Viewing apoptosis through a 'TUNEL'

Protective Action of Curcumin and Alpha-lipoic Acid, Against Experimental Ultraviolet-A/B Induced Dermal-injury in Rats

The objective of this study was to examine the therapeutic efficacy of curcumin (CUR) and α-lipoic acid (ALA) in mitigating UV-A and UV-B-induced damage (UVAB) in rat dorsal skin. This was achieved through the utilisation of immunohistochemical (TUNEL), biochemical and stereological techniques. The rats in the UVAB, UVAB + CUR, and UVAB + ALA groups were subjected to UVAB irradiation for a period of two hours per day over the course of one month. The UVAB + CUR and UVAB + ALA groups were administered 100 mg/kg/day of curcumin and 100 mg/kg/day of α-lipoic acid via gavage 30 min prior to UVAB irradiation. The CUR group was administered 100 mg/kg/day of curcumin via gavage, while the ALA group received the same dose of α-lipoic acid. A significant change in the volume ratio of the dorsal skin epidermis and dermis was observed in the stereological findings of the rats in the UVAB group. These changes exhibited a favourable progression as a consequence of the CUR and ALA applications. In the UVAB group, TOS and OSI were significantly elevated as a consequence of the rise in oxidative stress. Conversely, the treatment groups demonstrated a notable reduction in TOS and OSI levels. The study also revealed a substantial increase in the number of apoptotic cells within the UVAB group. However, the treatment groups exhibited a significant decline in apoptotic cells. In conclusion, the findings suggest that CUR and ALA possess a protective effect against UVAB-induced skin damage.

Suppressing Pro-Apoptotic Proteins by siRNA in Corneal Endothelial Cells Protects against Cell Death

Corneal endothelial cells (CE) are critical for the cornea's transparency. For severe corneal damage, corneal tissue transplantation is the most promising option for restoring vision. However, CE apoptotic cell death occurs during the storage of donor corneas for transplantation. This study used small interfering (si)RNA-mediated silencing of pro-apoptotic proteins as a novel strategy to protect CE against apoptosis. Therefore, the pro-apoptotic proteins Bax and Bak were silenced in the human corneal endothelial cell line (HCEC-12) by transfection with Accell™siRNA without any adverse effects on cell viability. When apoptosis was induced, e.g., etoposide, the caspase-3 activity and Annexin V-FITC/PI assay indicated a significantly reduced apoptosis rate in Bax+Bak-siRNA transfected HCECs compared to control (w/o siRNA). TUNEL assay in HCECs exposed also significantly lower cell death in Bax+Bak-siRNA (7.5%) compared to control (w/o siRNA: 32.8%). In ex vivo donor corneas, a significant reduction of TUNEL-positive CEs in Bax+Bak-siRNA corneas (8.1%) was detectable compared to control-treated corneas (w/o siRNA: 27.9%). In this study, we demonstrated that suppressing pro-apoptotic siRNA leads to inhibiting CE apoptosis. Gene therapy with siRNA may open a new translational approach for corneal tissue treatment in the eye bank before transplantation, leading to graft protection and prolonged graft survival.

Network pharmacology-based approach to understand the effect and mechanism of chrysophanol against cognitive impairment in Wilson disease

Wilson disease (WD) is a rare hereditary copper metabolism disorder, wherein cognitive impairment is a common clinical symptom. Chrysophanol (CHR) is an active compound with neuroprotective effects. The study aims to investigate the neuroprotective effect of CHR in WD and attempted to understand the potential mechanisms. Network pharmacology analysis was applied to predict the core target genes of CHR against cognitive impairment in WD. The rats fed with copper-laden diet for 12 weeks, and the effect of CHR on the copper content in liver and 24-h urine, the learning and memory ability, the morphological changes and the apoptosis level of neurons in hippocampal CA1 region, the expression level of Bax, Bcl-2, Cleaved Caspase-3, p-PI3K, PI3K, p-AKT, and AKT proteins were detected. Network pharmacology analysis showed that cell apoptosis and PI3K-AKT signaling pathway might be the main participants in CHR against cognitive impairment in WD. The experiments showed that CHR could reduce the copper content in liver, increase the copper content in 24-h urine, improve the ability of the learning and memory, alleviate the damage and apoptosis level of hippocampal neurons, down-regulate the expression of Bax, Cleaved Caspase-3, and up-regulate the expressions of Bcl-2, p-PI3K/PI3K, p-AKT/AKT. These results suggested that CHR could alleviate cognitive impairment in WD by inhibiting cell apoptosis and triggering the PI3K-AKT signaling pathway.

Acceptor Engineering Produces Ultrafast Nonradiative Decay in NIR-II Aza-BODIPY Nanoparticles for Efficient Osteosarcoma Photothermal Therapy via Concurrent Apoptosis and Pyroptosis

Small-molecule photothermal agents (PTAs) with intense second near-infrared (NIR-II, 1,000 to 1,700 nm) absorption and high photothermal conversion efficiencies (PCEs) are promising candidates for treating deep-seated tumors such as osteosarcoma. To date, the development of small-molecule NIR-II PTAs has largely relied on fabricating donor-acceptor-donor (D-A-D/D') structures and limited success has been achieved. Herein, through acceptor engineering, a donor-acceptor-acceptor (D-A-A')-structured NIR-II aza-boron-dipyrromethene (aza-BODIPY) PTA (SW8) was readily developed for the 1,064-nm laser-mediated phototheranostic treatment of osteosarcoma. Changing the donor groups to acceptor groups produced remarkable red-shifts of absorption maximums from first near-infrared (NIR-I) regions (~808 nm) to NIR-II ones (~1,064 nm) for aza-BODIPYs (SW1 to SW8). Furthermore, SW8 self-assembled into nanoparticles (SW8@NPs) with intense NIR-II absorption and an ultrahigh PCE (75%, 1,064 nm). This ultrahigh PCE primarily originated from an additional nonradiative decay pathway, which showed a 100-fold enhanced decay rate compared to that shown by conventional pathways such as internal conversion and vibrational relaxation. Eventually, SW8@NPs performed highly efficient 1,064-nm laser-mediated NIR-II photothermal therapy of osteosarcoma via concurrent apoptosis and pyroptosis. This work not only illustrates a remote approach for treating deep-seated tumors with high spatiotemporal control but also provides a new strategy for building high-performance small-molecule NIR-II PTAs.

A novel rat model of sarcopenic obesity based on aging and high-fat diet consumption

Sarcopenic obesity (SO) is defined as a combination of obesity and sarcopenia, leading to serious health consequences. However, a lack of suitable animal models has hampered research into this disorder. 12-month-old Sprague-Dawley rats were given a high fat content (HFD, SO group) or standard diet (DC groups) for 28 weeks (until 20 months of age). In addition, 2-month-old rats were fed a standard diet as an age control (YC group) until they reached 10 months of age. At the end of the intervention, quadriceps development in the rats was monitored using magnetic resonance examinations and MR spectroscopy. Age-related changes in muscle mass and strength, histopathology, HFD-induced adiposity, and metabolic disturbances were compared between the three groups. Comparing with DC group, rats of SO (20 months, and fed by high-fat diet) exhibited a more prominent loss of muscle mass and strength, a more pronounced decline in myofibre number, IFM, increase in myocyte apoptosis accompanied with increased visceral fat, remarkable glycolipid metabolic disorders, and insulin resistance. However, DC group rats (20 months with standard diet) only showed a decline in quadriceps cross-sectional area/body weight, forelimb grip strength, myofibre cross-sectional area and number, and intermyofibrillar mitochondria number (IFM), increased myocyte apoptosis, without significant metabolic disorder compared with YC group rats. After verifying, SO animal model was successfully set up by HFD induced obesity concomitant with aging-related sarcopenia.

Transmissible H-aggregated NIR-II fluorophore to the tumor cell membrane for enhanced PTT and synergistic therapy of cancer

Photothermal therapy (PTT) combined with second near-infrared (NIR-II) fluorescence imaging (FI) has received increasing attention owing to its capacity for precise diagnosis and real-time monitoring of the therapeutic effects. It is of great clinical value to study organic small molecular fluorophores with both PTT and NIR-II FI functions. In this work, we report a skillfully fluorescent lipid nanosystem, the RR₉ (RGDRRRRRRRRRC) peptide-coated anionic liposome loaded with organic NIR-II fluorophore IR-1061 and chemotherapeutic drug carboplatin, which is named RRIALP-C4. According to the structural interaction between IR-1061 and phospholipid bilayer demonstrated by molecular dynamics simulations, IR-1061 is rationally designed to possess the H-aggregated state versus the free state, thus rendering RRIALP-C4 with the activated dual-channel integrated function of intravital NIR-II FI and NIR-I PTT. Functionalization of RRIALP-C4 with RR₉ peptide endows the specifically targeting capacity for α_vβ₃-overexpressed tumor cells and, more importantly, allows IR-1061 to transfer the H-aggregated state from liposomes to the tumor cell membrane through enhanced membrane fusion, thereby maintaining its PTT effect in tumor tissues. In vivo experiments demonstrate that RRIALP-C4 can effectively visualize tumor tissues and systemic blood vessels with a high sign-to-background ratio (SBR) to realize the synergistic treatment of thermochemotherapy by PTT synergistically with temperature-sensitive drug release. Therefore, the strategy of enhanced PTT through H-aggregation of NIR-II fluorophore in the tumor cell membrane has great potential for developing lipid nanosystems with integrated diagnosis and treatment function.

A study of digital image analysis on the acrylamide derivative monomers induced apoptosis in rat cerebrum

Nowadays, apoptosis is mostly evaluated visually in histological studies. By using the quantitative digital image analysis, this study aimed to investigate the effect of acrylamide-based monomers (acrylamide [AAm], methacrylamide [MAAm], N-isopropylacrylamide [NIPAm]) on the cerebrum tissues in rats, which are the most common water-soluble monomers in the production of polymeric hydrogels used as biomaterials. The Wistar albino rats weighing ~220-240 g were divided into control and three test groups. The control group received 1 mL of saline, and the test groups received 1 mL of aqueous 50 mg/kg/day intramuscular injection of AAm, MAAm, and NIPAm, respectively. At the end of the experiments, brain tissues of all rats euthanized by intramuscular injection of sodium pentobarbital were removed. Terminal deoxynucleotide transferase dUTP nick and labeling (TUNEL) method was applied to brain tissue sections. The monomers have been shown to cause apoptosis due to oxidative stress in cerebrum tissue. Based on apoptosis by tunneling method, quantitative digital image analysis of cell fragments was performed with Olympus cellSens Dimension 1.15 software, and the number, total count area, selected area, average area, and ROI% values of the fragments were found. In addition, the total area and ROI% values of the fragments increased linearly with increasing the molar mass of monomers from the digital image analysis data. Quantitative digital image analysis can facilitate the monitoring of apoptosis caused by the oxidative stress of monomers used in the production of the biomaterials.

Detection of Apoptotic Cells in Planarians by Whole-Mount TUNEL

Planarians have gained a well-deserved reputation as an excellent model organism for research on the biology of adult stem cells and their role in regeneration. Though less widely recognized, these animals also offer many advantages for investigating mechanisms and functions of programmed cell death in self-renewing tissues. Apoptosis complements stem cell division during physiological cell turnover and constitutes a prominent feature of the tissue remodeling process that restores anatomical scale and proportion during regeneration. One technical advantage to studying apoptosis in planarians is the availability of a whole-mount TUNEL assay for visualizing dying cells throughout the animal. Here, we provide a detailed protocol for this assay that is likely to benefit researchers investigating planarian cell death in either physiological or pathological contexts.

The antifungal activity of the peptide, periplanetasin-2, derived from American cockroach Periplaneta americana

The cockroach, which is a household insect, is an established model organism in research. Periplanetasin-2, derived from the American cockroach Periplaneta americana, exerted potent antifungal effect against pathogenic fungi without causing hemolysis. Periplanetasin-2 induced oxidative stress by generation of reactive oxygen species (ROS) and lipid peroxidation. Periplanetasin-2 also caused apoptosis by exposure of phosphatidylserine and fragmentation of DNA, exerted in a concentration-dependent manner. Hence, we investigated the mitochondrial apoptotic mechanism of periplanetasin-2 in Candida albicans. After treatment with periplanetasin-2, we observed mitochondrial depolarization and calcium accumulation. Moreover, we observed a decrease in cytosolic glutathione, and an increase in mitochondrial glutathione, indicating that periplanetasin-2 induced oxidative stress and high ROS production in the mitochondria. Because of this mitochondrial dysfunction, cytochrome c was released from the mitochondria into the cytosol, and caspase was activated in a time-dependent manner. In summary, the antifungal peptide periplanetasin-2 activates apoptotic signals in the mitochondria by induction of oxidative stress.

A novel fungal killing mechanism of propionic acid

Propionic acid (PPA) is a weak acid that has been used in food products as a preservative because of its inhibitory effect on microorganisms. In the present study, we investigated the PPA fungal killing mechanism, which showed apoptotic features. First, reactive oxygen species (ROS) accumulation and metacaspase activation were detected by 2',7'-dichlorodihydrofluorescein diacetate and CaspACE FITC-VAD-FMK staining, respectively. Increased fluorescence intensities were observed following exposure to PPA, indicating that PPA produced an oxidative environment through the generation of ROS and activation of metacaspase, which can promote apoptosis signaling. We also examined phosphatidylserine externalization (an early apoptosis marker) and DNA and nuclear fragmentation (late apoptosis markers) after exposure to PPA. Based on the results, we determined that PPA exerts its antifungal effect by inducing apoptotic cell death. Moreover, three additional mitochondrial experiments showed mitochondrial membrane depolarization, calcium accumulation and cytochrome c release after cells were exposed to PPA, indicating that the PPA-induced apoptosis pathway is mediated by mitochondria. In conclusion, PPA induces fungal cell death through mitochondria-mediated apoptosis. Results of this study contribute to a deeper understanding of the preservative effects of PPA.

Apoptosis as a Mechanism for Keratinocyte Death in Canine Toxic Epidermal Necrolysis

In humans and dogs, toxic epidermal necrolysis (TEN) is a life-threatening dermatosis characterized by sudden epidermal death resulting in extensive skin detachment. There is little information on the pathogenesis of keratinocyte cell death in canine TEN. We studied the occurrence of apoptosis in skin lesions of dogs with TEN to determine if apoptosis contributes to the pathogenesis of this disease. Immunostaining with antibodies to activated caspase-3 and the terminal deoxynucleotidyl-transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick-end labeling technique revealed positive apoptotic keratinocytes in basal and suprabasal epidermal compartments in 17 biopsy specimens collected from 3 dogs with TEN and 16 from 3 dogs with erythema multiforme (EM). There was no significant difference in the number of positively stained epidermal cells between TEN and EM. These results suggest that apoptosis of epidermal keratinocytes and lymphocytic satellitosis represent one of the early steps in the pathogenesis of canine TEN, as in the human disease counterpart.

Proliferation, apoptosis, and fractal dimension analysis for the quantification of intestinal trophism in sole (Solea solea) fed mussel meal diets

Background

The evaluation of intestinal trophism, mainly the mucosal layer, is an important issue in various conditions associated with injury, atrophy, recovery, and healing of the gut. The aim of the present study was to evaluate the kinetics of the proliferation and apoptosis of enterocytes by immunohistochemistry and to assess the complexity of intestinal mucosa by fractal dimension (FD) analysis in Solea solea fed different experimental diets.

Results

Histomorphological evaluation of all intestinal segments did not show signs of degeneration or inflammation. Cell proliferation index and FD were significantly reduced with a diet high in mussel meal (MM; p = 0.0034 and p = 0.01063, respectively), while apoptotic index did not show any significant difference for the same comparison (p = 0.3859). Linear regression analysis between apoptotic index (independent variable) and FD (dependent variable) showed a statistically significant inverse relationship (p = 0.002528). Linear regression analysis between cell proliferation index (independent variable) and FD (dependent variable) did not show any significant correlation (p = 0.131582).

Conclusions

The results demonstrated that diets containing increasing levels of mussel meal in substitution of fishmeal did not incite a hyperplastic response of the intestinal mucosa. The mussel meal, which is derived from molluscs, could mimic the characteristics of the sole’s natural prey, being readily digestible, even without increasing the absorptive surface of intestinal mucosa. Interestingly, from this study emerged that FD could be used as a numeric indicator complementary to in situ quantification methods to measure intestinal trophism, in conjunction with functional parameters.

Alantolactone induces cell apoptosis partially through down-regulation of testes-specific protease 50 expression

Testes-specific protease 50 (TSP50) is aberrantly expressed in many cancer biopsies and plays a crucial role in tumorigenesis, which make it a potential cancer therapeutic target for drug discovery. Here, we constructed a firefly luciferase reporter driven by the TSP50 gene promoter to screen natural compounds capable of inhibiting the expression of TSP50. Then we identified alantolactone, a sesquiterpene lactone, could efficiently inhibit the promoter activity of TSP50 gene, further results revealed that alantolactone also efficiently inhibited the expression of TSP50 in both mRNA and protein levels. Moreover, we found alantolactone could increase the ratio of Bax/Bcl-2, and activate caspase-9 and caspase-3 in the cancer cells with high expression of TSP50, surprisingly, the same effects can also be observed in the same cells just by knockdown of TSP50 gene expression. Furthermore, our results suggested that overexpression of TSP50 decreased the cell sensitivity to alantolactone-induced apoptosis in those cancer cells. Taken together, these results suggest that alantolactone induces mitochondrial-dependent apoptosis at least partially via down-regulation of TSP50 expression.

In vivo fluorescence imaging of apoptosis during foreign body response

Quantification of apoptotic tissues during inflammatory processes induced by biomaterials is challenging in vivo. Here we present a non-invasive method using a fluorescence imaging system which facilitates intermittent snap shots of the current state of local apoptotic tissue. For this purpose, apoptotic cells around two different subcutaneously implanted materials (titanium discs and copper-coated titanium discs) in hairless but immunocompetent mice were quantified after 4, 8 and 23 days of implantation. For validation, the results of fluorescence signals were compared to the histology of the inflammatory tissue using apoptotic-specific TUNEL-, macrophage-specific F4/80-, neutrophile-specific NIMP-R14- and chloroacetate esterase-staining. We could demonstrate that the fluorescence signals were well suited to quantify the extent of apoptosis in vivo and this is a good indication for the biocompatibility of biomaterials. This study shows that non-invasive monitoring of tissue processes following the implantation of biomaterials is possible in vivo and may help to reduce the number of animals in studies addressing biocompatibility.

Tissue-specific effects of allergic rhinitis in mouse nasal epithelia

Allergic rhinitis (AR) can cause significant olfactory loss, but few studies have specifically investigated AR effects on olfactory and nasal respiratory tissues per se. To address this, we used a murine AR protocol employing nasal allergen infusion for both sensitization and challenges. Seven- to 11-week BALB/c mice were bilaterally infused with 1% ovalbumin (OVA) in phosphate-buffered saline (PBS) or PBS alone for 6 or 11 weeks, given single bilateral PBS or OVA infusions 24 h before sacrifice, or left untreated. High OVA-specific IgE serum levels and eosinophil infiltration confirmed AR induction. Olfactory (OE) and respiratory (RE) epithelia showed distinctly different responses, most conspicuously, massive eosinophil infiltration of immediately RE-subjacent lamina propria. In OE, such infiltration was minimal. Significant RE hypertrophy and hyperplasia also occurred, although OE organization was generally maintained and extensive disruption localized despite a 20% reduction in sensory neurons and globose basal cells after 11 weeks OVA. Pronounced Bowman's gland hypertrophy crowded both OE and olfactory nerve bundles. Cellular proliferation was widely distributed in RE but in OE was localized to normally thinner OE and RE-proximal OE, suggesting possible indirect RE influences. Terminal deoxynucleotide transferase (TdT) nick end labeling was greater in OE than RE and, in contrast to other effects, occurred with acute infusions and chronic PBS alone, often unilaterally. Following chronic OVA, AR-related bilateral increases appeared superimposed on those. These findings indicate AR effects on olfactory function may be complex, reflecting various levels of RE/OE responses and interactions.

Kinetics of GADD45α, TP53 and CASP3 gene expression in the rat lens in vivo in response to exposure to double threshold dose of UV-B radiation

The purpose of the present study was to investigate the evolution of expression of mRNA message for the genes for the genome stress sensor GADD45α, the apoptosis initiator TP53 and the apoptosis executor CASP3 in the rat lens in vivo in response to exposure to UVR around 300 nm. Forty six week old female albino Sprague-Dawley rats were unilaterally exposed to double threshold dose for cataract induction, 8 kJ/m(2) (8.9 W/m(2) for 15 min), of UVR (λ(max) = 300 nm). The animals were sacrificed at 1, 5, 24 and 120 h following exposure to UVR-B. For each of the GADD45α, TP53 and CASP3 genes, respectively, mRNA expression in the lenses was measured by quantitative RT-PCR. It was found that expression of mRNA for GADD45α transiently increases between 5 and 24 h after exposure. TP53 is slightly downregulated in exposed lenses at 1 and 5 h after exposure and thereafter the mRNA expression increases with a constant rate of 9.4\ 10(-3) rel. units/h to a 1.8 fold increase at 120 h after exposure. Expression of mRNA for CASP3 is downregulated at 1, 5 and 24 h after in vivo exposure and then increases with a constant rate of 4.7 10(-3) rel. units/h, upto a 1.3 fold upregulation at 120 h. Double threshold dose of UVR, for short delay onset of cataract, in vivo causes a transient upregulation of the stress sensor GADD45α, a concurrent downregulation of TP53 and CASP3, followed by a constant upregulation of TP53 that precedes a constant upregulation of CASP3.

Morphological and apoptotic changes in the intestinal mucosa and lung parenchyma after ischaemic/reperfusion injury of the jejunum

Ischaemic/reperfusion (IR) injury of the small intestine may lead to the development of multiple organ failure. Little is known about the morphological changes occurring in the organs during the subacute course of this syndrome. The objective of this study was to observe histopathological features and the role of apoptosis in the jejunal mucosa and lung parenchyma after intestinal IR injury in a long-term experiment. Wistar rats (n = 36) were divided into 4 experimental groups (IR(10), IR(20), IR(30), S). Groups IR(10), IR(20) and IR(30) (each n = 10) were subjected to 1-hour ischaemia of the cranial mesenteric artery followed by 10, 20 or 30 days of reperfusion, respectively. The control group S (n = 6) was not subjected to ischaemia. The jejunal mucosa remained intact after all periods of reperfusion. Apoptotic cells were found particularly in the lamina propria, with the most significant difference observed in the IR(30) group (P < 0.01). The lung parenchyma had lower regenerative capacity, which was confirmed by a high index of histological damage after 30 days of reperfusion (P < 0.01) and by the presence of an increased number of apoptotic cells, especially in the pulmonary interstitium. The number of apoptotic cells was ten times higher than in the control group (P < 0.001).

Fas ligand expression in lynch syndrome-associated colorectal tumours

Fas Ligand (FasL) expression by cancer cells may contribute to tumour immune escape via the Fas counterattack against tumour-infiltrating lymphocytes (TILs). Whether this plays a role in colorectal carcinogenesis in Lynch syndrome was examined studying FasL expression, tumour cell apoptosis and number of TILs in colorectal neoplasms from Lynch syndrome patients (50 adenomas, 20 carcinomas) compared with sporadic cases (69 adenomas, 52 carcinomas). FasL expression was observed in 94% of Lynch syndrome adenomas and in all carcinomas. FasL expression patterns and apoptotic indices were similar in Lynch syndrome-associated neoplasms and sporadic cases. The number of TILs was higher in Lynch syndrome neoplasms than in sporadic cases. There were no correlations between FasL expression and tumour cell apoptosis or number of TILs in Lynch syndrome-associated neoplasms. So, FasL expression is an early event in Lynch syndrome and sporadic colorectal carcinogenesis, but not related to TIL number. Taken together, our data do not support a role for the Fas counterattack in colorectal carcinogenesis in Lynch syndrome.

Apoptosis in the colonic crypt, colorectal adenomata, and manipulation by chemoprevention

This review discusses the biology and the methods of assessment of apoptosis, of which, the monoclonal antibody M30 would seem to be the most useful; the role of apoptosis in the etiology of colorectal cancer; and its use as a marker to monitor the beneficial effects of chemopreventative interventions to reduce the development of colorectal cancer within the context of clinical trials.

Targeted deletion of tumor suppressor PTEN augments neutrophil function and enhances host defense in neutropenia-associated pneumonia

Neutropenia and related infections are the most important dose-limiting toxicities in anticancer chemotherapy and radiotherapy. In this study, we explored a new strategy for augmenting host defense in neutropenia-related pneumonia. Phosphatidylinositol-3,4,5-trisphosphate (PtdIns(3,4,5)P(3)) signaling in neutrophils was elevated by depleting PTEN, a phosphatidylinositol 3'-phosphatase that hydrolyzes PtdIns(3,4,5)P(3). In myeloid-specific PTEN knockout mice, significantly more neutrophils were recruited to the inflamed lungs during neutropenia-associated pneumonia. Using an adoptive transfer technique, we demonstrated that this enhancement could be caused directly by PTEN depletion in neutrophils. In addition, disruption of PTEN increased the recruitment of macrophages and elevated proinflammatory cytokines/chemokine levels in the inflamed lungs, which could also be responsible for the enhanced neutrophil recruitment. Depleting PTEN also significantly delayed apoptosis and enhanced the bacteria-killing capability of the recruited neutrophils. Finally, we provide direct evidence that enhancement of neutrophil function by elevating PtdIns(3,4,5)P(3) signaling can alleviate pneumonia-associated lung damage and decrease pneumonia-elicited mortality. Collectively, these results not only provide insight into the mechanism of action of PTEN and PtdIns(3,4,5)P(3) signaling pathway in modulating neutrophil function during lung infection and inflammation, but they also establish PTEN and related pathways as potential therapeutic targets for treating neutropenia-associated pneumonia.

The magnitude and temporal dependence of apoptosis early after myocardial ischemia with or without reperfusion

In view of the conventional wisdom in the cardiology literature that apoptosis is extensive early after myocardial ischemia, predicated largely from results with the TUNEL assay known to be nonspecific, this study was performed to delineate its extent with multiple assays and at multiple intervals. Coronary occlusion with and without subsequent revascularization was induced in 10-wk-old C57BL6 mice subjected to 1 or 4 h of transient ligation followed by 24 h of reperfusion, or 24 h persistent ligation. Apoptosis was quantified throughout the left ventricle immunohistochemically by assay of TUNEL, single-stranded DNA (ssDNA), and cleaved caspase 3; electron microscopy (EM); and activity assays of caspase 3 and 8. TUNEL staining was marked, but ssDNA and cleaved caspase 3 staining were significantly less (P<0.001 compared with TUNEL), and apoptosis defined by EM was virtually absent in all groups. Caspase 3 and caspase 8 activities per milligram protein were not significantly different from those in normal hearts. Only rare, potentially apoptotic cells were seen by EM in hearts from any group. Thus, the results with TUNEL were not specific, and the extent of apoptosis was markedly less than that predicated on the results with the TUNEL procedure. Apoptosis is de minimus early after transitory or persistent ischemia, though it is overestimated by TUNEL assays. Thus, antiapoptotic interventions per se are not likely to preserve substantial amounts of myocardium early after ischemic insults.

Apoptosis and anti-apoptotic heat shock proteins in canine cutaneous infundibular keratinizing acanthomas and squamous cell carcinomas

Cell stress and death are linked in the neoplastic process, and heat shock proteins appear to play an important role by inhibiting apoptotic pathways. The apoptotic rates in 9 canine infundibular keratinizing acanthomas (IKAs) and 17 canine squamous cell carcinomas (SCCs) were correlated with the immunohistochemical expression of caspase-3 and the antiapoptotic heat shock proteins Hsp27, 72 and 73. Apoptosis was evaluated using the terminal deoxynucleotidyl transferase biotin-dUTP nick end labelling (TUNEL) method. The absence of a correlation between the TUNEL index and active-caspase-3 expression, a paucity of active-caspase-3-positive cells and Hsp72 over-expression were considered to be indicative of inhibition of apoptosis, and suggestive that inhibition of cell death plays a key role in oncogenesis and tumour growth of some canine skin neoplasms.

Cytokeratin fragments in the serum: their utility for the management of oral cancer

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common malignancy and is a major cause of cancer morbidity and mortality worldwide. Oral cancer is the most predominant malignancy in the Indian subcontinent due to the widespread habits of chewing tobacco and related products. Patients with oral tumours have a high risk of early locoregional relapse. Early detection of disease progression remains a challenging task mainly due to the lack of adequate early prognostic markers. CEA, SCC Ag, CA-125, serum cytokeratin (CK) fragments, Cyfra 21-1 (CK 19), TPS (CK 18), TPA (CK 8, 18, and 19) etc. are being used as serum markers for the prediction of prognosis of various malignancies. This review presents the available literature on serum CK markers in different malignancies evaluates their utility in the management of oral cancer, and identifies the lacunae which need to be addressed to develop sensitive and specific assays for early detection of recurrence, prognosis, and treatment monitoring.

Morphological and cytochemical determination of cell death by apoptosis

Several modes of cell death are now recognized, including necrosis, apoptosis, and autophagy. Oftentimes the distinctions between these various modes may not be apparent, although the precise mode may be physiologically important. Accordingly, it is often desirable to be able to classify the mode of cell death. Apoptosis was originally defined by structural alterations in cells observable by transmitted light and electron microscopy. Today, a wide variety of imaging and cytochemical techniques are available for the investigation of apoptosis. This review will highlight many of these methods, and provide a critique on the advantages and disadvantages associated with them for the specific identification of apoptotic cells in culture and tissues.

A novel dual staining method for identification of apoptotic cells reveals a modest apoptotic response in infarcted mouse myocardium

Confocal scanning laser microscopy was used to investigate the myocardium of control C57BL/6 and plasminogen activator inhibitor 1 knockout (PAI-1KO) mice 3 days following persistent ligation of the left descending coronary artery. Paraffin sections taken from infarcted areas of the left ventricle were stained with antibodies recognizing cardiomyocytes, neutrophils, macrophages and apoptotic cells. In both animal groups, a strong neutrophil response was noted in the infarcted myocardium, with a large proportion of these cells also displaying staining for anti-alpha-sarcomeric actin in the PAI-1KO animals. Abundant macrophages were also identified in the infarcted regions of both animal groups, forming demonstrable streams at the border region in the C57BL/6 control animals. Surprisingly, only sparse cells from both animal groups were labeled with the apoptotic markers anti-cleaved caspase 3 antibody and anti-single stranded DNA antibody (following formamide treatment). A dual immunostaining protocol was developed to localize both of these apoptotic markers in the same cell. Again, only scattered cells were found displaying both markers in the zones of infarction, suggesting that 3 days of persistent ischemia results in a robust necrotic response, but only a very minor apoptotic response in this mouse model.

Myocyte Apoptosis in Primary Obstructive Megaureters: The Role of Decreased Vascular and Neural Supply

PURPOSE

We compared myocyte apoptosis index, microvessel density and nerve supply as well as muscular and collagen composition in the obstructed ureteral endings of children with primary obstructive megaureter and normal controls.

MATERIALS AND METHODS

Tissue specimens were obtained during ureteral reimplantation in 16 patients with primary obstructive megaureter. For the control group normal ureteral endings were taken at autopsy from 19 age and sex matched children. In all specimens we determined the myocyte apoptosis index, number of CD31 positive microvessels, alpha-actin positive muscular component and number of nerve terminals. The collagen fibers were also specifically stained.

RESULTS

The myocyte apoptosis index was higher in obstructed vesicoureteral junctions (10.14%+/-1.03%) compared to controls (2.11%+/-0.21%, p<0.001). Mean number of vascular elements per microscopic field was lower in ureteral endings of patients with obstructive megaureter compared to controls (p<0.001). The number of nerve endings was also significantly lower in obstructed ureteral endings. There was a negative correlation between the number of microvessels and myocyte apoptosis index in both study groups. In obstructed megaureters the number of nerve endings was also negatively correlated with myocyte apoptosis index but positively correlated with the number of microvessels. In obstructed vesicoureteral junctions the proportion of muscular component was lower and the proportion of collagen fibers was higher compared to normal controls. Positive correlation was found between the myocyte apoptosis index and the percentage of collagenous component in both study groups.

CONCLUSIONS

Congenital defective vascular development may result in myocyte apoptosis, and reduction of neural elements and muscular components in obstructed vesicoureteral junctions. Subsequent substitution of connective tissue may lead to functional obstruction in primary obstructive megaureter.

Epithelial apoptosis in mechanistically distinct methods of injury in the murine small intestine

Gut epithelial apoptosis is involved in the pathophysiology of multiple diseases. This study characterized intestinal apoptosis in three mechanistically distinct injuries with different kinetics of cell death. FVB/N mice were subjected to gamma radiation, Pseudomonas aeruginosa pneumonia or injection of monoclonal anti-CD3 antibody and sacrificed 4, 12, or 24 hours post-injury (n=10/time point). Apoptosis was quantified in the jejunum by hematoxylin and eosin (H&E), active caspase-3, terminal deoxynucleotidyl transferase dUTP-mediated nick end labeling (TUNEL), in situ oligoligation reaction (ISOL,) cytokeratin 18, and annexin V staining. Reproducible results were obtained only for H&E, active caspase-3, TUNEL and ISOL, which were quantified and compared against each other for each injury at each time point. Kinetics of injury were different with early apoptosis highest following radiation, late apoptosis highest following anti CD3, and more consistent levels following pneumonia. ISOL was the most consistent stain and was always statistically indistinguishable from at least 2 stains. In contrast, active caspase-3 demonstrated lower levels of apoptosis, while the TUNEL assay had higher levels of apoptosis in the most severely injured intestine regardless of mechanism of injury. H&E was a statistical outlier more commonly than any other stain. This suggests that regardless of mechanism or kinetics of injury, ISOL correlates to other quantification methods of detecting gut epithelial apoptosis more than any other method studied and compares favorably to other commonly accepted techniques of quantifying apoptosis in a large intestinal cross sectional by balancing sensitivity and specificity across a range of times and levels of death.

Dual roles of intermediate filaments in apoptosis

New roles have emerged recently for intermediate filaments (IFs), namely in modulating cell adhesion and growth, and providing resistance to various forms of stress and to apoptosis. In this context, we first summarize findings on the IF association with the cell response to mechanical stress and growth stimulation, in light of growth-related signaling events that are relevant to death-receptor engagement. We then address the molecular mechanisms by which IFs can provide cell resistance to apoptosis initiated by death-receptor stimulation and to necrosis triggered by excessive oxidative stress. In the same way, we examine IF involvement, along with cytolinker participation, in sequential caspase-mediated protein cleavages that are part of the overall cell death execution, particularly those that generate new functional IF protein fragments and uncover neoantigen markers. Finally, we report on the usefulness of these markers as diagnostic tools for disease-related aspects of apoptosis in humans. Clearly, the data accumulated in recent years provide new and significant insights into the multiple functions of IFs, particularly their dual roles in cell response to apoptotic insults.

Immunohistochemical measurement of endothelial cell apoptosis and proliferation in formalin-fixed, paraffin-embedded human cancer tissue

There is a need for simple, reproducible methodology for measurement of endothelial cell (EC) apoptosis and proliferation in formalin-fixed, paraffin-embedded (FFPE) human tissue obtained in clinical trials of potential anti-angiogenic agents. Therefore, we developed colorimetric, dual-label immunohistochemical techniques for use on FFPE tissue, based on the use of single-stranded (ss) DNA and Ki-67 as markers of EC apoptosis and proliferation, respectively. Digital image analysis was used to obtain the total tumour microvessel density (MVD), from which the EC apoptosis index (AI) and proliferation index (PI) were derived manually as the number of positive ECs per vessel. Immunohistochemical measurement of EC apoptosis and proliferation was validated on human colorectal cancer liver metastases from a randomized, placebo-controlled trial of the selective cyclooxygenase-2 inhibitor rofecoxib. Proliferating and apoptotic ECs clustered in discrete areas of the tumour vasculature. ECAI (median [inter-quartile range, IQR] 0.0018 [0.0003-0.0064]) and ECPI (median [IQR] 0.0043 [0.002-0.014]) values were low and highly variable in tumours from both placebo- and rofecoxib-treated patients. Our novel dual-label immunohistochemical methods will be generally applicable in FFPE human cancer tissue and should prove invaluable for measuring the anti-angiogenic activity of experimental therapies in clinical trials. The low absolute level of and variability in EC apoptosis and proliferation detectable in human colorectal cancer liver metastases indicates that similar intervention studies using these end-points will need to ensure adequate size in order to be able to detect anti-angiogenic activity by immunohistochemical methods.

Apoptosis-independent Poor Morphology of Bovine Embryos Produced by Multiple Ovulation

In multiple ovulation and embryo transfer (MOET) programmes in cattle, a considerable number of morphologically poor-quality embryos continue to be produced; this is one of the limiting factors of the technique. Apoptosis has often been implicated in developmental arrest and fragmentation; these are regarded as poor traits of embryonic quality in mammalian pre-implantation embryos. In the present study, apoptosis was assessed in morphologically poor-quality embryos in comparison with good-quality embryos that were recovered from a MOET programme. Retarded embryos (two to 16 cell stage), morulae with severe fragmentation and morphologically good-quality morulae recovered from superstimulated cows at day 7 post-insemination were subjected to TdT-mediated dUTP nick-end labelling (TUNEL) and Hoechst staining. Cell nuclei that showed both TUNEL staining and apoptotic morphology were considered to be apoptotic. Apoptotic index (AI) was calculated as the percentage of apoptotic cells per embryo. Fifteen of 17 retarded embryos and 10 of 15 morphologically poor-quality morulae did not show signs of apoptosis. The mean AIs in the morphologically poor-quality embryos (two to 16 cell stage, 2.2%; poor morulae, 1.3%) were as low as that in the good-quality embryos (2.9%). These results suggest that another mode of developmental arrest and/or fragmentation that is independent of apoptosis occurs in morphologically poor-quality embryos recovered from MOET programmes.

Osteochondritis dissecans of the elbow: Histopathological assessment of the articular cartilage and subchondral bone with emphasis on their damage and repair

Osteochondritis dissecans (OCD) of the elbow is a localized injury of the articular cartilage and subchondral bone that is commonly seen in the young athlete. In the present study, the extent of damage and repair on the articular cartilage and subchondral bone was examined histologically using specimens of 25 osteochondral cylinders and seven loose bodies obtained from 25 young athletes who had undergone osteochondral autograft surgery. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) assays for detecting apoptotic cells and immunohistochemistry of matrix metalloproteinases (MMP) were performed on the osteochondral cylinder specimens. The histological findings of the OCD of the elbow showed that the articular cartilage exhibited degenerative change, mimicking osteoarthritis, and was markedly damaged as the lesion progressed. TUNEL-positive cells and MMP-3- and -13-expressing cells were distributed in the degenerative articular cartilage and reparative fibrocartilage tissue. Separation occurred at either the deep articular cartilage or the subchondral bone, with the former being dominant in the early OCD lesions. The present results suggest that the primary pathological changes in OCD of the elbow were due to damage of articular cartilage induced by repeated stress following degenerative and reparative process of articular cartilage and subchondral fracturing, and separation subsequently occurred on the cartilage and developed onto the subchondral bone in its advanced stages.

Immunohistochemical expression of activated caspase-3 as a marker of apoptosis in glomeruli of human lupus nephritis

BACKGROUND

The role of apoptosis in lupus nephritis (LN) is still controversial. One of the key events in the process of apoptosis is activation of caspase-3. Studies of experimental models suggested that activated caspase-3 is a reliable indicator of apoptotic rate, with a favorable comparison against terminal transferase-mediated DNA nick-end labeling (TUNEL) assay. Our aim is to study apoptosis in various forms of LN and its relationship to histomorphological changes and selected laboratory findings by using activated caspase-3 as a novel marker of apoptosis.

METHODS

We investigated glomerular cell apoptosis in 51 biopsy specimens from patients with LN classified according to the International Society of Nephrology/Renal Pathology Society classification by using the TUNEL method and immunohistochemistry against activated caspase-3. In addition, activity and chronicity indices were calculated and anti-Ki-67 antibody was used to estimate proliferative activity.

RESULTS

Activated caspase-3-positive cells were present in glomeruli of 88.2% of cases, observed in the glomerular tuft and cellular and fibrocellular crescents. In the glomerular tuft, they were found mainly in segments with active inflammatory lesions. There was good correlation between apoptotic index assessed by using activated caspase-3 immunolabeling and the TUNEL method (r = 0.72; P < 0.01). We observed a significant positive correlation between apoptotic index and LN class (P < 0.001). Apoptotic index correlated significantly with activity index, proliferation index, and daily protein excretion (P < 0.001), but not chronicity index, creatinine concentration, or anti-DNA antibody-binding activity in serum.

CONCLUSION

Apoptotic rate is greater in severe active glomerular lesions in human LN, suggesting that apoptosis may be involved in augmenting inflammation in human LN.

Increased occurrence of caspase-dependent apoptosis in unfavorable neuroblastomas

Neuroblastoma frequently shows spontaneous regression in which two distinct types of programmed cell death, ie, caspase-dependent apoptosis and H-Ras-mediated autophagic degeneration, have been suggested to play a key role. The current study was conducted to determine which of these cell suicide pathways predominated in this tumor regression. Periodic acid-Schiff (PAS) staining and immunostaining for H-Ras and for the full-length and cleaved forms of caspase-3, poly (ADP-ribose) polymerase (PARP), and lamin A were carried out on 55 archival tumor specimens. The incidence of caspase-dependent apoptosis in each tumor was quantified by cleaved lamin A staining and compared with clinicopathologic prognostic factors. Although a recent report has shown that neuroblastic cells undergoing autophagic degeneration were readily detectable by PAS and H-Ras staining, we could not confirm this result in any of our samples with the exception of one tumor. Instead, many of our neuroblastoma samples showed nonspecific PAS and Ras staining in areas of necrosis, suggesting that autophagic "degeneration" indeed corresponds to coagulation necrosis or oncosis. Unexpectedly, the incidence of caspase-dependent apoptosis was significantly correlated with indicators of a poor prognosis in these tumors, including Shimada's unfavorable histology, MYCN amplification, and a higher mitosis-karyorrhexis index, but not with factors related to tumor regression such as clinical stage and mass screening. These results indicate that neither caspase-dependent apoptosis nor autophagic "degeneration" may be involved in spontaneous neuroblastoma regression. This suggests that other mechanisms, perhaps such as tumor maturation, may be responsible for this phenomenon.

Induction of apoptosis with tobacco smoke and related products in A549 lung epithelial cells in vitro

Background

This study has investigated the ability of tobacco smoke, and ingredients of tobacco smoke, to induce apoptosis in the airway epithelial cell line A549.

Method

A549 cells were treated with 80 μg/ml Tobacco smoke condensate (TSC), 10 mM Nicotine, 10 μM paraldehyde, 10 μM hydrogen peroxide, 1 μM Taxol^® (Paclitaxel), 100%, 50% and 25% cigarette smoke extract (CSE). Following 4–48 h incubation apoptosis was measured morphologically following staining of cells with DAPI. TUNEL staining was also used to assess DNA damage after 24 and 48 h incubation. In addition, loss of mitochondrial cytochrome C and activation of Bax-α, early events in the apoptotic process, were measured after 4 h of incubation.

Results

Incubation of A549 cells with vehicle, Taxol, TSC, nicotine, paraldehyde, hydrogen peroxide and CSE caused a time-dependent detachment of the cells from the flask between 6 and 48 h. DAPI staining revealed that the cells remaining adhered to the flask appeared healthy whereas some of those that had detached appeared to be either apoptotic or indeterminate. Treatment with Taxol, TSC, nicotine, paraldehyde, hydrogen peroxide and CSE caused a significant increase in the number of apoptotic cells. Similarly, treatment with Taxol, TSC, nicotine, hydrogen peroxide and CSE caused a significant increase in the number of apoptotic cells among the cells that had detached from the culture plate. After 4 h of incubation, Taxol, TSC, hydrogen peroxide and CSE caused a significant reduction in mitochondrial cytochrome C and an increase in cytosolic cytochrome C. At the same time point, hydrogen peroxide and CSE significantly increased the concentration of Bax-α in the mitochondria.

Conclusion

Tobacco smoke initiates apoptosis in A549 airway epithelial cells as a result of mitochondrial damage and that this results in a cell detachment and full apoptosis. This effect appears to result from factors in tobacco smoke other than nicotine and may result from free radical activity. However, additional stable factors may also be involved since the free radical content of TSC is likely to be low.

Immunohistochemical expression of activated caspase-3 in human myocardial infarction

There is mounting evidence that apoptosis is important in the pathogenesis of myocardial infarction (MI). One of the key events in the process of apoptosis is activation of caspase-3. Much attention has been recently paid to caspase inhibition as a potential treatment for ischemic cardiac disease. To predict the long-term effect of such treatment, it is essential to understand the significance of caspase-3 in the evolution of MI. Our aim was therefore to analyze immunohistochemical expression of activated caspase-3 in MI. Our study included autopsy samples of infarcted heart tissue from 50 patients with MI. Immunohistochemistry was performed by a sensitive peroxidase-streptavidin method on formalin-fixed, paraffin-embedded tissue, using monoclonal antibodies against activated (cleaved) caspase-3. We found caspase-3-positive myocytes in 18 MI less than 24 h old and in 3 MI that were presumably 48 h old. Their density (number of labeled myocytes/mm(2)) was greater in patients who received reperfusion treatment (mean 0.160+/-0.373 vs 0.025+/-0.037, p=0.06). In MI older than 48 h, positive reaction was observed in neutrophil granulocytes in the interstitium and, in subacute MI, it was observed in mononuclear inflammatory cells, myofibroblasts, and vascular endothelial cells. Our results suggest that apoptosis of myocytes is an important mode of cell death in the early MI, being enhanced in patients who received reperfusion treatment. After 48 h, apoptosis is an important mechanism of the clearance of neutrophil granulocytes and other inflammatory cells and of scar formation. Treatment with caspase inhibitors therefore will not only affect myocyte loss but will also interfere with the clearance of neutrophils and with the transformation of granulation tissue into a scar.

Targeted biallelic inactivation of Pten in the mouse prostate leads to prostate cancer accompanied by increased epithelial cell proliferation but not by reduced apoptosis

The PTEN tumor suppressor gene is frequently inactivated in human tumors, including prostate cancer. Based on the Cre/loxP system, we generated a novel mouse prostate cancer model by targeted inactivation of the Pten gene. In this model, Cre recombinase was expressed under the control of the prostate-specific antigen (PSA) promoter. Conditional biallelic and monoallelic Pten knock-out mice were viable and Pten recombination was prostate-specific. Mouse cohorts were systematically characterized at 4 to 5, 7 to 9, and 10 to 14 months. A slightly increased proliferation rate of epithelial cells was observed in all prostate lobes of monoallelic Pten knock-out mice (PSA-Cre;Pten-loxP/+), but minimal pathologic changes were detected. All homozygous knock-out mice (PSA-Cre;Pten-loxP/loxP) showed an increased size of the luminal epithelial cells, large areas of hyperplasia, focal prostate intraepithelial neoplasia lesions and an increased prostate weight at 4 to 5 months. More extensive prostate intraepithelial neoplasia and focal microinvasion occurred at 7 to 9 months; invasive prostate carcinoma was detected in all male PSA-Cre;Pten-loxP/loxP mice at 10 to 14 months. At 15 to 16 months, a rare lymph node metastasis was found. In hyperplastic cells and in tumor cells, the expression of phospho-AKT was up-regulated. In hyperplastic and tumor cells, expression of luminal epithelial cell cytokeratins was up-regulated; tumor cells were negative for basal epithelial cell cytokeratins. Androgen receptor expression remained detectable at all stages of tumor development. The up-regulation of phospho-AKT correlated with an increased proliferation rate of the epithelial cells, but not with a reduced apoptosis.

Calcium, vitamin D, and apoptosis in the rectal epithelium

OBJECTIVE

Decreased apoptosis in the colon is potentially an early indicator of colon cancer risk and may be influenced by calcium and vitamin D. This report describes the associations of calcium intake and 25-hydroxyvitamin D levels with apoptosis in colorectal epithelium.

METHODS

Consecutive patients undergoing colonoscopies were recruited for a study designed to examine risk and etiologic factors for colorectal adenomas. Diet was assessed by food frequency questionnaire, and in one subpopulation, serum 25-hydroxyvitamin D levels were measured using an enzyme immunoassay. Apoptosis was scored from normal rectal mucosal pinch biopsies. Linear and logistic regression analyses were used to examine associations between calcium, serum vitamin D, and apoptotic scores. Data were available for 498 and 280 patients for the calcium and vitamin D analyses, respectively.

RESULTS

Associations of calcium intake and vitamin D with apoptosis were modified by adenoma case-status. In an adjusted logistic regression model, patients with adenomas in the highest versus lowest tertile of dietary calcium intake had 3.4 times higher odds [95% confidence interval (CI), 0.9-12.9] of elevated apoptotic scores. In adenoma-free patients, high calcium intake was not related to apoptosis (OR, 1.2; 95% CI, 0.6-2.7). In contrast, the highest level of 25-hydroxyvitamin D was associated with higher apoptosis in adenoma-free patients (OR, 2.6; 95% CI, 1.1-6.2) and slightly lower levels in patients with adenomas (OR, 0.6; 95% CI, 0.2-2.2).

CONCLUSION

These results are consistent with a calcium and vitamin D-mediated apoptotic mechanism in colon carcinogenesis.

Assessment of apoptosis by M30 immunoreactivity and the correlation with morphological criteria in normal colorectal mucosa, adenomas and carcinomas

AIMS

To investigate the monoclonal antibody M30 for the assessment of apoptosis in colorectal tissues. Although Terminal deoxyribonucleotidyl transferase mediated nick end labelling (TUNEL) and in-situ end labelling (ISEL) are the methods most often used to demonstrate and quantify apoptosis in histological tissue sections, the interpretation and specificity of these techniques have been controversial. Immunohistochemistry using the monoclonal antibody M30 that recognizes caspase-cleaved cytokeratin 18 is considered to be a promising alternative but has yet to be validated against a generally accepted standard.

METHODS AND RESULTS

Paraffin sections of normal colonic mucosa (n = 30), normal mucosa obtained from resection margins from carcinomas (n = 30), colorectal adenomas (n = 84) and carcinomas (n = 40) were studied. Apoptosis of epithelial cells was assessed by M30 immunoreactivity and morphological criteria and expressed as a proportion of the total number of cells counted (apoptotic index). Mean apoptotic indices using M30 were 0.18 +/- 0.04% in normal mucosa, 0.42 +/- 0.04% in adenomas and 1.97 +/- 0.24% in carcinomas. Using morphological criteria, these indices were 0.23 +/- 0.03%, 0.62 +/- 0.06% and 1.78 +/- 0.19%, respectively. Apoptotic counts were higher in normal mucosa obtained from resection margins than in genuinely normal mucosa using the M30 antibody. Apoptotic indices obtained by M30 immunoreactivity and morphological criteria were positively correlated (r = 0.71, P < 0.01).

CONCLUSION

Assessment of apoptotic cells by M30 immunoreactivity correlates well with morphological criteria. Apoptotic indices increase in the course of the adenoma-carcinoma sequence. Apoptosis in normal mucosa obtained from resection margins differs from genuinely normal mucosa necessitating caution when interpreting studies of apoptosis in normal colonic mucosa. Our findings support the use of the M30 method in the study of apoptosis in colorectal tissues.

Colorectal proliferation and apoptosis in serrated versus conventional adenoma-carcinoma pathway: growth, progression and survival

BACKGROUND

Hyperplastic polyp, serrated adenoma and serrated adenocarcinoma form a morphological continuum, and are likely to be biologically related. The growth rate and malignant conversion rate of serrated adenoma are postulated to be higher than those of conventional adenoma.

METHODS

Immunohistochemistry for M30 and Ki67 was used to compare apoptosis and proliferation in colorectal hyperplastic polyps, serrated adenomas and serrated adenocarcinomas, and in relation to conventional adenomas and adenocarcinomas.

RESULTS

There was an abrupt increase in the apoptosis in carcinomas of serrated adenoma-serrated adenocarcinoma pathway, indicating that inhibition of apoptosis is not maintained in serrated adenocarcinomas. Proliferation was significantly lower at the invasive margin than in the central part in adenocarcinomas, particularly in serrated adenocarcinomas (P < 0.005, Wilcoxon). Apoptosis was lower at the invasive margin than in the central part in serrated adenocarcinomas, but not in conventional adenocarcinomas.

CONCLUSIONS

Disordered regulation of apoptosis occurs later in serrated pathway than in conventional adenoma-carcinoma pathway during malignant conversion. Serrated adenoma growth is not likely to be slower than adenoma growth, as judged by the proliferation and apoptosis rates in serrated adenomas and adenomas. In cancer, the decrease of proliferation and apoptosis in the invasive margin is likely to influence the behaviour of the tumour.

Apoptosis levels increase after castration in the CWR22 human prostate cancer xenograft

BACKGROUND

The role of apoptosis in the regression of human prostate cancer after androgen deprivation therapy remains controversial. Detection of caspase-3, an ubiquitous effector of apoptosis, is a highly specific technique for in vivo evaluation of apoptosis.

METHODS

Apoptotic rates were evaluated in the androgen-dependent CWR22 human prostate cancer xenograft in tumors that represented time points throughout the progression from androgen-stimulated to recurrent prostate cancer. Caspase-3 levels in formalin-fixed, paraffin-embedded specimens were quantified using immunohistochemical detection and video image analysis. Western blot analysis was used to confirm the results of immunodetection.

RESULTS

Expression of caspase-3 reached a maximum on day 2 after castration, decreased on day 6, and remained low until tumor recurrence. The percentage of tumor area expressing caspase-3 increased from 2.51 +/- 0.44% in tumors from intact mice to 20.84 +/- 1.75% on day 2 after castration. Among immunopositive cells, the intensity of caspase-3 expression measured using the mean optical density (MOD) increased 45% (0.3762 +/- 0.003 to 0.5461 +/- 0.001) on day 2 after castration compared to levels detected in tumors from intact mice.

CONCLUSIONS

Apoptosis contributes to tumor regression after castration in the CWR22 human prostate cancer xenograft model.

Wound splinting regulates granulation tissue survival

PURPOSE

Fibroblast survival within an in vitro collagen matrix is dependent on matrix anchorage to a rigid substratum. The purpose of this study was to determine whether granulation tissue survival in vivo also is dependent on matrix anchorage. We hypothesized that splinting an excisional wound (i.e., anchoring the wound edges) would promote granulation tissue survival and that desplinting a splinted wound would produce granulation tissue apoptosis.

METHODS

Eighteen Wistar rats (3 months, 350 g) underwent excisional wounding (2 x 2 cm, dorsal skin) with immediate wound splinting (a metal template affixed with sutures) on day 0. On day 6, rats (n = 6 per group) underwent splint removal (desplinted), splint removal with circumferential incision of the wound edge (desplint/release), or no intervention (splinted); sacrifice of all animals was on day 7. Frozen sections of granulation tissue were stained with TUNEL or H and E; data were analyzed with ANOVA and the unpaired t test.

RESULTS

The cross-sectional and surface area of the desplinted and desplint/release granulation tissue both decreased compared to the splinted granulation tissue (*P < 0.05). The nuclear density of the desplint/release granulation tissue was 25% less compared to the splinted granulation tissue (*P < 0.05). The desplinted and desplint/release apoptotic rates were twice and >10x greater than the splinted apoptotic rate, respectively (*P < 0.05).

CONCLUSIONS

The rate of cell death in a splinted wound (an in vivo equivalent of an anchored FPCM) is minimal to nil, which is consistent with our hypothesis. Desplinting and releasing the wound edge of a previously splinted wound (the in vivo equivalent of a detached FPCM) results in granulation tissue regression and a large increase in apoptosis. Desplinting a wound alone results in changes somewhat intermediate to the splinted and desplint/release conditions. Loss of wound anchorage acutely promotes granulation tissue apoptosis.