Tumor and peritumoral adipose tissue crosstalk: De-differentiated adipocytes influence spread of colon carcinoma cells.

Colorectal cancer is the second leading cause of cancer and often has a fatal course. There are many studies in the literature that have described a close functional relationship between the tumor mass and surrounding tissue, or tumor stroma, which is affected by the continuous metabolic exchange that occurs at the interface between tumor and tissues in contact with it. There is much evidence that the presence of adipose tissue in stroma plays a fundamental role in modulating the tumor microenvironment and promote tumor development, growth, and angiogenesis due to its endocrine characteristics. In this analysis, we have studied the alterations of adipose tissue surrounding colorectal tumors with MRI and optical imaging in vivo techniques to monitor tumor progression and also performed histological and molecular analysis. We detected differences in the principal adipose markers expressed by adipocytes residing around the rectal colon and observed that peritumoral adipose tissue is exposed to a mesenchymal transition process that leads to the acquisition of a less differentiated phenotype of adipocyte that represents the main cellular type present in tumor stroma. The mesenchymal transition correlated with the acquisition of more aggressive tumor phenotype and could represent a valid target for tumor therapy.

CROCC-mutated rhabdoid colorectal carcinoma showing in intercellular spaces lamellipodia and cellular projections revealed by electron microscopy.

BACKGROUND: Rhabdoid colorectal carcinoma (RC) is a rare lesion localized to the proximal colon of patients with a mean age at diagnosis of around 70 years. This tumor shows an aggressive behavior with an overall survival period shorter than 12 months. The diagnostic hallmark is the presence of rhabdoid cells. Alterations in chromatin remodeling (SMARCB1) and in the centrosome structure (CROCC) are reported in RC usually BRAFmut and MSI-H. RKO intestinal neoplastic cells culture (BRAFmut, SMARCB1wt, MSI-H) with CROCC knockdown exhibit rhabdoid features and develop prominent projections from the edge of the cell. METHODS: Here, we investigated two cases of CROCCmutSMARCB1wt RC by scanning and transmission electron microscopy (SEM, TEM). RESULTS: TEM confirmed the diagnostic presence of intermediate cytoplasmic filaments and nucleolar margination. SEM showed cellular protrusions (lamellipodia) in the intercellular spaces not evident at light microscopy. CONCLUSIONS: These protrusions CROCC-related might represent the pathogenetic mechanism underlying the rhabdoid aggressive behavior, independently of tumor staging. To our knowledge, the SEM technique was applied in the study of this neoplasm for the first time.

Histological evaluation of periodontal ligament in human after orthodontic treatment with piezosurgery and monolateral tooth dislocation and ligament distraction technique: a first morphologic and histologic evaluation.

Traditional orthodontic tooth movement is based on the concept that application of a protracted force causes alveolar bone remodelling and adaptive changes in periodontal and dental tissues. Thus, if orthodontic tooth movement is described as a biological bone reaction to orthodontic forces mediated by the periodontal ligament (PDL), this event involves a series of sophisticated signal transduction processes that allows the PDL compression with specific histologic and biomolecular modifications. However, the preservation of the integrity of the PDL is generally difficult to achieve when it is associated with a long duration of orthodontic treatment. A total of 20 Caucasian patients with different dental-skeletal were treated using the Monocortical Tooth Dislocation and Ligament Distraction (MTDLD) technique with Piezosurgery associated with morphologic and histological evaluation of the PDL. The histological results obtained, confirm a good clinical outcome with an improvement of the speed on orthodontic treatment without any signs of tissue injury of PDL fiber without areas of hyalinization. The data suggests that MTDLD with Piezosurgery seems to be a valid alternative to the traditional orthodontic movement in adult patients preserving the anatomy and the integrity of PDL.

Characterization of magnetic nanoparticles from Magnetospirillum Gryphiswaldense as potential theranostics tools.

We investigated the theranostic properties of magnetosomes (MNs) extracted from magnetotactic bacteria, promising for nanomedicine applications. Besides a physico-chemical characterization, their potentiality as mediators for magnetic fluid hyperthermia and contrast agents for magnetic resonance imaging, both in vitro and in vivo, are here singled out. The MNs, constituted by magnetite nanocrystals arranged in chains, show a superparamagnetic behaviour and a clear evidence of Verwey transition, as signature of magnetite presence. The phospholipid membrane provides a good protection against oxidation and the MNs oxidation state is stable over months. Using an alternate magnetic field, the specific absorption rate was measured, resulting among the highest reported in literature. The MRI contrast efficiency was evaluated by means of the acquisition of complete NMRD profiles. The transverse relaxivity resulted as high as the one of a former commercial contrast agent. The MNs were inoculated into an animal model of tumour and their presence was detected by magnetic resonance images two weeks after the injection in the tumour mass.

Chromium-induced diffuse dermatitis with lymph node involvement resulting from Langerhans cell histiocytosis after metal-on-metal hip resurfacing.

Total hip arthroplasty (THA) is a highly effective surgical treatment for severe joint involvement. However, due to the release of metal ions in the blood, the patients who undergo hip replacement with metal-on-metal (MOM) bearings may develop signs of allergic skin disease. We report a case of a 60-year-old man who had received MOM hip resurfacing 5 years earlier for osteoarthritis. He presented with a 3-year history of diffuse dermatitis that did not respond to antihistamines and corticosteroids and also had elevated serum levels of chromium and cobalt. A patch test revealed chromium-sulfate hypersensitivity. A skin biopsy showed nonspecific perivascular lymphocytic infiltrate associated with histiocytes. A biopsy of an inguinal lymph node demonstrated large aggregates of Langerhans cells, suggesting type IV delayed-type hypersensitivity. The prosthesis was replaced using ceramic-on-ceramic bearings and the dermatitis resolved after 3 months. The lymph nodes decreased in volume and the serum chromium levels normalized within 24 months of revision surgery. The high levels of serum ions associated with the metal debris from MOM-THAs may induce sensitization and type IV hypersensitivity reactions. Replacing the prosthesis using alternative coupling surfaces is the only approach that has the capacity to resolve these symptoms. Physicians who are not familiar with this issue may misdiagnose systemic symptoms and provide inadequate treatment.

3D printing of rat salivary glands: The submandibular-sublingual complex.

The morphology and the functionality of the murid glandular complex, composed of the submandibular and sublingual salivary glands (SSC), were the object of several studies conducted mainly using magnetic resonance imaging (MRI). Using a 4.7 T scanner and a manganese-based contrast agent, we improved the signal-to-noise ratio of the SSC relating to the surrounding anatomical structures allowing to obtain high-contrast 3D images of the SSC. In the last few years, the large development in resin melting techniques opened the way for printing 3D objects starting from a 3D stack of images. Here, we demonstrate the feasibility of the 3D printing technique of soft tissues such as the SSC in the rat with the aim to improve the visualization of the organs. This approach is useful to preserve the real in vivo morphology of the SCC in living animals avoiding the anatomical shape changes due to the lack of relationships with the surrounding organs in case of extraction. It is also harmless, repeatable and can be applied to explore volumetric changes occurring during body growth, excretory duct obstruction, tumorigenesis and regeneration processes. 3D printing allows to obtain a solid object with the same shape of the organ of interest, which can be observed, freely rotated and manipulated. To increase the visibility of the details, it is possible to print the organs with a selected zoom factor, useful as in case of tiny organs in small mammalia. An immediate application of this technique is represented by educational classes.

Morphogenetic events in the perinodal connective tissue in a metastatic cancer model.

BACKGROUND: The modifications of connective tissue surrounding metastatic lymph nodes in a murine model of rectal cancer are described. METHODS: Athymic nude mice (n=36) were inoculated with 10×10(5) ht-29 cancer cells into the submucosal layer of the rectum. Control mice (n=5) were treated with a sterile buffer. Tumor and the involved lymph nodes were visualized in vivo by magnetic resonance imaging at 1 to 4 weeks after cell injection. After the sacrifice, the excised samples were processed for histology. RESULTS: After one week from cell injection all treated animals developed rectal cancer. Since the first week, neoplastic cells were visible in the nodes. In the surrounding connective tissue, the diameter of the adipocytes was reduced and a mesenchymal-like pattern with stellate cells embedded in an oedematous environment was visible. Since the second week, in the perinodal connective an enlargement of the stroma was present. The tissue was organized in cords and areas with extracellular accumulation of lipids were found. At the fourth week, we observed an enlargement of multilocular areas and lobules of elongated elements almost devoid of lipid droplets. In control animals, in absence of neoplastic masses, pelvic nodes were surrounded by a typical connective tissue characterized by unilocular adipocytes with groups of multilocular adipocytes. CONCLUSIONS: We have developed a model of rectal cancer with nodal metastases. Using this model, the work demonstrates that around secondary lesions, the morphogenetic events follow a standard evolution characterized by an early phase with lipolysis and mesenchymalization and later phases with a brown-like phenotype acquisition.

Optical imaging of radioisotopes: a novel multimodal approach to molecular imaging.

In this review there will be presented an overview of the literature about the recent developments on radiotracers imaging using optical methods and their applications. We will begin with a short summary regarding the discovery of Cerenkov radiation (CR) and then focus on the early developments and experimental validation of planar Cerenkov luminescence imaging. A significant improvement in Cerenkov luminescence imaging was given by the development of tomographic methods in order to obtain in vivo whole body 3D images of Cerenkov sources. An interesting and original application discussed in this review is the use of CR as the excitation source of quantum dots and fluorophores. We will also present some recent experimental results on in vivo radio luminescence imaging of alpha and gamma emitters. All these results make optical radioisotopes imaging an interesting cost-effective tool for the screening of new probes for both imaging and therapeutic applications. Other interesting aspects are the uses of Cerenkov radiation for radiotherapy and for radiopharmaceuticals synthesis applications. We will conclude by summarising the most important results and the future challenges.

The trochanteric fat pad.

Technological developments based on the use of autologous white adipose tissue (WAT) attracted attention to minor fat depots as possible sources of adipose tissue. In plastic surgery, the trochanteric fatty pad is one of the most used WAT depots for its location and organoleptic characteristics that make it particularly suitable for reconstructive procedures. Despite its wide use in clinic, the structure of this depot has never been studied in detail and it is not known if structural differences exist among trochanteric fat and other subcutaneous WAT depots. The present study was performed on trochanteric fat pad with the aim to clarify the morphology of its adipocytes, stroma and microcirculation, with particular reference to the stem niches. Histological and ultrastructural studies showed that the main peculiar feature of the trochanteric fat concerns its stromal component, which appears less dense than in the other subcutaneous WATs studied. The intra-parenchymal collagen stroma is poor and the extracellular compartment shows large spaces, filled with electron-light material, in which isolated collagen bundles are present. The adipocytes are wrapped in weak and easily detachable collagen baskets. These connective sheaths are very thin compared to the sheaths in other subcutaneous WAT depots. The capillaries are covered by large, long and thin elements surrounded by an external lamina; these perivascular cells are poor in organelles and mainly contain poly-ribosomes. In conclusion, when compared to other WAT deposits, the trochanteric fatty pad shows structural peculiarities in its stroma and microcirculation suggesting a high regenerative potential. Resistance, dissociability, microvascular weft and high regenerative potential make the trochanteric fatty pad a privileged source for harvesting in autologous WAT-based regenerative procedures.

Luminescence and fluorescence of essential oils. Fluorescence imaging in vivo of wild chamomile oil.

Essential oils are currently of great importance to pharmaceutical companies, cosmetics producers and manufacturers of veterinary products. They are found in perfumes, creams, bath products, and household cleaning substances, and are used for flavouring food and drinks. It is well known that some of them act on the respiratory apparatus. The increasing interest in optical imaging techniques and the development of related technologies have made possible the investigation of the optical properties of several compounds. Luminescent properties of essential oils have not been extensively investigated. We evaluated the luminescent and fluorescent emissions of several essential oils, in order to detect them in living organisms by exploiting their optical properties. Some fluorescent emission data were high enough to be detected in dermal treatments. Consequently, we demonstrated how the fluorescent signal can be monitored for at least three hours on the skin of living mice treated with wild chamomile oil. The results encourage development of this technique to investigate the properties of drugs and cosmetics containing essential oils.

A new model of rectal cancer with regional lymph node metastasis allowing in vivo evaluation by imaging biomarkers.

OBJECT: The work is aimed to develop a murine model of rectal cancer, which could be used to monitor lymph node metastasis development by magnetic resonance imaging (MRI) and optical imaging (OI) techniques. SUBJECTS AND METHODS: Ht-29 cancer cells were directly injected into the submucosal layer of the rectum of athymic nude mice using trans-anal rectal cancer cell injection (TARCI). Thirty-six mice were inoculated with 10×10(5) cells and five mice were treated with sterile phosphate buffer solution. One to 4 weeks after cell injection, tumor growth was evaluated in vivo using T2-weighted MRI at 4.7T. A further group of animal (n=6) treated with ht-29_luc cells, with the same protocol, was monitored by optical imaging. In both groups, the presence of the primary tumor and of lymph nodes metastasis was confirmed by histology. RESULTS: In all animals, primary tumors were detectable by MRI, 1 week from TARCI. After 4 weeks primary tumors showed a mean longitudinal diameter of about 2cm. All animals developed regional lymph node metastases. Others organs (e.g. lung or liver) were not affected. In fat-suppressed, T2-weighted MRI, lymph nodes appeared as small areas characterized by hyper-intense signal compared to muscle. OI permitted evaluation of the primary tumor growth in perineal region. CONCLUSIONS: TARCI of ht-29 cells into the rectum of nude mice is a feasible way to obtain a easily reproducible model of regional lymph node metastases could be monitored by magnetic resonance and optical imaging techniques.

Clinical target volume delineation in glioblastomas: pre-operative versus post-operative/pre-radiotherapy MRI.

OBJECTIVES: Delineation of clinical target volume (CTV) is still controversial in glioblastomas. In order to assess the differences in volume and shape of the radiotherapy target, the use of pre-operative vs post-operative/pre-radiotherapy T(1) and T(2) weighted MRI was compared. METHODS: 4 CTVs were delineated in 24 patients pre-operatively and post-operatively using T(1) contrast-enhanced (T1(PRE)CTV and T1(POST)CTV) and T(2) weighted images (T2(PRE)CTV and T2(POST)CTV). Pre-operative MRI examinations were performed the day before surgery, whereas post-operative examinations were acquired 1 month after surgery and before chemoradiation. A concordance index (CI) was defined as the ratio between the overlapping and composite volumes. RESULTS: The volumes of T1(PRE)CTV and T1(POST)CTV were not statistically different (248 ± 88 vs 254 ± 101), although volume differences >100 cm(3) were observed in 6 out of 24 patients. A marked increase due to tumour progression was shown in three patients. Three patients showed a decrease because of a reduced mass effect. A significant reduction occurred between pre-operative and post-operative T(2) volumes (139 ± 68 vs 78 ± 59). Lack of concordance was observed between T1(PRE)CTV and T1(POST)CTV (CI = 0.67 ± 0.09), T2(PRE)CTV and T2(POST)CTV (CI = 0.39 ± 0.20) and comparing the portion of the T1(PRE)CTV and T1(POST)CTV not covered by that defined on T2(PRE)CTV images (CI = 0.45 ± 0.16 and 0.44 ± 0.17, respectively). CONCLUSION: Using T(2) MRI, huge variations can be observed in peritumoural oedema, which are probably due to steroid treatment. Using T(1) MRI, brain shifts after surgery and possible progressive enhancing lesions produce substantial differences in CTVs. Our data support the use of post-operative/pre-radiotherapy T(1) weighted MRI for planning purposes.

DCE-MRI data analysis for cancer area classification.

OBJECTIVES: The paper aims at improving the support of medical researchers in the context of in-vivo cancer imaging. Morphological and functional parameters obtained by dynamic contrast-enhanced MRI (DCE-MRI) techniques are analyzed, which aim at investigating the development of tumor microvessels. The main contribution consists in proposing a machine learning methodology to segment automatically these MRI data, by isolating tumor areas with different meaning, in a histological sense. METHODS: The proposed approach is based on a three-step procedure: i) robust feature extraction from raw time-intensity curves, ii) voxel segmentation, and iii) voxel classification based on a learning-by-example approach. In the first step, few robust features that compactly represent the response of the tissue to the DCE-MRI analysis are computed. The second step provides a segmentation based on the mean shift (MS) paradigm, which has recently shown to be robust and useful for different and heterogeneous clustering tasks. Finally, in the third step, a support vector machine (SVM) is trained to classify voxels according to the labels obtained by the clustering phase (i.e., each class corresponds to a cluster). Indeed, the SVM is able to classify new unseen subjects with the same kind of tumor. RESULTS: Experiments on different subjects affected by the same kind of tumor evidence that the extracted regions by both the MS clustering and the SVM classifier exhibit a precise medical meaning, as carefully validated by the medical researchers. Moreover, our approach is more stable and robust than methods based on quantification of DCE-MRI data by means of pharmacokinetic models. CONCLUSIONS: The proposed method allows to analyze the DCE-MRI data more precisely and faster than previous automated or manual approaches.

Inhibition of tyrosine kinase receptors by SU6668 promotes abnormal stromal development at the periphery of carcinomas.

Dynamic contrast-enhanced (albumin-Gd-DTPA) magnetic resonance imaging, performed during 2 weeks of daily administration of an inhibitor of tyrosine kinase receptors (SU6668) in an HT-29 colon carcinoma model, revealed the onset of a hyper-enhancing rim, not observed in untreated tumours. To account for tissue heterogeneity in the quantitative analysis, we segmented tumours into three subunits automatically identified by cluster analysis of the enhancement curves using a k-means algorithm. Transendothelial permeability (Kps) and fractional plasma volume (fPV) were calculated in each subunit. An avascular and necrotic region, an intermediate zone and a well-vascularised periphery were reliably identified. During untreated tumour growth, the identified sub-regions did not substantially change their enhancement pattern. Treatment with SU6668 induced major changes at tumour periphery where a significant increase of Kps and fPV was observed with respect to control tumours. Histology revealed a sub-capsular layer composed of hyper-dense viable tumour cells in the periphery of untreated tumours. The rim of viable neoplastic cells was reduced in treated tumours, and replaced by loose connective tissue characterised by numerous vessels, which explains the observed hyper-enhancement. The present data show a peripheral abnormal development of cancer-associated stroma, indicative of an adaptive response to anti-angiogenic treatment.

Synthesis and characterization of polyethylenimine-based iron oxide composites as novel contrast agents for MRI.

OBJECT: Use of polyethylenimines (PEIs) of different molecular weight and selected carboxylated-PEI derivatives (PEI-COOH) in the synthesis and stabilization of iron oxide nanoparticles, to obtain possible multifunctional contrast agents. MATERIALS AND METHODS: Oxidation of Fe(II) at slightly elevated pH and temperature resulted in the formation of highly soluble and stable nanocomposites of iron oxides and polymer. Composites were characterized and studied by atomic force microscopy (AFM), transmission electron microscopy (TEM), X-ray diffractometry, AC and DC magnetometry, NMR relaxometry and magnetic resonance imaging (MRI). RESULTS: From AFM the dimensions of the aggregates were found to be in the ~150-250 nm size region; the mean diameter of the magnetic core of the compounds named PEI-25, PEI-500 and PEI-COOH60 resulted d approximately 20 +/- 5 nm for PEI-25, d approximately 9.5 +/- 1.0 nm for PEI-500 and d approximately 6.8 +/- 1.0 nm for PEI-COOH60. In PEI-COOH60 TEM and X-ray diffractometry revealed small assemblies of mineral magnetic cores with clear indications that the main constituents are maghemite and/or magnetite as confirmed by AC and DC SQUID magnetometry. For PEI-COOH60, the study of NMR-dispersion profiles revealed r (1) and r (2) relaxivities comparable to superparamagnetic iron-oxide commercial compounds in the whole investigated frequency range 7 < or = nu < or = 212 MHz. CONCLUSION: PEI-25 was studied as possible MRI contrast agent (CA) to map the cerebral blood volume (CBV) and cerebral blood flow (CBF) in an animal model obtaining promising results. The reported compounds may be further functionalized to afford novel multifunctional systems for biomedical applications.

Mesenchymal stem cells share molecular signature with mesenchymal tumor cells and favor early tumor growth in syngeneic mice.

Tumor microenvironment in carcinomas recruits mesenchymal cells with an abnormal proangiogenic and invasive phenotype. It is not clear whether mesenchymal tumor cells (MTCs) derive from the activation of mature fibroblasts or from their stem cell precursors. However, stromal cell activation in tumors resembles in several aspects the mesenchymal rearrangement which normally occurs during reparative processes such as wound healing. Mesenchymal stem cells (MSCs) play a crucial role in developmental and reparative processes and have extraordinary proangiogenic potential, on the basis of which they are thought to show great promise for the treatment of ischemic disorders. Here, we show that MTCs have proangiogenic potential and that they share the transcriptional expression of the best-known proangiogenic factors with MSCs. We also found that MTCs and MSCs have the same molecular signature for stemness-related genes, and that when co-implanted with cancer cells in syngeneic animals MSCs determine early tumor appearance, probably by favoring the angiogenic switch. Our data (1) reveal crucial aspects of the proangiogenic phenotype of MTCs, (2) strongly suggest their stem origin and (3) signal the risk of therapeutic use of MSCs in tumor-promoting conditions.

Pathological animal models in the experimental evaluation of tumour microvasculature with magnetic resonance imaging.

PURPOSE: The purpose of this study was to evaluate the applications of magnetic resonance imaging (MRI), and in particular, dynamic contrast-enhanced MRI (DCE-MRI), in the assessment of tumour microvasculature by means of animal tumour models evaluated before and after antiangiogenic treatment. MATERIALS AND METHODS: Forty-two MRI exams were performed with intravascular contrast media in 21 rats: tumours were induced by subcutaneous injection of colon carcinoma cells in 7 rats and mammary adenocarcinoma cells in 14 rats. Perfusion and permeability parameters of the implanted tumours were evaluated by using two contrast media (B22956/1 and Gd-DTPA37-albumin) to establish response to treatment with two different antiangiogenic drugs (tamoxifen and SU6668). These parameters were correlated with histology to obtain a radiological-histological map of tumour microvasculature. RESULTS: DCE-MRI revealed greater enhancement in the peripheral area than in the central area in all the examined animal models. In the mammary carcinoma experiment, vascular permeability measured by means of B22956/1 in the animals treated with the antiangiogenic drug (0.0043317+/-0.0040418 ml/min(-1)/ml(-1)) was significantly less than in untreated animals (0.0090460+/-0.0043680 ml/min(-1)/ml(-1)), whereas no significant difference was observed with Gd-DTPA-albumin (13.14+/-13.94 ml/min(-1)/ml(-1) in treated animals and 18.07+/-11.92 ml/min(-1)/ml(-1) in untreated animals). In the colon carcinoma experiment, mean permeability and perfusion decreased by 51% (from 5.2+/-1.1 to 2.5+/-0.8 ml/100 ml) and 59% (from 0.00165+/-5.1 to 0.0067+/-4.8 ml/min(-1)/ml(-1) of tissue), respectively, in all animals after antiangiogenic drug administration. CONCLUSIONS: DCE-MRI permits a noninvasive evaluation of tumour microcirculation and in particular of its dynamic characteristics and vascularity before and after antiangiogenic treatment.

A new fate for old cells: brush cells and related elements.

Over the past 50 years, hundreds of studies have described those cells that are characterized by a brush of rigid apical microvilli with long rootlets, and which are found in the digestive and respiratory apparatuses. These cells have been given names such as brush cells, tuft cells, fibrillovesicular cells, multivesicular cells and caveolated cells. More recently, it has been realized that all these elements may represent a single cell type, probably with a chemosensory role, even if other functions (e.g. secretory or absorptive) seem to be possible. Very recent developments have permitted a partial definition of the chemical code characterizing these elements, revealing the presence of molecules involved in chemoreceptorial cell signalling. A molecular cascade, similar to those characterizing the gustatory epithelium, seems to be present in these elements. These new data suggest that these elements can be considered solitary chemosensory cells with the presence of the apical 'brush' as an inconsistent feature. They seem to comprise a diffuse chemosensory system that covers large areas (probably the whole digestive and respiratory apparatuses) with analogies to chemosensory systems described in aquatic vertebrates.

Gluten sensitivity and 'normal' histology: is the intestinal mucosa really normal?

BACKGROUND: Early pathogenetic events of gluten intolerance may be overlooked in patients with serologic markers of celiac disease and normal intestinal mucosa by both conventional histology and immunohistochemistry. AIMS: To investigate if a submicroscopical damage of the absorptive cell surface was associated with developing gluten sensitivity. PATIENTS AND METHODS: Duodenal biopsies of seven subjects with positive anti-endomysial antibodies and normal histology underwent ultrastructural evaluation of the epithelial surface by means of both scanning and transmission electron microscopy. Specimens of intestinal mucosa of 14 children with non-celiac conditions were used as controls. RESULTS: In four patients, electron microscopy revealed alterations of the enterocyte brush border with a significant reduction of the height of microvilli. After several months, three of them had a second biopsy that eventually showed histological modifications suggestive of celiac disease. In the other three patients, no significant alteration of enterocyte ultrastructure was observed. One of them, rebiopsied after 12 months, still showed a normal duodenal histology. CONCLUSIONS: Gluten sensitivity can be associated with 'minimal' mucosal changes not detectable with conventional light microscopy. Such lesions, which primarily involve microvillous structure, may imply a reduction of intestinal absorptive surface already in the latent stage of the disease.