Histomorphometric and microarchitectural analysis of bone in metastatic breast cancer patients.

BACKGROUND: Despite widespread use of repeated doses of potent bone-targeting agents (BTA) in oncology patients, relatively little is known about their in vivo effects on bone homeostasis, bone quality, and bone architecture. Traditionally bone quality has been assessed using a trans-iliac bone biopsy with a 7 mm "Bordier" core needle. We examined the feasibility of using a 2 mm "Jamshidi™" core needle as a more practical and less invasive technique. METHODS: Patients with metastatic breast cancer on BTAs were divided according to the extent of bone metastases. They were given 2 courses of tetracycline labeling and then underwent a posterior trans-iliac trephine biopsy and bone marrow aspirate. Samples were analyzed for the extent of tumor invasion and parameters of bone turnover and bone formation by histomorphometry. RESULTS: Twelve patients were accrued, 1 had no bone metastases, 3 had limited bone metastases (LSM) (<3 lesions) and 7 had extensive bone metastases (ESM) (>3 lesions). Most of the primary tumors were estrogen receptor (ER)/progesterone receptor (PR) positive. The procedure was well tolerated. The sample quality was sufficient to analyze bone trabecular structure and bone turnover by histomorphometry in 11 out of 12 patients. There was a good correlation between imaging data and morphometric analysis of tumor invasion. Patients with no evidence or minimal bone metastases had no evidence of tumor invasion. Most had suppressed bone turnover and no detectable bone formation when treated with BTA. In contrast, 6 out of 7 patients with extensive bone invasion by imaging and evidence of tumor cells in the marrow had intense osteoclastic activity as measured by the number of osteoclasts. Of these 7 patients with ESM, 6 were treated with BTA with 5 showing resistance to BTA as demonstrated by the high number of osteoclasts present. 3 of these 6 patients had active bone formation. Based on osteoblast activity and bone formation, 3 out of 6 patients with ESM responded to BTA compared to all 3 with LSM. Compared to untreated patients, all patients treated with BTA showed a trend towards suppression of bone formation, as measured by tetracycline labelling. There was also a trend towards a significant difference between ESM and LSM treated with BTA, highly suggestive of resistance although limited by the small sample size. DISCUSSION: Our results indicate that trans-iliac bone biopsy using a 2 mm trephine shows excellent correlation between imaging assessment of tumor invasion and tumor burden by morphometric analysis of bone tissues. In addition, our approach provides additional mechanistic information on therapeutic response to BTA supporting the current clinical understanding that the majority of patients with extensive bone involvement eventually fail to suppress bone turnover (Petrut B, et al. 2008). This suggests that antiresorptive therapies become less effective as disease progresses.

The Chemical and Physical Properties of Poly(ε-caprolactone) Scaffolds Functionalised with Poly(vinyl phosphonic acid-co-acrylic acid).

There is a clinical need for a synthetic alternative to bone graft substitute (BGS) derived from demineralised bone matrix. We report the electrospinning of Poly(ε-caprolactone) (PCL) to form a 3-dimensional scaffold for use as a synthetic BGS. Additionally, we have used Poly(vinyl phosphonic acid-co-acrylic acid) (PVPA) to improve bone formation. Fibres were formed using a 10% w/v PCL/acetone solution. Infrared spectroscopy confirmed that the electrospinning process had no effect on the functional groups present in the resulting structure. The electrospun scaffolds were coated with PVPA (PCL/PVPA), and characterised. The stability of the PVPA coating after immersion in culture medium was assessed over 21 days. There was rapid release of the coating until day 2, after which the coating became stable. The wettability of the PCL scaffolds improved significantly, from 123.3 ± 10.8° to 43.3 ± 1.2° after functionalisation with PVPA. The compressive strength of the PCL/PVPA scaffolds (72 MPa) was significantly higher to that of the PCL scaffold (14 MPa), and an intermediate between trabecular and cortical bone (7 MPa and 170 MPa, resp.). The study has demonstrated that the PCL/PVPA scaffold has the desired chemical and biomechanical characteristics required for a material designed to be used as a BGS.

Diet and tumor LKB1 expression interact to determine sensitivity to anti-neoplastic effects of metformin in vivo.

Hypothesis-generating epidemiological research has suggested that cancer burden is reduced in diabetics treated with metformin and experimental work has raised questions regarding the role of direct adenosine monophosphate-activated protein kinase (AMPK)-mediated anti-neoplastic effects of metformin as compared with indirect effects attributable to reductions in circulating insulin levels in the host. We treated both tumor LKB1 expression and host diet as variables, and observed that metformin inhibited tumor growth and reduced insulin receptor activation in tumors of mice with diet-induced hyperinsulinemia, independent of tumor LKB1 expression. In the absence of hyperinsulinemia, metformin inhibited only the growth of tumors transfected with short hairpin RNA against LKB1, a finding attributable neither to an effect on host insulin level nor to activation of AMPK within the tumor. Further investigation in vitro showed that cells with reduced LKB1 expression are more sensitive to metformin-induced adenosine triphosphate depletion owing to impaired ability to activate LKB1-AMPK-dependent energy-conservation mechanisms. Thus, loss of function of LKB1 can accelerate proliferation in contexts where it functions as a tumor suppressor, but can also sensitize cells to metformin. These findings predict that any clinical utility of metformin or similar compounds in oncology will be restricted to subpopulations defined by host insulin levels and/or loss of function of LKB1.

Effects of Plagiorchis elegans (Digenea: Plagiorchiidae) infection of Biomphalaria glabrata (Pulmonata: Planorbidae) on a challenge infection with Schistosoma mansoni (Digenea: Schistosomatidae).

Prior exposure of Biomphalaria glabrata to the eggs of an incompatible digenean, Plagiorchis elegans, rendered this snail host less suitable to a compatible species, Schistosoma mansoni. Although P. elegans failed to develop patent infections in B. glabrata, it reduced the production of S. mansoni cercariae by 88%. Concomitantly, host attributes such as reproduction, growth, and survival were compromised. The effect of P. elegans infection was most severe among snails that, in addition, had developed patent schistosome infections. Although few S. mansoni cercariae were produced, egg production by B. glabrata was only 4% of control values. Furthermore, no doubly infected snails survived for more than 3 wk after patency, whereas controls experienced no mortality during the same time period. The above effects were attributable to the establishment and persistence of P. elegans sporocysts in the tissues of the incompatible snail host. Their indirect antagonistic interaction with thelarval stages of S. mansoni may be mediated, in part, through their long-term stimulation of the host's internal defense mechanisms. These findings are discussed with a view to use P. elegans and other plagiorchiid digeneans as agents in the biological control of snails and snail-borne diseases.

Plagiorchis elegans (Digenea: Plagiorchiidae) infections in Stagnicola elodes (Pulmonata: Lymnaeidae): host susceptibility, growth, reproduction, mortality, and cercarial production.

Eggs of Plagiorchis elegans were readily ingested by Stagnicola elodes of all ages, but were more infective to immature than mature snails. Infection enhanced the growth of the host in a dose-dependent manner. The number of cercariae released by immature snails increased with the age of the snail host; mature snails yielded fewer cercariae. Heavily infected snails tended to die prematurely, thereby reducing their total production of cercariae to levels below those of more lightly infected individuals. Even light infections castrated the snail host. Snails that acquired the infection as juveniles never produced eggs. Actively reproducing snails ceased egg laying within days of infection and never recovered. All parasite effects on the growth and reproduction of the snail host first manifested themselves during the early stages of infection, long before the development of daughter sporocysts and cercariae, and are therefore attributable to the effects of mother sporocysts. The study provides insight into how this natural enemy of mosquito larvae may be established in natural snail populations by means of strategically timed introductions of parasite eggs, with a goal of maximizing cercarial production for the biological control of sympatric mosquito larvae.

Effects of Plagiorchis elegans (Digenea: Plagiorchiidae) infection on the reproduction of Biomphalaria glabrata (Pulmonata: Planorbidae).

Infection with the digenean parasite Plagiorchis elegans dramatically reduced the reproductive output of Biomphalaria glabrata exposed to the parasite as juveniles or adults. The total number of eggs produced by infected snails was reduced to approximately 7 and 13% of control values, respectively. Parasitic castration was attributed to the presence of mother sporocysts that readily established in the tissues of this incompatible host. Infection did not result in the production of cercariae but significantly shortened the life span of juvenile and adult B. glabrata by approximately 23 and 10%, respectively. Plagiorchis elegans also castrated its compatible host, Stagnicola elodes.

The effects of temperature and light on the survival, development, and infectivity of Plagiorchis elegans eggs.

Plagiorchis elegans eggs were incubated at 0, 4, 10, 20, or 30 C under a 12-hr:12-hr (L:D) photoperiod for 120 days. Approximately one-quarter of the eggs had already initiated the process of embryonation when passed with the feces of the hamster (Mesocricetus auratus), the experimental definitive host. Eggs failed to embryonate at 0 C and died within 2 days. Incubation at 4 C allowed full embryonation, but the mean number of embryonated eggs per day (1.32+/-0.15) and the mean number of eggs available over the course of incubation (egg days) (219.00+/-2.24) remained low. These values increased progressively as incubation temperatures rose and reached levels of 3.59+/-0.30 and 1,467.50+/-4.56, respectively, at 20 C. Although incubation at 30 C further increased the mean number of eggs per day (5.45+/-0.56), the mean number of egg days declined sharply to 735.25+/-4.71, suggesting that elevated temperatures enhanced embryonation but lowered the survival of embryonated eggs. This was also reflected in the infectivity of eggs over time. Embryonated eggs incubated at 10 and 20 C remained infective significantly longer than eggs incubated at higher or lower temperatures. Incubation in constant light yielded significantly lower mean numbers of embryonated eggs per day (1.86+/-0.09) and mean number of egg days (96.25+/-0.99) than incubation in constant darkness (2.23+/-0.17 and 701.50+/-2.86 eggs, respectively) but did not affect the infectivity of embryonated eggs. The data suggest that at moderate temperatures and shielded from light, fully embryonated eggs of P. elegans may survive in the aquatic environment for a period of months. Such eggs may serve as a source of infection for populations of Stagnicola elodes and ensure the sustained production of the highly entomopathogenic cercariae required for mosquito control.