Randomised clinical trial: faecal microbiota transplantation for recurrent Clostridum difficile infection - fresh, or frozen, or lyophilised microbiota from a small pool of healthy donors delivered by colonoscopy

BACKGROUND

Faecal microbiota transplantation (FMT) has become routine in managing recurrent C. difficile infection (CDI) refractory to antibiotics.

AIM

To compare clinical response and improvements in colonic microbiota diversity in subjects with recurrent CDI using different donor product.

METHODS

Seventy-two subjects with ≥3 bouts of CDI were randomised in a double-blind study to receive fresh, frozen or lyophilised FMT product via colonoscopy from 50 g of stool per treatment from eight healthy donors. Recipients provided stools pre- and 7, 14 and 30 days post-FMT for C. difficile toxin and, in a subset, microbiome composition by 16S rRNA gene profiling.

RESULTS

Overall resolution of CDI was 87% during 2 months of follow-up after FMT. Stool samples before FMT had significantly decreased bacterial diversity with a high proportion of Proteobacteria compared to donors. Cure rates were highest for the group receiving fresh product seen in 25/25 (100%), lowest for the lyophilised product 16/23 (78%; P = 0.022 vs. fresh and 0.255 vs. frozen) and intermediate for frozen product 20/24 (P = 0.233 vs. fresh). Microbial diversity was reconstituted by day 7 in the subjects receiving fresh or frozen product. Improvement in diversity was seen by day 7 in those randomised to lyophilised material with reconstitution by 30 days.

CONCLUSIONS

Comparative efficacy in faecal microbiota transplantation was observed in subjects receiving fresh or frozen faecal product from the same donors. The lyophilised product had a slightly lowered efficacy compared with fresh product, but it resembled other treatments in microbial restoration 1 month after faecal microbiota transplantation.

Guillain-Barré syndrome after solid organ transplantation

BACKGROUND

Neurological complications occur frequently in solid organ transplant recipients. However, the peripheral nerves are usually spared significant toxicity. Guillain Barré syndrome (GBS) is the most common cause of acute neuropathy in adults. Despite numerous reports of GBS in recipients of bone marrow transplants, GBS has rarely been reported in recipients of solid organ transplants. Recent evidence supports the role of the immune system in initiating and perpetuating the ongoing neural damage in this entity. Infectious agents may initiate the immune attack, and the association of GBS with cytomegalovirus (CMV) infection has been studied extensively.

METHODS

To alert clinicians to the occurrence of GBS in the latter setting, we report five new cases of GBS after solid organ transplant and summarize five other cases previously reported in the literature.

RESULTS

The GBS cases (published and unpublished) have much in common: all the patients were men, most had evidence of active CMV infection at or before the onset of GBS, and all but one developed GBS within 1 year after transplantation (range 1-26 months).

CONCLUSION

The association of GBS with cytomegalovirus (CMV) infection in the nontransplant population and evidence of CMV infection in almost all reported cases of GBS in solid organ transplant recipients suggest that CMV may have a role in triggering this illness.

Hypoxic stimulation of vascular endothelial growth factor expression in activated rat hepatic stellate cells

The tissue repair response to hypoxic stimuli during wound healing includes enhanced production of angiogenic factors, such as vascular endothelial growth factor (VEGF). Hepatic stellate cells are oxygen-sensing cells, capable of producing VEGF. We hypothesized that hypoxia-stimulated signaling in activated stellate cells mediate VEGF secretion during liver injury. The specific aim was to evaluate the effect of hypoxia on the gene expression of VEGF in HSC-T6 cells, an immortalized rat hepatic stellate cell line, and in rat primary cultures of stellate cells. Hypoxic induction of VEGF mRNA was dose- and time-dependent. The hypoxic stimulation of VEGF messenger RNA (mRNA) correlated with the secretion of VEGF protein in conditioned media by hypoxic T6 cells. S-Nitroso-N-acetyl-D, L-penicillamine (SNAP), a nitric oxide (NO) donor, and desferrioxamine (DFx) and cobalt chloride, mimics of cellular hypoxia, similarly stimulated VEGF mRNA expression and secretion. Four previously described splice variants of the VEGF mRNA (VEGF-120, 144, 164, 188) were detected in both normoxic- or hypoxic-activated stellate cells. There was differential expression of the VEGF receptors, Flt-1 and Flk-1, in hypoxic T6 cells. Hypoxic conditions selectively stimulated Flt-1 mRNA expression, whereas Flk-1 mRNA remained unchanged. Hypoxic induction of VEGF was also demonstrated in primary stellate cell cultures and after in vivo injury. Hypoxia stimulates cell signaling in stellate cells, culminating in the rapid induction of VEGF and Flt-1 mRNA expression and VEGF secretion. The hypoxic induction of VEGF is mimicked by NO and may be of mechanistic importance in the pathogenesis of hepatic wound healing and hepatocarcinogenesis.

The role of choledochoscopy in the diagnosis and management of biliary tract diseases

BACKGROUND

The diagnosis and management of biliary tract disorders in certain cases may be incomplete without direct visualization of the bile ducts.

METHODS

We report our experience of 61 choledochoscopies (33 women, 27 men, mean age 44.6 years). Twenty patients had previously undergone orthotopic liver transplantation. All except two choledochoscopies were performed via the transpapillary route. Indications included suspected large bile duct stones in 18 patients, anastomotic strictures in 16, abnormal cholangiograms in 5, elevated liver function tests in 7, suspected cholangiocarcinoma in 4, occluded biliary metallic stent in 4, hemobilia in 4, primary sclerosing cholangitis in 2 and ischemic bile duct injury in 1 patient.

RESULTS

Choledochoscopy confirmed the anticipated diagnosis in 36 of 61 (59%) patients. Importantly, it provided additional unsuspected diagnostic information in 18 of the 61 (29.5%) patients. In addition, for patients in whom standard cholangiography was deemed abnormal, choledochoscopy demonstrated normal results in 7 (11.4%) patients. Fifty-two choledochoscopies were performed with therapeutic intentions, and the procedure was helpful in providing targeted treatment in 27 (44.2%) patients.

CONCLUSIONS

Choledochoscopy is a safe and useful endoscopic modality that can provide specific diagnoses and direct treatment in various biliary tract diseases. The additional information provided by choledochoscopy may change overall patient management and outcome.

Coordinated induction of VEGF receptors in mesenchymal cell types during rat hepatic wound healing

Homology PCR has been used to identify receptor tyrosine kinases (RTKs) expressed during activation of rat hepatic stellate cells, the key fibrogenic mesenchymal element in the liver. Partial cDNAs encoding several RTKs were cloned from stellate cells activated in vivo, including those of Flt-1, Flk-1, c-met, PDGFR, and Tyro10/DDR2. RNAse protection from cells activated in vivo demonstrated biphasic induction of flt-1 and flk-1 mRNAs, receptors for vascular endothelial growth factor (VEGF). Culture-activation of stellate cells was associated with increased [125I]VEGF binding and Flt-1 and Flk-1 receptor protein. Induction of VEGF binding sites correlated with an 2.5-fold increase in DNA synthesis in response to VEGF, but only if cells were activated by growth on collagen 1, whereas cells maintained in a quiescent state on a basement membrane-like substratum (EHS matrix) were nonproliferative. In both stellate and endothelial cells VEGF-induced mitogenesis was augmented by co-incubation with basic fibroblast growth factor (bFGF), a cytokine with known synergy with VEGF. These findings suggest that the cellular targets of VEGF in liver may not be confined to sinusoidal endothelial cells, and that VEGF responses reflect combined effects on both hepatic stellate cells and sinusoidal endothelium.

Brain glutamate and gamma-aminobutyrate (GABA) metabolism in thiamin-deficient rats

The brain metabolism of glutamate and gamma-aminobutyrate (GABA) was investigated in thiamin-deficient and pair-fed control rats, in order to determine whether the GABA shunt may provide an important alternative to 2-oxo-glutarate dehydrogenase (EC 1.2.4.2) in energy-yielding metabolism in thiamin deficiency. Brains from thiamin-deficient animals contained less glutamate, 2-oxo-glutarate and GABA than those from control animals. The brain content of ATP was unaffected by thiamin deficiency. After intracerebroventricular injection of [14C]glutamate, the specific radioactivity of GABA in the brains from deficient animals was 45-50% higher than that in controls, suggesting a considerable increase in the metabolic flux through the GABA shunt in thiamin deficiency. Brain GABA showed a marked circumannual variation, with a peak in mid-summer and a minimum value in mid-winter.