A monoclonal antibody raised against a synthetic oxytocin peptide stains mouse hypothalamic neurones

Primary autoimmune hypothalamitis: management strategies and long-term outcomes in a tertiary care setting with a focused review of literature

BACKGROUND

Primary autoimmune hypothalamitis is an exceptionally rare inflammatory condition of the hypothalamus. Its etiology, clinical presentation, and management are not well established, with significant overlap and distinctions from hypophysitis.

MATERIAL AND METHODS

This study presents management and outcomes of patients with autoimmune hypothalamitis managed at a tertiary care centre. A literature review was also performed analyzing clinico-demographic, biochemical, radiological, and therapeutic characteristics.

RESULTS

There were 4 cases of autoimmune hypothalamitis out of 2200 sellar-suprasellar lesions managed over the past decade at our centre. Case 1 presented with arginine vasopressin (AVP) deficiency and adipsia, showing partial radiological response to glucocorticoids. Case 2 presented with neuropsychiatric features, with limited improvement on therapy. Case 3 had panhypopituitarism with stable disease on imaging, while Case 4 had AVP deficiency and hypogonadism with no significant radiological or hormonal recovery post therapy. Literature review (n = 34) of all cases showed female predominance (88%), but minimal association with pregnancy (6%). Polyuria-polydipsia was the most common presentation (81%), followed by memory disturbances and/or confusion (35%). Secondary hypogonadism was most common (88%) hormone deficiency followed by hypocortisolism (85%) and AVP deficiency (82%). T2 hyperintensity was the most common feature (95%) on MRI. Glucocorticoids enabled partial radiological response in most cases (82%), with hormonal recovery being less common (18%). Adjunctive medical therapy was required in 54.1% cases (most commonly azathioprine). Surgery was primarily used for biopsy and adjunctive radiotherapy in 3 cases. FDG-PET demonstrated utility in diagnosis, systemic involvement and follow-up.

CONCLUSION

Autoimmune hypothalamitis remains a challenging diagnosis due to its rarity and overlapping features with other sellar pathologies. Histopathological evaluation or circulating antibodies can point towards the diagnosis. FDG-PET can be valuable in diagnosis and follow-up. Glucocorticoids are the mainstay of treatment, with partial radiological response commonly observed.

A comprehensive overview of the relationship between RET gene and tumor occurrence

RET gene plays significant roles in the nervous system and many other tissues. Rearranged during transfection (RET) mutation is related to cell proliferation, invasion, and migration. Many invasive tumors (e.g., non-small cell lung cancer, thyroid cancer, and breast cancer) were found to have changes in RET. Recently, great efforts have been made against RET. Selpercatinib and pralsetinib, with encouraging efficacy, intracranial activity, and tolerability, were approved by the Food and Drug Administration (FDA) in 2020. The development of acquired resistance is inevitable, and a deeper exploration should be conducted. This article systematically reviewed RET gene and its biology as well as the oncogenic role in multiple cancers. Moreover, we also summarized recent advances in the treatment of RET and the mechanism of drug resistance.

Identification of peripheral oxytocin-expressing cells using systemically applied cell-type specific adeno-associated viral vector

Oxytocin is primarily synthesised in the brain and is widely known for its role in lactation and parturition after being released into the blood from the posterior pituitary gland. Nevertheless, peripheral tissues have also been reported to express oxytocin. Using systemic injection of a recombinant adeno-associated virus vector, we investigated the expression of the green fluorescent protein Venus under the control of the oxytocin promoter in the gastrointestinal tract, pancreas and testes of adult rats. Here, we confirm that the vector infects oxytocin neurones of the enteric nervous system in ganglia of the myenteric and submucosal plexuses. Venus was detected in 25%-60% of the ganglia in the myenteric and submucosal plexuses identified by co-staining with the neuronal marker PGP9.5. Oxytocin expression was also detected in the islets of Langerhans in the pancreas and the Leydig cells of the testes. Our data illustrate that peripheral administration of the viral vector represents a powerful method for selectively labelling oxytocin-producing cells outside the brain.

Involvement of MCH-oxytocin neural relay within the hypothalamus in murine nursing behavior

Multiple sequential actions, performed during parental behaviors, are essential elements of reproduction in mammalian species. We showed that neurons expressing melanin concentrating hormone (MCH) in the lateral hypothalamic area (LHA) are more active in rodents of both sexes when exhibiting parental nursing behavior. Genetic ablation of the LHA-MCH neurons impaired maternal nursing. The post-birth survival rate was lower in pups born to female mice with congenitally ablated MCH neurons under control of tet-off system, exhibiting reduced crouching behavior. Virgin female and male mice with ablated MCH neurons were less interested in pups and maternal care. Chemogenetic and optogenetic stimulation of LHA-MCH neurons induced parental nursing in virgin female and male mice. LHA-MCH GABAergic neurons project fibres to the paraventricular hypothalamic nucleus (PVN) neurons. Optogenetic stimulation of PVN induces nursing crouching behavior along with increasing plasma oxytocin levels. The hypothalamic MCH neural relays play important functional roles in parental nursing behavior in female and male mice.