Expression of Pit-1 mRNA and activin/inhibin subunits in clinically nonfunctioning pituitary adenomas. In situ hybridization and immunohistochemical analysis

How to Classify the Pituitary Neuroendocrine Tumors (PitNET)s in 2020

Adenohypophyseal tumors, which were recently renamed pituitary neuroendocrine tumors (PitNET), are mostly benign, but may present various behaviors: invasive, “aggressive” and malignant with metastases. They are classified into seven morphofunctional types and three lineages: lactotroph, somatotroph and thyrotroph (PIT1 lineage), corticotroph (TPIT lineage) or gonadotroph (SF1 lineage), null cell or immunonegative tumor and plurihormonal tumors. The WHO 2017 classification suggested that subtypes, such as male lactotroph, silent corticotroph and Crooke cell, sparsely granulated somatotroph, and silent plurihormonal PIT1 positive tumors, should be considered as “high risk” tumors. However, the prognostic impact of these subtypes and of each morphologic type remains controversial. In contrast, the French five-tiered classification, taking into account the invasion, the immuno-histochemical (IHC) type, and the proliferative markers (Ki-67 index, mitotic count, p53 positivity), has a prognostic value validated by statistical analysis in 4 independent cohorts. A standardized report for the diagnosis of pituitary tumors, integrating all these parameters, has been proposed by the European Pituitary Pathology Group (EPPG). In 2020, the pituitary pathologist must be considered as a member of the multidisciplinary pituitary team. The pathological diagnosis may help the clinician to adapt the post-operative management, including appropriate follow-up and early recognition and treatment of potentially aggressive forms.

Phrenic nerve conduction in the early stage of Guillain-Barre syndrome might predict the respiratory failure

OBJECTIVE

To investigate whether phrenic nerve conduction in the early phase of Guillain- Barre syndrome (GBS) predicts the need for respiratory assistance during the subsequent clinical course.

MATERIAL AND METHODS

We performed electrophysiological examinations of conventional peripheral nerve conduction and phrenic nerve conduction for GBS patients within 14 days from the onset. We excluded patients who had already been treated with immuno-related therapy and respiratory assistance.

RESULTS

Fifteen patients were enrolled. Three patients with the sum of phrenic nerve latency longer than 30 ms and the sum of bilateral diaphragmatic compound muscle action potential amplitude smaller than 0.3 mV required respiratory assistance after the conduction test.

CONCLUSION

Our findings showed that not only delayed distal latency but also decreased amplitude may predict the need for respiratory assistance during the subsequent disease course.

Changes in intracranial pressure associated with chest physiotherapy

INTRODUCTION

Management of intracranial hypertension is pivotal in the care of brain-injured patients.

SUMMARY OF CASE

We report the case of a patient with both a closed head injury and anoxic encephalopathy, who subsequently experienced episodes of refractory intracranial hypertension. The patient's care was complicated by the development of a pneumonia, which required frequent turning of the patient and chest physiotherapy. Conventional wisdom suggests that these interventions may stimulate the patient and worsen intracranial pressure, and therefore should be avoided.

RESULTS

Our observations on this patient, however, contradict this belief. This single-subject study presents data to support the use of chest physiotherapy in patients at risk for intracranial hypertension.

CONCLUSIONS

Further, the evidence is compelling that a randomized-controlled trial is indicated to test the hypothesis that chest physiotherapy may actually result in short-term resolution of high intracranial pressure, and thus provide one more clinical tool in the management of elevated intracranial pressure.

Use of high frequency oscillatory ventilation (HFOV) in neurocritical care patients

INTRODUCTION

Adult respiratory distress syndrome (ARDS) can be a common problem associated with the treatment of acute brain injury. High frequency oscillatory ventilation (HFOV) is a developing therapy for the treatment of ARDS in adult patients that can be life saving. However, often patients with acute, severe brain injury demonstrate intracranial hypertension (hICP) due to a variety of injuries (e.g., traumatic brain injury, mass lesion, acute hydrocephalus). There is concern over the use of HFOV due to its effects on intracranial pressure in patients with hICP.

METHODS

Retrospective case series study.

RESULTS

We describe the effects of HFOV on hemodynamics, respiratory function, and intracranial pressure in five patients with acute brain injury being treated for ARDS.

CONCLUSIONS

HFOV did not cause unmanageable or sustained increases in ICP in our series of patients. It appears HFOV may be a relatively safe and effective means of oxygenating patients with severe ARDS and concomitant hICP secondary to acute brain injury.

Prognosis and risk factors of early onset pneumonia in ventilated patients with Guillain–Barré syndrome

OBJECTIVE

Invasive mechanical ventilation is required in 30% of patients with Guillain-Barré syndrome (GBS) and is associated with pneumonia and increased mortality. Our objective was to determine the incidence, characteristics, outcomes, and risk factors of pneumonia in GBS patients receiving mechanical ventilation.

DESIGN AND SETTING

Study of a prospective database in an intensive care unit of a university hospital.

PATIENTS

The study included 81 patients who required intubation for GBS. Neurological findings, vital capacity, and signs of respiratory distress were recorded at admission and at intubation. A score predicting the risk of intubation (0-4) was calculated for each patient. Pneumonia was diagnosed based on predefined criteria and retrospectively confirmed by two observers. Early-onset pneumonia was defined as pneumonia diagnosed within 5 days after intubation.

MEASUREMENTS AND RESULTS

Mean vital capacity was 57 +/- 22% of predicted at admission and 33 +/- 11% at intubation. Pneumonia developed in 63 patients (78%), including 48 with early-onset pneumonia. Bacteria were consistent with aspiration. Of the 63 patients with pneumonia 11 (18%) had septic shock, 6 (10%) had acute respiratory distress syndrome, and 9 (14%) died. In the univariate analysis milder weakness, a lower risk of intubation (score < 2), and time from admission to intubation longer than 2 days were associated with early-onset pneumonia. Time from admission to intubation was the only independent predictor in the multivariate logistic regression model.

CONCLUSIONS

Early-onset pneumonia is a common and severe complication that is related to aspiration in patients with GBS. Delaying intubation may increase the risk of early-onset pneumonia.

Immunonegative "null cell" adenomas and gonadotropin (Gn) subunit (SUs) immunopositive adenomas share frequent expression of multiple transcription factors

The differentiation of pituitary cells and human pituitary adenomas follow three cell lineages: GH-PRL-TSH, ACTH, and FSH/LH, which are regulated by a combination of various transcription factors and co-factors. We have used RT-PCR and immunohistochemistry to show that immunonegative, "null cell" adenomas are equipped with multiple transcription factors and co-factors. The "null cell" adenomas showed similar frequencies of transcription factors as did the gonadotropin subunit (GnSU)-positive adenomas, with the exception that there were fewer instances of SF1 in the former. We speculate, therefore, that null cell adenomas and GnSU-positive adenomas share common molecular mechanisms in functional differentiation, even though the former do not produce hormones. From the high frequency of various transcription factors, we also speculate that both null cell adenomas and GnSU-positive adenomas are derived from "committed" pituitary progenitor stem cells. The questions, why a certain proportion of these pituitary tumor groups lack hormone production and why they are molecularly more committed to Gn transcription, remain to be further investigated.

GH-, PRL-, POMC-, beta-TSH-, beta-LH-, beta-FSH-mRNA in gonadotroph adenomas of the pituitary by in situ hybridization in comparison with immunostaining and clinical data

In situ hybridization (ISH) enables the visualization of specific mRNA for pituitary hormones. Our collection consists of 40 surgically removed pituitary adenomas that were classified as follicle stimulating hormone/luteinizing hormone (FSH/LH) cell adenomas by structure and by immunostaining (IH) for all pituitary hormones. All forty adenomas were regarded as clinically inactive. The aim of our study was to examine nonfunctioning adenomas by ISH for demonstration of mRNAs for all pituitary hormones. The results were compared with proliferation markers, invasiveness and clinical data. ISH detected signals for all pituitary hormones at a range of 30% for prolactin (PRL) to 85% for proopiomelanocortin (POMC). mRNA for beta-FSH was detected in 70% and beta-LH mRNA in 43% of adenomas. Thirty-three percent of adenomas revealed negative mRNA detection for beta-LH but positive hormone content. The majority of adenomas (75%) expressed more than two mRNAs simultaneously, mostly the combination of POMC mRNA together with beta-FSH mRNA and one to four others. Comparison with clinical data showed no significant differences except for one adenoma with a high Ki-67 index (> 2.1% positive nuclei). This adenoma showed very high signals for PRL and beta-TSH mRNA.

Paracrine/autocrine control of female reproduction

Neuropeptides, growth factors and cytokines are expressed in reproductive organs and tissues, where they interact with afferent endocrine messages to modulate cell proliferation and differentiation, local hormone secretion and vascular function. These events regulate complex processes such as gonadotropin pulsatility, ovulation, implantation and parturition. During reproductive life, a number of neuropeptides produced within the hypothalamus play a modulatory role in the control of gonadotropin-releasing hormone (GnRH) release, hence characterizing a hypothalamic paracrine system. The pituitary gland is a source and target of inhibin-related proteins, and these typical 'gonadal' products, once secreted by the pituitary cells, acquire the function of paracrine modulators of follicle-stimulating hormone (FSH) secretion. In the ovary, the effect of gonadotropins is locally modulated by growth factors acting in an autocrine/paracrine manner, although their precise role in folliculogenesis remains uncertain. Numerous local factors are involved in the control of endometrial growth, differentiation, receptivity and menstruation. Alterations in the paracrine endometrial system may underlie pathological processes such as infertility or endometrial neoplasia. The human placenta and its related membranes produce cytokines, hormones and growth factors that participate in the control of gestational development as well as in the maternal-fetal adaptation to gestational diseases. There is increasing evidence that paracrine signaling plays a fundamental role in all spheres of female reproductive function, and future research will concentrate on clarifying which of these local mechanisms play a decisive role in both physiology and disease, thus giving rise to new therapeutic strategies.

Pit-1 positive alpha-subunit positive nonfunctioning human pituitary adenomas: a dedifferentiated GH cell lineage?

Pit-1 is a transcription factor which has been reported to regulate differentiation toward GH, PRL and TSH in the anterior pituitary glands. In the human pituitary adenomas, Pit-1 is highly expressed in GH secreting and TSH secreting adenomas as it can well be anticipated. Interestingly, human non-functioning pituitary adenomas also express Pit-1, especially it was expressed in all alpha SU positive nonfunctioning adenomas. The human anterior pituitary cells are special in comparison with rodents in a finding that alpha SU is frequently colocalized with GH. As alpha SU is the first hormone appearing during fetal development in the rodent pituitary glands, it may be postulated that alpha SU Pit-1 positive cells undergo differentiation in the GH cell lineage. From this background, this paper proposes that "alpha SU positive Pit-1 Positive" cells are the ones in the GH cell lineage, more specifically a dedifferentiated cell lineage toward alpha SU/GH/Pit-1.

Correlation of Pit-1 gene expression and Pit-1 content with proliferation and differentiation in human myeloid leukemic cells

The transcription factor pituitary-1 (Pit-1) is a homeodomain-containing protein that is expressed mainly in the pituitary, where it drives the expression of growth hormone, prolactin, and thyroid-stimulating hormone beta chain genes. In addition, Pit-1 is required for adequate pituitary cell growth and may be involved in the pathogenesis of pituitary adenomas. Pit-1 expression has been also reported in nonpituitary tissues, where it might be involved in the control of cell proliferation. In order to elucidate such a possibility, we have investigated the changes in both Pit-1 mRNA and Pit-1 immunoreactivity in HL-60 cells following the addition of several differentiating agents. Our results show that while high Pit-1 levels are found in exponentially growing HL-60 cells, a significant decrease occurs after induction of cells to differentiate along the macrophage lineage with 12-O-tetradecanoylphorbol-13-acetate (TPA). In contrast no changes were observed when cells were treated with interferon-alpha, which also induces differentiation of HL-60 cells that, at odds with TPA, is not accompanied with growth arrest. In all, these findings suggest that Pit-1 expression is specifically associated with proliferation in HL-60 cells, thus supporting the idea that one of the functions of nonpituitary Pit-1 may be the control of cell proliferation.