Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P61278 (somatostatin)
 22,083 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In a 40-year-old man who had suffered from vague and generalized bone pains for 7 years due to oncogenic osteomalacia, the causative tumour was finally detected by Indium-111 octreotide scintigraphy. Some characteristics of the tumour associated with oncogenic osteomalacia, such as its size, growth rate, location and origin, often make the diagnosis difficult. However, the recent discovery of somatostatin receptors in mesenchymal tumours, which are the most common cause of oncogenic osteomalacia, has raised the possibility of early detection of this devastating disorder. Here, we report that radiolabelled octreotide scintigraphy has a potential role as a diagnostic tool in oncogenic osteomalacia. However, the exact role of somatostatin receptors in tumours associated with oncogenic osteomalacia still remains elusive.
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PMID:Oncogenic osteomalacia associated with mesenchymal tumour detected by indium-111 octreotide scintigraphy. 1131 93

Oncogenic osteomalacia, an acquired hypophosphataemic syndrome associated with mesenchymal tumours, is characterised by hypophosphataemia secondary to inappropriate phosphaturia, reduced concentrations of serum calcitriol, and defective bone mineralisation. Removal of these tumours results in complete reversal of these biochemical defects. However, because these tumours are small, slow-growing, and frequently situated in unusual anatomical sites, conventional imaging techniques often fail to detect them. Since mesenchymal tumours express somatostatin receptors, we postulated that somatostatin analogues would be able to detect these tumours. We did Indium-111 labeled pentetreotide imaging in seven patients with oncogenic osteomalacia. In five patients, we identified a mesenchymal tumour, and clinical improvement occurred after tumour resection. Our findings suggest that 111In-pentetreotide imaging effectively detects occult mesenchymal tumours and facilitates surgical treatment of oncogenic osteomalacia.
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PMID:Localisation of mesenchymal tumours by somatostatin receptor imaging. 1188 89

Somatostatin is a hormone that regulates several physiological cell processes via specific receptors expressed throughout the body, in particular by nerve cells, many neuroendocrine cells, and cells mediating inflammation and immune responses. Somatostatin receptor scintigraphy achieved by administration of somatostatin labeled with a gamma-emitting isotope has become an integral part of the work-up and treatment-monitoring program in patients with neuroendocrine tumors, most of which overexpress somatostatin receptors. Several studies have convincingly established that somatostatin receptor scintigraphy benefits patients with a number of chronic inflammatory diseases, including sarcoidosis and other granulomatous diseases. In the evaluation of hematological diseases and detection of mesenchymatous tumors manifesting as oncogenic osteomalacia, the preliminary results are sufficiently promising to warrant larger studies aimed at defining the role for this noninvasive whole-body imaging technique. In the treatment area, the development of somatostatin analogs with antisecretory and antiproliferative effects has radically changed the management of gastroenteropancreatic neuroendocrine and pituitary tumors. The antiinflammatory and analgesic effects of these drugs remain incompletely understood, but may prove useful in a number of autoimmune diseases.
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PMID:Somatostatin and somatostatin analog scintigraphy: any benefits for rheumatology patients? 1558 34

Clinical application of natural somatostatin is limited due to its short effect (the half-life of the preparation is less than 3 min), and a rebound effect after its administration. For these reasons, synthetic analogues of somatostatin, among which sandostatin (octreotide acetate) was the first one, were developed. Other cyclic analogues with similar sensitivity and activity profile, such as lanreotide (somatulin), somatostatin-14, and SOM 230, have been developed as well. These preparations seem to possess certain antiproliferative activity. Somatostatin analogues may be administered in repeated hypodermic injections, or repeated or prolonged intravenous infusions. Long-acting intramuscular preparations (sandostatin LAR) are usually administered once in four weeks, while long-acting lanreotide (somatulin) is administered once in two weeks. Sandostatin therapy is indicated to patients with functionally active neuroendocrine tumors of the stomach, duodenum, small bowel, or appendix. Glucagonomas, vipomas, and, to a lesser degree, gastrinomas and metastatic insulinomas are examples of functionally active endocrine pancreatic tumors that should be treated with sandostatin. Patients are selected according to a positive result of OcreoScan test. Other syndromes, which should be treated with octreotide, include ectopic secretion of adrenocorticotropic hormone in Cushing syndrome, oncogenic osteomalacia, and hypercalciemia resulting from ectopic secretion of parathyroid-like peptide. In patients with an advanced carcinoid syndrome, the starting dose of sandostatin (ocreotide) is 150 mcgr administered three times a day in hypordermic injections during 10 to 14 days, after which sandostatin LAR is administered in a dose of 20 mg once a month. Sandostatin is usually administered for the life-term of the patient, exept cases of intractable adverse effects or the development of total insensitivity.
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PMID:[Somatostatin analogues in treatment of gastrointestinal and pancreatic neuroendocrine tumors]. 1675 46

Oncogenic osteomalacia is a rare paraneoplastic syndrome of acquired hypophosphatemic osteomalacia, resulting from a deficit in renal tubular phosphate reabsorption, in which fibroblast growth factor 23 (FGF23) seems to be implicated. This condition is usually associated with a phosphaturic mesenchymal tumor of mixed connective tissue located in the bone or soft tissue. The clinical and the radiologic findings are the same as those seen in osteomalacia, and the biochemical features include renal phosphate loss, low serum phosphate and 1,25-(OH)(2) vitD(3) levels, increased alkaline phosphatase, and normal calcium, PTH, calcitonin, 25-OH-vitD(3) and 25,25-(OH)(2) vitD(3). We present two cases of oncogenic osteomalacia associated with phosphaturic mesenchymal tumors, which were histologically similar, but presented a completely different evolution. In the first patient, the tumor developed on the sole of the foot. Following removal of the mass, the symptoms resolved and biochemical and radiological parameters returned to normal. However, in the second patient, a liver tumor developed and resection did not resolve the disease. Multiple lesions appeared in several locations during follow-up. This disease usually remits with complete tumor resection. Nevertheless, if this is not possible, oral treatment with phosphate, calcium and calcitriol can improve the symptoms. If scintigraphy of the tumor shows octreotide receptors, patients may respond partially to therapy with somatostatin analogs, with stabilization of the lesion.
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PMID:Oncogenic osteomalacia: two case reports with surprisingly different outcomes. 1912 58

Oncogenic osteomalacia (OOM) is a rare disease characterized by renal phosphate wasting and osteomalacia and is caused by the secretion of fibroblast growth factor 23 (FGF-23) from causative tumors. Scintigraphy with octreotide, which binds to somatostatin receptors (SSTRs), is a useful way to locate causative tumors in OOM patients. However, the therapeutic effects of octreotide acetate are still controversial. Two OOM patients were administered octreotide acetate intramuscularly. Ten causative OOM tumors, including two resected from the patients participating in the octreotide administration study, were examined for expression of genes encoding SSTRs by quantitative real-time RT-PCR and immunohistochemistry. Octreotide therapy did not improve hypophosphatemia in either case, despite temporal decreases in FGF-23 levels in one patient. The mean expression levels of SSTR1, SSTR3, and SSTR5 were similar in the OOM and non-OOM tumors. Expression of SSTR2 was significantly higher in the OOM tumors than in the non-OOM tumors. Immunohistochemical examinations revealed the presence of SSTR2A, SSTR2B, and SSTR5 in both the OOM and non-OOM tumors. The expression of SSTR genes in OOM tumors contributes to positive imaging using octreotide scintigraphy. However, the levels of SSTRs seem to be insufficient for the octreotide therapy to improve hypophosphatemia. Further studies are needed to clarify the mechanisms by which FGF-23 secretion from OOM tumors is suppressed by octreotide acetate.
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PMID:The levels of somatostatin receptors in causative tumors of oncogenic osteomalacia are insufficient for their agonist to normalize serum phosphate levels. 2045 78

Bilateral insufficiency fractures of the proximal femur often have a pathological basis. Diagnosis of rare causes of insufficiency fractures can be challenging. Tumour-induced osteomalacia (TIO) is a rare paraneoplastic syndrome of mesenchymal tumours which leads to hypophosphataemia and osteomalacia. Suspected pathological fractures should be investigated thoroughly including a fasting serum phosphate level. Further investigations should include serum levels of fibroblast growth factor 23 (FGF23) which is a peptide hormone secreted by mesenchymal tumours. Available imaging modalities include Octreotide scanning which detects somatostatin receptors commonly expressed on mesenchymal tumours. After localisation and resection of the tumour, a full recovery from TIO is achievable.
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PMID:Bilateral subtrochanteric fractures in tumour-induced osteomalacia caused by a nasal haemangiopericytoma. 2254 77

The patient with a history of bone pain and muscle weakness, was thought to have oncogenic osteomalacia as a result of biochemical investigations and directed to Nuclear Medicine Department for a whole-body bone scintigraphy and 111In-octreotide scintigraphy. There was no focal pathologic tracer uptake, but generalized marked increase in skeletal uptake on bone scintigraphy. Octreotide scintigraphy showed accumulation of octreotide in the region of the left lobe of the thyroid gland in the neck. Thereafter, parathyroid scintigraphy was performed with technetium-99m labeled metroxy-isobutyl-isonitryl (99mTc-MIB) and MIBI scan demonstrated radiotracer uptake at the same location with octreotide scintigraphy. The patient underwent left inferior parathyroidectomy and histopathology confirmed a parathyroid adenoma. Somatostatin receptor positive parathyroid adenoma may show octreotide uptake. Octreotide scintigraphy may be promising and indicate a possibility of using somatostatin analogues for the medical treatment of somatostatin receptor positive Conflict of interest:None declared.
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PMID:Octreotide uptake in parathyroid adenoma. 2348 97

Tumor-induced osteomalacia (TIO) is a paraneoplastic syndrome characterized by renal phosphate wasting, hypophosphatemia and low calcitriol levels as well as clinical symptoms like diffuse bone and muscle pain, fatigue fractures or increased fracture risk. Conventional imaging methods, however, often fail to detect the small tumors. Lately, tumor localization clearly improved by somatostatin-receptor (SSTR) imaging, such as octreotide scintigraphy or octreotide SPECT/CT. However, recent studies revealed that still a large number of tumors remained undetected by octreotide imaging. Hence, studies focused on different SSTR imaging methods such as 68Ga DOTA-NOC, 68Ga DOTA-TOC and 68Ga DOTA-TATE PET/CT with promising first results. Studies comparing different SSTR imaging methods for tumor localization in TIO are rare and thus little is known about diagnostic alternatives once a particular method failed to detect a tumor in patients with TIO. Here, we report the data of 5 consecutive patients suffering from TIO, who underwent both 111Indium-octreotide scintigraphy (111In-OCT) SPECT/CT as well as 68Ga DOTA-TATE PET/CT for tumor detection. While 111In-OCT SPECT/CT allowed tumor detection in only 1 of 5 patients, 68Ga DOTA-TATE PET/CT was able to localize the tumor in all patients. Afterwards, anatomical imaging of the region of interest was performed with CT and MRI. Thus, successful surgical resection of the tumor was achieved in all patients. Serum phosphate levels returned to normal and all patients reported relief of symptoms within weeks. Moreover, an iliac crest biopsy was obtained from every patient and revealed marked osteomalacia in all cases. Follow-up DXA revealed an increase in BMD of up to 34.5% 1-year postoperative, indicating remineralization. No recurrence was observed. In conclusion our data indicates that 68Ga DOTA-TATE PET/CT is an effective and promising diagnostic tool in the diagnosis of TIO, even in patients in whom 111In-OCT prior failed to detect a tumor.
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PMID:68Ga DOTA-TATE PET/CT allows tumor localization in patients with tumor-induced osteomalacia but negative 111In-octreotide SPECT/CT. 2476 33

Somatostatins are peptide hormones that regulate diverse cellular processes, such as neurotransmission, cell proliferation, apoptosis, and endocrine signaling as well as inhibiting the release of many hormones and other secretory proteins. SSTR1 is a member of the superfamily of somatostatin receptors possessing seven-transmembrane segments. Aberrant expression of SSTR1 has been implicated in several human diseases, including pseudotumor cerebri, and oncogenic osteomalacia. In this study, we investigated a potential role of SSTR1 in the regulation of neuronal apoptosis in the course of intracerebral hemorrhage (ICH). A rat ICH model in the caudate putamen was established and subjected to behavioral tests. Western blot and immunohistochemistry indicated a remarkable up-regulation of SSTR1 expression surrounding the hematoma after ICH. Double-labeled immunofluorescence showed that SSTR1 was mostly co-localized with neurons, and was rarely distributed in activated astrocytes and microglia. Additionally, SSTR1 co-localized with active-caspase-3 and bcl-2 around the hematoma. The expression of active-caspase-3 was parallel with that of SSTR1 in a time-dependent manner. In addition, SSTR1 knockdown specifically resulted in reduced neuronal apoptosis in PC12 cells. All our findings suggested that up-regulated SSTR1 contributed to neuronal apoptosis after ICH, which was accompanied with reduced expression of bcl-2.
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PMID:Upregulated expression of SSTR1 is involved in neuronal apoptosis and is coupled to the reduction of bcl-2 following intracerebral hemorrhage in adult rats. 2503 58


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