Protein-losing enteropathy (PLE) is a rare syndrome of gastrointestinal protein loss that may complicate a variety of diseases. The primary causes can be divided into erosive gastrointestinal disorders, nonerosive gastrointestinal disorders, and disorders involving increased central venous pressure or mesenteric lymphatic obstruction. The diagnosis of PLE should be considered in patients with hypoproteinemia after other causes, such as malnutrition, proteinuria, and impaired protein synthesis due to cirrhosis, have been excluded. The diagnosis of PLE is most commonly based on the determination of fecal α-1 antitrypsin clearance. Treatment of PLE targets the underlying disease but also includes dietary modification, supportive care, and maintenance of nutritional status. In this article, cases illustrating a variety of clinical presentations and etiologies of PLE are presented, and its diagnostic approach and treatment are reviewed.

The role of the gut microbiome in arresting pathogen colonization and growth is important for protection against Clostridium difficile infection (CDI). Observational studies associate proton pump inhibitor (PPI) use and CDI incidence. We hypothesized that PPI use affected the distal gut microbiome over time, an effect that would be best explored by time-longitudinal study of healthy subjects on PPI in comparison to treatment-naïve CDI subjects. This study enrolled nine healthy human subjects and five subjects with treatment-naïve CDI. After random assignment to a low (20 mg/day) or high (2× 20 mg/day) dose group, fecal samples were collected from the nine healthy subjects before, during, and after 28 days of PPI use. This was done in conjunction with pre-treatment fecal collection from CDI subjects. High-throughput sequencing (16S rRNA) was performed on time-longitudinal samples to assess changes to the healthy gut microbiome associated with prolonged PPI usage. The healthy samples were then compared to the CDI subjects to explore changes over time to the gut microbiome associated with PPI use and potentially related to CDI.

Energy balance is an equilibrium between the amount of energy extracted from the diet and the amount expended. Selective pressures throughout evolution have programmed animals to protect energy stores through the accumulation of adipose tissue; as diets have changed and energy-dense foods have become readily available, obesity rather than malnutrition has become the primary concern in developed nations. Nevertheless, factors other than the types of food and their availability appear to be important. Recent evidence suggests that the gut microbiota play a role in energy harvest, storage, and expenditure. The preponderance of the evidence demonstrates that germ-free mice are protected against obesity and that the transfer of gut microbes from conventionally raised animals results in dramatic increases in body fat content and insulin resistance. Moreover, the composition of the gut microbiota has been shown to differ in lean and obese humans and animals and to change rapidly in response to dietary factors. The gut microbiota may also influence the development of conditions characterized by low-level inflammation, such as obesity and type 2 diabetes, through systemic exposure to bacterial lipopolysaccharide derived from the intestinal microbiota. Together, these data suggest that modification of the gut microbiota may be a relevant therapeutic avenue for obesity and other metabolic disorders.