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PubMed2005

New aspects of laser microdissection in research and routine.

Laser microdissection has opened a window to new technologies. The scientific fields of genomics, transcriptomics, and proteomics need pure samples for rendering reliable results. Homogeneous sample preparation is a prerequisite for modern molecular analyses, both qualitative and quantitative. Laser microdissection and pressure catapulting (LMPC) is a tool for isolating specific cells from complex tissues in a non-contact and contamination-free manner. Because LMPC technology is an optimal method for obtaining fast and reliable access to single cells, the possibility of automatic isolation of single fetal cells has the promise of being a big step forward in developing protocols for non-invasive prenatal diagnosis.

Animals↗
PubMed2004

Absence of Mycobacterium avium subsp. paratuberculosis in the microdissected granulomas of Crohn's disease.

The etiology of Crohn's disease remains unknown with inflammatory, infectious, and/or genetic causes suspected. Granulomatous inflammation is a characteristic feature of the disorder, resembling the tissue response to mycobacterium. Mycobacterium avium subsp. paratuberculosis (MAP) is the causative agent in Johne's disease, a chronic ulcerative intestinal condition in cattle, and has been implicated as a likely candidate. We carefully microdissected the granulomas from the paraffin-embedded resection specimens of 18 patients with well-established Crohn's disease. The DNA obtained was PCR amplified for the IS900 and IS1311 repeat elements of MAP, PCR product size maintained at 101 and 124 base pairs, respectively. Archival tissue from bovine Johne's disease was used as a positive control. MAP-specific DNA, confirmed by sequencing and comparison with prototype strain sequence, was appropriately amplified from the positive control. None of the Crohn's disease cases yielded a positive amplification product, failing to support a role for the organism in the pathogenesis of this illness.

Adolescent↗
PubMed2006

Merger of laser capture microdissection and mass spectrometry: a window into the amyloid plaque proteome.

The occurrence of protein accumulation and aggregation in the brain is one of the pathological hallmarks of neurodegenerative diseases such as Alzheimer's disease (AD). Although it is instructive to analyze the aggregated proteins in the brain, biochemical purification and identification of these proteins have been challenging. Recent developments in laser capture microdissection (LCM) and mass spectrometry (MS) enable large-scale protein profiling of captured tissue samples. We present here the method of analyzing senile plaques from postmortem AD brains by coupling LCM and highly sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS). First, the senile plaques were stained with thioflavin-S and precisely isolated by adjusted laser beams under a microscope. Total proteins in the isolated tissues were extracted and resolved on an SDS gel. To identify all proteins in the samples, the gel was excised into multiple pieces followed by trypsin digestion. The resulting peptides were further separated by reverse-phase chromatography and analyzed by tandem mass spectrometry. A database search of acquired MS/MS spectra allowed the identification of hundreds to thousands of peptides/proteins in the original samples. Moreover, quantitative comparison of protein composites in different LCM samples could be achieved by MS strategies. For instance, the comparison between plaques and surrounding nonplaque tissues from the same specimen revealed tens of proteins specifically enriched in the plaques. Finally, the data were corroborated by independent experiments using the approach of immunohistochemistry. Taken together, the merger of LCM and MS is a powerful tool to probe the proteome of any given pathological lesions.

Animals↗
PubMed2005

Laser microdissection in clinical cardiovascular research.

Laser microdissection (LMD) is an accurate and fast method to procure pure populations of cells from complex, heterogeneous tissues under direct microscopic visualization. It can be applied to a wide range of cell preparation, including paraffin-embedded material. The morphology of the captured cells is retained, and DNA, RNA, and proteins can be extracted for molecular analysis. The potential applications of LMD to human cardiovascular research are multiple, including viral/autoimmune myocarditis and arteritis, atherosclerotic lesions, and myocardial and vascular cell proliferation and death. Molecular and genetic analysis of LMD-procured cells in cardiac and vascular tissues may provide a better understanding of several cardiac diseases.

Biopsy↗
PubMed2003

Application of differential display, with in situ hybridization verification, to microscopic samples of breast cancer tissue.

The technique of differential display (DD) has been used widely to identify potentially interesting overexpressed or repressed genes in a variety of compared samples. When used in studying tissue samples, it inevitably confronts problems of limited amount of input material and cell-type heterogeneity. We report here the application of in situ hybridization as a method of confirmatory test for DD as well as definition of cell type expressing differential cDNA. This procedure employed material derived from a single case of human mammary, grade III, infiltrating ductal carcinoma, using free-hand microdissection, where we have compared gene expression profiles in invasive tumour with those in adjacent normal tissue. A total of 21 cDNAs were found to be differentially expressed between the two tissue types; 11 upregulated in the tumour sample and 10 upregulated in the normal sample. Six cDNAs were utilized as probes for in situ hybridization analysis of a further five cases of comparably staged breast cancer. One of these clones, 11AT1, which was found to be homologous to Hsc70, was shown to be overexpressed in tumour cells relative to adjacent normal stroma and to benign glandular epithelium in all five cases; an increase in expression was further confirmed at protein level by immunohistochemistry. The study demonstrated the applicability of in situ hybridization as a screening test in DD strategy for studying tissue material and a reasonable technique combination of identifying changes in gene expression associated with tumour development.

Base Sequence↗
PubMed2000

Gene expression profiles of the collecting duct in the mouse renal inner medulla.

UNLABELLED: Gene expression profiles of the collecting duct in the mouse renal inner medulla. BACKGROUND: Gene expression profiles, constructed from 1000 to 2000 cloned cDNA sequences, depict their relative abundance of expression in a tissue. Establishing such a profile for mouse inner renal medullary collecting ducts (IMCDs), we compared expression patterns with those in other tissues including proximal tubule. METHODS: A nonbiased 3'-end cDNA library was prepared from microdissected mouse IMCDs. Single-pass sequencing of 2000 randomly selected cDNA clones collected short sequences (approximate length, 250 bp) following poly (A), called gene signatures (GS). Identical sequences were considered a single GS. GS occurrence was quantitated to yield a list of expressed genes indicating their abundance. RESULTS: Among 2000 clones, 1613 types of transcripts were found in IMCDs; 155 were identical or homologous to reported genes. The gene most expressed in IMCDs was alphaB-crystallin, a small stress (heat-shock) protein that is also a major structural protein in the ocular lens. According to Northern analysis, renal expression of this mRNA was induced by dehydration, presumably via tissue hypertonicity. However, expression did not change with acute NaCl loading. Also, a new member of the glutathione-S-transferase family was identified by comparing the IMCD expression profile with those of other tissues. CONCLUSION: With our database of genes expressed in mouse IMCDs, we are devising an IMCD-specific microarray to study gene-expression responses to various physiologic alterations.

Amino Acid Sequence↗
PubMed2004

Expression of survivin in primary and metastatic gastric cancer cells obtained by laser capture microdissection.

AIM: Survivin, a recently identified member of the inhibitor of apoptosis protein family, is expressed during development and in various human cancers. However, its expression in normal tissues and clinical relevance in cancers are still debated. In the present study, we analyzed the expression of the survivin gene in human primary and metastatic gastric cancer cells as well as in paired epithelial cells from normal gastric mucosa by means of a novel laser capture microdissection (LCM) technique coupled with reverse transcription-polymerase chain reaction (RT-PCR). METHODS: Thirty patients who had undergone gastrectomy with lymph node dissection for gastric cancer without preoperative treatments were included. Neoplastic tissue, metastatic lymph nodes, and apparently uninvolved normal tissue were collected from each patient. LCM-captured "pure" cell groups were respectively subjected to RT-PCR analysis with primers specific for the survivin gene. RESULTS: Of the paired samples from 30 gastric cancer patients studied, 24 (80%) primary gastric cancer cell groups and 7 (23%) adjacent morphologically "normal" gastric epithelial cell groups were shown to have a detectable survivin expression. There was a statistically significant difference in suvivin expression between these two groups (P<0.01). Meanwhile, 95% (19/20) of the metastatic gastric cancer cell groups from lymph nodes had a clear expression of te survivin gene. However, no significant correlation between survivin expression and clinicopathological features of gastric cancer was observed in the present study. CONCLUSION: Survivin expression is present in the majority of gastric cancer cell groups obtained by LCM techniques. The high expression rate in metastatic lesions suggests a possible role of survivin in cancer invasiveness and metastasis. It may contribute to the detection of gastric cancer micrometastasis as a potential molecular marker. In addition, the high expression percentage renders survivin a potential target in the therapy for gastric cancer.

Adult↗
PubMed2006

Involvement of chemokine receptor CCR6 in colorectal cancer metastasis.

Various chemokine receptors, namely CXCR4, CCR6 and CCR7, have recently been shown to be involved in the regulation of metastasis in malignant tumors. However, little is known about the role of these receptors in promoting tumor metastasis of colorectal cancer (CRC) to the primary site of CRC metastasis in the liver. To investigate this issue, we analyzed the expression of the chemokine receptors CXCR4, CCR6 and CCR7 in colorectal tumors and colorectal liver metastases. In the present study, 30 human cancer samples from colorectal tissue, 30 human samples from colorectal liver metastases and the adjacent nontumorous liver tissues were screened using quantitative real-time PCR, Western blot analysis, histochemistry, microdissection and the enzyme-linked immunosorbent assay (ELISA). While an overexpression of all the chemokine receptors was found in CRC, in colorectal liver metastases only the chemokine receptors CXCR4 and CCR6 were significantly upregulated. Consequently, we investigated the expression of the corresponding ligands CXCL12/SDF1alpha, CCL20/MIP3alpha, CCL19/MIP3beta and CCL21/6Ckine in various organs, such as the stomach, esophagus, pancreas, colon and rectum, in comparison with their expression in the liver as the primary site of metastatic spread in CRC. We found that only CCL20 exhibits peak levels of expression in the liver, thus indicating that an increased production of CCL20 may contribute to the selective recruitment of CCR6-expressing cancer cells in CRC. Furthermore, we could demonstrate that CRC patients who developed liver metastases express significantly more CCL20 and CCL21 in the liver in comparison with an unaffected control group. Therefore, our findings strongly suggest an association between CCL20/CCR6 expression in human CRC and the promotion of colorectal liver metastasis.

Blotting, Western↗
PubMed2006

Gene expression profiling of lymph node metastasis by oligomicroarray analysis using laser microdissection in esophageal squamous cell carcinoma.

We applied oligomicroarray analysis of 17086 genes to identify the genes related to lymph node metastasis in esophageal squamous cell carcinoma (ESCC). The samples of cancer and non-cancerous paired tissue were taken from 16 patients with ESCC who underwent esophagectomy with lymph node dissection. Total ribonucleic acid was extracted from the cancer cells obtained by using laser microdissection and was amplified by T7 based-amplification for the application to the oligomicroarray. The oligomicroarray demonstrated 43 overexpressed genes, such as cell-cycle regulators, cell adhesion related genes, anti-apoptosis related genes, and 138 suppressed genes such as cell differentiation related and apoptosis related genes in ESCC cells with lymph node metastasis. Among them, 5 overexpressed genes (SPP-1, CKS2, CCT5, STMN1, NDUFB9) and one suppressed expression gene (GJB2) were selected in the gene profiles, and then the expressions of those genes were confirmed by real-time semi-quantitative reverse transcriptional polymerase chain reaction (RT-PCR) method for confirmation of the result not only in study cases but also in additional 21 cases. The gene expression by real-time semi-quantitative RT-PCR was in accordance with the microarray data. Although we were able to extract some genes related to nodal metastasis in ESCC, further examination is necessary in other genes as well as the interaction of stromal tissues.

Aged↗
PubMed2004

Association between gene expression profile and tumor invasion in oral squamous cell carcinoma.

There are limited studies attempting to correlate the expression changes in oral squamous cell carcinoma with clinically relevant variables. We determined the gene expression profile of 16 tumor and 4 normal tissues from 16 patients by means of Affymetrix Hu133A GeneChips. The hybridized RNA was isolated from cells obtained with laser capture microdissection, then was amplified and labeled using T7 polymerase-based in vitro transcription. The expression of 53 genes was found to differ significantly (33 upregulated, 20 downregulated) in normal versus tumor tissues under two independent statistical methods. The expression changes in four selected genes (LGALS1, MMP1, LAGY, and KRT4) were confirmed with reverse transcriptase polymerase chain reaction. Two-dimensional hierarchical clustering of the 53 genes resulted in the samples clustering according to the extent of tumor infiltration: normal epithelial tissue, tumors less than or equal to 4 cm in dimension, and tumors more than 4 cm in dimension (P = 0.0014). The same pattern of clustering was also observed for the 20 downregulated genes. We did not observe any associations with lymph node metastasis (P = 0.097).

Adult↗
PubMed2005

Design and assessment of a tissue-engineered model of human phalanges and a small joint.

OBJECTIVES: To develop models of human phalanges and small joints by suturing different cell-polymer constructs that are then implanted in athymic (nude) mice. DESIGN: Models consisted of bovine periosteum, cartilage, and/or tendon cells seeded onto biodegradable polymer scaffolds of either polyglycolic acid (PGA) or copolymers of PGA and poly-L-lactic acid (PLLA) or poly-epsilon-caprolactone (PCL) and PLLA. Constructs were fabricated to produce a distal phalanx, middle phalanx, or distal interphalangeal joint. SETTING AND SAMPLE POPULATION: Studies of more than 250 harvested implants were conducted at the Northeastern Ohio Universities College of Medicine. EXPERIMENTAL VARIABLE: Polymer scaffold, cell type, and implantation time were examined. OUTCOME MEASURE: Tissue-engineered specimens were characterized by histology, transmission electron microscopy, in situ hybridization, laser capture microdissection and qualitative and quantitative polymerase chain reaction analysis, magnetic resonance microscopy, and X-ray microtomography. RESULTS: Over periods to 60 weeks of implantation, constructs developed through vascularity from host mice; formed new cartilage, bone, and/or tendon; expressed characteristic genes of bovine origin, including type I, II and X collagen, osteopontin, aggrecan, biglycan, and bone sialoprotein; secreted corresponding proteins; responded to applied mechanical stimuli; and maintained shapes of human phalanges with small joints. CONCLUSION: Results give insight into construct processes of tissue regeneration and development and suggest more complete tissue-engineered cartilage, bone, and tendon models. These should have significant future scientific and clinical applications in medicine, including their use in plastic surgery, orthopaedics, craniofacial reconstruction, and teratology.

Animals↗
PubMed2003

An organ culture system for the study of the nucleus pulposus: description of the system and evaluation of the cells.

STUDY DESIGN: The goal of this study was to develop a methodology to maintain intervertebral discs in organ culture, thereby preserving tissue architecture and metabolic function in a three-dimensional environment. METHODS: Using a microdissection technique, intervertebral discs were removed from rat lumbar vertebrae. The discs were maintained in organ culture, and cell viability was evaluated histochemically and using probes that measured mitochondrial function and thiol status. The biosynthetic activity of the cells was evaluated by Western blot and RT-PCR analysis. RESULTS: The in vitro organ culture system maintained the vitality of the nucleus pulposus cells. Cells exhibited a high membrane potential for 1 week. When cells were exposed to carbonyl cyanide 4-trifluoromethoxy phenylhydrazone, a known protonophore, the fluorescence was lost, indicating that the staining was specific for viable cells. In many cells, Celltracker Green, probe for reduced thiols, colocalized with the membrane potential. Histologic studies revealed that in culture for 1 week, normal nucleus pulposus structure was maintained; after this time period, alterations were observed. We evaluated the two tissues for characteristic phenotypic markers HIF-1alpha and MMP-2. We noted that the nucleus pulposus expressed these proteins. The RT-PCR profile at 7 days indicated that the cells also expressed collagen type II, aggrecan, and decorin. DISCUSSION: Three factors contributed to success in maintaining the vitality of the nucleus pulposus in vitro. First, the cells were confined within the disc itself; second, the medium was hyperosmotic; third, the medium was supplemented with transforming growth factor-beta. The fluorescence measurement provided a rapid method for evaluation of the status of nucleus pulposus cells. Histologic analysis confirmed that the cells remained viable for at least 1 week. Viability in terms of biosynthetic activity was further confirmed using RT-PCR and Western blot analysis. We conclude that short-term intervertebral disc organ culture can be used as a suitable in vitro model to study effects of environmental factors linked to disc degeneration and/or regeneration.

Animals↗
PubMed1989

Sensory innervation of soft tissues of the lumbar spine in the rat.

The purpose of this study was to investigate neurophysiologically and anatomically the soft tissues of the dorsal compartment of the lumbar spine in order to understand better their possible role in low back pain. The focus was primarily on the lumbar facet joint and supraspinous ligament of the Sprague-Dawley rat. Microdissection of the dorsal ramus and electrophysiological and neuroanatomical studies of the dorsal ramus and its terminations in paravertebral tissue revealed that (a) there are mechanosensitive, slowly adapting fibers in the rat lumbar facet joint capsule; (b) there are slowly adapting, mechanosensitive units in the rat supraspinous ligaments that respond to tensile loading; both types of mechanosensitive units have high threshold; (c) mechanical stimulation of these tissues sometimes elicits afterdischarges lasting several minutes; (d) many extracellular recordings from the medial branch of the dorsal ramus appear to be reflex activity to mechanical stimulation; (e) silver impregnation of the rat joint capsule reveals individual axons, very few of which were encapsulated, suggesting that they terminate in free nerve endings; and (f) the nerves of the rat facet joint capsule contain 68, 160, and 200 kdalton polypeptide subunits of neurofilament protein (NFP). These results indicate that neurons of lumbar facet joint capsules and ligaments in the back are sensitive to mechanical strain and that the higher threshold neurons may serve a nociceptive (pain) function.

Animals↗
PubMed1993

Fetal dopamine cell survival after transplantation is dramatically improved at a critical donor gestational age in nonhuman primates.

Mesencephalic tissue containing newly generated dopamine neurons was collected from brains of embryonic African green monkeys at 44 and 49 days of gestation and stereotaxically implanted into multiple sites in the caudate nucleus of adult monkeys previously treated with the dopamine protoxin, 1-methyl-4-phenyl-1,2,3,6-tetrathydropyridine. Ultrasonography was utilized to assess the developmental stage prior to hysterotomy. Brains were removed for combined histochemical and biochemical analyses at 3 1/2 months after grafting to determine the extent of graft survival and growth. The dopamine content of the target nucleus was assessed from microdissected "punches" placed in proximity to grafts identified in unfixed brain slices prior to fixation. Tissue dopamine levels adjacent to the grafts were elevated markedly, reaching 25-50% of control levels at some sites in the caudate nucleus. Morphometric analysis of graft size and dopamine cell numbers was performed with computer-enhanced, video-based imaging. Exceptionally large grafts that far exceeded their initial size at the time of implantation were seen at each placement site. The dopamine cell count was as high as 3500 in a single graft from E44 tissue, but only as high as 550 from the E49 donor. Up to 15,000 tyrosine hydroxylase-positive neurons were stained in the host monkey that received E44 tissue; only 1/10 as many were seen in each of the recipients of E49 day samples. The earlier donor grafts occupied as much as 15% of the caudate nucleus as seen in a single coronal section; summation of all sections that contained grafts at each placement from the E44 donor revealed average areas occupied by the grafts ranging from 3 to 8% of the caudate nucleus. In comparison, grafts produced from an E49 donor averaged between 2.4 and 5.4% of the area of the target. Qualitatively, grafts from each gestational stage showed well-developed dopamine neurons with morphological characteristics equivalent to those of all three ventral mesencephalic dopamine cell groups. The attainment of large, well-differentiated grafts with thousands of dopaminergic neurons from early gestation tissue suggests that optimal cell survival in primates is dependent on the degree of postgerminal development of the dopamine neuron. Neurite extension may be critical in this regard as well as other, at present, undefined factors. Maximal graft development and cell survival may be a critical element in the ability of neural grafts to reverse a neurological disability and to maintain improvement in the event of continued degeneration of host dopamine neurons.

Animals↗
PubMed1998

Heterogeneity of mutant versus wild-type Ki-ras in primary and metastatic colorectal carcinomas, and association of codon-12 valine with early mortality.

The point mutations occurring in codons 12 and 13 of Ki-ras in 78 patients with colorectal carcinoma (31 Dukes' A and B, 21 Dukes' C, and 26 Dukes' D) have been determined by allele-specific oligonucleotide hybridization and sequencing. Duplicate samples of invasive primary carcinoma, adjacent normal tissue, and available lymph node and liver metastases from the same patients were microdissected from paraffin sections. There were no differences in the mutation rate between primary carcinomas and secondary deposits: 26 of 78 (33 per cent) primary carcinomas, 10 of 32 (31 per cent) lymph node metastases, and 10 of 26 (38 per cent) liver metastases. Multiple sampling revealed frequent heterogeneity within carcinomas: 9 of 26 primaries with Ki-ras mutations also contained areas of carcinoma with only the wild-type gene, implying that Ki-ras mutation, even when present in a colonic carcinoma, may not have been necessary for establishing the malignant phenotype. Also, 2 of 26 (8 per cent) Dukes' D patients had a mutation in their primary carcinoma but none in liver metastases and 6 of 47 (13 per cent) Dukes' C and D patients had mutations in liver or lymph node metastases but none in the primary carcinoma. Such heterogeneity may modify the effectiveness of novel therapies targeting mutant Ki-ras function, such as farnesyltransferase inhibition. Mutation of codon 12 from GGT (glycine) to GTT (valine) was more prevalent in primary and metastatic deposits of Dukes' C/D carcinomas (P = 0.01) than in primary carcinomas from Dukes' A/B patients. Mutations of codon 12 to GAT, AGT, GCT and codon 13 GGC to GAC were also found, but no correlation with carcinoma aggressiveness was apparent. Follow-up of 71/78 patients (up to 12 years) revealed decreased overall survival (P = 0.001) in patients with the GGT to GTT transversion in codon 12, even when the analysis was restricted to Dukes' D cases, supporting the suggestion that this mutation may confer a more aggressive phenotype in colorectal carcinoma.

Adenocarcinoma↗
PubMed1987

Alzheimer's disease: glutamate depletion in the hippocampal perforant pathway zone.

The perforant pathway is the primary source of cortical input to the hippocampal formation. Its cells of origin, in the entorhinal cortex, are destroyed in Alzheimer's disease. Because the principal neurotransmitter of the perforant pathway's excitatory action is thought to be glutamate, we microdissected a portion of the pathway's terminal zone and assayed the excised tissue for glutamate. There was an 83% decrease in the level of free glutamate in subjects with Alzheimer's disease as compared to control subjects not affected by dementia (p less than 0.005). We believe that this diminution in the glutamate content is a direct neurochemical correlate of perforant pathway destruction and that disruption of this crucial corticolimbic pathway contributes to the memory dysfunction in Alzheimer's disease.

Aged↗
PubMed2003

High-resolution comparative genomic hybridization detects extra chromosome arm 12p material in most cases of carcinoma in situ adjacent to overt germ cell tumors, but not before the invasive tumor development.

High-resolution comparative genomic hybridization (HR-CGH) analysis was performed on DNA purified from laser-capture microdissected carcinoma in situ (CIS) cells from nine cases of CIS, either from tissue without any invasive tumor or from testicular parenchyma adjacent to seminoma, nonseminoma, or a combined germ cell tumor. Before CGH analysis, DNA was amplified by degenerate oligonucleotide primed PCR (DOP-PCR) and directly labeled with a mixture of FITC-dUTP and FITC-dCTP. CGH analysis revealed extra chromosome arm 12p material in six out of seven cases with CIS adjacent to overt tumors, but only a diminutive gain of 12q was noted in one of the two cases of CIS without invasive elements. In addition, gains of parts of chromosome 8 (3/7) and losses of chromosome 5 (2/7) were demonstrated in CIS adjacent to invasive tumors. Gains of parts of chromosome 7 were found in CIS adjacent to seminoma (4/4), whereas relative gains of chromosome 15 were identified in some cases of CIS adjacent to seminoma and in isolated CIS in comparison to CIS adjacent to nonseminoma. Our data seem to indicate that extra 12p material is not present in the "dormant" CIS cell before development of an invasive tumor. The gain of extra chromosome 12 material may not be an early event in the neoplastic transformation, but is most likely associated with a more malignant progression of the CIS cell.

Adolescent↗
PubMed1991

Increased beta-endorphin and dynorphin concentrations in discrete hypothalamic regions of genetically obese (ob/ob) mice.

Disturbances in hypothalamic beta-endorphin and dynorphin levels were investigated in non-fasted genetically obese (ob/ob) and homozygous lean mice at 14-15 weeks of age. Eight brain regions were microdissected from fresh, unfixed brain slices, and opioid peptide concentrations were determined in tissue micropunches by radioimmunoassay. A two-fold and five-fold increase in beta-endorphin levels in ob/ob versus lean mice were found in the ventromedial and dorsomedial hypothalamic nuclei respectively. Dynorphin levels were comparable between ob/ob and lean mice in the anterior, lateral, ventromedial and paraventricular hypothalamic areas, but a 5-fold increase in dynorphin concentrations was detected in the dorsomedial hypothalamic nucleus of the ob/ob mouse. These results demonstrate that increased concentrations of beta-endorphin and dynorphin occur in discrete hypothalamic nuclei, which are known to influence food intake and glucose homeostasis. This could signify an important central defect contributing to hyperphagia and glucoregulatory dysfunction in obese mice.

Animals↗