The Pharmacodynamic Effects of a Dopamine-Somatostatin Chimera Agonist on the Cardiovascular System

Dopamine agonists for the treatment of pituitary tumours: From ergot extracts to next generation therapies

Dopamine agonists are a key tool in the therapeutic arsenal of endocrinologists worldwide. They exert their effects by binding to dopamine-2 (D2) receptors expressed by pituitary tumour cells to modulate hormonal secretion and tumour size. They are the established first-line treatment for prolactinomas which express high levels of D2 receptors. Growing data support their use as an adjuvant treatment option for other pituitary tumours including growth hormone, adrenocorticotrophic hormones, thyroid hormone secreting adenomas and nonfunctional pituitary tumours, all of which have been shown to express D2 receptors as well, albeit to varying extents. For those pituitary tumours inadequately treated by dopamine agonist alone, combined agonism of D2 and somatostatin receptors represent a new frontier in clinical development. Here we review the development and role of dopamine agonist for the treatment of prolactinomas, the literature supporting their adjuvant use for the treatment of all other pituitary tumours, and recent progress in the development of the next generation of chimeric compounds that target D2 and other receptor subtypes highly expressed on pituitary tumour cells.

Effects of somatostatin in combination with early hemoperfusion on inflammatory, hemorheological and oxidative parameters during the treatment of acute pancreatitis

We aimed to evaluate the effects of somatostatin combined with early hemoperfusion on inflammatory and stress responses during acute pan-creatitis (AP) treatment.A total of 159 AP patients treated from September 2016 to January 2020 were randomly divided into three groups A-C (n=53). In addition to routine treatment, groups A-C were additionally given somatostatin, early hemoperfusion, and somatostatin combined with early hemoperfusion, re-spectively. Their inflammatory factors, stress response, intestinal mucosal bar-rier, hemorheological indices, recovery time, length of stay, clinical efficacy, and adverse reactions were compared. The levels of serum interleukin-10 (IL -10), catalase and glutathione peroxidase rose in the three groups after ten days of treatment, compared with values before treatment, being the highest rise in group C. The levels of IL -18, tumor necrosis factor-α, soluble intercellular adhe-sion molecule-1, procalcitonin, high mobility group protein B1, lipid hydrogen peroxide, advanced oxidation protein products, epinephrine, cortisol, D-lactic acid, diamine oxidase, and endotoxin decreased after ten days of treatment compared with those before treatment, which were lowest in group C (P<0.05). After ten days of treatment, the levels of hemorheological indices were signifi-cantly lower than those before treatment (P<0.05). Compared with groups A and B, group C had a shorter recovery time of urine amylase, bowel sound and passing gas, remission time of abdominal pain, length of stay, and a higher to-tal response rate (P<0.05).During AP treatment, somatostatin combined with early hemoperfusion effectively relieved inflammatory and stress responses, protected the intestinal mucosal barrier function and improved the hemorheol-ogy, thereby promoting the recovery and benefiting the prognosis of patients.

Somatostatin-Dopamine Chimeric Molecules in Neuroendocrine Neoplasms

Neuroendocrine neoplasms (NENs) are a widely heterogeneous family of neoplasms arising from neuroendocrine cells, which are interspersed throughout the body. Despite NENs are relatively rare, their incidence and prevalence are constantly increasing probably due to the improvement in earlier diagnosis and patients’ management. When surgery is not curative, particularly for patients with metastatic disease, several medical options are available. Somatostatin analogues (SSA) are the first-line medical therapy for well-differentiated NENs. Interestingly, the heterodimerization of somatostatin receptors (SSTs) with dopamine receptors (DRs) has been discovered in NENs. This phenomenon results in hybrid receptors with enhanced functional activity. On these bases, chimeric molecules embracing somatostatin and dopamine features have been recently developed. The aim of this review is to provide a comprehensive overview of the available preclinical and clinical data regarding chimeric somatostatin-dopamine agonists as a new class of “magic bullet” in the therapy of NENs.

Quantification of the endogenous growth hormone and prolactin lowering effects of a somatostatin-dopamine chimera using population PK/PD modeling

A phase 1 clinical trial in healthy male volunteers was conducted with a somatostatin-dopamine chimera (BIM23B065), from which information could be obtained on the concentration-effect relationship of the inhibition of pulsatile endogenous growth hormone and prolactin secretion. Endogenous growth hormone profiles were analyzed using a two-step deconvolution-analysis-informed population pharmacodynamic modeling approach, which was developed for the analyses of pulsatile profiles. Prolactin concentrations were modelled using a population pool model with a circadian component on the prolactin release. During treatment with BIM23B065, growth hormone secretion was significantly reduced (maximal effect [E_MAX] = − 64.8%) with significant reductions in the pulse frequency in two out of three multiple ascending dose cohorts. A circadian component in prolactin secretion was identified, modelled using a combination of two cosine functions with 24 h and 12 h periods. Dosing of BIM23B065 strongly inhibited (E_MAX = − 91%) the prolactin release and demonstrated further reduction of prolactin secretion after multiple days of dosing. This study quantified the concentration-effect relationship of BIM23B065 on the release of two pituitary hormones, providing proof of pharmacology of the chimeric actions of BIM23B065.