Expression of somatostatin receptors in splanchnic blood vessels of normal and cirrhotic rats

Reynaert, Hendrik; Rossen, Elke Van; Uyama, Naoki; Chatterjee, Nirjhar; Kumar, Ujendra; Urbain, Daniël; Geerts, Albert

doi:10.1111/j.1478-3231.2007.01503.x

Cited by 7 publications

(5 citation statements)

References 26 publications

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“…It was stated that the PEG layer around the NPs reduced the adsorption of opsonins and other serum proteins could be reduced by the presence of PEG on the surface of NPs (Vannucci et al, 2012, Xin et al, 2012, Simsek et al, 2013). Here we found that the unmodified Qdots which carry PEG amine on its surface showed a high accumulation in the liver, which cannot explain the long circulation time of the formulated Qdots-VAP because VAP binds to the SSTR2 expressed in blood cells (Bhathena and Recant, 1980, Perez et al, 2003, Lichtenauer-Kaligis et al, 2004, Petrak, 2005, Reynaert et al, 2007, ter Veld et al, 2007, Muscarella et al, 2011). The SSTRs overexpressed on RBCs could so interact with Qdots-VAP expressed in RBCs.…”

Section: Discussionmentioning

confidence: 83%

Targeting of somatostatin receptors expressed in blood cells using quantum dots coated with vapreotide

Abdellatif

Abou-Taleb

Ghany

et al. 2018

Saudi Pharmaceutical Journal

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Cancer may be difficult to target, however, if cancer targeted this provides the chance for a better and more effective treatment. Quantum dots (Qdots) coated vapreotide (VAP) as a somatostatin receptors (SSTRs) agonist can be efficient targeting issue since may reduce side effects and increase drug delivery to the target tissue. This study highlights the active targeting of cancer cells by cells imaging with improving the therapeutic outcomes. VAP was conjugated to Qdots using amine-to-sulfhydryl crosslinker. The synthesized Qdots-VAP was characterized by determination of size, measuring the zeta-potential and UV fluorometer. The cellular uptake was studied using different cell lines. Finally, the Qdots-VAP was injected into a rat model. The results showed a size of 479.8 ± 15 and 604.88 ± 17 nm for unmodified Qdots and Qdots-VAP respectively, while the zeta potential of particles went from negative to positive charge which proved the conjugation of VAP to Qdots. The fluorometer recorded a redshift for Qdots-VAP compared with unmodified Qdots. Moreover, cellular uptake exhibited high specific binding with cells which express SSTRs using confocal microscopy and flow cytometry (17.3 MFU comparing to 3.1 MFU of control, P < 0.001). Finally, an in vivo study showed a strong accumulation of Qdots-VAP in the blood cells (70%). In conclusion, Qdots-VAP can play a crucial role in cancer diagnosis and treatment of blood cells diseases when conjugated with VAP as SSTRs agonist.

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Section: Discussionmentioning

confidence: 83%

Targeting of somatostatin receptors expressed in blood cells using quantum dots coated with vapreotide

Abdellatif

Abou-Taleb

Ghany

et al. 2018

Saudi Pharmaceutical Journal

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“… 51 Moreover, the former potency could be the strongest at SSTR5 compared to other SSTR subtypes. 54 SST28 is secreted after meals, 28 and SSTR5 is constitutively expressed in the vascular smooth muscle cells, 55 , 56 which indicates that SST28/SSTR5 activation causes reduced exposure to insulin and glucose uptake in the liver postprandially. Therefore, the improvement in hepatic insulin sensitivity by the SSTR5 antagonist may be due to the recovery of the SST/SSTR5‐mediated hepatic blood flow decrease through SSTR5 blocking.…”

Section: Discussionmentioning

confidence: 99%

Selective somatostatin receptor 5 inhibition improves hepatic insulin sensitivity

Tamura

Sugama

Abe

et al. 2022

Pharmacology Res & Perspec

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Diabetes is a metabolic disorder with an increasing global prevalence. Somatostatin (SST), a peptide hormone, regulates hormone secretion via five SST receptor (SSTR) subtypes (SSTR1–5) in a tissue‐specific manner. As SSTR5 is expressed in pancreatic β‐cells and intestinal L‐cells, studies have suggested that SSTR5 regulates glucose tolerance through insulin and incretin secretion, thereby having a prominent role in diabetes. Moreover, SSTR5 knockout (KO) mice display enhanced insulin sensitivity; however, the underlying mechanism has not been clarified. Therefore, in this study, we investigate the effect of SSTR5 blockade on insulin resistance and the target organ using SSTR5 KO mice and a selective SSTR5 antagonist (compound‐1). High‐fat diet (HFD)‐fed SSTR5 KO mice exhibited significantly lower homeostasis model assessment of insulin resistance (HOMA‐IR) than HFD‐fed wild‐type mice. Two‐week oral administration of compound‐1 dose‐dependently and significantly reduced changes in the levels of glycosylated hemoglobin (GHb), plasma glucose, plasma insulin, and HOMA‐IR in male KK‐A y /Ta Jcl mice (KK‐A y mice), a model of obese type 2 diabetes with severe insulin resistance. Additionally, compound‐1 significantly increased the glucose infusion rate while decreasing hepatic glucose production in male KK‐A y mice, as evidenced by hyperinsulinemic‐euglycemic clamp analyses. In addition, compound‐1 ameliorated the insulin‐induced Akt phosphorylation suppression by octreotide in the liver of male C57BL/6J mice. Collectively, our results demonstrate that selective SSTR5 inhibition can improve insulin sensitivity by enhancing liver insulin action; thus, selective SSTR5 antagonists represent potentially novel therapeutic agents for type 2 diabetes.

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“…The large Cd content in the blood is due to the circulation of OCD-coated QDs as the OCD bound to the SSTR 2 in blood cells (2). It has been reported that SSTR 1-5 are overexpressed on the surface of monocytes (14,39,42,47,48,52,59).…”

Section: Discussionmentioning

confidence: 99%

Fluorescent Nanoparticles Coated with a Somatostatin Analogue Target Blood Monocyte for Efficient Leukaemia Treatment

et al. 2020

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Background Leukaemia is the most prevalent form of cancer-causing death in a large number of populations and needs prompt and effective treatment. Chemotherapeutics can be used to treat leukaemia, but their pronounced killing effects to other living cells is still an issue. Active targeting to certain specific receptors in leukaemic cells is the best way to avoid damage to other living cells. Leukaemic cells can be targeted using novel nanoparticles (NPs) coated with a specific ligand, such as octreotide (OCD), to target somatostatin receptor type 2 (SSTR 2 ), which is expressed in leukaemic cells. Methods Amino-PEGylated quantum dots (QDs) were chosen as model NPs. The QDs were first succinylated using succinic anhydride and then coated with OCD. The reactivity and selectivity of the formulated QDs-OCD were studied in cell lines with well-expressed SSTR 2 , while fluorescence was detected using confocal laser scanning microscopy (CLSM) and flow cytometry (FACS). Conclusively, QD-OCD targeting to blood cells was studied in vivo in mice and detected using inductively coupled plasma mass spectrometry and CLSM in tissues.Results Highly stable QDs coated with OCD were prepared. FACS and CLSM showed highly definite interactions with overexpressed SSTR 2 in the investigated cell lines. Moreover, the in vivo results revealed a higher concentration of QDs-OCD in blood cells. The fluorescence intensity of the QDs-OCD was highly accumulated in blood cells, while the unmodified QDs did not accumulate significantly in blood cells. Conclusion: The formulated novel QDs-OCD can target SSTR 2 overexpressed in blood cells with great potential for treating blood cancer.

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Expression of somatostatin receptors in splanchnic blood vessels of normal and cirrhotic rats

Abstract: All five SSTR are expressed in splanchnic blood vessels. Our results suggest that cirrhosis reduces expression of SSTR1 in portal vein. In other vessels, no major differences between the normal and cirrhotic state were noted.

Cited by 7 publications

References 26 publications

Targeting of somatostatin receptors expressed in blood cells using quantum dots coated with vapreotide

Targeting of somatostatin receptors expressed in blood cells using quantum dots coated with vapreotide

Selective somatostatin receptor 5 inhibition improves hepatic insulin sensitivity

Fluorescent Nanoparticles Coated with a Somatostatin Analogue Target Blood Monocyte for Efficient Leukaemia Treatment

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