。方法：术前用美蓝沿腋毛边缘外0.5～1.0 cm画线,标记出手术范围,局部肿胀麻醉。然后按照设计好的切口线沿皮纹内切长约2～2.5cm皮肤切口进行锐性分离,形成带毛囊、汗腺、脂肪及浅筋膜的皮瓣,用眼科剪剪除毛囊和大汗腺等组织,保留真皮乳头层血管网。结果：经术后3个月～1年随访,所有患者腋区皮肤无坏死,瘢痕不明显,治愈率96%。结论：本方法治疗腋臭具有创伤小、恢复快、疗效确切的优点。