The cerebrovascular risks associated with tamoxifen use

Hormone Concentration Measurement in Intracranial Dural Arteriovenous Fistulae

OBJECTIVE

Intracranial dural arteriovenous fistulae (DAVFs) represent a subset of cerebral vascular malformations associated with significant morbidity and mortality. In Japan, DAVF exhibits sex-based differences in anatomical distribution, with female predominance in the cavernous sinus (CS) and male predominance in the transverse sinus (TS). Nevertheless, the pathophysiology of DAVF is not fully understood, and hormonal influences are hypothesized to play a role in its development. This study aimed to investigate changes in the concentrations of sex steroid hormones between intracranial and peripheral sampling sites in patients with CS- and TS-DAVF.

METHODS

We recruited 19 patients with CS-DAVF (n = 12) and TS-DAVF (n = 7) in this study. Blood hormone measurements were obtained from peripheral and jugular bulb samples during endovascular intervention. Hormone concentrations were analyzed using enzyme-linked immunosorbent assay kits, and statistical analyses were performed.

RESULTS

Our study revealed a higher prevalence of CS-DAVF in females and TS-DAVF in males, which is consistent with previous studies. Estradiol concentration was significantly lower in the jugular bulb compared with in the periphery in both patients with CS- and TS-DAVF. This decrease in estradiol was observed irrespective of the patient's sex and independent of follicle-stimulating hormone levels.

CONCLUSIONS

These findings indicate a local decrease in estradiol levels within the intracranial vasculature of patients with DAVF. This suggests a potential multifactorial role of estradiol in the pathomechanism of DAVFs, warranting further investigation to understand its influence on DAVF formation and potential targeted therapies, thereby enhancing patient outcomes.

Spontaneous Cerebrospinal Fluid Rhinorrhea in a Patient With Breast Cancer

Despite the well documented increased risk of osteopenia in patients with breast cancer during chemotherapy and endocrine therapy, spontaneous cerebrospinal fluid rhinorrhea (CSFR) is still rare. The authors present a case of spontaneous CSFR that occurred during chemotherapy and endocrine therapy for breast cancer. The patient underwent a repair using myofascia and adipose tissue and was started on mannitol. There was no recurrence at 1-year follow-up. Therefore, clinicians should pay attention to the possibility of CSFR in patients with breast cancer, to avoid misdiagnosis.

The selective estrogen receptor modulator tamoxifen protects against subtle cognitive decline and early markers of injury 24 h after hippocampal silent infarct in male Sprague-Dawley rats

Silent infarcts (SI) are subcortical cerebral infarcts occurring in the absence of typical ischemia symptoms and are linked to cognitive decline and dementia development. There are no approved treatments for SI. One potential treatment is tamoxifen, a selective estrogen receptor modulator. It is critical to establish whether treatments effectively target the early consequences of SI to avoid progression to complete injury. We induced SI in the dorsal hippocampal CA1 of rats and assessed whether tamoxifen is protective 24 h later against cognitive deficits and injury responses including gliosis, apoptosis, inflammation and changes in estrogen receptors (ERs). SI led to subtle cognitive impairment on the object place task, an effect ameliorated by tamoxifen administration. SI did not lead to detectable hippocampal cell loss but increased apoptosis, astrogliosis, microgliosis and inflammation. Tamoxifen protected against the effects of SI on all measures except microgliosis. SI increased ERα and decreased ERβ in the hippocampus, which were mitigated by tamoxifen. Exploratory data analyses using scatterplot matrices and principal component analysis indicated that SI rats given tamoxifen were indistinguishable from controls. Further, SI rats were significantly different from all other groups, an effect associated with low levels of ERα and increased apoptosis, gliosis, inflammation, ERβ, and time spent with the unmoved object. The results demonstrate that tamoxifen is protective against the early cellular and cognitive consequences of hippocampal SI 24 h after injury. Tamoxifen mitigates apoptosis, gliosis, and inflammation and normalization of ER levels in the CA1, leading to improved cognitive outcomes after hippocampal SI.

A case of dural arteriovenous fistula of superior sagittal sinus after tamoxifen treatment for breast cancer

We are reporting an unusual case of dural arteriovenous fistula (AVF) of the superior sagittal sinus (SSS) after tamoxifen treatment for breast cancer. A 30-year-old female arrived at the emergency room with a sudden headache and left sided weakness and sensory loss. In her past medical history, she was diagnosed with breast cancer 1 year prior, and subsequently underwent a breast conserving mastectomy with whole breast radiation and adjuvant chemotherapy with tamoxifen. At the time of admission, computed tomography showed a small acute intracerebral hemorrhage at the right parietal cortex, and magnetic resonance imaging showed that a dural AVF at the SSS with a prominent and tortuous venous enhancement along the centrum semiovale was present. Cerebral angiography showed that the dural AVF at the mid-portion of the SSS with meningeal arterial feeding vessels entering the wall of the SSS, then draining through the dilated cortical veins. Our patient had no signs of active malignancy or any abnormalities in her coagulation profile, so it can be concluded that the tamoxifen was the likely cause of the SSS thrombosis and dural AVF. The dural AVF was treated by an endovascular coil embolization for the arterialized segment of the SSS. The patient dramatically recovered favorably from left side motor and sensory deficit. The best clinical approach is to screen potential patients of tamoxifen hormonal therapy and educate them on the sign and symptoms of life threatening thromboembolic events while taking tamoxifen.

Cerebral venous sinus thrombosis risk factors

Cerebral venous sinus thrombosis is an uncommon disease marked by clotting of blood in cerebral venous, or dural sinuses, and, in rare cases, cortical veins. It is a rare but potentially fatal cause of acute neurological deterioration previously related to otomastoid, orbit, and central face cutaneous infections. After the advent of antibiotics, it is more often related to neoplasm, pregnancy, puerperium, systemic diseases, dehydration, intracranial tumors, oral contraceptives, and coagulopathies are the most common causes, but in 30% of cases no underlying etiology can be identified. It has been found in association with fibrous thyroiditis, jugular thrombosis after catheterization, or idiopathic jugular vein stenosis. Other factors include surgery, head trauma, arterio-venous malformations, infection, paraneoplastic, and autoimmune disease. This article presents a comprehensive review of cerebral venous sinus thrombosis etiologies.

New findings with old drugs for osteoporosis

BACKGROUND

Postmenopausal osteoporosis is common and is associated with stooped posture, loss of height, back pain and fractures.

OBJECTIVES/METHODS

This evaluation is of clinical outcome trials with tibolone (Long-Term Intervention of Fractures with Tibolone) and strontium ranelate (Spinal Osteoporosis Therapeutic Intervention) in postmenopausal osteoporosis.

RESULTS

Although the Long-Term Intervention of Fractures with Tibolone trial established that tibolone decreased the incidence of vertebral and non-vertebral fractures in postmenopausal osteoporosis, it also showed that tibolone caused a small increase in the incidence of stoke. The Spinal Osteoporosis Therapeutic Intervention trial established that strontium ranelate decreased the incidence of vertebral fractures, but had little effect on the incidence of non-vertebral fractures.

CONCLUSIONS

As some of the bisphosphonates (alendronate, risedronate, zoledronic acid) have been shown to prevent hip fractures without increasing the incidence of stroke, they should be preferred to tibolone and strontium in the treatment of postmenopausal osteoporosis.

Effects of selective oestrogen receptor modulators on proliferation in tissue cultures of pre- and postmenopausal human endometrium

We characterised the effects of selective oestrogen receptor modulators (SERM) in explant cultures of human endometrium tissue. Endometrium tissues were cultured for 24h in Millicell-CM culture inserts in serum-free medium in the presence of vehicle, 17beta-estradiol (17beta-E2, 1nM), oestrogen receptor (ER) antagonist ICI 164.384 (40nM), and 4-OH-tamoxifen (40nM), raloxifene (4nM), lasofoxifene (4nM) and acolbifene (4nM). Protein expression of ERalpha, ERbeta1 and Ki-67 were evaluated by immunohistochemistry (IHC). The proliferative fraction was assessed by counting the number of Ki-67 positive cells. Nuclear staining of ER( and ER(1 was observed in the glandular epithelium and stroma of pre- and postmenopausal endometrium. ER(1 protein was also localized in the endothelial cells of blood vessels. Treating premenopausal endometrium tissue with 17beta-E2 increased the fraction of Ki-67 positive cells (p<0.001) by 55% in glands compared to the control. Raloxifene (4nM) increased (p<0.05) the Ki-67 positive fraction. All other SERMS did not affect proliferation in this model. Treating postmenopausal endometrium with 17(-E2 increased (p<0.001) the fraction of Ki-67 positive cells by 250% in glands compared to the control. A similar effect was also seen for 4-OH-tamoxifen, whereas the rest of SERMs did not stimulate proliferation. We demonstrated that oestradiol increases the fraction of proliferating cells in short term explant cultures of postmenopausal endometrium. In addition, we were able to reveal the agonistic properties of 4-OH-tamoxifen and confirm that raloxifene and next-generation SERMs acolbifene and lasofoxifene were neutral on the human postmenopausal endometrium.

Selective estrogen receptor modulators (SERMS)

Hormone receptors and, specifically, estrogen receptors were described about four decades ago. For estrogens, there are two receptors, estrogen receptor alpha (ERalpha) and estrogen receptor beta (ERbeta). The two receptors are coded by different genes and their tissue expression varies across organs. ERalpha is predominantly expressed in reproductive tissues (uterus, breast, ovaries) liver and central nervous system, whereas ERbeta is expressed in other tissues such as bone, endothelium, lungs, urogenital tract, ovaries, central nervous system and prostate. More than seventy molecules that belong to the SERMS class have been described. There are 5 chemical groups: triphenylethylenes, benzotiophenes, tetrahydronaphtylenes, indoles and benzopyrans. All of these non-hormonal compounds are capable of activating the ER, reduce bone turnover rate and, as an antiresorptive, clearly improve bone density. Estrogens reduce bone turnover rate and, as an antiresorptive, clearly improve bone density. They are also beneficial for the relief of menopausal symptoms. An ongoing debate that extends over the decades, relates to to overall benefit/risk profile of estrogen or estrogen-progestin therapy since these therapies can increase the risk of serious health disorders, such as breast cancer. SERMs have increased our understanding of hormone-receptor regulatory mechanisms. Their development has permitted a targeted efficacy profile avoiding some of the side effects of the hormone therapy. Their clinical utility relies today mostly on the effects on breast cancer and bone.

Stroke in cancer patients

Cancer patients are at increased risk for stroke from direct and indirect effects of their malignancy. Some tumors are at high risk for cerebrovascular complications. Certain stroke mechanisms are specific to cancer, such as compression and occlusion of cerebral vessels by tumor, coagulopathy predisposing to hemorrhage and thrombosis, and treatment-related atherosclerosis. Special consideration for these mechanisms needs to be made when evaluating cancer patients, and treatment aimed at secondary prevention needs to incorporate overall prognosis and goals of care.