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TouchREVIEWS in Endocrinology Apr 2024Injectable somatostatin receptor ligands (iSRL) are the most frequently utilized medical therapy in patients with acromegaly; however, satisfaction rates are suboptimal.... (Review)
Review
Injectable somatostatin receptor ligands (iSRL) are the most frequently utilized medical therapy in patients with acromegaly; however, satisfaction rates are suboptimal. Injections can result in local erythema, discomfort and subcutaneous nodule formation, encompassed with the inconvenience of attending either primary or secondary care medical facilities for injections every 4 weeks. Some patients also note breakthrough of acromegaly-related symptoms towards the end of the injection cycle. To improve acceptance and ultimately improve wellbeing of these individuals, two oral SRLs, oral octreotide capsules (OOC) and paltusotine, have been developed. The OOC combines an enteric coating to allow delivery to the small intestines and a transient permeability enhancer to enable oral bioavailability. Comparable octreotide levels are obtained with twice-daily OOC and subcutaneous octreotide 100 µg. Phase III studies show OOC to maintain equivalent biochemical control in at least 60% of patients previously receiving a stable dose of iSRL. In longer-term studies, the response to OOC was durable up to 3 years. Paltusotine is a novel potent orally available non-peptidyl somatostatin receptor subtype-2 ligand. Studies in healthy volunteers show dose-dependent suppression of growth hormone-releasing hormone-induced growth hormone secretion and suppression of insulin-like growth factor-I (IGF-I) with repeat doses. In the recent phase II study, patients with acromegaly who were partial responders (IGF-I 1.0 - 2.5 x upper limit of normal) to monotherapy with iSRL when switched to once-daily paltusotine maintained control of IGF-I within 20% of baseline or lower in 87% after 13 weeks. Adverse events with both OOC and paltusotine were reflective of those recognized with iSRL and occurred at a similar frequency. OOC and paltusotine are well-received additions to the therapeutic armamentarium in medical therapy for the management of acromegaly; however, further data on efficacy, tumour control and shrinkage are required to allow positioning of this medication within the management algorithm for acromegaly.
PubMed: 38812672
DOI: 10.17925/EE.2023.20.1.3 -
Journal of Cancer Research and Clinical... May 2024Somatostatin receptor (SSTR)-targeted PET imaging has emerged as a common approach to evaluating those patients with well-differentiated neuroendocrine tumors (NETs)....
PURPOSE
Somatostatin receptor (SSTR)-targeted PET imaging has emerged as a common approach to evaluating those patients with well-differentiated neuroendocrine tumors (NETs). The SSTR reporting and data system (SSTR-RADS) version 1.0 provides a means of categorizing lesions from 1 to 5 according to the likelihood of NET involvement, with SSTR-RADS-3A (soft-tissue) and SSTR-RADS-3B (bone) lesions being those suggestive of but without definitive NET involvement. The goal of the present study was to assess the ability of Ga-DOTATATE PET/MR imaging data to predict outcomes for indeterminate SSTR-RADS-3A and 3B lesions.
METHODS
NET patients with indeterminate SSTR-RADS-3A or SSTR-RADS-3B lesions who underwent Ga-DOTATATE PET/MR imaging from April 2020 through August 2023 were retrospectively evaluated. All patients underwent follow-up through December 2023 (median, 17 months; (3-31 months)), with imaging follow-up or biopsy findings ultimately being used to classify lesions as malignant or benign. Lesion maximum standardized uptake value (SUVmax) along with minimum and mean apparent diffusion coefficient (ADCmin and ADCmean) values were measured and assessed for correlations with outcomes on follow-up.
RESULTS
In total, 33 indeterminate SSTR-RADS-3 lesions from 22 patients (19 SSTR-RADS-3A and 14 SSTR-RADS-3B) were identified based upon baseline Ga-DOTATATE PET/MR findings. Over the course of follow-up, 16 of these lesions (48.5%) were found to exhibit true NET positivity, including 9 SSTR-RADS-3A and 7 SSTR-RADS-3B lesions. For SSTR-RADS-3A lymph nodes, a diameter larger than 0.7 cm and an ADCmin of 779 × 10mm/s or lower were identified as being more likely to be associated with metastatic lesions. Significant differences in ADCmin and ADCmean were identified when comparing metastatic and non-metastatic SSTR-RADS-3B bone lesions (P < 0.05), with these parameters offering a high predictive ability (AUC = 0.94, AUC = 0.86).
CONCLUSION
Both diameter and ADCmin can aid in the accurate identification of the nature of lesions associated with SSTR-RADS-3A lymph nodes, whereas ADCmin and ADCmean values can inform the accurate interpretation of SSTR-RADS-3B bone lesions.
Topics: Humans; Neuroendocrine Tumors; Male; Female; Middle Aged; Organometallic Compounds; Aged; Retrospective Studies; Receptors, Somatostatin; Adult; Positron-Emission Tomography; Magnetic Resonance Imaging; Radiopharmaceuticals; Aged, 80 and over; Prognosis
PubMed: 38795250
DOI: 10.1007/s00432-024-05776-5 -
Cancers May 2024The overexpression of somatostatin receptor type 2 (SSTR2) is a property of various tumor types. Hybrid imaging utilizing...
The overexpression of somatostatin receptor type 2 (SSTR2) is a property of various tumor types. Hybrid imaging utilizing [Ga]1,4,7,10-tetraazacyclododecane-1,4,7,10-tetra-acetic acid (DOTA) may improve the differentiation between tumor and healthy tissue. We conducted an experimental study on 47 anonymized patient cases including 30 meningiomas, 12 PitNET and 5 SBPGL. Four independent observers were instructed to contour the macroscopic tumor volume on planning MRI and then reassess their volumes with the additional information from DOTA-PET/CT. The conformity between observers and reference volumes was assessed. In total, 46 cases (97.9%) were DOTA-avid and included in the final analysis. In eight cases, PET/CT additional tumor volume was identified that was not detected by MRI; these PET/CT findings were potentially critical for the treatment plan in four cases. For meningiomas, the interobserver and observer to reference volume conformity indices were higher with PET/CT. For PitNET, the volumes had higher conformity between observers with MRI. With regard to SBGDL, no significant trend towards conformity with the addition of PET/CT information was observed. DOTA PET/CT supports accurate tumor recognition in meningioma and PitNET and is recommended in SSTR2-expressing tumors planned for treatment with highly conformal radiation.
PubMed: 38791956
DOI: 10.3390/cancers16101877 -
International Journal of Molecular... May 2024A novel nanotechnology-based drug delivery system (DDS) targeted at pancreatic cancer cells was developed, characterized, and tested. The system consisted of liposomes...
A novel nanotechnology-based drug delivery system (DDS) targeted at pancreatic cancer cells was developed, characterized, and tested. The system consisted of liposomes as carriers, an anticancer drug (paclitaxel) as a chemotherapeutic agent, and a modified synthetic somatostatin analog, 5-pentacarbonyl-octreotide, a ligand for somatostatin receptor 2 (SSTR2), as a targeting moiety for pancreatic cancer. The cellular internalization, cytotoxicity, and antitumor activity of the DDS were tested in vitro using human pancreatic ductal adenocarcinoma (PDAC) cells with different expressions of the targeted SSTR2 receptors, and in vivo on immunodeficient mice bearing human PDAC xenografts. The targeted drug delivery system containing paclitaxel exhibited significantly enhanced cytotoxicity compared to non-targeted DDS, and this efficacy was directly related to the levels of SSTR2 expression. It was found that octreotide-targeted DDS proved exceptionally effective in suppressing the growth of PDAC tumors. This study underscores the potential of octreotide-targeted liposomal delivery systems to enhance the therapeutic outcomes for PDAC compared with non-targeted liposomal DDS and Paclitaxel-Cremophor EL, suggesting a promising avenue for future cancer therapy innovations.
Topics: Animals; Humans; Pancreatic Neoplasms; Receptors, Somatostatin; Mice; Cell Line, Tumor; Paclitaxel; Liposomes; Drug Delivery Systems; Xenograft Model Antitumor Assays; Octreotide; Somatostatin; Nanotechnology; Antineoplastic Agents; Carcinoma, Pancreatic Ductal
PubMed: 38791582
DOI: 10.3390/ijms25105545 -
Archives of Endocrinology and Metabolism May 2024Hemangioblastomas associated with von Hippel-Lindau (VHL) disease are frequently multiple and recur during prolonged follow-up. Currently, no systemic treatment is... (Review)
Review
Expression of somatostatin receptors in hemangioblastomas associated with von Hippel-Lindau disease as a novel diagnostic, therapeutic, and follow-up opportunity: A case report and literature review.
Hemangioblastomas associated with von Hippel-Lindau (VHL) disease are frequently multiple and recur during prolonged follow-up. Currently, no systemic treatment is available for these tumors. Recent studies have shown the expression of somatostatin receptors in these types of hemangioblastomas. Notably, increased somatostatin receptor expression in a tumor, as determined by peptide-receptor radionuclide imaging, is a predictive factor of response to treatment with somatostatin analogs and peptide-receptor radionuclide therapy. The aim of this study was to describe the case of a patient with increased expression of somatostatin receptors in a suprasellar hemangioblastoma associated with VHL disease and conduct a literature review on somatostatin receptor expression in patients with VHL-associated hemangioblastomas. We describe herein the case of a 51-year-old man with VHL disease who had a suprasellar hemangioblastoma detected on magnetic resonance imaging. Peptide-receptor radionuclide imaging using gallium-68-DOTATOC (Ga-DOTATOC) identified increased expression of somatostatin receptors in the suprasellar hemangioblastoma, along with multiple pancreatic neuroendocrine tumors and bilateral pheochromocytomas. The patient was treated for 1 year with lanreotide, a somatostatin analog. A repeat Ga-DOTATOC 1 year after starting lanreotide revealed decreased radiotracer uptake by the hemangioblastoma, consistent with a metabolic response. The presence of somatostatin receptors in hemangioblastomas associated with VHL disease is a novel finding. The decreased expression of these receptors after treatment with a somatostatin analog, as described in the present case, positions the somatostatin receptor as a new target for novel diagnostic, therapeutic, and follow-up opportunities in patients with VHL disease.
Topics: Humans; Hemangioblastoma; von Hippel-Lindau Disease; Receptors, Somatostatin; Male; Middle Aged; Octreotide; Cerebellar Neoplasms; Follow-Up Studies; Magnetic Resonance Imaging; Radiopharmaceuticals
PubMed: 38788146
DOI: 10.20945/2359-4292-2023-0181 -
JCEM Case Reports May 2024We report a case of interstitial nephritis, likely secondary to oxalate nephropathy, due to the development of pancreatic exocrine dysfunction after commencement of...
We report a case of interstitial nephritis, likely secondary to oxalate nephropathy, due to the development of pancreatic exocrine dysfunction after commencement of pasireotide for acromegaly. Pasireotide is known to impair insulin secretion but can also impair pancreatic exocrine function, hypothezised to result from high-affinity binding of somatostatin receptors 1, 2, 3, and 5. This has been an advantage in postoperative tissue anastomoses after pancreatic surgery, but exocrine insufficiency has not been reported when used for the treatment of acromegaly. A 73-year-old woman, diagnosed with acromegaly, was unable to achieve biochemical control despite 2 surgical resections of an invasive mammosomatotroph pituitary tumor and treatment with cabergoline and maximal-dose lanreotide. The tumor expressed somatostatin receptor type 5 but not somatostatin receptor type 2, predicting good response from pasireotide, which was commenced at 40 mg every 4 weeks. IGF-1 rapidly normalized, but the patient presented with nausea, anorexia, and acute kidney injury. Renal biopsy revealed acute-on-chronic interstitial nephritis, with numerous oxalate crystals. Increased fecal fat globules were noted on fat stain (3+), supporting malabsorption as an etiology of secondary enteric hyperoxaluria. Renal function recovered to near baseline over months following pasireotide withdrawal and high-dose glucocorticoids.
PubMed: 38770226
DOI: 10.1210/jcemcr/luae071 -
BioRxiv : the Preprint Server For... Apr 2024Persistent pain affects one in five people worldwide, often with severely debilitating consequences. Current treatment options, which can be effective for mild or acute...
UNLABELLED
Persistent pain affects one in five people worldwide, often with severely debilitating consequences. Current treatment options, which can be effective for mild or acute pain, are ill-suited for moderate-to-severe persistent pain, resulting in an urgent need for new therapeutics. In recent years, the somatostatin receptor 4 (SSTR ), which is expressed in sensory neurons of the peripheral nervous system, has emerged as a promising target for pain relief. However, the presence of several closely related receptors with similar ligand-binding surfaces complicates the design of receptor-specific agonists. In this study, we report the discovery of a potent and selective SSTR peptide, consomatin Fj1, derived from extensive venom gene datasets from marine cone snails. Consomatin Fj1 is a mimetic of the endogenous hormone somatostatin and contains a minimized binding motif that provides stability and drives peptide selectivity. Peripheral administration of synthetic consomatin Fj1 provided analgesia in mouse models of postoperative and neuropathic pain. Using structure-activity studies, we designed and functionally evaluated several Fj1 analogs, resulting in compounds with improved potency and selectivity. Our findings present a novel avenue for addressing persistent pain through the design of venom-inspired SSTR -selective pain therapeutics.
ONE SENTENCE SUMMARY
Venom peptides from predatory marine mollusks provide new leads for treating peripheral pain conditions through a non-opioid target.
PubMed: 38746149
DOI: 10.1101/2024.04.29.591104 -
International Immunopharmacology Jun 2024Although the pathophysiological mechanism of septic cardiomyopathy has been continuously discovered, it is still a lack of effective treatment method. Cortistatin (CST),...
BACKGROUND
Although the pathophysiological mechanism of septic cardiomyopathy has been continuously discovered, it is still a lack of effective treatment method. Cortistatin (CST), a neuroendocrine polypeptide of the somatostatin family, has emerged as a novel cardiovascular-protective peptide, but the specific mechanism has not been elucidated.
PURPOSE
The aim of our study is to explore the role of CST in cardiomyocytes pyroptosis and myocardial injury in sepsis and whether CST inhibits cardiomyocytes pyroptosis through specific binding with somastatin receptor 2 (SSTR2) and activating AMPK/Drp1 signaling pathway.
METHODS AND RESULTS
In this study, plasma CST levels were significantly high and were negatively correlated with N-terminal pro-B type natriuretic peptide (NT-proBNP), a biomarker for cardiac dysfunction, in patients with sepsis. Exogenous administration of CST significantly improved survival rate and cardiac function in mouse models of sepsis by inhibiting the activation of the NLRP3 inflammasome and pyroptosis of cardiomyocytes (decreased cleavage of caspase-1, IL-1β and gasdermin D). Pharmacological inhibition and genetic ablation revealed that CST exerted anti-pyroptosis effects by specifically binding to somatostatin receptor subtype 2 (SSTR2), thus activating AMPK and inactivating Drp1 to inhibit mitochondrial fission in cardiomyocytes.
CONCLUSIONS
This study is the first to report that CST attenuates septic cardiomyopathy by inhibiting cardiomyocyte pyroptosis through the SSTR2-AMPK-Drp1-NLRP3 pathway. Importantly, CST specifically binds to SSTR2, which promotes AMPK phosphorylation, inhibits Drp1-mediated mitochondrial fission, and reduces ROS levels, thereby inhibiting NLRP3 inflammasome activation-mediated pyroptosis and alleviating sepsis-induced myocardial injury.
Topics: Animals; Pyroptosis; Myocytes, Cardiac; Receptors, Somatostatin; NLR Family, Pyrin Domain-Containing 3 Protein; Humans; Sepsis; Signal Transduction; AMP-Activated Protein Kinases; Neuropeptides; Mice; Male; Mice, Inbred C57BL; Cardiomyopathies; Disease Models, Animal; Mice, Knockout
PubMed: 38733824
DOI: 10.1016/j.intimp.2024.112186 -
Diagnostics (Basel, Switzerland) Apr 2024The present report describes the history of a 58-year-old woman with a rapidly progressing neuroendocrine pancreatic tumor (initially G2) presenting with extensive...
Impressive Response to TANDEM Peptide Receptor Radionuclide Therapy with Lu/AcDOTA-LM3 Somatostatin Receptor Antagonist in a Patient with Therapy-Refractory, Rapidly Progressive Neuroendocrine Neoplasm of the Pancreas.
The present report describes the history of a 58-year-old woman with a rapidly progressing neuroendocrine pancreatic tumor (initially G2) presenting with extensive liver, bone, and lymph node metastases. Previous treatments included chemotherapy, hemithyroidectomy for right lobe metastasis, Peptide Receptor Radionuclide Therapy (PRRT) with [Lu]Lu-DOTATATE, Lanreotide, Everolimus, and liver embolization. Due to severe disease progression, after a liver biopsy revealing tumor grade G3, PRRT with the somatostatin receptor antagonist LM3 was initiated. [Ga]GaDOTA-LM3 PET/CT showed intense tracer uptake in the liver, pancreatic tumor, lymph nodes, and bone metastases. Three TANDEM-PRRT cycles using [Lu]LuDOTA-LM3 and [Ac]AcDOTA-LM3, administered concurrently, resulted in significant improvement, notably in liver metastases, hepatomegaly reduction, the complete regression of bone and lymph node metastases, and primary tumor improvement. Partial remission was confirmed by positron emission tomography/computed tomography, chest-abdomen-pelvis contrast-enhanced computed tomography, and magnetic resonance of the abdomen, with marked clinical improvement in pain, energy levels, and quality of life, enabling full resumption of physical activity.
PubMed: 38732321
DOI: 10.3390/diagnostics14090907 -
International Journal of Molecular... Apr 2024Bivalves hold an important role in marine aquaculture and the identification of growth-related genes in bivalves could contribute to a better understanding of the...
Bivalves hold an important role in marine aquaculture and the identification of growth-related genes in bivalves could contribute to a better understanding of the mechanism governing their growth, which may benefit high-yielding bivalve breeding. Somatostatin receptor (SSTR) is a conserved negative regulator of growth in vertebrates. Although genes have been identified in invertebrates, their involvement in growth regulation remains unclear. Here, we identified seven s (s) in the Yesso scallop, , which is an economically important bivalve cultured in East Asia. Among the three s (, , and ) expressed in adult tissues, showed significantly lower expression in fast-growing scallops than in slow-growing scallops. Then, the function of this gene in growth regulation was evaluated in dwarf surf clams (), a potential model bivalve cultured in the lab, via RNA interference (RNAi) through feeding the clams containing plasmids expressing double-stranded RNAs (dsRNAs) targeting . Suppressing the expression of , the homolog of in , resulted in a significant increase in shell length, shell width, shell height, soft tissue weight, and muscle weight by 20%, 22%, 20%, 79%, and 92%, respectively. A transcriptome analysis indicated that the up-regulated genes after expression inhibition were significantly enriched in the fat digestion and absorption pathway and the insulin pathway. In summary, we systemically identified the s in and revealed the growth-inhibitory role of in bivalves. This study indicates the conserved function of somatostatin signaling in growth regulation, and ingesting dsRNA-expressing bacteria is a useful way to verify gene function in bivalves. is a candidate target for gene editing in bivalves to promote growth and could be used in the breeding of fast-growing bivalves.
Topics: Animals; Pectinidae; Bivalvia; Receptors, Somatostatin; Phylogeny; RNA Interference; Gene Expression Regulation, Developmental
PubMed: 38732036
DOI: 10.3390/ijms25094813