A steamed broccoli sprout diet preparation that reduces colitis via the gut microbiota

Sulforaphane is a bioactive metabolite with anti-inflammatory activity and is derived from the glucosinolate glucoraphanin, which is highly abundant in broccoli sprouts. However, due to its inherent instability its use as a therapeutic against inflammatory diseases has been limited. There are few studies to investigate a whole food approach to increase sulforaphane levels with therapeutic effect and reduce inflammation. In the current study, using a mouse model of inflammatory bowel disease, we investigated the ability of steamed broccoli sprouts to ameliorate colitis and the role of the gut microbiota in mediating any effects. We observed that despite inactivation of the plant myrosinase enzyme responsible for the generation of sulforaphane via steaming, measurable levels of sulforaphane were detectable in the colon tissue and feces of mice after ingestion of steamed broccoli sprouts. In addition, this preparation of broccoli sprouts was also capable of reducing chemically-induced colitis. This protective effect was dependent on the presence of an intact microbiota, highlighting an important role for the gut microbiota in the metabolism of cruciferous vegetables to generate bioactive metabolites and promote their anti-inflammatory effects.

A Specific Broccoli Sprout Preparation Reduces Chemically-Induced Colitis Via Gut Microbiota

Objectives

Sulforaphane is a bioactive metabolite with anti-inflammatory activity that is derived from glucosinolates, which are highly abundant in cruciferous vegetables including broccoli sprouts. There have been limited studies to investigate a whole foods approach to increase sulforaphane levels with therapeutic effect and reduce inflammation. In the current study, using a mouse model of inflammatory bowel disease, we aimed to investigate the ability of steamed broccoli sprouts to ameliorate colitis and the role of the microbiota in mediating any effects.

Methods

C57BL/6J male mice were fed base diet or 5% steamed broccoli sprout diet for 2 weeks prior to induction of colitis with 2–3% DSS (5–7 days) and kept on their respective diets until sacrifice. Body weight and disease activity index scores were recorded daily, and histological assessment was performed on H&E sections of colon. Urine, feces, blood, and GI tract tissues and intestinal content were collected for LC-MS/MS quantification of sulforaphane and glucoraphanin. The 16S rRNA sequencing was performed to analyze gut microbiome. Germ-free mice were fed base diet or 5% steamed broccoli sprout diet for 2 weeks followed by treatment with 5 days of DSS to determine the role of gut microbiota in mediating the anti-inflammatory effects of the steamed broccoli sprout diet.

Results

We observed that despite inactivation of the plant myrosinase enzyme responsible for the generation of sulforaphane via steaming, measurable levels of sulforaphane were detectable in the colon tissue and feces of mice after ingestion of steamed broccoli sprouts. In addition, this preparation of broccoli sprouts was also capable of reducing chemically-induced colitis. This protective effect was dependent on the presence of an intact gut microbiota, highlighting an important role for the microbiota in the metabolism of cruciferous vegetables to generate bioactive metabolites and promote their anti-inflammatory effects.

Conclusions

Altogether, these results suggest that the incorporation of a steamed broccoli sprouts diet is a viable dietary intervention to complement current medical therapies for patients with inflammatory bowel disease.

Funding Sources

This work was supported by USDA-NIFA-AFRI Foundational Program [Grant No. 2018–67,017-27,520].

Abnormal Somatosensory Behaviors Associated With a Gain-of-Function Mutation in TRPV3 Channels

Thermosensitive transient receptor potential V3 (TRPV3) is a polymodal receptor implicated in nociceptive, thermoceptive, pruritoceptive, and inflammatory pathways. Reports focused on understanding the role of TRPV3 in thermoception or nociception are not conclusive. Previous studies also show that aberrant hyperactivity of TRPV3 channels results in spontaneous itch and dermatitis-like symptoms, but the resultant behavior is highly dependent on the background of the animal and the skin microbiome. To determine the function of hyperactive TRPV3 channels in somatosensory sensations, we tested different somatosensory behaviors using a genetic mouse model that carries a gain-of-function point mutation G573S in the Trpv3 gene (Trpv3G573S). Here we report that Trpv3G573S mutants show reduced perception of cold, acetone-induced cooling, punctate, and sharp mechanical pain. By contrast, locomotion, noxious heat, touch, and mechanical itch are unaffected in Trpv3G573S mice. We fail to observe any spontaneous itch responses and/or dermatitis in Trpv3G573S mutants under specific pathogen (Staphylococcus aureus)-free conditions. However, we find that the scratching events in response to various pruritogens are dramatically decreased in Trpv3G573S mice in comparison to wild-type littermates. Interestingly, we observe sensory hypoinnervation of the epidermis in Trpv3G573S mutants, which might contribute to the deficits in acute mechanical pain, cool, cold, and itch sensations.

Gut Microbiota Modulate CD8 T Cell Responses to Influence Colitis-Associated Tumorigenesis

There is increasing evidence that gut microbiome perturbations, also known as dysbiosis, can influence colorectal cancer development. To understand the mechanisms by which the gut microbiome modulates cancer susceptibility, we examine two wild-type mouse colonies with distinct gut microbial communities that develop significantly different tumor numbers using a mouse model of inflammation-associated tumorigenesis. We demonstrate that adaptive immune cells contribute to the different tumor susceptibilities associated with the two microbial communities. Mice that develop more tumors have increased colon lamina propria CD8+ IFNγ+ T cells before tumorigenesis but reduced CD8+ IFNγ+ T cells in tumors and adjacent tissues compared with mice that develop fewer tumors. Notably, intratumoral T cells in mice that develop more tumors exhibit increased exhaustion. Thus, these studies suggest that microbial dysbiosis can contribute to colon tumor susceptibility by hyperstimulating CD8 T cells to promote chronic inflammation and early T cell exhaustion, which can reduce anti-tumor immunity.

Effect of captopril (SQ 14225) on blood pressure, plasma renin activity and angiotensin I converting enzyme activity

Seven patients with essential hypertension and seven patients with hypertension associated with renal artery stenosis received captopril (SQ 14225), an inhibitor of angiotensin I converting enzyme. There was a significant reduction in mean blood pressure, from 176/113 +/- 4/3 mm Hg during the control period to 140/90 +/- 5/3 mm Hg during captopril administration. Five patients received captopril alone and nine patients needed hydrochlorothiazide in addition to control their blood pressure. Captopril produced a significant increase in peripheral plasma renin activity. When measured 12 hours after the administration of captopril the angiotensin I converting enzyme activity was found to be similar to that during the control period even though the blood pressure was at or near normal. These findings indicate that although captopril is an effective antihypertensive agent, its action does not depend only on inhibition of plasma angiotensin I converting enzyme activity.

Innappropriate renin secretion unmasked by captopril (SQ 14 225) in hypertension of chronic renal failure

Captopril (SQ 14 225), an orally active inhibitor of angiotensin-converting enzyme, was given to 7 hypertensive patients with chronic renal failure whose plasma-creatinine ranged from 1.5--7.4 mg/dl; whose plasma-renin activity was normal; whose hypertension was not controlled by previous therapy consisting in 5 patients of three or more antihypertensive drugs; and whose blood-pressures averaged 176/111 +/- 11/3 mm Hg. Inhibition of converting enzyme by oral captopril, 200 mg twice daily, reduced blood-pressure to 156/100 +/- 9/5 mm Hg. 5 patients needed additional treatment by frusemide 40--250 mg/day orally. With this combined regimen the blood-pressure of all patients averaged 126/85 +/- 4/3 mm Hg after 8 +/- 2 weeks of captopril. The drug was well tolerated. These results suggest that inhibition of angiotensin-converting enzyme with or without sodium depletion is an efficient treatment for hypertension associated with chronic renal failure. It appears that although renin levels in patients with this condition may be "normal", they are inappropriate in relation to the subtle degree of sodium retention that occurs with this disorder.