Reduced STMN2 and pathogenic TDP-43, two hallmarks of ALS, synergize to accelerate motor decline in mice

Pathological TDP-43 loss from the nucleus and cytoplasmic aggregation occurs in almost all cases of ALS and half of frontotemporal dementia patients. Stathmin2 (Stmn2) is a key target of TDP-43 regulation and aberrantly spliced Stmn2 mRNA is found in patients with ALS, frontotemporal dementia, and Alzheimer's Disease. STMN2 participates in the axon injury response and its depletion in vivo partially replicates ALS-like symptoms including progressive motor deficits and distal NMJ denervation. The interaction between STMN2 loss and TDP-43 dysfunction has not been studied in mice because TDP-43 regulates human but not murine Stmn2 splicing. Therefore, we generated trans-heterozygous mice that lack one functional copy of Stmn2 and express one mutant TDP-43Q331K knock-in allele to investigate whether reduced STMN2 function exacerbates TDP-43-dependent pathology. Indeed, we observe synergy between these two alleles, resulting in an early onset, progressive motor deficit. Surprisingly, this behavioral defect is not accompanied by detectable neuropathology in the brain, spinal cord, peripheral nerves or at neuromuscular junctions (NMJs). However, the trans-heterozygous mice exhibit abnormal mitochondrial morphology in their distal axons and NMJs. As both STMN2 and TDP-43 affect mitochondrial dynamics, and neuronal mitochondrial dysfunction is a cardinal feature of many neurodegenerative diseases, this abnormality likely contributes to the observed motor deficit. These findings demonstrate that partial loss of STMN2 significantly exacerbates TDP-43-associated phenotypes, suggesting that STMN2 restoration could ameliorate TDP-43 related disease before the onset of degeneration.

Sarm1 knockout prevents type 1 diabetic bone disease in females independent of neuropathy

Patients with diabetes have a high risk of developing skeletal diseases accompanied by diabetic peripheral neuropathy (DPN). In this study, we isolated the role of DPN in skeletal disease with global and conditional knockout models of sterile-α and TIR-motif-containing protein-1 (Sarm1). SARM1, an NADase highly expressed in the nervous system, regulates axon degeneration upon a range of insults, including DPN. Global knockout of Sarm1 prevented DPN, but not skeletal disease, in male mice with type 1 diabetes (T1D). Female wild-type mice also developed diabetic bone disease but without DPN. Unexpectedly, global Sarm1 knockout completely protected female mice from T1D-associated bone suppression and skeletal fragility despite comparable muscle atrophy and hyperglycemia. Global Sarm1 knockout rescued bone health through sustained osteoblast function with abrogation of local oxidative stress responses. This was independent of the neural actions of SARM1, as beneficial effects on bone were lost with neural conditional Sarm1 knockout. This study demonstrates that the onset of skeletal disease occurs rapidly in both male and female mice with T1D completely independently of DPN. In addition, this reveals that clinical SARM1 inhibitors, currently being developed for treatment of neuropathy, may also have benefits for diabetic bone through actions outside of the nervous system.

A SARM1-mitochondrial feedback loop drives neuropathogenesis in a Charcot-Marie-Tooth disease type 2A rat model

Charcot-Marie-Tooth disease type 2A (CMT2A) is an axonal neuropathy caused by mutations in the mitofusin 2 (MFN2) gene. MFN2 mutations result in profound mitochondrial abnormalities, but the mechanism underlying the axonal pathology is unknown. Sterile α and Toll/IL-1 receptor motif-containing 1 (SARM1), the central executioner of axon degeneration, can induce neuropathy and is activated by dysfunctional mitochondria. We tested the role of SARM1 in a rat model carrying a dominant CMT2A mutation (Mfn2H361Y) that exhibits progressive dying-back axonal degeneration, neuromuscular junction (NMJ) abnormalities, muscle atrophy, and mitochondrial abnormalities - all hallmarks of the human disease. We generated Sarm1-KO (Sarm1-/-) and Mfn2H361Y Sarm1 double-mutant rats and found that deletion of Sarm1 rescued axonal, synaptic, muscle, and functional phenotypes, demonstrating that SARM1 was responsible for much of the neuropathology in this model. Despite the presence of mutant MFN2 protein in these double-mutant rats, loss of SARM1 also dramatically suppressed many mitochondrial defects, including the number, size, and cristae density defects of synaptic mitochondria. This surprising finding indicates that dysfunctional mitochondria activated SARM1 and that activated SARM1 fed back on mitochondria to exacerbate the mitochondrial pathology. As such, this work identifies SARM1 inhibition as a therapeutic candidate for the treatment of CMT2A and other neurodegenerative diseases with prominent mitochondrial pathology.

Macrophage depletion blocks congenital SARM1-dependent neuropathy

Axon loss contributes to many common neurodegenerative disorders. In healthy axons, the axon survival factor NMNAT2 inhibits SARM1, the central executioner of programmed axon degeneration. We identified 2 rare NMNAT2 missense variants in 2 brothers afflicted with a progressive neuropathy syndrome. The polymorphisms resulted in amino acid substitutions V98M and R232Q, which reduced NMNAT2 NAD+-synthetase activity. We generated a mouse model to mirror the human syndrome and found that Nmnat2V98M/R232Q compound-heterozygous CRISPR mice survived to adulthood but developed progressive motor dysfunction, peripheral axon loss, and macrophage infiltration. These disease phenotypes were all SARM1-dependent. Remarkably, macrophage depletion therapy blocked and reversed neuropathic phenotypes in Nmnat2V98M/R232Q mice, identifying a SARM1-dependent neuroimmune mechanism as a key driver of disease pathogenesis. These findings demonstrate that SARM1 induced inflammatory neuropathy and highlight the potential of immune therapy as a treatment for this rare syndrome and other neurodegenerative conditions associated with NMNAT2 loss and SARM1 activation.

Disentangling glial diversity in peripheral nerves at single-nuclei resolution

The peripheral nerve contains diverse cell types that support its proper function and maintenance. In this study, we analyzed multiple peripheral nerves using single-nuclei RNA sequencing, which allowed us to circumvent difficulties encountered in analyzing cells with complex morphologies via conventional single-cell methods. The resultant mouse peripheral nerve cell atlas highlights a diversity of cell types, including multiple subtypes of Schwann cells (SCs), immune cells and stromal cells. We identified a distinct myelinating SC subtype that expresses Cldn14, Adamtsl1 and Pmp2 and preferentially ensheathes motor axons. The number of these motor-associated Pmp2⁺ SCs is reduced in both an amyotrophic lateral sclerosis (ALS) SOD1^G93A mouse model and human ALS nerve samples. Our findings reveal the diversity of SCs and other cell types in peripheral nerve and serve as a reference for future studies of nerve biology and disease.

Constitutively active SARM1 variants that induce neuropathy are enriched in ALS patients

Background

In response to injury, neurons activate a program of organized axon self-destruction initiated by the NAD⁺ hydrolase, SARM1. In healthy neurons SARM1 is autoinhibited, but single amino acid changes can abolish autoinhibition leading to constitutively active SARM1 enzymes that promote degeneration when expressed in cultured neurons.

Methods

To investigate whether naturally occurring human variants might disrupt SARM1 autoinhibition and potentially contribute to risk for neurodegenerative disease, we assayed the enzymatic activity of all 42 rare SARM1 alleles identified among 8507 amyotrophic lateral sclerosis (ALS) patients and 9671 controls. We then intrathecally injected mice with virus expressing SARM1 constructs to test the capacity of an ALS-associated constitutively active SARM1 variant to promote neurodegeneration in vivo.

Results

Twelve out of 42 SARM1 missense variants or small in-frame deletions assayed exhibit constitutive NADase activity, including more than half of those that are unique to the ALS patients or that occur in multiple patients. There is a > 5-fold enrichment of constitutively active variants among patients compared to controls. Expression of constitutively active ALS-associated SARM1 alleles in cultured dorsal root ganglion (DRG) neurons is pro-degenerative and cytotoxic. Intrathecal injection of an AAV expressing the common SARM1 reference allele is innocuous to mice, but a construct harboring SARM1^V184G, the constitutively active variant found most frequently among the ALS patients, causes axon loss, motor dysfunction, and sustained neuroinflammation.

Conclusions

These results implicate rare hypermorphic SARM1 alleles as candidate genetic risk factors for ALS and other neurodegenerative conditions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13024-021-00511-x.

Neurotoxins subvert the allosteric activation mechanism of SARM1 to induce neuronal loss

SARM1 is an inducible TIR-domain NAD+ hydrolase that mediates pathological axon degeneration. SARM1 is activated by an increased ratio of NMN to NAD+, which competes for binding to an allosteric activating site. When NMN binds, the TIR domain is released from autoinhibition, activating its NAD+ hydrolase activity. The discovery of this allosteric activating site led us to hypothesize that other NAD+-related metabolites might activate SARM1. Here, we show the nicotinamide analog 3-acetylpyridine (3-AP), first identified as a neurotoxin in the 1940s, is converted to 3-APMN, which activates SARM1 and induces SARM1-dependent NAD+ depletion, axon degeneration, and neuronal death. In mice, systemic treatment with 3-AP causes rapid SARM1-dependent death, while local application to the peripheral nerve induces SARM1-dependent axon degeneration. We identify 2-aminopyridine as another SARM1-dependent neurotoxin. These findings identify SARM1 as a candidate mediator of environmental neurotoxicity and suggest that SARM1 agonists could be developed into selective agents for neurolytic therapy.

Cell-autonomous expression of the acid hydrolase galactocerebrosidase

Lysosomal storage diseases (LSDs) are typically caused by a deficiency in a soluble acid hydrolase and are characterized by the accumulation of undegraded substrates in the lysosome. Determining the role of specific cell types in the pathogenesis of LSDs is a major challenge due to the secretion and subsequent uptake of lysosomal hydrolases by adjacent cells, often referred to as "cross-correction." Here we create and validate a conditional mouse model for cell-autonomous expression of galactocerebrosidase (GALC), the lysosomal enzyme deficient in Krabbe disease. We show that lysosomal membrane-tethered GALC (GALCLAMP1) retains enzyme activity, is able to cleave galactosylsphingosine, and is unable to cross-correct. Ubiquitous expression of GALCLAMP1 fully rescues the phenotype of the GALC-deficient mouse (Twitcher), and widespread deletion of GALCLAMP1 recapitulates the Twitcher phenotype. We demonstrate the utility of this model by deleting GALCLAMP1 specifically in myelinating Schwann cells in order to characterize the peripheral neuropathy seen in Krabbe disease.

Disrupting insulin signaling in Schwann cells impairs myelination and induces a sensory neuropathy

Although diabetic mice have been studied for decades, little is known about the cell type specific contributions to diabetic neuropathy (DN). Schwann cells (SCs) myelinate and provide trophic support to peripheral nervous system axons. Altered SC metabolism leads to myelin defects, which can be seen both in inherited and DNs. How SC metabolism is altered in DN is not fully understood, but it is clear that insulin resistance underlies impaired lipid metabolism in many cell types throughout the body via the phosphoinositide 3-kinase/protein kinase b (PKB)/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway. Here, we created an insulin resistant SC by deleting both insulin receptor (INSR) and insulin-like growth factor receptor 1 (IGF1R), to determine the role of this signaling pathway in development and response to injury in order to understand SC defects in DN. We found that myelin is thinner throughout development and adulthood in INSR/IGF1R Schwann cell specific knock out mice. The nerves of these mutant mice had reduced expression of key genes that mediate fatty acid and cholesterol synthesis due to reduced mTOR-sterol regulatory element-binding protein signaling. In adulthood, these mice show sensory neuropathy phenotypes reminiscent of diabetic mice. Altogether, these data suggest that SCs may play an important role in DN and targeting their metabolism could lead to new therapies for DN.

Gene therapy targeting SARM1 blocks pathological axon degeneration in mice

Axonal degeneration (AxD) following nerve injury, chemotherapy, and in several neurological disorders is an active process driven by SARM1, an injury-activated NADase. Axons of SARM1-null mice exhibit greatly delayed AxD after transection and in models of neurological disease, suggesting that inhibiting SARM1 is a promising strategy to reduce pathological AxD. Unfortunately, no drugs exist to target SARM1. We, therefore, developed SARM1 dominant-negatives that potently block AxD in cellular models of axotomy and neuropathy. To assess efficacy in vivo, we used adeno-associated virus-mediated expression of the most potent SARM1 dominant-negative and nerve transection as a model of severe AxD. While axons of vehicle-treated mice degenerate rapidly, axons of mice expressing SARM1 dominant-negative can remain intact for >10 d after transection, similar to the protection observed in SARM1-null mice. We thus developed a novel in vivo gene therapeutic to block pathological axon degeneration by inhibiting SARM1, an approach that may be applied clinically to treat manifold neurodegenerative diseases characterized by axon loss.

Prevention of vincristine-induced peripheral neuropathy by genetic deletion of SARM1 in mice

Peripheral polyneuropathy is a common and dose-limiting side effect of many important chemotherapeutic agents. Most such neuropathies are characterized by early axonal degeneration, yet therapies that inhibit this axonal destruction process do not currently exist. Recently, we and others discovered that genetic deletion of SARM1 (sterile alpha and TIR motif containing protein 1) dramatically protects axons from degeneration after axotomy in mice. This finding fuels hope that inhibition of SARM1 or its downstream components can be used therapeutically in patients threatened by axonal loss. However, axon loss in most neuropathies, including chemotherapy-induced peripheral neuropathy, is the result of subacute/chronic processes that may be regulated differently than the acute, one time insult of axotomy. Here we evaluate if genetic deletion of SARM1 decreases axonal degeneration in a mouse model of neuropathy induced by the chemotherapeutic agent vincristine. In wild-type mice, 4 weeks of twice-weekly intraperitoneal injections of 1.5 mg/kg vincristine cause pronounced mechanical and heat hyperalgesia, a significant decrease in tail compound nerve action potential amplitude, loss of intraepidermal nerve fibres and significant degeneration of myelinated axons in both the distal sural nerve and nerves of the toe. Neither the proximal sural nerve nor the motor tibial nerve exhibit axon loss. These findings are consistent with the development of a distal, sensory predominant axonal polyneuropathy that mimics vincristine-induced peripheral polyneuropathy in humans. Using the same regimen of vincristine treatment in SARM1 knockout mice, the development of mechanical and heat hyperalgesia is blocked and the loss in tail compound nerve action potential amplitude is prevented. Moreover, SARM1 knockout mice do not lose unmyelinated fibres in the skin or myelinated axons in the sural nerve and toe after vincristine. Hence, genetic deletion of SARM1 blocks the development of vincristine-induced peripheral polyneuropathy in mice. Our results reveal that subacute/chronic axon loss induced by vincristine occurs via a SARM1 mediated axonal destruction pathway, and that blocking this pathway prevents the development of vincristine-induced peripheral polyneuropathy. These findings, in conjunction with previous studies with axotomy and traumatic brain injury, establish SARM1 as the central determinant of a fundamental axonal degeneration pathway that is activated by diverse insults. We suggest that targeting SARM1 or its downstream effectors may be a viable therapeutic option to prevent vincristine-induced peripheral polyneuropathy and possibly other peripheral polyneuropathies.

Hepatobiliary cystadenomas

INTRODUCTION

Hepatobiliary cystadenomas are rare cystic tumours that can arise from any portion of the biliary tract but most commonly develop intrahepatically. They typically cause non-specific symptoms and are often detected incidentally. Cystadenomas can be mistaken for simple hepatic cysts on radiological imaging, which leads to inadequate treatment. Hepatobiliary cystadenomas have a malignant predisposition and a high recurrence rate. Complete excision including hepatic resection is therefore generally recommended.

METHODS

Three cases of hepatobiliary cystadenoma were identified at one unit over a six-month period. Their clinical details and management are reported.

RESULTS

Three female patients are described aged 25, 37 and 73 years. One patient presented because of recurrent infection, one presented because of pressure related symptoms and one lesion was identified incidentally. All patients were investigated by ultrasonography and computed tomography (CT), two additionally had magnetic resonance imaging (MRI) and one had a liver biopsy. The tumours were 4-16cm in size and all lesions were excised by non-anatomical, parenchyma sparing resections. Histology revealed mixed epithelium with underlying ovarian-like stroma.

CONCLUSIONS

The management of hepatic cystadenomas as well as operative and pathological findings are discussed. Preoperative ultrasonography, CT and MRI is recommended, and early referral for specialist hepatobiliary review is advised. Operative resection is also recommended and complete excision was achieved in these cases. This strategy is supported by the current literature and recurrence has been shown to be unlikely.

Aberrant Schwann cell lipid metabolism linked to mitochondrial deficits leads to axon degeneration and neuropathy

Mitochondrial dysfunction is a common cause of peripheral neuropathy. Much effort has been devoted to examining the role played by neuronal/axonal mitochondria, but how mitochondrial deficits in peripheral nerve glia (Schwann cells [SCs]) contribute to peripheral nerve diseases remains unclear. Here, we investigate a mouse model of peripheral neuropathy secondary to SC mitochondrial dysfunction (Tfam-SCKOs). We show that disruption of SC mitochondria activates a maladaptive integrated stress response (ISR) through the actions of heme-regulated inhibitor (HRI) kinase, and causes a shift in lipid metabolism away from fatty acid synthesis toward oxidation. These alterations in SC lipid metabolism result in depletion of important myelin lipid components as well as in accumulation of acylcarnitines (ACs), an intermediate of fatty acid β-oxidation. Importantly, we show that ACs are released from SCs and induce axonal degeneration. A maladaptive ISR as well as altered SC lipid metabolism are thus underlying pathological mechanisms in mitochondria-related peripheral neuropathies.

Predictors of patient-assessed illness severity in irritable bowel syndrome

BACKGROUND

Conceptual models suggest that "irritable bowel syndrome (IBS) severity" is a multidimensional outcome that is related to, yet distinct from, health-related quality of life (HRQOL). Existing severity questionnaires are largely based on physician rather than patient-based ratings. Since severity is a patient-centered outcome, it is essential that future instruments are based on patients' self-perceptions of severity. We measured patient-derived predictors of severity in a large cohort of IBS patients.

METHODS

We performed a cross-sectional analysis in 755 IBS patients recruited at a university-based center. Subjects completed a bowel symptom questionnaire, SCL-90, and SF-36. The main outcome was patient-assessed "overall severity of gastrointestinal symptoms," as measured on a 0-20 scale (20 = most severe). We first developed a conceptual model of IBS, and then performed bivariate analyses to identify biopsychosocial predictors of severity. We then entered significant predictors into a multivariable model to measure the independent association of each predictor with severity.

RESULTS

Six factors predicted severity: (a) abdominal pain rating (P < 0.001); (b) belief that "something serious is wrong with body" (P < 0.001); (c) straining with defecation (P= 0.001); (d) myalgias (P= 0.02); (e) urgency with defecation (P= 0.03); and (f) bloating (P= 0.05). Severity correlated highly with HRQOL in bivariate, but not multivariate, analysis.

CONCLUSION

Patient-derived severity in IBS is related to, yet distinct from, generic HRQOL. IBS severity is predicted by abdominal pain, bloating, straining, urgency, myalgias, and disease-related concern. These symptoms fall along both poles of the "brain-gut axis," indicating that a full assessment of patient severity must include a balanced biopsychosocial history.

ATTAX: Randomised phase II study evaluating weekly docetaxel-based chemotherapy combinations in advanced esophago- gastric cancer, final results of an AGITG trial

4528

Background: Docetaxel (T), cisplatin (C) and 5FU(F) are active agents in esophago-gastric cancer. A recent phase III study evaluating 3-weekly TCF demonstrated a survival advantage over standard therapy, but TCF was associated with high rates of hematological toxicity (30% incidence of febrile neutropenia/neutropenic infection) as well as non-hematological side effects (Van Cutsem et al, J. Clin Oncol. 24 4991–4997 2006). Weekly docetaxel is associated with a lower incidence of hematological toxicity. This randomized phase II study aimed to test weekly docetaxel based combination chemotherapy regimens with the aim of maintaining the activity of such regimens but reducing toxicity. Methods: Eligibility included; histologically confirmed, metastatic esophageal or gastric (OG) carcinoma, measurable disease, PS0–2, adequate organ function, no prior treatment, informed consent. Patients (Pts) were randomized to receive weekly (w) T 30mg/m2 d1,8 C 60 mg/m2 d1 F 200 mg/m2/d continuously q 3w or wT 30 mg/m2 d1,d8 and capecitabine (X)1,600 mg/m2/d d1–14 q3w. The primary endpoint is confirmed response rate (RR), with each arm analyzed independently. Simon’s 2-stage design was used, with 5/21 responses required in the first stage to allow continuation to 50 pts per arm. Results: Response rates in each arm satisfied the first stage, and complete accrual of 106 pts was completed in May 2006. Demographics, toxicity and response rates are shown in the table . With a median follow-up of 14.6 months, progression free and overall survival times are 5.9 m and 12.8 m, and 4.2m and 10.1 m for wTCF and wTX, respectively. Conclusions: wTCF and wTX have encouraging activity and a far more favorable toxicity profile than TCF administered 3-weekly. Weekly docetaxel-based combination regimens should be evaluated further in this disease.

[Table: see text]

[Table: see text]

Somatostatin receptor expression, tumour response, and quality of life in patients with advanced hepatocellular carcinoma treated with long-acting octreotide

Octreotide may extend survival in hepatocellular carcinoma (HCC). Forty-one per cent of HCCs have high-affinity somatostatin receptors. We aimed to determine the feasibility, safety, and activity of long-acting octreotide in advanced HCC; to identify the best method for assessing somatostatin receptor expression; to relate receptor expression to clinical outcomes; and to evaluate toxicity. Sixty-three patients with advanced HCC received intramuscular long-acting octreotide 20 mg monthly until progression or toxicity. Median age was 67 years (range 28–81 years), male 81%, Child–Pugh A 83%, and B 17%. The aetiologies of chronic liver disease were alcohol (22%), viral hepatitis (44%), and haemochromatosis (6%). Prior treatments for HCC included surgery (8%), chemotherapy (2%), local ablation (11%), and chemoembolisation (6%). One patient had an objective partial tumour response (2%, 95% CI 0–9%). Serum alpha-fetoprotein levels decreased more than 50% in four (6%). Median survival was 8 months. Thirty four of 61 patients (56%) had receptor expression detected by scintigraphy; no clear relationship with clinical outcomes was identified. There were few grade 3 or 4 toxicities: hyperglycaemia (8%), hypoglycaemia (2%), diarrhoea (5%), and anorexia (2%). Patients reported improvements in some symptoms, but no major changes in quality of life were detected. Long-acting octreotide is safe in advanced HCC. We found little evidence of anticancer activity. A definitive randomised trial would identify whether patients benefit from this treatment in other ways.

Chemotherapy and radiotherapy for inoperable advanced pancreatic cancer

BACKGROUND

Pancreatic cancer has a poor prognosis. The benefit of chemotherapy, radiotherapy or both as a palliative treatment of advanced or relapsed disease is uncertain.

OBJECTIVES

To assess the effects of chemotherapy and/or radiotherapy in the management of pancreatic adenocarcinoma in people with inoperable advanced disease.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), which includes the Cochrane Upper Gastrointestinal and Pancreatic Diseases (UGPD) Group Trials Register (The Cochrane Library 2005, Issue 1); CANCERLIT (1975-2002); MEDLINE (1966 to January 2005); and EMBASE (1980 to January 2005). We handsearched reference lists from trials revealed by electronic searches to identify further relevant trials. We searched published abstracts from relevant conference proceedings. We contacted colleagues and experts in the field, and asked them to provide details of outstanding clinical trials and any relevant unpublished materials.

SELECTION CRITERIA

Randomised controlled trials (single- or double-blind) in patients with advanced inoperable pancreatic cancer, in which one of the intervention types (chemotherapy or radiotherapy) was contrasted with either placebo or another type of intervention. Studies comparing non-chemotherapy agents such as biological agents, hormones, immunostimulants, vaccines and cytokines were excluded.

DATA COLLECTION AND ANALYSIS

Studies were assessed for eligibility and quality. Data were extracted by groups of two independent reviewers, with conflicts resolved by a third reviewer. Study authors were contacted for more information.

MAIN RESULTS

Fifty trials (7043 participants) were included. Chemotherapy significantly reduced the one-year mortality (odds ratio (OR) 0.37, 95% confidence interval (CI) 0.25 to 0.57, P value < 0.00001) when compared to best supportive care. Also, chemoradiation improved one year survival (0% versus 58%, P value 0.001) when compared to best supportive care. There was no significant difference in one-year mortality for 5FU alone versus 5FU combinations (OR 0.90, 95% CI 0.62 to 1.30); single-agent chemotherapy versus gemcitabine (OR 1.34, 95% CI 0.88 to 2.02, P value 0.17); or gemcitabine alone versus gemcitabine combinations (OR 0.88, 95% CI 0.74 to 1.05). However, subgroup analysis showed that platinum-gemcitabine combinations reduced six-month mortality compared to gemcitabine alone (OR 0.59, 95% CI 0.43 to 0.81, P value 0.001). A qualitative overview suggested that chemoradiation produced better survivals than either best supportive care or radiotherapy. Chemoradiation treatment was associated with more toxicity.

AUTHORS' CONCLUSIONS

Chemotherapy appears to prolong survival in people with advanced pancreatic cancer and can confer clinical benefits and improve quality of life. Combination chemotherapy did not improve overall survival compared to single-agent chemotherapy. Gemcitabine is an acceptable control arm for future trials investigating scheduling and combinations with novel agents. There is insufficient evidence to recommend chemoradiation in patients with locally advanced inoperable pancreatic cancer as a superior alternative to chemotherapy alone.

Tslc1 (nectin-like molecule-2) is essential for spermatozoa motility and male fertility

The nectin-like molecule-2 (TSLC1) is a cell-cell adhesion molecule expressed in testicular germ cells. To directly examine the role of Tslc1 in male fertility, we generated Tslc1+/- mice that have greater than 90% reduction in Tslc1 expression. Tslc1+/- males exhibited reduced fertility and rarely transmitted the Tslc1 mutant allele, whereas Tslc1+/- females were consistently able to transmit the mutant allele. Histologic and electron microscopic analyses of the testes in Tslc1+/- mice demonstrated disruption of the junctional scaffold between germ cells and Sertoli cells. Reduced Tslc1 expression had no effect on germ cell proliferation or apoptosis. While evidence of normal spermatozoal maturation was supported by Fluorescence Activated Cell Sorting (FACS) analysis, spermatozoa from Tslc1+/- mice demonstrated markedly reduced motility without compromised viability. Collectively, these results establish an essential role for Tslc1 in spermatozoal maturation and motility, distinct from other members of the nectin family.

Randomised phase II study evaluating weekly docetaxel in combination with cisplatin and 5FU or capecitabine in metastatic oesophago-gastric cancer

4067

Background: Docetaxel (T), cisplatin (C) and 5FU (F) are active agents in oesophago-gastric cancer. A recent phase III study using TCF achieved a survival advantage but was associated with high rates of haematological toxicity (30% incidence of febrile neutropenia/neutropenic infection) as well as non-haematological side effects (Moiseyenko et al, 2005 Pr ASCO abstr 4002). Weekly docetaxel is associated with a lower incidence of haematological toxicity. This randomised phase II study aimed to test weekly docetaxel based combination chemotherapy regimens with the aim of maintaining the activity of docetaxel based combination regimens but reducing toxicity. Methods: Eligibility included; histologically confirmed, metastatic oesophageal or gastric (OG) carcinoma, measurable disease, PS0–2, adequate organ function, no prior treatment, informed consent. Pts were randomised to receive weekly (w) T 30 mg/m2 d1, 8 C 60 mg/m2 d1 F 200 mg/m2/d continuously q 3w or wT 30 mg/m2 d1, d8 and capecitabine (×)1600 mg/m2/d d1–14 q3w. The primary endpoint is confirmed response rate (RR), with each arm analysed independently. Simon’s 2 stage design was used, with 5/21 responses required in the first stage to allow continuation to 48 pts per arm. Results: 79 pts enrolled to date. Protocol specified interim analysis of efficacy after 21 pts per arm and of toxicity after 25 pts per arm ( Table ). In the first 21 pts per arm; 12 responses (11 confirmed) in wTCF arm, 6 responses (5 confirmed) in wTX arm. Trial continues accrual to target of 48 pts per arm. Complete accrual expected by April 2006. Updated data will be presented at the meeting. Conclusions: wTCF and wTX have encouraging activity and and a more favourable toxicity profile than TCF administered 3-weekly.

[Table: see text]

[Table: see text]

Mice expressing a dominant-negative Ret mutation phenocopy human Hirschsprung disease and delineate a direct role of Ret in spermatogenesis

The Ret receptor tyrosine kinase mediates physiological signals of glial cell line-derived neurotrophic factor (GDNF) family ligands (GFLs) and is essential for postnatal survival in mice. It is implicated in a number of human diseases and developmental abnormalities. Here, we describe our analyses of mice expressing a Ret mutant (RetDN) with diminished kinase activity that inhibits wild-type Ret activity, including its activation of AKT. All RetDN/+ mice died by 1 month of age and had distal intestinal aganglionosis reminiscent of Hirschsprung disease (HSCR) in humans. The RetDN/+ proximal small intestine also had severe hypoganglionosis and reduction in nerve fiber density, suggesting a potential mechanism for the continued gastric dysmotility in postsurgical HSCR patients. Unlike Ret-null mice, which have abnormalities in the parasympathetic and sympathetic nervous systems, the RetDN/+ mice only had defects in the parasympathetic nervous system. A small proportion of RetDN/+ mice had renal agenesis, and the remainder had hypoplastic kidneys and developed tubulocystic abnormalities postnatally. Postnatal analyses of the testes revealed a decreased number of germ cells, degenerating seminiferous tubules,maturation arrest and apoptosis, indicating a crucial role for Ret in early spermatogenesis.

Epirubicin, cisplatin, and prolonged or brief infusional 5-fluorouracil in the treatment of carcinoma of unknown primary site

The cytotoxic regimen of epirubicin, cisplatin, and continuous infusional 5-fluorouracil (ECF) has demonstrated activity in a range of malignancies, including gastroesophageal, breast, and pancreatic cancers. Prolonged infusional central venous catheter (CVC) mediated therapy is not always feasible and modifications of the 5-fluorouracil (5FU) schedule have been reported. We reviewed our experience of both the standard and a modified ECF regimen in patients diagnosed with carcinoma of unknown primary site (CUPS). A retrospective analysis of all patients diagnosed with CUPS (31 adenocarcinoma and 5 poorly differentiated carcinoma) and treated with ECF between June 1994 and June 1998 was undertaken. Thirty-six patients, median age 56 (range: 24-74), were treated thrice-weekly with 50 mg/m2 epirubicin, 60 mg/m2 cisplatin, and 5-FU administered either by continuous infusion 200 mg/m2/d via a CVC (standard ECF) or as a 6-h infusion 600 mg/m2 through a peripheral venous catheter (modified ECF). Thirteen patients were treated with standard ECF and 23 received modified ECF. The median number of cycles administered was 4 (range: 1-10). Thirty-two patients had evaluable disease, seven (22%; 95% confidence interval: 8-36%) demonstrated a partial response, including three patients that received standard ECF and four treated with modified ECF. There were no complete responses. The median survival for all 36 patients was 9.0 mo. Median survival for patients treated with standard ECF was 11.7 mo as compared to 5.1 mo for the modified ECF schedule (p = 0.052). Liver involvement and elevation of serum CA19.9 were identified as possible adverse prognostic factors. Both regimens were well tolerated, with the only grade 3/4 toxicity recorded being leukopenia (four patients), nausea/vomiting (seven patients), and diarrhea (one patient). CVC complications in the standard ECF group were thrombosis (one patient) and infection (three patients). There were no treatment-related deaths. We conclude that ECF, whether modified or standard, has modest activity in the setting of CUPS. Patient survival is comparable to survival documented in previous reports of CUPS treatment. The apparent survival difference between the two ECF schedules may be the result of patient selection factors. The optimal treatment of CUPS remains unknown and can only be determined through randomized controlled trials.

Repetitive high-dose therapy with ifosfamide, thiotepa and paclitaxel with peripheral blood progenitor cell and filgrastim support for metastatic and locally advanced breast cancer: results of a phase I study

BACKGROUND

This phase I study was designed to determine the optimal dosages of a novel repetitive high-dose therapy regimen for patients with metastatic breast cancer (MBC).

PATIENTS AND METHODS

The planned treatment was three cycles of high-dose ifosfamide, thiotepa and conventional-dose paclitaxel delivered every 28 days with progressive dose-escalation in successive cohorts. Each cycle was supported by peripheral blood progenitor cells (PBPC) and filgrastim.

RESULTS

Twenty-three patients were entered into this trial. Of the planned 69 treatment cycles, 59 were delivered and fifteen patients completed all three cycles. The dose-limiting toxicities were renal tubular acidosis, encephalopathy, mucositis and enterocolitis. There was one treatment-related hemorrhagic death.

CONCLUSIONS

The recommended doses for phase II or III studies are ifosfamide (10 g/m2), thiotepa (350 mg/m2) and paclitaxel (175 mg/m2).

The effect of glycosylation trimming enzyme inhibitors on monoclonal antibody recognition of alpha-sialoglycoprotein epitopes

The human erythrocyte membrane contains four sialoglycoproteins, denoted alpha, beta, gamma and delta (also known as glycophorins A, C, D and B respectively), of which alpha-sialoglycoprotein (alpha-SGP) is the most predominant species. The extracellular portion of alpha-SGP is heavily glycosylated with approximately 15 O-linked carbohydrate side-chains and a single N-linked group. We have used inhibitors of carbohydrate trimming enzymes to investigate the contribution of this single N-glycan moiety towards the recognition of a range of antibody binding sites on alpha-SGP. Two erythromyeloid cell lines, K562 and HEL, were cultured in the presence of these inhibitors and altered binding of antibodies to epitopes adjacent to the N-glycan was observed. Digoxigenin-coupled lectins were used to stain cytocentrifuge preparations and Western blots of cell lysates in order to confirm that modification of N-linked carbohydrate side-chains had been achieved. We suggest that the N-glycan side chain of alpha-SGP has a role in conferring conformational stability upon epitopes which lie in its vicinity.

Persistent hypertransaminasemia as the presenting finding of childhood muscle disease

Four children with isolated, persistent elevations of serum transaminases were investigated for hepatic disease and followed for 4 to 24 months before serum creatine kinase determinations were obtained and found to be markedly elevated. Evidence of muscle disease was obtained by close questioning, retrospectively, and mild abnormalities were found on physical examination. Review of laboratory tests in our center for 6 months revealed 30 additional cases of anicteric hypertransaminasemia (20% of those with elevated enzymes), only two of which were unexplained by the admitting diagnosis. Serum transaminase values are elevated in a variety of diseases of different organ systems. Creatine kinase determinations may provide the clue to the diagnosis of occult muscle disease in some children with unexplained anicteric hypertransaminasemia.

Cardiac rehabilitation--an occupational therapist's approach

The inclusion of the occupational therapist as a member of the treatment team for cardiac rehabilitation is a new approach used by Durham Regional Home Care Program. The cardiac classifications and the energy costs of the various activities used to develop the Occupational Home Care Program are described. The goals of the program are discussed, and the two types of patients who benefit the most from the program are identified. Finally, an outline of the treatment program by the occupational therapist is set out.