Immunological signatures and predictive biomarkers for first-generation somatostatin receptor ligand resistance in Acromegaly.

PURPOSE: Predicting resistance to first-generation Somatostatin Receptor Ligands (fg-SRL) in Acromegaly patients remains an ongong challenge. Tumor-associated immune components participate in various pathological processes, including drug-resistance. We aimed to identify the immune components involved in resistance of fg-SRL, and to investigate biomarkers that can be targeted to treat those drug-resistant Acromegaly. METHODS: We conducted a retrospective study involving 35 Acromegaly patients with somatotropinomas treated postoperatively with fg-SRL. Gathering clinicopathological data, SSTR2 expression, and immunological profiles, we utilized univariate, binary logistic regression, and ROC analyses to assess their predictive roles in fg-SRL resistance. Spearman correlation analysis further examined interactions among interested characteristics. RESULTS: 19 patients (54.29%) exhibited resistance to postoperative fg-SRL. GH level at diagnosis, preoperative tumor volume, T2WI-MRI intensity, granularity, PD-L1, SSTR2, and CD8 + T cell infiltration showed association with clinical outcomes of fg-SRL. Notably, T2WI-MRI hyperintensity, PD-L1-IRS > 7, CD8 + T cell infiltration < 14.8/HPF, and SSTR2-IRS < 5.4 emerged as reliable predictors for fg-SRL resistance. Correlation analysis highlighted a negative relationship between PD-L1 expression and CD8 + T cell infiltration, while showcasing a positive correlation with preoperative tumor volume of somatotropinomas. Additionally, 5 patients with fg-SRL resistance underwent re-operation were involved. Following fg-SRL treatment, significant increases in PD-L1 and SSTR5 expression were observed, while SSTR2 expression decreased in somatotropinoma. CONCLUSION: PD-L1 expression and CD8 + T cell infiltration, either independently or combined with SSTR2 expression and T2WI-MRI intensity, could form a predictive model guiding clinical decisions on fg-SRL employment. Furthermore, targeting PD-L1 through immunotherapy and embracing second-generations of SRL with higher affinity to SSTR5 represent promising strategies to tackle fg-SRL resistance in somatotropinomas.

Acromegaly, inflammation and cardiovascular disease: a review.

Acromegaly is characterized by Growth Hormone (GH) and Insulin-like Growth Factor 1 (IGF-1) excess. Uncontrolled acromegaly is associated with a strongly increased risk of cardiovascular disease (CVD), and numerous cardiovascular risk factors remain present after remission. GH and IGF-1 have numerous effects on the immune and cardiovascular system. Since endothelial damage and systemic inflammation are strongly linked to the development of CVD, and have been suggested to be present in both controlled as uncontrolled acromegaly, they may explain the presence of both micro- and macrovascular dysfunction in these patients. In addition, these changes seem to be only partially reversible after remission, as illustrated by the often reported presence of endothelial dysfunction and microvascular damage in controlled acromegaly. Previous studies suggest that insulin resistance, oxidative stress, and endothelial dysfunction are involved in the development of CVD in acromegaly. Not surprisingly, these processes are associated with systemic inflammation and respond to GH/IGF-1 normalizing treatment.

Overcoming Hurdles in Nanoparticle Clinical Translation: The Influence of Experimental Design and Surface Modification.

Nanoparticles are becoming an increasingly popular tool for biomedical imaging and drug delivery. While the prevalence of nanoparticle drug-delivery systems reported in the literature increases yearly, relatively little translation from the bench to the bedside has occurred. It is crucial for the scientific community to recognize this shortcoming and re-evaluate standard practices in the field, to increase clinical translatability. Currently, nanoparticle drug-delivery systems are designed to increase circulation, target disease states, enhance retention in diseased tissues, and provide targeted payload release. To manage these demands, the surface of the particle is often modified with a variety of chemical and biological moieties, including PEG, tumor targeting peptides, and environmentally responsive linkers. Regardless of the surface modifications, the nano-bio interface, which is mediated by opsonization and the protein corona, often remains problematic. While fabrication and assessment techniques for nanoparticles have seen continued advances, a thorough evaluation of the particle's interaction with the immune system has lagged behind, seemingly taking a backseat to particle characterization. This review explores current limitations in the evaluation of surface-modified nanoparticle biocompatibility and in vivo model selection, suggesting a promising standardized pathway to clinical translation.

Plasma thrombin-activatable fibrinolysis inhibitor (TAFI) antigen levels in acromegaly patients in remission

Background/aim: Acromegaly is associated with increased morbidity andmortality, mostly due to cardiovascular complications.Plasma thrombin-activatable fibrinolysis inhibitor (TAFI) antigen levels are associated with coagulation/fibrinolysis and inflammation. Plasma TAFI may play a role in arterial thrombosis in cardiovascular diseases. In this study, it was aimed to evaluate the thrombin-activatable fibrinolysis inhibitor (TAFI) antigen and homocysteine levels in patients with acromegaly and healthy control subjects. Materials and methods: Plasma TAFI antigen and homocysteine levels in 29 consecutive patients with acromegaly and 26 age-matched healthy control subjects were measured. All patients included in the study were in remission. The TAFIa/ai antigen in the plasma samples was measured using a commercially available ELISA kit. Results: Routine biochemical parameters, fasting blood glucose, prolactin, thyroid stimulating hormone, total-cholesterol, low density lipoprotein cholesterol, triglyceride, and homocysteine levels were similar in the 2 groups (P > 0.05), whereas the plasma TAFI antigen levels were significantly elevated in the acromegalic patients (154.7 ± 94.0%) when compared with the control subjects (107.2 ± 61.6%) (P = 0.033). No significant correlation was identified by Pearson's correlation test between the plasma TAFI antigen and homocysteine levels (r = 0.320, P = 0.250). Conclusion: A significant alteration in the plasma TAFI antigen levels was detected in acromegaly. Increased plasma TAFI antigen levels might aggravate prothrombotic and thrombotic events in patients with acromegaly.

Thyroid autoimmune disorders in patients with acromegaly.

PURPOSE: Disorders of the hypothalamic-pituitary-thyroid axis are common in patients with acromegaly and thyroid enlargement is present in the majority of them. The exact prevalence of goiter in patients with acromegaly remains uncertain and the presence of thyroid autoimmunity has not been extensively evaluated so far. METHODS: We retrospectively evaluated thyroid biochemical and morphological findings in 116 acromegalic patients who attended our hospital. Serum TSH, total thyroxine levels and anti-thyroid peroxidase (ATPO) antibodies were measured by standard ultrasensitive techniques in all the patients. Thyroid ultrasound was performed in 75 out of them. The antibody control group was composed by healthy Argentinean individuals who attended the blood bank of our hospital in whom ATPO antibodies were measured. RESULTS: Twenty-nine out of the 116 acromegalic patients (25 %) showed elevated titers of thyroid antibodies (79 % were women and 21 % men). The control group had a 10 % prevalence of thyroid autoimmunity. The prevalence of goiter by ultrasound was 36 %, being more common in females (41 %) than in males (28 %). Thirty-five percent of patients who presented thyroid nodules and 44 % of patients with ultrasound diagnosed goiters had positive thyroid autoimmunity. There was no significant correlation between the presence of nodules and IGF-1 levels, duration of disease or age. CONCLUSION: We found a high prevalence of thyroid autoimmunity in our patients with acromegaly as compared to the normal population. Thyroid autoimmunity seems to be an additional mechanism for the development of thyroid disorders in acromegaly.

Prevalence of antipituitary antibodies in acromegaly.

Acromegaly is a rare disorder due to an excessive production of growth hormone (GH), typically caused by a GH-secreting pituitary adenoma. Anti-pituitary antibodies (APAs) are often seen in patients with different kinds of pituitary pathologies. Because GH has been proposed as a possible antigen recognized by such antibodies, the prevalence of APAs may be higher in conditions characterized by excessive GH secretion. The primary aim of this study was to compare the prevalence of APAs in patients with acromegaly and in controls with other types of pituitary tumors and healthy subjects. Secondary aim was to characterize the pituitary cells targeted by the APAs. Thirty eight acromegaly patients and 215 controls, including 38 patients with prolactinomas, 64 with non-functioning pituitary adenomas (NFPA), and 113 healthy subjects were enrolled in the study. All subjects were tested for APAs using indirect immunofluorescence. Target cells recognized by APAs were identified by double staining immunofluorescence. APAs were significantly more prevalent in acromegaly cases than in healthy controls (10.5% vs. 1.8%, P < 0.05). This prevalence was similar to that found in patients with prolactinomas (7.9%) and NFPA (12.5%). Among APAs-positive subjects, antibodies recognizing somatotrope cells were more common in acromegaly cases than in healthy controls (3/4 vs. 0/113, P < 0.0001), but had similar frequencies in NFPA (2/8) and prolactinomas (1/3). APAs are more frequently found in patients with pituitary adenomas than healthy subjects, with no significant difference among the tumor types studied. GH-secreting cells could represent a target of the autoimmune response.

Co-Occurrence of ANCA-Associated Vasculitis and Sjögren's Syndrome in a Patient With Acromegaly: A Case Report and Retrospective Single-Center Review of Acromegaly Patients.

Background: ANCA-associated vasculitis (AAV) and Sjögren's syndrome (SS) are uncommon autoimmune diseases. The co-occurrence in the same patient has been rarely described. Acromegaly has been associated with autoimmune thyroiditis, but the prevalence of other autoimmune disorders such as AAV and SS has not been evaluated in acromegaly. Methods: Characterization of a patient with acromegaly and two rare autoimmune diseases-SS and AAV (microscopic polyangiitis (MPA))-by autoantibody-array and whole exome sequencing (WES). Single-center retrospective review of medical records of acromegaly patients to explore the prevalence of diagnosed autoimmune diseases. Results: We report a Caucasian woman in her 50's with a serologically (anti-SSA/Ro, anti-MPO-ANCA antibodies) and histologically confirmed diagnosis of symptomatic SS and MPA. SS with MPO-ANCA positivity preceded MPA. An exploratory autoantigen array detected a broad spectrum of autoantibodies. WES revealed heterozygous carrier status of the PTPN22 mutation R620W, which is associated with an increased risk for autoimmunity. A similar combination of positive anti-SSA/Ro autoantibodies and ANCA was only present in 5/1184 (0.42%) other patients tested for both antibodies in our clinic over six years. Amongst 85 acromegaly patients seen at our clinic in a 20-year period, 12% had a clinically relevant associated immunological disease. Conclusion: We present a rare case of SS and AAV in a patient with acromegaly and multiple autoantibody specificities. Patients with SS and ANCA should be closely monitored for the development of (subclinical) AAV. Whether acromegaly represents a risk for autoimmunity should be further investigated in prospective acromegaly cohorts.

Evaluation of blood neutrophil to lymphocyte and platelet to lymphocyte ratios according to plasma glucose status and serum insulin-like growth factor 1 levels in patients with acromegaly.

INTRODUCTION: Cardiovascular, respiratory, and cerebrovascular diseases and malignancies are responsible for morbidity and mortality in acromegaly. Also these diseases are associated with chronic inflammation. The neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR) are currently gaining interest as new markers of inflammation. Moreover, increased morbidity and mortality are positively correlated with the presence of diabetes and levels of insulin-like growth factor 1 (IGF-1) in acromegaly. The objective of the present study was to investigate the relationship between these markers and acromegaly according to plasma glucose status and serum IGF-1 levels. MATERIALS AND METHODS: We retrospectively analyzed data from 61 acromegaly patients who were in a newly diagnosed period (35 male, 26 female; mean age 38.13 ± 13.98). Patients with normal plasma glucose (n = 27), impaired fasting glucose (n = 18), and diabetes mellitus (n = 16) were categorized into three different groups. NLR and PLR were compared between the study groups and were evaluated according to IGF-1 levels. RESULTS: There were no statistically significant differences in NLR and PLR measurements among the study groups (p > 0.05). However, there were significant positive correlations between NLR and IGF-1 levels and between PLR and IGF-1 levels when all patients were evaluated (r = 0.334, p = 0.011 and r = 0.277, p = 0.035, respectively). CONCLUSIONS: This is the first report studying the relationship of NLR and PLR with glucose status and IGF-1 levels in acromegaly patients. Our study results suggest that subclinical inflammation may play a role in increased incidence of mortality and morbidity, which depends on uncontrolled IGF-1 levels in patients with acromegaly.

Certain large forms of circulating immunoreactive human growth hormone are in fact immunoglobulins.

To explain frequent discordances between serum GH levels and clinical manifestation of acromegaly, we investigated the possibility that certain immunoglobulins G (IgGs) might be responsible for the displacement of [125I]human (h) GH in the hGH RIA. We incubated dilute sera from seven active acromegalics (basal immunoreactive hGH, 22-313 micrograms/L) with rat adipocyte plasma membranes adsorbed on polystyrene plates. IgGs that bound to GH receptor sites in the absence and presence of 250 nM hGH (for nonspecific binding) were detected using anti-hIgG (Fc-specific) antibody conjugated with alkaline phosphatase. In this system two of the seven sera studied tested positive for IgGs against GH-binding sites (serum 4 in 1:400 dilution, and serum 7 in 1:10 dilution). We studied further the serum with the highest titer. On Sephadex G-100, most of the GH-like immunoreactivity (assayed by RIA) present in serum 4 coeluted with IgGs (assayed by immunodiffusion) as a high mol wt (greater than or equal to 150 kDa) component. To confirm its IgG nature, this material was then adsorbed on protein-A-Sepharose and eluted with 0.1 M sodium citrate, pH 3.0. The protein-A-purified IgGs from serum 4 bound specifically to GH receptor sites in adipocyte membranes and displaced [125I]hGH in the hGH RIA. In contrast, IgGs purified from another acromegalic patient (313 micrograms/L hGH) repeatedly tested negative in the membrane binding assay and hGH RIA.(ABSTRACT TRUNCATED AT 250 WORDS)

Decreased chemotaxis of neutrophils in acromegaly and hyperprolactinemia.

Both growth hormone (GH) and prolactin (PRL) modulate immune responses in vitro. We studied chemotaxis under agarose of polymorphonuclear cells from patients with acromegaly or hyperprolactinemia. Polymorphonuclear cells were purified by dextran sedimentation and subjected to stimulation with N-formylmethionyl-phenylalanine. The results showed a decrease in both directed migration (acromegaly: 971 +/- 155 microns; hyperprolactinemia: 1123 +/- 137 microns, expressed as mean +/- SEM) and spontaneous migration (acromegaly: 270 +/- 77 microns; hyperprolactinemia: 298 +/- 77 microns) when compared to similar features from normal controls (directed migration: 2019 +/- 99 microns; spontaneous migration: 590 +/- 49 microns) and from patients with non-GH/PRL-secreting pituitary tumours (directed migration: 1633 +/- 282 microns; spontaneous migration: 562 +/- 116 microns), suggesting that this defect is selective for acromegaly and hyperprolactinemia. Our results point to a putative direct or indirect effect of GH and PRL on polymorphonuclear cell chemotaxis.

Elevated levels of smooth muscle autoantibodies in patients with acromegaly.

Screening of sera from patients with central nervous system (CNS) tumors for serum antibodies to tumor and normal tissue antigens revealed that the sera from a significant percentage of patients with pituitary adenoma demonstrated reactivity for smooth muscle antibodies (SMA) at a serum titer (1/25) at which other CNS tumors are devoid of this reaction. The sera were assessed by an indirect immunofluorescent antibody assay on fresh cryostat sections of rat kidney, liver, diaphragm, and stomach tissue. Absorption of SMA-positive sera with extracts containing smooth muscle tissue abolished the reaction. The overall incidence of SMA among patients harboring pituitary tumors was 30% (12/40). Assessment of the functional types of the tumor revealed a distinct predilection for such findings among patients with clinical acromegaly. Among patients with hypersecretion of growth hormone (CA) 90% (9/10) have SMA (both IgG and IgM type) whereas SMA was positive in only 10% (3/30) of corresponding group of patients with pituitary tumors resulting in hypercortisolemia or those that did not result in a hyperfunctional endocrine state.

[Familial acromegaly. Apropos of a case. Review of the literature]. / L'acromégalie familiale. A propos d'une observation. Revue de la littérature.

Two brothers and a sister with acromegaly--one of them with acromegalogigantism--are described. They all presented pituitary adenomas, and the diagnosis was made between the ages of 17 and 29. There was no feature of multiple endocrine neoplasia. The familial investigation consisted of detailed interrogation, basal hormonal evaluation and HLA determination (haplotypes A and B) in 14 members, including the patients themselves. Despite basal plasma GH levels ranging from 8.00 to 10.00 ng/ml in 3 other family members, the normality of both GH response to induced-hyperglycemia and CT-imaging of the pituitary gland excluded the diagnosis of acromegaly in these subjects. No correlation with the HLA haplotypes was observed. Differential diagnosis with familial multiple endocrine neoplasia (MEN type 1) is discussed. Previous reports of familial acromegaly are reviewed and analysed. It appears that familial acromegaly may be considered as a specific entity for two main reasons: 1) owing to the low incidence of acromegaly in the general population, familial cases are unlikely to be fortuitous. 2) most of the reported cases share some common clinical features, such as a male predominance, a high incidence of acromegalogigantism, and the presence of a pituitary macroadenoma. However, the primitive disorder and the genetic transmission of the disease are still unknown.

[The CD2, CD4 and CD8 mRNA expression of T lymphocytes in patients with acromegaly and hyperprolactinemia].

The CD2, CD4 and CD8 mRNA expression of human peripheral blood lymphocytes (HPBL) from 49 female patients with acromegaly and hyperprolactinemia and 15 healthy women were studied by dot blotting assay using corresponding CD2, CD4 and CD8 antisense RNA probes. It was found that CD2 mRNA expression increased in women with growth hormone over-expression and the ratio of CD4 and CD8 mRNA declined significantly in the women with prolactin over-expression. These suggested that the mRNA expression of these cluster differentiation antigens in peripheral T lymphocytes was affected by the pituitary hormones. The significance of these findings relevant to the study of the neuroendocrine and immune network was discussed.

Inflammatory adipokines contribute to insulin resistance in active acromegaly and respond differently to different treatment modalities.

BACKGROUND: Active acromegaly is associated with insulin resistance, but it is uncertain whether inflammation in adipose tissue is a contributing factor. AIM: To test if GH/IGF1 promotes inflammation in adipocytes, and if this is relevant for systemic insulin resistance in acromegaly. Furthermore, to investigate the effect of treatment modalities (transsphenoidal surgery (TS), somatostatin analogs (SAs), and pegvisomant (PGV)) on glucose metabolism and inflammatory biomarkers in acromegaly. METHODS: The in vitro effects of GH/IGF1 on gene expression of adipokines in human adipocytes were investigated. Body composition, glucose metabolism, and circulating adipokines (adiponectin (AD), high-molecular weight AD (HMWAD), leptin, vascular endothelial growth factor-A (VEGF-A), monocyte chemotactic protein 1 (MCP1), and thioredoxin (TRX)) were measured in 37 patients with active acromegaly before and after treatment. RESULTS: In vitro GH, but not IGF1, increased VEGF and MCP1 in human adipocytes. In all treatment groups, body fat increased and IGF1 decreased to the same extent. Fasting glucose decreased in the TS (P=0.016) and PGV (P=0.042) groups, but tended to increase in the SA group (P=0.078). Insulin and HOMA-IR decreased in both TS and SA groups, while the PGV group showed no changes. Serum VEGF and MCP1 decreased significantly in the TS group only (P=0.010, P=0.002), while HMWAD increased with PGV treatment only (P=0.018). A multivariate analysis model identified the changes in GH and VEGF as predictors of improvement in HOMA-IR after treatment (R²=0.39, P=0.002). CONCLUSIONS: i) GH directly promotes inflammation of human adipocytes by increasing VEGF and MCP1 levels; ii) glucose metabolism and inflammation (VEGF and MCP1) improve to some extent after treatment, despite an increase in adipose tissue mass; and iii) the decrease in insulin resistance after therapy in acromegaly depends, to some extent, on treatment modalities.

Does Apolipoprotein E genotype affect cardiovascular risk in subjects with acromegaly?

Acromegaly is a syndrome that results when the pituitary gland produces excess growth hormone after epiphyseal closure at puberty. Usually, subjects with acromegaly exhibit a 2- to 3-fold higher mortality rate from diseases that are associated with cardiovascular complications when compared to the normal population. In this study, we therefore aimed to evaluate whether a well-established cardiovascular risk factor, the Apolipoprotein E (Apo E) genotype, contributes to increased risk of cardiovascular complications in subjects with acromegaly. A total of 102 unrelated acromegaly subjects were prospectively included into this case-control association study and constituted our study group. The study group was comparable by age and gender with 200 unrelated healthy subjects constituting our control group. Genomic DNA was isolated from the peripheral blood leukocytes of all subjects and Apo E genotype (codon 112/158) was assessed by melting temperature analyses after using a real-time PCR protocol. The Apolipoprotein E4 allele was found at a significantly higher frequency in the study group when compared with the control group (P = 0.032). Subjects with the E2 allele, on the other hand, had significantly increased values in body mass index (P = 0.004), waist circumference (P = 0.001), C-reactive protein (CRP) (P < 0.001), and left-side carotid intima media thickness (P = 0.025). The Apolipoprotein E2 genotype might contribute to increased risk of cardiovascular complications in subjects with acromegaly since it is concurrently present with other cardiovascular risk factors such as the left-side carotid intima media thickness and CRP.

Adipocytes as a source of increased circulating levels of nicotinamide phosphoribosyltransferase/visfatin in active acromegaly.

BACKGROUND: Nicotinamide phosphoribosyltransferase (NAMPT)/visfatin is a widely expressed protein with various effects on glucose and lipid metabolism, cell survival, and inflammation. AIM: We hypothesized that NAMPT was related to metabolic disturbances in active acromegaly. METHODS: Body composition, glucose metabolism, and NAMPT levels were measured in 47 patients with active, untreated acromegaly and 24 age-, sex-, and body mass index-matched controls. The in vitro effects of GH/IGF-I on NAMPT expression in human sc adipocytes (SCA), visceral adipocytes, osteoblasts, and hepatocytes were studied. The effects of overnight incubation with the highly specific NAMPT inhibitor FK866 on the GH-stimulated monocyte chemotactic protein-1 and IL-6 expression in mature SCA were evaluated. RESULTS: NAMPT was increased in active acromegaly (P = 0.004) and correlated negatively with limb (arms + legs) fat percentage (% fat, r = -0.32; P = 0.032). After adjusting for age, gender, leptin, and GH, the circulating NAMPT correlated negatively with limb and total body fat percentage (% fat limbs, r = -0.43, P = 0.006; % fat total body, r = -0.36, P = 0.022) and correlated positively with limb and total body lean percentage (% lean limbs, r = 0.31, P = 0.047; % lean total body, r = 0.33, P = 0.034). No correlation between NAMPT and glucose metabolic parameters was found. In vitro studies revealed that GH increased NAMPT expression in adipocytes. The inhibition of NAMPT enzymatic activity attenuated GH-induced monocyte chemotactic protein-1 expression in SCA. CONCLUSIONS: NAMPT is increased in active acromegaly and may be an inflammatory mediator that causes monocyte infiltration in adipose tissue.

Micronucleus evaluation in mitogen-stimulated lymphocytes of patients with acromegaly.

Acromegaly is a syndrome characterized by a sustained elevation of circulating growth hormone and insulin-like growth factor-1 (IGF-1). Insulin-like growth factor-1 is a potent mitogen and has a role in the transformation of normal cells to malignant cells. This study aims to evaluate the spontaneous micronucleus (MN) frequency by using the cytokinesis-block MN assay to determine genetic damage in the lymphocytes of patients with acromegaly. The study was carried out in 20 patients who had active acromegaly and in 20 age- and sex-matched healthy controls. The MN values were measured in binucleated cells obtained from mitogen-stimulated lymphocytes of patients and control subjects. The distribution of binucleated cells with 1, 2, 3, or more MNs was also measured. We found significantly higher MN frequency values in the lymphocytes of acromegalic patients than in those of the control subjects (2.23 ± 0.68 vs 1.03 ± 0.54, P = .001). The MN frequency increased with increasing IGF-1 levels of acromegalic patients (P = .036, R = 0.47). We observed that the number of binucleated cells with 2 MNs was higher for the majority of patients with acromegaly than for control subjects. Furthermore, the receiver operating characteristic curve (area under the curve = 0.914, P < .0001) was calculated to assess the discriminative power of the MN frequency. Our results indicate that increased MN frequency in the lymphocytes of patients with acromegaly may reflect genomic instability and this increased MN frequency may be associated with elevated levels of circulating growth hormone and IGF-1.