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Molecular Pharmaceutics Jun 2024Oral delivery of potent peptide drugs provides key formulation challenges in the pharmaceutical industry: stability, solubility, and permeability. Intestinal permeation...
Oral delivery of potent peptide drugs provides key formulation challenges in the pharmaceutical industry: stability, solubility, and permeability. Intestinal permeation enhancers (PEs) can overcome the low oral bioavailability by improving the drug permeability. Conventional and models for assessing PEs fail to predict efficacy . Here, we compared Caco-2 cells cultured in the conventional static Transwell model to a commercially available continuous flow microfluidic Gut-on-a-Chip model. We determined baseline permeability of FITC-Dextan 3 kDa (FD3) in Transwell (5.3 ± 0.8 × 10 cm/s) vs Chip (3.2 ± 1.8 × 10 cm/s). We screened the concentration impact of two established PEs sodium caprate and sucrose monolaurate and indicated a requirement for higher enhancer concentration in the Chip model to elicit equivalent efficacy e.g., 10 mM sodium caprate in Transwells vs 25 mM in Chips. Fasted and fed state simulated intestinal fluids (FaSSIF/FeSSIF) were introduced into the Chip and increased basal FD3 permeability by 3-fold and 20-fold, respectively, compared to 4-fold and 4000-fold in Transwells. We assessed the utility of this model to peptides (Insulin and Octreotide) with PEs and observed much more modest permeability enhancement in the Chip model in line with observations in and preclinical models. These data indicate that microfluidic Chip models are well suited to bridge the gap between conventional and models.
PubMed: 38941485
DOI: 10.1021/acs.molpharmaceut.4c00210 -
The American Journal of Case Reports Jun 2024BACKGROUND When people in their 60s experiences abdominal pain, vomiting, and unexplained weight loss without a history of abdominal surgery, the usual diagnosis is...
BACKGROUND When people in their 60s experiences abdominal pain, vomiting, and unexplained weight loss without a history of abdominal surgery, the usual diagnosis is obstruction caused by a neoplastic mass. Nevertheless, in exceptionally rare cases, these symptoms arise from complications linked to a visceral artery aneurysm. CASE REPORT We present a case of a 60-year-old man with immunodeficiency and Sneddon-Wilkinson disease (a rare subcorneal pustular dermatosis), who developed a pancreaticoduodenal aneurysm of uncertain origin, associated with pancreatic mass, retroperitoneal hematoma, and duodenal obstruction. The treatment approach included transcatheter arterial coil embolization with supportive measures such as parenteral nutrition, a nasogastric tube, octreotide administration, and antiemetics. Despite these interventions, persistence gastrointestinal symptoms prompted an endoscopic ultrasound fine-needle aspiration to rule out malignancy. The biopsy confirmed localized fibro-inflammation. Although he was initially considered for a gastro-jejunal bypass, conservative management effectively improved the pancreatic lesion and duodenal obstruction, leading to discontinuation of parenteral nutrition. The patient was able to resume a regular diet 4 weeks after embolization. CONCLUSIONS Pancreaticoduodenal artery aneurysm is a rare visceral aneurysm with multiple etiologies and potentially fatal consequences. We report an unusual case of a pancreaticoduodenal artery aneurysm associated with pancreatic mass and duodenal obstruction. This diagnosis warrants consideration when an immunodeficient patient presents symptoms of abdominal pain and vomiting. Early endovascular embolization, combined with conservative approaches, effectively alleviated the symptoms in our patient.
Topics: Humans; Male; Middle Aged; Aneurysm, False; Pancreas; Duodenal Obstruction; Duodenum; Embolization, Therapeutic
PubMed: 38932438
DOI: 10.12659/AJCR.943879 -
Acta Pharmacologica Sinica Jun 2024Somatostatin receptor 5 (SSTR5) is highly expressed in ACTH-secreting pituitary adenomas and is an important drug target for the treatment of Cushing's disease. Two...
Somatostatin receptor 5 (SSTR5) is highly expressed in ACTH-secreting pituitary adenomas and is an important drug target for the treatment of Cushing's disease. Two cyclic SST analog peptides (pasireotide and octreotide) both can activate SSTR5 and SSTR2. Pasireotide is preferential binding to SSTR5 than octreotide, while octreotide is biased to SSTR2 than SSTR5. The lack of selectivity of both pasireotide and octreotide causes side effects, such as hyperglycemia, gastrointestinal disturbance, and abnormal glucose homeostasis. However, little is known about the binding and selectivity mechanisms of pasireotide and octreotide with SSTR5, limiting the development of subtype-selective SST analog drugs specifically targeting SSTR5. Here, we report two cryo-electron microscopy (cryo-EM) structures of SSTR5-Gi complexes activated by pasireotide and octreoitde at resolutions of 3.09 Å and 3.24 Å, respectively. In combination with structural analysis and functional experiments, our results reveal the molecular mechanisms of ligand recognition and receptor activation. We also demonstrate that pasireotide preferentially binds to SSTR5 through the interactions between Tyr(Bzl)/Trp of pasireotide and SSTR5. Moreover, we find that the Q, N, F and ECL2 of SSTR2 play a crucial role in octreotide biased binding of SSTR2. Our results will provide structural insights and offer new opportunities for the drug discovery of better selective pharmaceuticals targeting specific SSTR subtypes.
PubMed: 38926478
DOI: 10.1038/s41401-024-01314-8 -
Journal of Indian Association of... 2024Idiopathic chylopericardium (CP) in the pediatric population is a rare entity with very few reported cases and is characterized by the accumulation of chyle in the...
Idiopathic chylopericardium (CP) in the pediatric population is a rare entity with very few reported cases and is characterized by the accumulation of chyle in the pericardial cavity. There are no guidelines for the management of this rare entity. The present study reports a case of idiopathic CP in an infant and our experience of managing it by pericardial window creation using VATS and a multidisciplinary approach providing the optimum care for the child.
PubMed: 38912020
DOI: 10.4103/jiaps.jiaps_20_24 -
Frontiers in Endocrinology 2024This study explores tumor-induced osteomalacia (TIO) through a case series and literature review, assessing the diagnostic potential of F-AlF-NOTA-octreotide (F-OC)... (Review)
Review
INTRODUCTION
This study explores tumor-induced osteomalacia (TIO) through a case series and literature review, assessing the diagnostic potential of F-AlF-NOTA-octreotide (F-OC) positron emission tomography/computed tomography (PET/CT).
METHODS
We analyzed TIO patients who underwent F-OC PET/CT. Parameters such as tumor dimension, the maximum standardized uptake value (SUVmax), the mean standardized uptake value (SUVmean) and metabolic tumor volume (MTV) were meticulously assessed. Clinical features and imaging characteristics pertinent to TIO were reviewed.
RESULTS
6 patients with clinical suspicion of TIO exhibited hypophosphatemia (0.25 to 0.64 mmol/L), elevated alkaline phosphatase (ALP) levels (142 to 506 U/L), and increased parathyroid hormone (PTH) levels (92.9 to 281.7 pg/mL). Of these patients, two underwent FGF-23 testing, with results of 3185.00 pg/ml and 17.56 pg/ml, respectively. Conventional imaging modalities depicted widespread osteoporosis, with several cases demonstrating fractures indicative of osteomalacic and associated pathological fractures. Subsequent F-OC PET/CT facilitated the accurate localization of causative tumors, with histopathological examination confirming the diagnosis of phosphaturic mesenchymal tumor (PMT). The interval from initial clinical presentation to definitive TIO diagnosis spanned approximately 2.5 years (range: 1 - 4 years), with tumors varying in size (maximum diameter: 7.8 to 40.0 mm), SUVmax (5.47 to 25.69), SUVmean (3.43 to 7.26), and MTV (1.27 to 18.59 cm).
CONCLUSION
The implementation of whole-body F-OC PET/CT imaging emerges as a critical tool in the identification of occult tumors causing TIO. Future investigations incorporating a broader cohort are imperative to further delineate the diagnostic and therapeutic implications of F-OC PET/CT in managing TIO.
Topics: Humans; Fibroblast Growth Factor-23; Fluorine Radioisotopes; Heterocyclic Compounds; Heterocyclic Compounds, 1-Ring; Neoplasms, Connective Tissue; Octreotide; Osteomalacia; Paraneoplastic Syndromes; Positron Emission Tomography Computed Tomography; Radiopharmaceuticals
PubMed: 38887276
DOI: 10.3389/fendo.2024.1400751 -
The Oncologist Jun 2024Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are rare neoplasms with an increasing annual incidence and prevalence. Many are metastatic at presentation or...
BACKGROUND
Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are rare neoplasms with an increasing annual incidence and prevalence. Many are metastatic at presentation or recur following surgical resection and require systemic therapy, for which somatostatin analogs such as octreotide or lanreotide comprise typical first-line therapies. Nonetheless, treatment options remain limited. Epigenetic processes such as histone modifications have been implicated in malignant transformation and progression. In this study, we evaluated the anti-proliferative effects of a histone deacetylase (HDAC) inhibitor, entinostat, which was computationally predicted to show anti-cancer activity, as confirmed in in vitro and in vivo models of GEP-NETs.
METHODS
This was a phase II study to evaluate the efficacy and safety of entinostat in patients with relapsed or refractory abdominal NETs. The primary objective was to estimate the objective response rate to entinostat. Additionally, with each patient as his/her own control we estimated the rates of tumor growth prior to enrollment on study and while receiving entinostat. Patients received 5 mg entinostat weekly until disease progression or intolerable toxicity. The dose could be changed to 10 mg biweekly for patients who did not experience grade ≥ 2 treatment-related adverse events (AEs) in cycle 1, but was primarily administered at the starting 5 mg weekly dose.
RESULTS
The study enrolled only 5 patients due to early termination by the drug sponsor. The first patient that enrolled had advanced disease and died within days of enrollment before follow-up imaging due to a grade 5 AE unrelated to study treatment and was considered non-evaluable. Best RECIST response for the remaining 4 patients was stable disease (SD) with time on study of 154+, 243, 574, and 741 days. With each patient as his/her own control, rates of tumor growth on entinostat were markedly reduced with rates 20%, 33%, 54%, and 68% of the rates prior to enrollment on study. Toxicities possibly or definitely related to entinostat included grade 2/3 neutrophil count decrease [2/4 (50%)/ 2/4 (50%)], grade 3 hypophosphatemia [1/4, (25%)], grade 1/2 fatigue [1/4 (25%)/ 2/4 (50%)], and other self-limiting grade 1/2 AEs.
CONCLUSION
In the treatment of relapsed or refractory abdominal NETs, entinostat 5 mg weekly led to prolonged SD and reduced the rate of tumor growth by 32% to 80% with an acceptable safety profile (ClinicalTrials.gov Identifier: NCT03211988).
PubMed: 38886159
DOI: 10.1093/oncolo/oyae118 -
Proceedings of the National Academy of... Jun 2024Somatostatin receptor 5 (SSTR5) is an important G protein-coupled receptor and drug target for neuroendocrine tumors and pituitary disorders. This study presents two...
Somatostatin receptor 5 (SSTR5) is an important G protein-coupled receptor and drug target for neuroendocrine tumors and pituitary disorders. This study presents two high-resolution cryogenicelectron microscope structures of the SSTR5-G complexes bound to the cyclic neuropeptide agonists, cortistatin-17 (CST17) and octreotide, with resolutions of 2.7 Å and 2.9 Å, respectively. The structures reveal that binding of these peptides causes rearrangement of a "hydrophobic lock", consisting of residues from transmembrane helices TM3 and TM6. This rearrangement triggers outward movement of TM6, enabling Gα protein engagement and receptor activation. In addition to hydrophobic interactions, CST17 forms conserved polar contacts similar to somatostatin-14 binding to SSTR2, while further structural and functional analysis shows that extracellular loops differently recognize CST17 and octreotide. These insights elucidate agonist selectivity and activation mechanisms of SSTR5, providing valuable guidance for structure-based drug development targeting this therapeutically relevant receptor.
Topics: Receptors, Somatostatin; Humans; Octreotide; Neuropeptides; Cryoelectron Microscopy; Protein Binding; Peptides, Cyclic; Somatostatin; Models, Molecular; HEK293 Cells
PubMed: 38885377
DOI: 10.1073/pnas.2321710121 -
Gastroenterology Jun 2024
PubMed: 38880213
DOI: 10.1053/j.gastro.2024.04.034 -
Journal of Gastrointestinal Cancer Jun 2024The incidence of gastroenteropancreatic neuroendocrine tumors (GEP-NET) has steadily increased. These tumors are considered relatively indolent even when metastatic....
INTRODUCTION
The incidence of gastroenteropancreatic neuroendocrine tumors (GEP-NET) has steadily increased. These tumors are considered relatively indolent even when metastatic. What determines survival outcomes in such situations is understudied.
MATERIALS AND METHODS
Retrospective analysis of a prospectively maintained NET clinic database, to include patients of metastatic grade 1 GEP-NET, from January 2018 to December 2021, to assess factors affecting progression-free survival (PFS).
RESULTS
Of the 589 patients of GEP-NET treated during the study period, 100 were grade 1, with radiological evidence of distant metastasis. The median age was 50 years, with 67% being men. Of these, 15 patients were observed, while 85 patients received treatment in the form of surgery (n = 32), peptide receptor radionuclide therapy (n = 50), octreotide LAR (n = 22), and/or chemotherapy (n = 4), either as a single modality or multi-modality treatment. The median (PFS) was 54.5 months. The estimated 3-year PFS and 3-year overall survival rates were 72.3% (SE 0.048) and 93.4% (SE 0.026), respectively. On Cox regression, a high liver tumor burden was the only independent predictor of PFS (OR 3.443, p = 0.014). The 5-year OS of patients with concomitant extra-hepatic disease was significantly lower than that of patients with liver-limited disease (70.7% vs. 100%, p = 0.017).
CONCLUSION
A higher burden of liver disease is associated with shorter PFS in patients with metastatic grade I GEP-NETs. The OS is significantly lower in patients with associated extrahepatic involvement. These parameters may justify a more aggressive treatment approach in metastatic grade 1 GEP-NETs.
PubMed: 38874852
DOI: 10.1007/s12029-024-01077-9