Review article: olestra and its gastrointestinal safety

Alternative Excipients for Protein Stabilization in Protein Therapeutics: Overcoming the Limitations of Polysorbates

Given their safety and efficiency in protecting protein integrity, polysorbates (PSs) have been the most widely used excipients for the stabilization of protein therapeutics for years. In recent decades, however, there have been numerous reports about visible or sub-visible particles in PS-containing biotherapeutic products, which is a major quality concern for parenteral drugs. Alternative excipients that are safe for parenteral administration, efficient in protecting different protein drugs against various stress conditions, effective in protein stabilization in high-concentrated liquid formulations, stable under the storage conditions for the duration of the product's shelf-life, and compatible with other formulation components and the primary packaging are highly sought after. The aim of this paper is to review potential alternative excipients from different families, including surfactants, carbohydrate- and amino acid-based excipients, synthetic amphiphilic polymers, and ionic liquids that enable protein stabilization. For each category, important characteristics such as the ability to stabilize proteins against thermal and mechanical stresses, current knowledge related to the safety profile for parenteral administration, potential interactions with other formulation components, and primary packaging are debated. Based on the provided information and the detailed discussion thereof, this paper may pave the way for the identification or development of efficient excipients for biotherapeutic protein stabilization.

Persistent organic pollutants in adipose tissue should be considered in obesity research

Although low doses of persistent organic pollutants (POPs), strong lipophilic chemicals with long half-lives, have been linked to various endocrine, immune, nervous and reproductive system diseases, few obesity studies have considered adipose tissue as an important POPs exposure source. Because the toxicodynamics of POPs relate directly to the dynamics of adiposity, POPs might explain puzzling findings in obesity research. In two people exposed to the same amounts of environmental POPs, the one having more adipose tissue may be advantaged because POPs storage in adipose tissue can reduce burden on other critical organs. Therefore, adipose tissue can play a protective role against the POPs effects. However, two situations increase the POPs release from adipose tissue into the circulation, thereby increasing the risk that they will reach critical organs: (i) weight loss and (ii) insulin resistance. In contrast, weight gain reduces this possibility. Therefore, avoiding harmful health effects of POPs may mostly contradict conventional judgments about obesity and weight change. These contradictory situations can explain the obesity paradox, the adverse effects of intensive intentional weight loss and the protective effects of obesity against dementia. Future studies should consider that adipose tissue is widely contaminated with POPs in modern society.

Dietary fish oil increases fat absorption and fecal bile acid content without altering bile acid synthesis in 20-d-old weanling rats following massive ileocecal resection

INTRODUCTION

Dietary fish oil (FO) was reported to lower fecal fat excretion in a weanling rat model of short bowel syndrome (SBS) after ileocecal resection (ICR), and to induce changes in secretion and synthesis of bile acid (BA) in adults. We hypothesized that dietary FO, as compared with corn oil (CO), increases intestinal fat absorption in weanling SBS rats in part due to increased hepatic BA synthesis and luminal BA concentrations.

METHODS

After undergoing ICR, 20-d-old rats were fed ad lib for 7 d with a CO or FO diet containing 5% sucrose polybehenate (SPB), a marker for dietary fat absorption. Fecal fatty acid, fecal and intestine luminal BA, liver mRNA expressions of cholesterol 7α-hydroxylase (Cyp7α1) and sterol-12α-hydroxylase (Cyp8β1), and serum 7α-hydroxy-4-cholesten-3-1 (7αC4) levels were determined.

RESULTS

As compared with CO-ICR rats, FO-ICR rats had higher intestinal absorption of total fat and most individual fatty acids. Although the BA content per gram of dry stool was increased in FO-ICR rats, there were no differences between groups for the BA content in remnant jejunum, liver mRNA expression of BA biosynthetic enzymes, Cyp7α1 and Cyp8β1, or serum 7αC4, a marker for BA synthesis.

CONCLUSION

Dietary FO increases dietary fat absorption without increasing hepatic BA synthesis in weanling SBS rats.

Drug-induced nutrient deficiencies

Good clinical care extends beyond mere diagnosis and treatment of disease to appreciation that nutrient deficiencies can be the price of effective drug therapy. The major risk factors for developing drug-induced nutrient deficiencies are lack of awareness by the prescribing physician and long duration of drug therapy. The field of pharmacogenomics has potential to improve clinical care by detecting patients at risk for complications from drug therapy. Further improvements in patient safety rely on physicians voluntarily reporting serious suspected adverse drug reactions.

Canine obesity: an overview

Canine patients are generally regarded as being clinically obese when their body weight is at least 15% above ideal. The incidence of obesity in dogs is thought to be in the range of 20-40% of the general population and, since obesity is known to predispose or exacerbate a range of serious medical conditions, its importance cannot be overstated. Management of obesity through dietary restriction and increased exercise is often difficult to achieve and dependent upon owner compliance. Until recently there has been no authorized therapeutic medication available for weight reduction in dogs, and drugs used in people have proved unsuitable. However, with the development of microsomal triglyceride transfer protein inhibitors for canine use, such as dirlotapide, the veterinarian has a novel method with which to augment traditional weight control programmes. This approach has the additional advantage that weight loss is achieved without dietary restriction or change in exercise regimen, providing encouragement for the owner to comply with subsequent dietary and exercise recommendations, thereby increasing the likelihood for long-term success.

Authors' financial relationships with the food and beverage industry and their published positions on the fat substitute olestra

OBJECTIVES

This study examined the association between authors' published positions on the safety and efficacy in assisting with weight loss of the Procter & Gamble (P&G) fat substitute olestra and their financial relationships with the food and beverage industry.

METHODS

Journal articles about olestra, and their authors, were classified as supportive, critical, or neutral with respect to its use. Authors not known to have industry affiliations were surveyed about their financial relationships.

RESULTS

Supportive authors were significantly more likely than critical or neutral authors to have financial relationships with P&G (80% vs 11% and 21%, respectively; P <.0001). All authors disclosing an affiliation with P&G were supportive.

CONCLUSIONS

Because authors' published opinions were associated with their financial relationships, obtaining noncommercial funding may be more essential to maintaining objectivity than disclosing personal financial interests.

Hazard characterisation of chemicals in food and diet. dose response, mechanisms and extrapolation issues

Hazard characterisation of low molecular weight chemicals in food and diet generally use a no-observed-adverse-effect level (NOAEL) or a benchmark dose as the starting point. For hazards that are considered not to have thresholds for their mode of action, low-dose extrapolation and other modelling approaches may be applied. The default position is that rodents are good models for humans. However, some chemicals cause species-specific toxicity syndromes. Information on quantitative species differences is used to modify the default uncertainty factors applied to extrapolate from experimental animals to humans. A central theme for extrapolation is unravelling the mode of action for the critical effects observed. Food can be considered as an extremely complex and variable chemical mixture. Interactions among low molecular weight chemicals are expected to be rare given that the exposure levels generally are far below their NOAELs. Hazard characterisation of micronutrients must consider that adverse effects may arise from intakes that are too low (deficiency) as well as too high (toxicity). Interactions between different nutrients may complicate such hazard characterisations. The principle of substantial equivalence can be applied to guide the hazard identification and hazard characterisation of macronutrients and whole foods. Macronutrients and whole foods must be evaluated on a case-by-case basis and cannot follow a routine assessment protocol.

A role for olestra in body weight management

Olestra is a fat substitute made from fatty acids esterified to sucrose and can be used in the preparation of virtually any food made with fat. Foods made with olestra retain the mouthfeel, palatability and satiating effects of their full-fat counterparts without providing any digestible energy. Because olestra provides no energy, it has the potential to be a useful tool in weight loss and weight maintenance. Short-term studies of olestra replacement in foods demonstrate that fat replacement leads to a net reduction in fat intake. When excess total energy is available, fat replacement also reduces total energy intake in lean and obese men and women. In longer-term studies in which olestra is incorporated into the daily diet, there is an incomplete compensation for the fat energy replaced by olestra. When overweight men consumed olestra as part of a varied diet over nine months, weight loss continued for the duration of the study, whereas individuals receiving a typical low-fat diet regained most of the initial weight lost. Other studies are underway to examine the usefulness of olestra in long-term weight maintenance following weight loss. Post-marketing surveillance of olestra foods in the United States indicates that substitution of olestra for only 1-2 g of fat d-1 may be sufficient to prevent the average weight gain reported in adults of 0.5-1.0 kg year-1.